Master‘s thesis

Loss of longline-bait to northern fulmars

Economic balance between damage from bait-loss and costs of measures to reduce seabird bycatch on the Faroe Islands

Susanne Kühn

Advisor: Dr. Jan Andries van Franeker

University of Akureyri Faculty of Business and Science

University Centre of the Westfjords Master of Resource Management: Coastal and Marine Management

Ísafjörður, February, 2016

Supervisory Committee Advisor: Jan Andries van Franeker, Dr Marine Biologist, Institute for Marine Resources & Ecosystem Studies (IMARES), The Netherlands Reader: Ögmundur H. Knútsson, Ph.D. Dean of the School of Business and Science at the University of Akureyri, Iceland Program Director: Dagný Arnarsdóttir, MSc.

Susanne Kühn Loss of longline-bait to northern fulmars. Economic balance between damage from bait-loss and costs of measures to reduce seabird bycatch on the Faroe Islands.

45 ECTS thesis submitted in partial fulfilment of a Master of Resource Management degree in Coastal and Marine Management at the University Centre of the Westfjords, Suðurgata 12, 400 Ísafjörður, Iceland

Degree accredited by the University of Akureyri, Faculty of Business and Science, Borgir, 600 Akureyri, Iceland

Copyright © 2016 Susanne Kühn All rights reserved Printing: Háskólaprent, Reykjavík, February, 2016

Declaration

I hereby confirm that I am the sole author of this thesis and it is a product of my own academic research.

__________________________________________ Student‘s name

Abstract

On the Faroe Islands, longline fishermen experience a loss of bait to scavenging

seabirds. This Master thesis evaluates the economic impact of bait-stealing by a

seabird, the northern fulmar (Fulmarus glacialis), in the longline fisheries. Baits found

in stomachs of northern fulmars, caught accidentally in longline fisheries around the

Faroe Islands, were used to estimate the bait loss. From this an estimate was made of

the potential economic loss experienced by fishermen due to seabirds. Possible

mitigation measures were discussed regarding their suitability for the Faroese fisheries

and their economic viability. The results show that the economic loss for the fishermen

can range between 600 and 88,000 Danish Krona (DKK) per trip for one vessel,

depending on the fishing efficiency and the number of birds surrounding the vessel. As

a mitigation measure, tori lines are proposed to keep the birds out of the reach of bait. It

became clear that direct observer data is necessary to evaluate the situation on the Faroe

Islands and to make a realistic picture of the extent of the fisheries-seabird interaction.

Unfortunately the collection of data on board of fishing vessels was beyond the scope

of this thesis. Nevertheless a useful tool is provided for fishermen to calculate the

individual economic loss they suffer from seabirds and weigh the financial loss of

seabirds stealing baits against the costs of mitigation measures that might reduce

seabird fatalities and therefore create a situation where both, fishermen and seabirds

benefit.

A Faroese Fisherman speaks of drowning

But you can’t let fear cripple your will

When you are in the waves well above your neck

Or else your limbs will get heavier still

And then who’d dare risk pulling you on deck?

Guðrið Hansdóttir

xi

Table of Content

Abstract .............................................................................................................................. vii

List of Figures ................................................................................................................... xiii

List of Tables .......................................................................................................................xv

Acknowledgements .......................................................................................................... xvii

1 Introduction .....................................................................................................................1

2 State of Knowledge ..........................................................................................................5 Fishing technique .....................................................................................................5 2.1

2.1.1 Effects of longline fisheries on the environment ........................................... 6 Fishing on the Faroe Islands ....................................................................................9 2.2

2.2.1 Associated birds ........................................................................................... 12 General mitigation strategies ..................................................................................15 2.3

2.3.1 Fishing gear adaptations .............................................................................. 16 2.3.2 Operational adaptations ............................................................................... 18 2.3.3 Management options .................................................................................... 19

3 Methods ..........................................................................................................................21 Stomach content analysis .......................................................................................21 3.1 Analysis of the economic loss, simulations and costs of mitigation ......................23 3.2

3.2.1 Value of a fish .............................................................................................. 23 3.2.2 Costs of mitigation ....................................................................................... 24

Ethical issues ..........................................................................................................25 3.3

4 Results .............................................................................................................................27 Stomach content analysis .......................................................................................27 4.1

4.1.1 Catch rates per tour ...................................................................................... 27 4.1.2 Seabird mortality ......................................................................................... 28 4.1.3 Bait in seabird stomachs .............................................................................. 28

Calculation of economic loss .................................................................................31 4.2 Simulation of different scenarios ...........................................................................34 4.3 Costs of mitigation .................................................................................................36 4.4

5 Discussion .......................................................................................................................41 Catch rates ..............................................................................................................41 5.1 Economic loss calculations ....................................................................................43 5.2 Mitigation measures ...............................................................................................44 5.3

6 Conclusions .....................................................................................................................49

References ...........................................................................................................................51

xii

xiii

List of Figures

Figure 1: Demersal longline fisheries. (Drawing: U. Kühn) ............................................ 6

Figure 2: Bycatch of seabirds in demersal longline fishery (Drawing: U. Kühn) ............ 7

Figure 3: Map showing the Faroe Islands between Scotland and Iceland and a detailed map of the Faroe Islands (Created by Google Maps 2015) ............. 9

Figure 4: A haddock (Melanogrammus aeglefinus) caught on a longline vessel on the Faroe Islands. Northern fulmars are surrounding the vessel searching for food opportunities (Photo: J.A. van Franeker) ...................... 11

Figure 5: Northern fulmars following a longline vessel on the Faroe Islands and fighting for food (Photo: J.A. van Franeker) ............................................... 12

Figure 6: Northern fulmars in flight (left), in portrait (with clearly distinguishable tube on the bill; centre) and northern fulmars feeding around a fishing vessel (right; Photo‘s: S. Kühn) ................................................................... 13

Figure 7: Short term trends of the breeding population of northern fulmars in Europe (adapted from BirdLife International, 2015a) ................................. 15

Figure 8: Examples of bait found in the stomachs of northern fulmars, accidetally bycaught on the Faroe Islands (Photo‘s: J.A. van Franeker) ....................... 22

Figure 9: Number and distribution of fishing trips where northern fulmars were caught and collected between 2004 and 2012 ............................................. 27

Figure 10: Distribution of northern fulmars caught in Faroese longline fisheries per month and year ...................................................................................... 28

Figure 11: Count of baits found in northern fulmar stomachs between 2004 and 2012 ............................................................................................................. 29

Figure 12: Distribution of bait types found in the stomachs of northern fulmars caught accidentally in longeline fisheries .................................................... 29

Figure 13: Average number of baits per month in northern fulmar stomachs in comparison with the number of seabirds caught in this month ................... 30

Figure 14: Average bait loss and caught northern fulmars between 2004 and 2012 ..... 31

Figure 15: Species distribution in percentage caught by Faroese longline fisheries in 2014 (Hagstova Føroya, 2015b) .............................................................. 33

Figure 16: Comparison of the economic costs of mitigation measures and their efficiency in reducing bait loss and seabird bycatch ................................... 40

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xv

List of Tables

Table 1: Wet mass of different fish species and their percentage of the total landed longline catch on the Faroe Islands in 2014 (Hagstova Føroya, 2015b) .......................................................................................................... 10

Table 2: Sample size and distribution of northern fulmars caught accidentally during longline fishing operations on the Faroe Islands between 2005 and 2012 ...................................................................................................... 21

Table 3: Data on the average size of different fish species when caught, the calculated mass per individual fish, the average prices (in DKK) per kilogram fish and the calculated price per individual fish and species ....... 32

Table 4: Calculation of the average price per individual fish, considering the proportion of each species in longline fishery catches ................................ 33

Table 5: The price of the fish and the average number of baits found in northern fulmars has been calculated before, the number of birds searching for food around the vessel (x) and the fishing efficiency (y) can vary. ............ 35

Table 6: Simulation of different scenarios. Variables x and y (see Table 3) have now been replaced by numbers that estimate the number of birds searching for food around the vessel and a varying fishing efficiency. ...... 35

Table 7: Table of mitigation measures, their efficiencies and costs (if data available) and references ............................................................................. 37

xvi

xvii

Acknowledgements

First I want to thank my supervisor Jan van Franeker. I am extremely grateful for the

opportunities you are creating for me. Your dedication for this work and these beautiful

birds is inspiring and I am glad you are sharing your knowledge with me. Your

patience, your honesty and your support are impressive and I want to thank you for all

of this! Thanks to Ögmundur Knútsson, the external reader of this thesis, your

comment and advise were very valuable.

I want to thank the staff of the University Centre of the Westfjords; you created a

unique opportunity in this magical Ísafjörður-world for students. We’ve learned so

much, not only about Coastal and Marine Management, but about this beautiful place,

the life under special (winter) conditions and particularly about ourselves. Thanks for

the support and assistance during this awesome time. In Ísafjörður there is also a very

special club of people, the Kayak Center, thanks for the endless hours of teaching,

kayaking in the fjords, rolling in the pool and under ice, I had an awesome time! I also

want to thank the 2014/2015 student cohort, what an incredible group of passionate,

strong and beautiful people. I am glad that I was a part of this group; I loved (almost)

every minute we spent together, on land, at sea and in the helicopter. I also want to

thank my little sister Ulrike Kühn for the provision of the drawings in this thesis and

my presentation, your talent and your sense of humour are amazing!

xviii

1

1 Introduction

Longline fishery is a fishing technique that is used on a global scale. Even though this

type of fisheries is regarded as relatively environmentally friendly, seabirds all over the

world have been observed to target the baits on the hooks while the fishing lines are

deployed, often at the risk of their own life.

Fisheries therefore experience an economic loss, as stolen bait can result in reduced

gear efficiency, up to a level where trips become unprofitable (Sánchez & Belda, 2003).

In Norwegian longline fisheries a bait loss of up to 70% caused by seabirds has been

reported (Løkkeborg, 1998). Beside the direct loss of baits, entangled birds can also

impact the fisheries through changes in the buoyancy of the lines, resulting in an

unwanted and unpredictable change in depth and position of the fishing lines (Sánchez

& Belda, 2003). In Argentinian longline fisheries for example, Gandini & Frere (2012)

estimate a loss of 1.5 million and 2 million US Dollar (US$) in a ten year period

respectively, due to the loss of bait to seabirds.

At the same time, the birds get entangled or swallow the hook and subsequently drown

when the lines sink to the bottom (e.g. Anderson et al., 2011, Croxall et al., 2012).

Anderson et al. (2011) estimate that on a global scale between 160,000 and 320,000

seabirds die annually, due to longline activities. The effect of longline mortality can

even be a threat for whole populations of seabirds as described for various species of

the Southern Ocean (Cherel et al., 1996). The Faroe Islands belong to the Top 10 of

fishing fleets with the highest estimated seabird bycatch rates (Anderson et al. 2011).

The rate of seabird bycatch in longline fisheries has been studied intensively, especially

in the Southern Ocean; however the economic loss for the fisheries has often been

neglected (Sánchez & Belda, 2003; Ward et al., 2012). Another problem of these

studies has been described by Brothers et al. (2010). The authors state that the usual

approach of collecting bycaught birds might underestimate the loss of birds and

therefore also the loss of bait.

2

Many different approaches to reduce bait loss and seabird mortality have been

developed and tested. As mitigation measures can be expensive in acquisition or during

use, incentives are necessary to convince fishermen to use these measures, to their own

benefit and that of the seabird.

This master thesis is intended to provide data to show that mitigation measures might

not only contribute to seabird conservation, but at the same time can ultimately reduce

the economic loss of the fishermen by increasing the fishing efficiency of their gear. To

achieve this, the following questions need to be evaluated:

1) What are the pitfalls of using the approach of stomach content analysis of

bycaught seabirds to estimate bait loss rates and how can this approach be

improved?

2) What is the economic loss a fisherman on the Faroe Islands might

experience due to bait loss by seabirds?

3) What are suitable mitigation measures to reduce seabird bycatch and

consequently the economic loss experienced by Faroese fishermen?

This thesis intentionally focuses on the economic consequences of bait loss and not on

the biological and ecological implications that occur when a long living seabird species

loses an unknown number of individuals to the longline fishery. The reasons are on one

hand the lack of data on the severity of this impact on the Faroe Islands and on the

other hand the idea that a report on the economic consequences of bait loss might be of

higher interest and utility to Faroese fishermen.

As an initial part of this thesis, scientific literature was searched for information on

longline fishery practices in general and specifically on the Faroe Islands, the

interaction of seabirds with this fishery and general mitigation measures to reduce

harmful interaction (Chapter 2).

To answer the research questions mentioned above a set of methods was combined. The

stomach content of 634 northern fulmars (Fulmarus glacialis) was analysed and bait

was identified, counted and weighed. In a second step literature research and modelling

is used to find out important information on the costs of bait loss. Finally the mitigation

measures are tested for their suitability in the Faroese fisheries including their

3

efficiency in reducing bait and the general costs of implementation. All methods used

during this research are described more in detail in Chapter 3. Results evaluating the

bait loss by seabirds use an innovative approach by analysing bait found in stomachs of

northern fulmars, bycaught in longline fisheries around the Faroe Islands (Chapter 4).

This approach has been used once before in the Southern Ocean by Gandini & Frere

(2012), however they solely used the number of baits found in a few stomachs to

estimate bait loss as a secondary source of information and did not go much into detail

with this data. In a second step this data and additional literature research leads to an

estimation of the economic loss a fisherman on the Faroe Islands experience using

simulated scenarios. In a third step the mitigation measures introduced earlier are

analysed, regarding their suitability and the economic viability for the Faroese longline

fisheries. In the discussion (Chapter 5) the approach and the data are evaluated.

Alternative approaches are discussed to gain a deeper insight in the Faroese fisheries

and recommendations are made how in future research could support policy discussions

and how fisheries could benefit economically from this research. The conclusions of

this research and recommendation for further research as well as recommendations for

implementation are presented in Chapter 6.

4

5

2 State of Knowledge

Seabird-fishery interaction is a well-known phenomenon. There are various scenarios

wherein seabirds either suffer or benefit from fishery activities. Negative impacts on

seabirds include bycatch and disturbance in their habitat as well as competition for food

(mainly smaller fish). However, especially scavenging seabird populations can benefit

from discarded fish as an additional source of nutrition and the human-induced

depletion of competitive predatory fish species, that forage on the same fish as seabirds,

can also be beneficial to some seabird species (Montevecchi 2002). On the other hand

also fisheries can be influenced by seabirds. As seabirds concentrate on fish-rich areas

they may lead fishermen to these places and therefore might be economically

advantageous for the fisheries, even though it is impossible to express this effect in

money (Suazo et al. 2013). However, at the same time seabirds and fisheries are

competing for food. In 2004 the total annual consumption of fish by seabirds was

estimated at 70 million tonnes, while the commercial fishing activity was estimated to

catch around 80 million tonnes a year (Brooke 2004). Fishing down the food web also

occurs in the North Sea where the depletion of cod (Gadus morhua) and the

introduction of aquaculture led to an increasing commercial interest in the smaller sand

eel (Ammodytes marinus) (Furness 2002). By focussing on smaller fish species, the

fishery and seabird competition becomes more direct and obvious and in this case can

lead to economic disadvantages for the fishery (Brooke 2004). Another problem occurs

in the longline fishery where seabirds decrease the fishing efficiency by stealing the

bait from the deployed hooks. In this thesis it was the attempted to investigate whether

there is a method to indirectly gain more knowledge on the impact seabirds have on

fisheries and vice versa.

Fishing technique 2.1

Longline fishery is one of the largest fisheries for consumption fish worldwide. Bjordal

& Lokkeborg (1996) report that between 15 and 90% of the fish worldwide was caught

by longline boats. It is seen as a passive fishing technique, where fish is attracted to

static lines with baited hooks by odour or vision (Brothers et al., 1999). The fisheries

6

use lines up to kilometres in length. On these main lines, at intervals of a few metres up

to thousands of branch lines are connected with baited hooks (Figure 1). Fishes can be

caught at all water depths, pelagic, semi-pelagic and demersal (Bjordal & Lokkeborg,

1996).

Figure 1: Demersal longline fisheries. (Drawing: U. Kühn)

Large ships can operate in deep sea environments down to 3,000 meters depth

(Brothers et al., 1999). Pelagic longlining mainly targets large species as tunas

(Thunnus spec.) and tuna-related species in the water column while demersal longliners

often focus on the continental shelf with species living at, or close to, the seafloor such

as e.g. gadoids (Brothers et al., 1999). The hooks vary in size and shape, depending on

the target species. As bait, fish, squid or whelk are commonly used (Collins et al.,

2010).

2.1.1 Effects of longline fisheries on the environment

Compared to other fisheries longlining has been described as a relatively

environmental-friendly fishing technique. As there are species- and age-specific

differences in habitat choice, longlines can be deployed on specific areas or a specific

7

type or size of bait can be chosen to avoid non-target fish species and to select for fish

of the right size or age, other than other fishing techniques (Brothers et al., 1999).

Another advantage is, that in general longlining is not destructive to bottom structures

(Dunn & Steel, 2001).

The fishery is not totally free of environmental impacts as unintended bycatch of sharks

turtles and marine mammals and damage to cold water corals in deep sea longlining

occur (Hinman, 1998; Durán Muñoz et al., 2010). However, the fisheries main problem

concerns the unintentional bycatch of a range of seabirds. Furness (2003) described the

problem as one of the most urgent issues for seabird conservation.

Figure 2: Bycatch of seabirds in demersal longline fishery (Drawing: U. Kühn)

In the northern hemisphere more surface-feeding seabirds occur, while in the southern

hemisphere many seabird species forage while diving and therefore problems not only

occur in the very first phase of deployment when the baited hooks are close to the water

surface, but also in a later phase, as e.g. shearwaters (Procellariidae) are known to dive

8

down to considerable depth (Bull, 2007). As surface foraging seabirds often feed

indiscriminate and are known for scavenging, they are described as “preadapted” for

bait stealing and offal foraging (Camphuysen et al., 1995). Another factor playing a

role in vulnerability to longline entanglement is the size of the seabird. Seabirds as for

example storm petrels (Hydrobatidae) are too small to forage on baits used in longline

fisheries (Brothers et al., 1999). Larger birds also can benefit in competition and have

been found to be more aggressive when competing for bait, at the same time increasing

the vulnerability of getting caught by hooks (Brothers, 1991).

The exact extent of this problem is difficult to estimate, but it is evident that hundreds

of thousands of seabirds die annually worldwide, while trying to forage on bait

(Anderson et al., 2011). Brothers et al. (1999) made an extensive overview of different

bycatch rates over the world. They list 61 seabird species that have been recorded as

bycatch in longline fisheries, many of them are regarded as threatened species by IUCN

(International Union for Conservation of Nature).

It is difficult to prove a correlation between longline fisheries and impacts on seabird

population levels as many interconnected factors may play a role (Løkkeborg, 2011).

Indications for effects on population level are given by a few studies. Lewison &

Crowder (2003) for example estimate that in the Northern Pacific Ocean 5,000 to

10,000 black-footed albatrosses (Phoebastria nigripes) are killed annually in longline

interactions. As albatrosses are long-lived and slow in reproduction, this will result in a

population decline throughout the next 60 years. Also the rare Amsterdam Albatross

(Diomedea amsterdamensis) is likely to be negatively affected by longline fishing

activities around their breeding range (Inchausti & Weimerskirch, 20010). Belda &

Sanchez (2001) provide data on shearwaters in the Mediterranean, they link the

decrease in shearwater population to longline fisheries bycatch. In the Southern Ocean,

Ryan & Watkins (2002) estimated the mortality of more than 5,000 white-chinned

petrels (Procellaria aequinoctialis) in a four-year period, equalling 10-20% of the

breeding population. Most of these birds were caught during illegal fishing activities.

Tasker et al. (2000) calculate great negative impacts by longline mortality on

population levels for albatrosses in the southern hemisphere and moderate negative

impacts on petrels and shearwaters worldwide.

9

Fishing on the Faroe Islands 2.2

The Faroe Islands are a group of 18 small islands, located in the North East Atlantic,

between Scotland and Iceland (62º00’ N; 6º47’ W; Figure 3). About 48,000 people live

on the islands, that fall under the territory of Denmark (Føroya Landsstýri, 2015).

However, as they are self-governing, they decided to not become a member of the

European Union (EU) and therefore have their independent fisheries management

Figure 3: Map showing the Faroe Islands between Scotland and Iceland and a detailed map of the Faroe Islands (Created by Google Maps 2015)

10

regime. Their economy solely relies on fisheries, fish processing and aquaculture, 95%

of the Faroe exports since 1920 are fishery products (FAO, 2005). 240 fishing vessels

above 20 GRT (Gross Register Ton) are registered; furthermore the Faroese fleet

includes more than 1,000 smaller fishing vessels (Vinnhusid, 2015).

Longline fishing is a big contributor to the national income. In 2003, 92 longline

vessels of different sizes were registered (Løkkegaard et al., 2007). The main species

caught by longline fisheries are cod, haddock (Melanogrammus aeglefinus) (see Figure

4), tusk (Brosme brosme) ling (Molva molva) and saithe (Pollachius virens), which in

2014 generated an income of around 200 million DKK (Hagstova Føroya, 2015b).

Since 1993 fish is auctioned electronically and is owned by the fish suppliers. Often

more than 80% of the fish is sold even before the vessel reaches land (Fiskamarknadur

Foroya, 2015). Inside longline fisheries the species distribution caught in 2014 is

shown in Table 1 (Hagstova Føroya, 2015b).

Table 1: Wet mass of different fish species and their percentage of the total landed longline catch on the Faroe Islands in 2014 (Hagstova Føroya, 2015b)

Species Wet mass (kg) % Longline Cod 95,635 40.0 Haddock 42,547 17.8 Tusk 16,486 6.9 Ling 57,494 24.0 Saithe 3,296 1.4 Other 23,785 9.9 Total 239,243 100

The main tool to manage the harvest of fish on the Faroe is the effort control. This

policy was implemented in 1996, after a Total Allowable Catch system (TAC) failed,

due to high discard rates (Jákupsstovu et al., 2007). Therefore the focus lies on input

control rather than on output control as it is usually implemented in the EU, where they

focus mainly on landed fish (Hegland & Hopkins, 2014). The effort control based

system is known for being less bureaucratic and less expensive. However the biggest

advantage is, that especially in mixed demersal fisheries, a TAC leads to high bycatch

level of fish species with different quotas (Hegland & Hopkins, 2014). The main

components of the effort control policy are summarized by Hegland & Hopkins (2014).

They include a limit of fishing days for each type of fishing vessels (these days are

11

transferable in the same fishing category; Zeller & Reinert, 2004), fleet segmentation to

make sure not all types of fishing vessels are fishing in the same area at the same time

and capacity regulation to keep the number and capacity of the fleet to the level of

1997. Another regulation playing a big role in Faroe fisheries are spatial and temporal

closures. They were originally established to avoid gear conflicts and regulate access

rights, but later the protection of vulnerable habitats, species and stocks also became an

important issue. Technical

measures as mesh size

regulation, sorting grids etc.

were implemented to

decrease bycatch of too small

or non-target fish species

(Hegland & Hopkins, 2014).

As applicable as it appears for

the Faroese fishing to use this

kind of effort control, also

disadvantages have been

documented. The annual limit

of fishing days is decided by

the Faroese Ministry of

Fisheries and Natural

Resources. They get input

from the Faroe Marine

Research Institute and from

the Committee on Fishing Days, which is represented by the fishing sector. It appeared

that in the past, the minister tended to go with the recommendations the committee

made, rather than finding a compromise between the scientists and the fishery sector to

ensure sustainable fishing (Hegland & Hopkins, 2014). Other concerns regard the

difficult enforcement and the fact that there is actually no fishing management plan in

place (Jákupsstovu et al., 2007).

Figure 4: A haddock (Melanogrammus aeglefinus) caught on a longline vessel on the Faroe Islands. Northern fulmars are surrounding the vessel searching for food opportunities (Photo: J.A. van Franeker)

12

2.2.1 Associated birds

Bycatch of seabirds is common on the Faroe Islands. Anderson et al. (2011) estimate

that the Faroe Islands belong to the Top 10 of longline fleets with the highest estimated

seabird bycatch rate worldwide. Data regarding the species composition of longline

bycatch is not directly available from the Faroe Islands. Norwegian data by Dunn &

Steel (2001) shows that northern fulmars are the very dominant species which is caught

in longlines with more than 99% of the total bycatch. Personal observations from the

Faroe Islands by J.A. van Franeker confirm this picture (also see: Figure 5). Other bird

species associated in small numbers with longline fishing vessels are gull species

(Larus spec.), great skuas (Stercorarius skua), that use kleptoparasitic foraging

techniques to steal food from other birds and a few northern gannets (Morus bassanus)

which dive around the vessels, but were not observed to be caught.

Bycatch of seabirds in Faroese longline fisheries hasn’t been monitored yet. There are

no reliable numbers available. More recent estimates of bycatch in saithe longline

fishing in Faroese waters have been made by the Marine Stewardship Council (MSC,

2012). They estimate that 5,000 to 25,000 northern fulmars might get caught annually

Figure 5: Northern fulmars following a longline vessel on the Faroe Islands and fighting for food (Photo: J.A. van Franeker)

13

by longline vessels that catch saithe. Following their calculations this might be equal to

5% of the Faroese northern fulmar population. Tasker et al. (2000) argue that,

regarding the range of northern fulmars and the sheer number of breeding pairs, the

northern fulmar population might not be threatened by longline fishing mortality (also

see Brothers et al., 1999).

As northern fulmars seem to be the most affected species in the northeast Atlantic

Ocean (Dunn & Steel, 2001; Løkkeborg, 1998), this report will focus on them.

Northern fulmars (Figure 6) are seabirds that occur in all parts of the northern Atlantic,

from the Arctic to the North Sea and another population is found in the North Pacific.

Northern fulmars are members of the tubenose order (Procellariiformes), which for

example also includes the albatrosses. They are a long-lived species, can live up to 35

years and have a slow reproduction cycle as they start breeding when they are on

average 9.2 years old (Ollason & Dunnet, 1978). They breed in great numbers on rocky

cliffs but most of the year they spend on the ocean (BirdLife International, 2015c).

Northern fulmars forage exclusively at sea on fish, crustaceans, squid, jellyfish and

scavenge all sort of dead animals or fishing offal (Phillips et al., 1999; Ojowski et al.,

2001; Garthe et al., 2004). They are known to ingest large numbers of marine debris

(e.g. Van Franeker et al., 2011). Regularly they are found to follow fishing vessels day

and night, waiting for discards or bait (e.g. Thompson et al., 1995; Furness & Todd,

1984; Dunn & Steel, 2001).

The first record of northern fulmars following ships reaches back to 1671 on

Spitzbergen where they were observed to follow whalers (Fisher, 1952). Fisher (1952)

Figure 6: Northern fulmars in flight (left), in portrait (with clearly distinguishable tube on the bill; centre) and northern fulmars feeding around a fishing vessel (right; Photo‘s: S. Kühn)

14

also cites the fisherman, Henry Fitzler, who described the determined search for baited

hooks in 1946 as follows:

“The fulmar brain probably contains no innate mechanism whereby its owner is apt to

respond distrustfully with regard to human beings. The birds are apparently so

constituted that, when suitable food is available, they are incapable of associating the

manner in which it is presented – in this instance on hooks- with possible hazard to

themselves” (Fisher, 1952, p. 420).

The northern fulmar population estimate for the entire North Atlantic is more than

2,800,000 breeding pairs, on the Faroe Islands there are 600,000 breeding pairs found,

the population has been regarded as being secure (BirdLife International, 2015c),

however recent numbers show decreasing population trends. There have been

observations showing a slight decrease in Canada (Gaston et al., 2012) and an decrease

in most parts of the UK (except Wales; Mavor et al., 2005) as well as moderate

decreases on the Faroe Islands (See Figure 7; BirdLife International, 2015a). While the

IUCN keeps the northern fulmar in the “Least Concern” list (BirdLife International,

2015c) in 2012, in the European Red List assessment the fulmar is categorized as

“Endangered” (BirdLife International, 2015b).

15

Figure 7: Short term trends of the breeding population of northern fulmars in Europe (adapted from BirdLife International, 2015a)

General mitigation strategies 2.3

Even though the northern fulmar population seems not to be affected at the moment,

the Food and Agriculture Organization of the United Nations (FAO) Conduct for

Responsible Fisheries obliges member states to reduce non-target bycatch (FAO,

1995). Many measures to mitigate seabird mortality have been tested. However,

avoiding seabird bycatch is not enough. At the same time, the methods must be safe for

fishermen during operation, it must not or only marginally decrease fishing efficiency

and in best case even provide operational and economic benefits (Gilman et al., 2005).

To avoid bait loss by seabirds, three theoretic approaches are proposed by Brothers et

al. (1999): decrease the visibility of the bait, decrease the access to the bait and

decrease the chance of mortality when hooked.

16

The baited hooks are most prone to be taken by seabirds during setting operations. The

lines with baited hooks can float on the surface for a while, depending on the vessels

speed and tension of the line, weights used and the turbulence caused by the propeller

as most lines are set on the back of the ships (Brothers et al., 1999). As soon as the

lines sink, they get out of the reach of seabirds, depending on the seabird species and its

diving capacity. However, once hooked, birds themselves can decelerate the sinking

speed, as they struggle against the entanglement and change the floating behaviour of

the lines, attracting even more birds to steal bait (Barnes et al., 1997; BirdLife

International, 2014). Therefore most mitigation strategies focus on the setting process.

Hereafter the main strategies to avoid bait loss by seabirds are introduced. They are

split into adaptations of either fishing gear, fishing operation or management strategies.

2.3.1 Fishing gear adaptations

Underwater setting tubes: Underwater setting tubes are used in demersal and pelagic

longlining to bring the lines out of the reach of seabirds, preventing them from hunting

for bait. These are fixed tubes on the stern of the boat, which lead the lines with baited

hooks directly a few meters under the water surface. The tubes can be attached on an

vessel already in use but there are also systems that are integrated in the ship during

construction (Brothers et al., 1999). Significant seabird bycatch reduction has been

proven in several studies. For example, research by Gilman et al. (2003) shows that

20% more bait can be retained when using under water setting tubes in comparison

with the control situation without tube. Costs to install the tubes are expected to be high

initially but low once it is installed (Brothers et al., 1999; Gilman et al., 2003; Dunn &

Steel, 2001). Problems in handling can occur when the line tangles (Dunn & Steel,

2001). Another disadvantage can be observed when the lines still can reach the surface

due to high waves pulling up the stern with the fixed tube (Løkkeborg, 1998; Gilman et

al., 2003).

A comparable type of funnel is the chute. Here only the branch line with the baited

hooks are sent through the tunnel, decreasing the risk of tangling during deployment

activities (Bull, 2007). In pelagic longline fisheries a reduction of 95% of seabird

bycatch was achieved and fishing efficiency was increased by 15 to 30% (Gilman et al.,

2007).

17

Bird Scaring Lines (BSL): Bird Scaring Lines (sometimes also called tori lines) are a

group of different methods where colourful and fluttering lines, are attached on the

back of the ship flying above the actual fishing lines, preventing seabirds to reach the

baited hooks. These lines are hanging above the main lines and protect them from

seabirds during setting of the line (Bull, 2007; Brothers et al., 1999). The efficiency

depends on the sinking rate of the fishing line and the height of the scaring lines as this

defines the distance before the lines reach the water surface and loses its bait protection

ability. A significant reduction in seabird mortality and an increase in fishing efficiency

has been observed in several studies in the northeast Atlantic Ocean (e.g. Løkkeborg,

1998, 2003) and elsewhere (e.g. Boggs, 2001) with a reduction in seabird bycatch

ranging from 30-70% in pelagic longline fisheries (Brothers et al., 1999) and 90-98%

in demersal fisheries (Løkkeborg, 1998). Sometimes these lines can tangle with the

fishing gear and at those instances clearly decrease fishing efficiency (Weimerskirch et

al., 2000). The scaring lines (including the mounting pole) are regarded as relatively

cheap initially and during the use (Brothers et al., 1999).

Laser Deterrent: A newly developed method is the Seabird Saver laser method,

combined with a deterring sound system (SaveWave, 2014; AFMA, 2014). The laser is

attached on the stern of the vessel, pointing backwards in a line with the longline itself.

According to the producers, as soon as turned on in a test, all seabirds took off from the

water surface and kept distance to the laser light and the baited hooks. Added bird

stress sounds increased the deterring effect. Until now, this system has only been tried

in unpublished trials conducted by the developer SaveWave, who claim good results in

dark, foggy or rainy circumstances. However, as potential negative effects of laser

beams on birds have not been tested by independent scientists yet, the claimed

efficiency rate cannot be used in tabulated or graphical representations of mitigation

methods.

Weighted Lines: The time, fishing lines need to sink depends on the speed of the ship,

the tension on the line and its weight. Added weights on the lines or integrated heavy

lines ensure a fast sinking rate, out of reach for most seabirds (Robertson, 2000;

Robertson et al., 2006). The efficiency of weighted lines to reduce seabird bycatch

depends increases with the sinking rate and can reach 100% reduction (Robertson et al.,

18

2006). In demersal fisheries it is less complicated to add weights as they sink to the

seafloor anyway. In some cases even an increase of target species catch has been

observed, because the hooks are better positioned on the sea floor (Brothers et al.,

1999) or at least have shown no reduction in target species catch (Robertson et al.,

2006). However, as the tension of the line gets stronger, there is a higher risk for crew

members when the line snaps unintentionally (Brothers et al., 1999).

2.3.2 Operational adaptations

Offal discard: In many fisheries, discarding bycatch has been prohibited, including

fisheries on the Faroe Islands, However, when processing the fish on board, offal is still

discarded immediately. It has been proven to reduce the bait loss due to seabirds when

the discard of fishing offal (either intestines or other bycatch) is adapted time- and

place wise to fishing operations. As the lines are set on one side of the boat, it helps

when the offal is discarded on the opposite side of the ship as it leads the birds away

from the deployment. Also timing can be crucial, when deployed and discarded at the

same time, birds tend to steal much more bait as when setting the lines and discard take

place at the same time but opposite sides of the ship (Collins et al., 2010). So there are

two ways of thinking, either use the discard to distract birds from the setting or hauling

operations or retain all discard, including offal on board. In the latter case, fishermen

might be worried about the additional storage space needed for the offal (Bull, 2007).

The first option however, has been criticized as discarding of alleged edible items may

attract higher numbers of seabirds which may increase the initial number of entangled

birds (Brothers et al., 1999).

Dyed bait: In longline fisheries there have been some trials done to colour bait blueish

and therefore decrease the contrast with seawater and camouflage the bait to the

seabird`s eye (Gilman et al., 2007). Studies have been proven a bait loss reduction in

pelagic fisheries up to 95% (Boggs, 2001) however, in comparison with side setting

and chutes it was the least efficient measure (Gilman et al., 2007).

Smell distraction: There have been trials in distracting seabirds during the setting of

the fishing lines with a smell and therefore mislead them from the hooks. This smell

was created by fish oil retrieved from non-target fish bycatch (Pierre & Norden, 2006).

19

However the uncertain effects on the marine ecosystem, the effect of oil in bird feathers

and the chance of habituation seemed to make this mitigation strategy not suitable for a

larger scale of fishing operations.

2.3.3 Management options

Area closures: Area closures try to avoid overlap of areas of special importance to

seabirds and high fishing pressure. It is a commonly used method also to protect

spawning fish stock, or vulnerable habitats. Therefore areas where seabirds accumulate

could be closed to fisheries. This can be a very effective strategy in reducing bait loss

by seabirds, however, the fishermen might lose income as high densities of fish

naturally attract also high densities of birds, taking away important fishing grounds

(Brothers et al., 1999). Area closures are closely related to time closures, described

below.

Time closures: Temporal closures concern either diurnal or seasonal fishing

limitations and as spatial closures they try to prevent the overlap of seabirds and fishing

vessels in high densities (Bull, 2007). For example in the Southern Ocean toothfish

(Dissostichus eleginoides) fisheries, fishing during breeding season of seabirds

(September-April) is restricted as seabirds abundance around fishing boats seemed to

be higher during the breeding season and the birds are highly vulnerable throughout the

breeding season. Furthermore the fishermen are only allowed to set their lines during

night, when fewer seabirds are following the boats (Collins et al., 2010). Managing

area and time closures demand a high level of knowledge of the environment and the

ecology (e.g. breeding and migration patterns) of the particular target and non-target

species (Bull, 2007).

20

21

3 Methods

Stomach content analysis 3.1

Data on the frequency and quantity of bait in stomachs of bycaught northern fulmars on

the Faroe Islands has been recorded since 2004. A total of 634 northern fulmars have

been accidentally caught and collected during longline fishing operations between 2004

and 2012 (Table 2). The stomach contents were sorted as natural food, bait and non-

food as marine debris. The original reason for the collection is a research project on

marine debris ingested by northern fulmars. This research is conducted by Dr. Jan

Andries van Franeker, working for IMARES (Institute for Marine Resources and

Ecosystem Studies) in the Netherlands. As for this research a spreading over the

seasons was necessary, the fishermen did not necessarily collect all birds they caught

on a single trip. Unfortunately it is therefore impossible to calculate the average number

of birds that is caught during one fishing trip.

Table 2: Sample size and distribution of northern fulmars caught accidentally during longline fishing operations on the Faroe Islands between 2005 and 2012

The northern fulmars were dissected following the standard protocol for plastic in

seabird monitoring, described by Van Franeker (2004). As I am involved in the projects

searching for plastics in northern fulmars since 2011, I joined the dissection of all the

birds from the Faroe Islands, many of the birds I dissected myself, in other cases I

assisted the dissections. Before that time, dissections and analyses were performed by

Van Franeker and colleagues. We collected details on morphometric data such as the

length of the head, bill, wings and tarsus. We also noted the state of moult and down

feathers, visible fractures or wounds, as well as signs of entanglement and the colour

phase, as it can give us an indication of the origin of the birds. During the dissection we

removed the stomachs and store them frozen at -20 degree Celsius for later analysis.

Year 2004 2005 2006 2007 2008 2009 2010 2011 2012 Total Number of birds 43 238 47 0 46 38 11 198 13 634

22

For the stomach content analysis the stomachs were thawed again. Since 2011 the

content analysis of all the Faroese northern fulmar stomachs was done by a colleague

and me. We rinsed the stomach contents over a 1 millimetre sieve with cold water. The

wet stomach content was weighed and the number of bait items was counted, weighed

and categorized as fish, squid or whelk.

Bait is easily distinguished from natural food as being clearly cut pieces of fish, squid

or whelk (Figure 6). As the birds drown while scavenging on bait, bait pieces are very

fresh and show little signs of digestion. An exception forms the opercula of whelks, the

hard, calcareous “house door” which is attached to the foot of the gastropod and

protects it against desiccation and predation (Figure 8, bottom row centre). This part of

the snail body takes much longer to be digested in seabirds and therefore might stay

longer in the gastrointestinal tract than softer, fleshy parts. As whelk does not belong to

the natural prey of northern fulmars all opercula found in stomachs have been assigned

as being bait.

Figure 8: Examples of bait found in the stomachs of northern fulmars, accidetally bycaught on the Faroe Islands (Photo‘s: J.A. van Franeker)

23

Analysis of the economic loss, simulations 3.2

and costs of mitigation

From market and literature research, data is collected to estimate the financial loss of

Faroese fishermen due to bait-stealing seabirds. Therefore information on catch rates,

market prices and the number of birds following a vessel was collected. With the data

collected, different simulations were developed to create a broad range of scenarios

with minimum-maximum estimations. Different mitigation measures were evaluated

and recommendations were made concerning their suitability regarding costs and

fishing efficiency.

3.2.1 Value of a fish

To calculate the financial loss experienced by a Faroese fisherman, it is important to

know what a single lost piece of bait means to the success of catching a fish. In general

it can be assumed that every single piece of bait that is scavenged by a seabird means a

lost chance for the fishermen to catch a fish on this specific hook. Therefore the

reduction of bait loss is crucial to increase the fishing efficiency of each individual set

of line that is deployed. On the market (and in literature), catches are normally counted

in kilograms per species and catch. However for this research it is necessary to know

what the loss of an individual fish means to the fisherman in economic terms. The

landings, expressed in kilogram have to be transformed in the numbers of fish caught

per landing. The average size of the fish when caught can be found in the literature.

Furthermore the value per kilogram fish and species is needed to calculate the price per

individual fish. When no information on the relation of size to kilogram was available,

standardized regressions were used to calculate from fish length to mass. It is important

to note that these numbers represent the size and weight when most fish is caught, not

the numbers of general fish assemblages in the ocean. So first the price per fish species

has to be calculated. The following formula combines the factors mentioned above:

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑃𝑃𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴 𝑝𝑝𝐴𝐴𝐴𝐴 𝑓𝑓𝑃𝑃𝑓𝑓ℎ (𝐷𝐷𝐷𝐷𝐷𝐷) = 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑚𝑚𝐴𝐴𝑓𝑓𝑓𝑓 (𝑘𝑘𝐴𝐴) ∗ 𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴 𝑝𝑝𝐴𝐴𝐴𝐴 𝑘𝑘𝐴𝐴 (𝐷𝐷𝐷𝐷𝐷𝐷)

24

The Faroese longline fishery is a multispecies fisheries, meaning that fishermen target

not a single species but normally try to catch different species of the same size and

habitat. The average price per fish must be related to the percentage of the share per

fish species caught by longliners. Therefore the following formula is used correcting

for the different market prices per species:

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴 𝑝𝑝𝐴𝐴𝐴𝐴 𝑓𝑓𝑃𝑃𝑓𝑓ℎ = 𝑆𝑆𝑆𝑆𝑚𝑚 𝑜𝑜𝑓𝑓 (𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴 𝑝𝑝𝐴𝐴𝐴𝐴 𝑓𝑓𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴𝑓𝑓 (𝐷𝐷𝐷𝐷𝐷𝐷) ∗ 𝑝𝑝𝐴𝐴𝑜𝑜𝑝𝑝𝑜𝑜𝐴𝐴𝑝𝑝𝑃𝑃𝑜𝑜𝑝𝑝 𝑜𝑜𝑓𝑓 𝑃𝑃𝐴𝐴𝑝𝑝𝑃𝑃ℎ)

Knowing the average number of baits that northern fulmars scavenge and the economic

loss of a single fish, simulations can be made with additional data from literature

research regarding the estimated abundance of seabirds and different fishing

efficiencies that might occur. Therefore the data were combined in the following

formula

𝑃𝑃𝑜𝑜𝑝𝑝𝐴𝐴𝑝𝑝𝑝𝑝𝑃𝑃𝐴𝐴𝑃𝑃 𝑃𝑃𝑜𝑜𝑓𝑓𝑓𝑓 (𝐷𝐷𝐷𝐷𝐷𝐷; 𝑝𝑝𝐴𝐴𝐴𝐴 𝑝𝑝𝐴𝐴𝑃𝑃𝑝𝑝) = �(𝑥𝑥 ∗ 𝐴𝐴) ∗ 𝑏𝑏� ∗ 𝑦𝑦

whereby x is the variable number of birds around a vessel and y the fishing efficiency

defined as the percentage of hooks that actually catch a fish. In this formula, a is the

average number of bait that is found in bird stomachs and b is the average price per

fish. The two latter ones are calculated in this research while x and y are variable.

These simulations display the economic loss an individual vessel experiences during

one single trip.

3.2.2 Costs of mitigation

The costs for various mitigation measures were, when available, collected from

literature research or by contacting industrial producers and collected in one

overviewing Table. Here, when the information was available, several factors are

summarized:

• the type of mitigation measure

• the fishery (demersal or pelagic longlining)

• the reduction in seabird mortality or bait loss noted (varying per reference)

• the costs (numbers or descriptions)

• the region where the fishery takes place

• the seabirds associated

25

• the reference

As often no exact number was given, all identified estimations regarding the costs of

the mitigation strategy were categorized into five categories from 1=low to 5=high.

This data, together with the efficiency of reducing bycatch (in percentage) was put into

a graph to visualize the trade-offs of the different methods and to identify the most

efficient mitigation strategy regarding costs and efficiency. This analysis is to identify

all advantages and disadvantages, resulting in recommendations for the most suitable

mitigation measures for the Faroe Islands.

Ethical issues 3.3

All birds collected were accidental bycatch from longline boats; none of them was

killed intentionally for this study. The dissections were conducted by IMARES in the

Netherlands under permission by the Dutch Ministry of Economic Affairs (Permission

FF/75A/2013/22).

26

27

4 Results

Stomach content analysis 4.1

4.1.1 Catch rates per tour

During 81 fishing trips between 2004 and 2012, 634 birds were collected for research

purposes. Fishing vessels are mostly out at sea for a single day sometimes a few

consecutive days. As the date is the only data collected in this thesis trips are defined as

one day. Figure 9 shows the distribution of trips throughout the years and months. Most

trips when birds were collected were during the first half of the year. January was

sampled during 6 years while in the second half of the year most months were only

sampled once or twice (June to December), mainly in the year 2005. This year has the

best coverage over all the month except for November. No birds were sampled in

November during 2004 and 2012. In 2006 and 2012 only January was sampled and in

2009 March was the only month when birds were collected.

0

2

4

6

8

10

12

14

16

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Num

ber o

f trip

s (n=

81)

Month

2012

2011

2010

2009

2008

2006

2005

2004

Figure 9: Number and distribution of fishing trips where northern fulmars were caught and collected between 2004 and 2012

28

4.1.2 Seabird mortality

As mentioned in the methods, we cannot assume that the birds collected during one trip

equals the number of birds caught on this day by this vessel or on the other hand that

fishermen started collecting birds only when they caught sufficient birds. Therefore an

average number of birds caught during these trips cannot be defined. The numbers in

Figure 10 present the birds that were collected by the fishermen. In October 2005, a

maximum of 44 birds were collected during one trip. Most of the birds were collected

during winter and spring reflecting the high numbers of fishing trips presented above.

4.1.3 Bait in seabird stomachs

In 5 out of 634 northern fulmars collected there is no data available about the amount of

bait in the stomach, so they were excluded from the bait calculations. In total, 1,308

pieces of bait were recorded in the remaining 629 birds. At the point they got

entangled, the birds had an average of 2.1 baits in their stomach weighing in average

32.2 gram. The maximum number of bait found in one bird was 11 pieces, weighing

168.6 gram. 142 birds did not have any identifiable bait in their stomachs. The

distribution of the number of baits per bird is shown in Figure 11. For modelling

0

20

40

60

80

100

120

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Num

ber o

f bird

s (n=

634)

Month

2012

2011

2010

2009

2008

2006

2005

2004

Figure 10: Distribution of northern fulmars caught in Faroese longline fisheries per month and year

29

purposes in this study it is assumed that the average of 2.1 pieces bait per bird is

representative for all northern fulmars associated with a longlining fishing vessel.

Figure 11: Count of baits found in northern fulmar stomachs between 2004 and 2012

Baits were defined as either fish, squid or whelk. In most cases the identification to

species level was impossible. In many cases there was a combination of different bait

types found in individual birds. The main bait that was found in stomachs was fish,

followed by squid and a low percentage of whelk, see Figure 12.

0

20

40

60

80

100

120

140

160

none 1 2 3 4 5 6 7 8 9 10 11

Num

ber o

f bird

s (n=

629)

Number of bait in stomachs (n=1308)

Fish 65%

Squid 28%

Whelk 7%

Figure 12: Distribution of bait types found in the stomachs of northern fulmars caught accidentally in longeline fisheries

30

During the 81 trips, 1,308 pieces of bait were collected in the stomachs of the birds

caught. This equals a minimum of 16.1 baits per tour that are lost to seabirds. The

average number of baits stolen varies per month (Figure 13) and was high during the

breeding season with a maximum of an average of 3.9 and 3.8 baits per bird in June and

August respectively even though sample size was low in this period of time. For

November no birds were available.

Figure 13: Average number of baits per month in northern fulmar stomachs in comparison with the number of seabirds caught in this month

The average bait loss from 2004 to 2012 is presented in Figure 14. Over the whole

period a slightly upward trend can be observed, however in 2012 a sharp increase of the

average number of baits ingested is recorded.

0

20

40

60

80

100

120

00.5

11.5

22.5

33.5

44.5

Jan Feb Mrt Apr Mei Jun Jul Aug Sep Okt Nov Dec

Num

ber o

f bird

s cau

ght

Aver

age

num

ber o

f bai

ts

Month

Average number of bait Number of birds

31

Figure 14: Average bait loss and caught northern fulmars between 2004 and 2012

Calculation of economic loss 4.2

The economic loss of the fishermen is difficult to calculate, it has been tried only once

before by Gandini and Frere (2012). It is a combination of several factors that need to

be considered when approaching this issue and that can vary during every single fishing

trip conducted. First of all, there is the piece of bait that gets lost. In the worst case

every lost piece can equal a lost fish. However, also the behaviour of the line can play a

role when birds get entangled. Every bird attached to the lines can change the weight

and the sinking rate of the lines. When this leads to a suboptimal deployment on the

seafloor, a decrease in the catch rate of the target species can be the consequence.

Calculating the costs of a lost fish

From literature research the five most important fish species (in wet mass) have been

identified (Hagstova Føroya, 2015b) and are used in Table 3. The size of the fish is the

average size of fish in longline catches described in the literature. Together with the

data collected on individual size and mass per species and the prices for fish the

following formula was applied for each species separately:

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴 𝑝𝑝𝐴𝐴𝐴𝐴 𝑓𝑓𝑃𝑃𝑓𝑓ℎ (𝐷𝐷𝐷𝐷𝐷𝐷) = 𝑚𝑚𝐴𝐴𝑓𝑓𝑓𝑓 (𝑘𝑘𝐴𝐴) ∗ 𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴 𝑝𝑝𝐴𝐴𝐴𝐴 𝑘𝑘𝐴𝐴 (𝐷𝐷𝐷𝐷𝐷𝐷)

0

50

100

150

200

250

00.5

11.5

22.5

33.5

44.5

5

2004 2005 2006 2007 2008 2009 2010 2011 2012

Num

ber o

f biir

ds c

augh

t

Aver

age

num

ber o

f bai

ts

Years

Number of birds Average number of bait

32

The results of these calculations are also presented in Table 3 as “Price (DKK) per fish”

Table 3: Data on the average size of different fish species when caught, the calculated mass per individual fish, the average prices (in DKK) per kilogram fish and the calculated price per individual fish and species

The percentage of fisheries catch data is provided in Table 1 and summarized in Figure

15. This is important as the Faroese fisheries is a multispecies fishery and therefore the

caught proportion of each species should be considered.

Species Size

range (cm)

Mass per ind.

(kg)

Price per kg (DKK)

Price (DKK) per fish

References

Cod 45-85 4 14.3 57.2 Valtýsson, 2015; Magnussen, 1996; Syntesa, 2014; Hagstova Føroya, 2015a

Haddock 50-65 2 14.6 29.2 Valtýsson, 2015; Syntesa, 2014; Hagstova Føroya, 2015a

Saithe 70-110 7¹ 8 56 Valtýsson, 2015; Hagstova Føroya, 2015a

Ling 60-100 5² 10³ 50 Cohen et al., 1990; Magnússon et al., 1997; Hagstova Føroya, 2015a

Tusk 40-65 2² 7.5 15 Cohen et al., 1990; Valtýsson, 2015; Hagstova Føroya, 2015a

¹average weight calculated, using Leopold et al. (2001) regressions ²average weight calculated using Magnússon et al. (1997) regressions ³data by Hagstova Føroya, 2015a) from 07.10.2015 as no long term average was available

33

Figure 15: Species distribution in percentage caught by Faroese longline fisheries in 2014 (Hagstova Føroya, 2015b)

Considering the factors mentioned above the following formula is used and applied in

Table 4.

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴 𝑝𝑝𝐴𝐴𝐴𝐴 𝑓𝑓𝑃𝑃𝑓𝑓ℎ = 𝑆𝑆𝑆𝑆𝑚𝑚 𝑜𝑜𝑓𝑓 (𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴 𝑝𝑝𝐴𝐴𝐴𝐴 𝑓𝑓𝑝𝑝𝐴𝐴𝑃𝑃𝑃𝑃𝐴𝐴𝑓𝑓 ∗ 𝑝𝑝𝐴𝐴𝑜𝑜𝑝𝑝𝑜𝑜𝐴𝐴𝑝𝑝𝑃𝑃𝑜𝑜𝑝𝑝 𝑜𝑜𝑓𝑓 𝑃𝑃𝐴𝐴𝑝𝑝𝑃𝑃ℎ)

Table 4: Calculation of the average price per individual fish, considering the proportion of each species in longline fishery catches

Species Price (DKK) per fish (mass*price/kg)

% share of the catch Sum

Cod 57.2 40.00 22.88

Haddock 29.2 17.80 5.2

Saithe 56 1.40 0.78

Ling 50 24.00 12

Tusk 15 6.90 1.04

Average price per fish (in DKK) 41.9

COD 40%

HADDOCK 18%

TUSK 7%

LING 24%

SAITHE 1% Other

10%

34

The average price is therefore 41.9 DKK per fish. This is the monetary value that a

fisherman potentially loses for each piece of bait ingested by a seabird and will be used

in further calculations.

Simulation of different scenarios 4.3

As there is no reliable data available on the extent of bait loss by seabirds on the Faroe

Islands, different scenarios are presented to show the ranges of impact that different

numbers of birds can have on the fishing efficiency. We have minimum numbers of

birds caught in longline fisheries and the amount of bait ingested by them. In addition

the average price of fish has been calculated. What remains unknown is the amount and

variation of hooks deployed, this would be necessary to calculate the rate of

entanglement per set of hooks. Another factor playing role is the assumption that each

lost bait equals a lost fish (equalling a fishing efficiency of 100% in undisturbed

conditions). Firstly it is not clear, how efficient longline fishing is in reality, regarding

the average use of baited hooks by the target species, however this can be changed in

different scenarios. In contrast to autoliners, where baiting occurs automatically on

board (with a baiting efficiency of ca. 90-95%; Dunn & Steel, 2001), on the Faroe

Islands hooks are baited manually ashore on a daily base, resulting in a 100% baiting

efficiency, so this factor can be neglected in further calculations. Something that cannot

be corrected for is the assumption that the specific chunk of bait which was stolen by a

bird is the one which would have attracted a target-species fish. So we have to play

with different scenarios, as we might have to assume different percentages of fishing

efficiencies. This influences the economic loss of bait to seabirds. From literature, the

number of birds following a longline fishing vessel were taken into account. Dunn &

Steel (2001) observed an average of 300 seabirds, mainly northern fulmars around

longline fishing vessels in Norway, but also reported a maximum number of 1000

birds. Also in Norway, Løkkeborg & Robertson (2002) reported 70 to 600 northern

fulmars that were following the ship.

35

Table 5: The price of the fish and the average number of baits found in northern fulmars has been calculated before, the number of birds searching for food around the vessel (x) and the fishing efficiency (y) can vary.

Therefore, taking into account the number of birds around the ship, the average number

of bait in their stomachs, the fishing efficiency and the price of one fish we can

calculate different scenarios of individual trips, where two factors are fixed (price per

fish and the average number of bait per bird) and the two other factors are variable

(number of birds around the ship and the fishing efficiency; see Table 5).

The formula to calculate the potential economic loss looks like:

𝑃𝑃𝑜𝑜𝑝𝑝𝐴𝐴𝑝𝑝𝑝𝑝𝑃𝑃𝐴𝐴𝑃𝑃 𝑃𝑃𝑜𝑜𝑓𝑓𝑓𝑓 (𝐷𝐷𝐷𝐷𝐷𝐷; 𝑝𝑝𝐴𝐴𝐴𝐴 𝑝𝑝𝐴𝐴𝑃𝑃𝑝𝑝) = �(𝑥𝑥 ∗ 2.1) ∗ 41.9� ∗ 𝑦𝑦

Now we can simulate different scenarios using the numbers that were found in

literature. The number of birds varies between 70 and 1000 and the fishing efficiency

ranges from 100% to 10% (Table 6).

Table 6: Simulation of different scenarios. Variables x and y (see Table 3) have now been replaced by numbers that estimate the number of birds searching for food around the vessel and a varying fishing efficiency.

Price of fish (DKK)

Number of birds

Average nr. bait

Fishing efficiency

Potential Loss (DKK)

41.9 70 2.1 1.0 6.159 41.9 300 2.1 1.0 26.397 41.9 600 2.1 1.0 52.794 41.9 1000 2.1 1.0 87.990 41.9 70 2.1 0.5 3.080 41.9 300 2.1 0.5 13.199 41.9 600 2.1 0.5 26.397 41.9 1000 2.1 0.5 43.995 41.9 70 2.1 0.3 2.053 41.9 300 2.1 0.3 8.799 41.9 600 2.1 0.3 17.598 41.9 1000 2.1 0.3 29.330 41.9 70 2.1 0.1 616 41.9 300 2.1 0.1 2.640

Price of fish (DKK) Number of birds Average bait/bird Fishing efficiency 41.9 x 2.1 y

36

41.9 600 2.1 0.1 5.279 41.9 1000 2.1 0.1 8.799

Following such calculation models, the possible economic impact during a fishing trip

or a part of it without any mitigation measures can range from 616 DKK assuming only

70 birds surround the vessel and a low fishing efficiency (10% of the hooks will catch a

fish) up to 88,000 DKK when 1,000 birds follow the boat and a fishing efficiency is

100%. The real economic loss will be somewhere in between these numbers and may

vary per trip, season, type of fish caught and other external factors.

Costs of mitigation 4.4

Worldwide many studies have been performed to find the best mitigation measure to

reduce seabird bycatch in longline fisheries without compromising safety and

efficiency of fishing operations. From the different studies it becomes clear that all

measures only can work under specific circumstances, such as the type of boat, gear

and fisheries, target and seabird species, weather and geographic environments. In the

North East Atlantic, northern fulmars are the seabird species most affected by

accidental longline bycatch. Beside the fact that the northern fulmar population is

supposed to be decreasing, fishermen can experience severe economic loss from bait

loss to northern fulmars. Therefore a solution for this problem is necessary. Analysing

the literature (Table 7) shows that there are many ways to reduce seabird mortality and

bait loss, however many factors as the type of fishery, the region and the associated

birds can play a role.

37

Table 7: Table of mitigation measures, their efficiencies and costs (if data available) and references

Mea

sure

Pela

gic

(P),

Dem

ersa

l (D

)

Red

uctio

n (in

bir

ds

per

1000

hoo

ks)

befo

re a

nd a

fter

Red

uctio

n in

bai

t lo

ss (%

)

Red

uctio

n bi

rd

mor

talit

y (%

)

redu

ctio

n de

scri

ptio

n

Cos

t des

crip

tion

Loc

atio

n

Seab

ird

spec

ies

Ref

eren

ces

BSL (Bird Scaring Line)

P 76 N Pacific, Hawaii Alb Boggs, 2001

BSL D very high

1,500 AU$, low ongoing

n/a Brothers et al., 1999

BSL 1.06 to 0/0.03

20/30 to 15

NE Atlantic, Norway

N. fulmar

Løkkeborg, 1998

BSL P 52 79 N Pacific, Hawaii n/a McNamara et

al., 1999

BSL D 88-100 N Pacific, Alaska

N fulmar

Melvin et al., 2001

BSL D 71-94 N Pacific, Bering Sea

N fulmar

Melvin et al., 2001

BSL D 98-100 NE Atlantic, Norway

N fulmar

Løkkeborg, 2003

BSL D cheap n/a BirdLife International, 2014

Dyed bait P 94 N Pacific, Hawaii Alb Boggs, 2001

Dyed bait 68% for squid

S Pacific, Australia n/a Cocking et

al., 2008

Dyed bait P 60 63

max 15 US$ per set. rel. inexp.

N Pacific, Hawaii Alb Gilman et al.,

2003

Dyed bait P 77 95 N Pacific, Hawaii McNamara et

al., 1999 Strategic offal dumping

D 98 great reduction

S Atlantic, Kerguelen

WC Petrel

Cherel et al., 1996

Strategic offal dumping

D 54 Indian Ocean

WC Petrel

Weimerskirch et al., 2000

Night setting P 93 98 N Pacific,

Hawaii Alb Boggs, 2003

Night setting DP 60/96 very

high widely none n/a Brothers et

al., 1999

Night setting 97 N Pacific,

Hawaii n/a McNamara et al., 1999

38

Mea

sure

Pela

gic

(P),

Dem

ersa

l (D

)

Red

uctio

n (in

bir

ds

per

1000

ho

oks)

be

fore

and

aft

er

Red

uctio

n in

ba

it lo

ss (%

)

Red

uctio

n bi

rd

mor

talit

y (%

)

redu

ctio

n de

scri

ptio

n

Cos

t des

crip

tion

Loc

atio

n

Seab

ird

spec

ies

Ref

eren

ces

Night setting D 41/85 Indian

Ocean WC Petrel

Cherel et al., 1996

Night setting D 100 S Atlantic,

S. Georgia Alb, G petrels

Ashford et al., 1995

Night setting D 100 S Atlantic,

Falklands BB Alb

Reid & Sullivan, 2004

Night setting D 81-99 Indian

Ocean

WC petrel, Alb

Weimerskirch et al., 2000

Night setting + Blue bait

P 99 100 N Pacific, Hawaii Alb Boggs, 2003

Reduce offal D mod. Initially n/a Brothers et

al., 1999

Side setting + curtain P

? To 0.01-0.002

most effective

1,000 US$ / 50US$ (bird curtain), cheap

N Pacific, Hawaii Alb Gilman et al.,

2007

Side setting D negligible Sullivan,

2004

Smell distraction

Sign. decrease

S Pacific, New Zealand

Pierre & Norden, 2006

Sp./temp. closures D unknown n/a Brothers et

al., 1999

Strategic discard P 53 86 no extra

costs N Pacific, Hawaii n/a McNamara et

al., 1999

Tube + scaring line D 0.022

3 times lower

S Ocean, Pr. Edw. Isl.

WC Petrel

Ryan & Watkins, 2002

Underwater setting tube D 0.03/0.04

to 0.01 40,000 B£ (in 1997)

NE Atlantic, Norway

N fulmar

Dunn & Steel, 2001

Underwater setting tube P 0.06 to 0 95 100

recouped after 2 trips, 4,000 US$

N Pacific, Hawaii L Alb Gilman et al.,

2003

Underwater setting tube D Rel. exp.,

5,000 US$ N Pacific, Hawaii Alb Gilman et al.,

2007

Underwater setting tube D 1.75 to

0.49 72-92 NE Atlantic, Norway

N fulmar

Løkkeborg, 1998

Underwater setting tube D 37/76

Significant decrease

N Pacific, Alaska

N fulmar

Melvin et al., 2001

39

Mea

sure

Pela

gic

(P),

Dem

ersa

l (D

)

Red

uctio

n (in

bir

ds

per

1000

ho

oks)

be

fore

and

aft

er

Red

uctio

n in

ba

it lo

ss (%

)

Red

uctio

n bi

rd

mor

talit

y (%

)

redu

ctio

n de

scri

ptio

n

Cos

t des

crip

tion

Loc

atio

n

Seab

ird

spec

ies

Ref

eren

ces

Underwater setting tube D

considerable, 20,000 US$

n/a BirdLife International, 2014

Weighted lines P 92 N Pacific,

Hawaii Alb Boggs, 2001

Weighted lines D 0.4 to

0.05 93-98 14-23% more exp. Than UW

S Pacific, New Zealand

petrels, shearw.

Robertson et al., 2006

Weighted lines D

91-100 N Pacific, Bering Sea

fulmar, gulls, shearw.

Dietrich et al., 2008

Weighted lines D 80 S Atlantic,

S Georgia

BB Alb, WC Petrel

Agnew et al., 2000

Weighted lines D 61/94-

99 S Pacific, New Zealand

WC Petrel, Sooty Shw.

Robertson et al., 2006

Weighted lines P

18 times lower

S Africa petrels, Alb

Melvin et al., 2013

It is about to find the best trade-off between the costs that the fishermen have to pay for

a specific mitigation strategy and the economic gain they can reach on a longer term

with reducing the bait loss (is this case expressed as the reduction in seabird bycatch).

The trade-off between costs and efficiency is summarized in Figure 16 showing that

most mitigation measures do have a high efficiency between 75 and 100%, except for

the line shooter that showed a low efficiency of reducing bycatch. More differences can

be observed in the costs of mitigation measures where offal regulations and Bird

Scaring Lines seem to be the cheapest variations to reduce bycatch while closures

(either temporal or spatial), the laser and tubes are placed in the higher cost categories.

As the information on costs of mitigation measures in literature is scarce the lacking

data has been estimated to provide an overview of expected costs. There is no

estimation in the literature of how much spatial and temporal closures might cost.

Therefore the costs are assumed to be high (5) as fishing areas might become closed

40

and the fishing effort has to increase to keep up with the same amount of catch.

Consequently fishing might be more time-consuming and more fuel might be

necessary. Night setting might have an serious impact on the lifestyle of Faroese

fisherman as normal fishing trips occur over day and therefore has been nominated as

being relatively high (4) in costs. Underwater tubes have been described as “relatively

expensive” (Gilman et al., 2007) or “considerable” (BirdLife International, 2014) in

costs as they urge construction adaptions on the hull of the ship. Weighted lines have

been categorized as moderate costly (3), as the single source of information states an

additional cost of 14-23% (Robertson et al., 2006). Dyed bait has been described as

relatively inexpensive by Gilman et al. (2003). Bird Scaring Lines are “cheap”

(BirdLife International, 2014) or „low ongoing“ in costs (Brothers et al., 1999), while

offal management is expected as being almost cost-free.

Figure 16: Comparison of the economic costs of mitigation measures and their efficiency in reducing bait loss and seabird bycatch

BSL

weights

closures

tubes night

offal

dyed

shooter

side

0

1

2

3

4

5

0 10 20 30 40 50 60 70 80 90 100

Cost

s (1=

low

, 5=h

igh)

Seabird bycatch reduction (%)

41

5 Discussion

In the framework of this master thesis, the suitability of stomach contents to identify

bait loss in longline fisheries was evaluated. The potential economic loss to fishermen

due to bait stealing by seabirds was simulated using various scenarios. In addition

possible mitigation measures to increase fishing efficiency and decrease seabird

mortality on the Faroe Islands were discussed.

Catch rates 5.1

Many factors influence bait loss and the suitability of different methods to avoid

seabird-fisheries interaction. Much more information is necessary to estimate a realistic

numbers of seabirds that scavenge on longline bait and the rate at which they remove

baits from hooks. In this research we calculated minimum numbers of stolen bait, but

for a realistic number, experienced fisheries observers are unavoidable, to collect data

on:

a. the number of birds around the ship during setting and hauling

b. turn-over rate (or fluctuation) of birds throughout a trip

c. the species distribution of the birds

d. the rate of stolen baits (including attempt and success rates)

e. the rate of entangled (and killed) birds

Almost all studies consulted for this thesis base their information on observers that are

on board of the vessels. Although model scenarios can be calculated, predictions would

certainly benefit from field observations.

We were also interested in the bait types and possible implications regarding a

preference for a specific bait type, however, again a lack of detailed information made

this attempt not more than a general description of what we found in our specific birds.

The mixed type of bait in single birds shows that all three bait types must have been

used during a single fishing trip. As there is no data available how the availability of

bait during the specific fishing trips was, we cannot conclude whether the northern

fulmars show selectivity in baits or the general abundance of different bait types. Again

42

fishery observers on board of the vessels could help to get a better insight in the type of

baits used on the Faroe Islands and which one are preferred by the seabirds.

During the breeding month the numbers of baits per stomach were much higher than

outside the breeding season, even though sample sizes were low in June and August.

The seasonal trend shows a pattern that also has been observed by Dunn & Steel (2001)

and can be explained by a more urgent and higher need for food during chick-rearing

times (Furness, 1987).

The annual differences however are much more difficult to analyse. The average

amount of baits in stomachs increases slightly throughout the time from one to two

pieces between 2004 and 2011, in 2012 however the number rises sharply to an average

of more than four pieces of bait per stomach. In the literature there is no data on trends

between years and many factors might influence these findings. Unfortunately 2012 is

the last year of collection so this could be either an establishing trend or an outlier.

However when looking at the dataset it appears that the 2012 data were collected in

only one trip that took place in January, so an outlier seems to be likely. Cold weather,

storms or other environmental impacts might have caused a more desperate search for

easily available food by seabirds (Camphuysen et al., 1999; Schreiber et al., 2001).

With the exception of one study, no data is available from literature regarding the

amount of baits in stomachs. Gandini & Frere (2012) found in average four pieces of

bait in black-browed albatrosses (Thalassarche melanophris) and white-chinned

petrels, so higher than in our birds (average 2.1) however their range was much smaller

(0-6) while in our birds the range was 0 to 11. Seabirds may not only steal bait during

setting of the lines, but may also ingest baits removed from lines at hauling in, and

possibly discarded together with other offal. This could lead to overestimation of the

amount of stolen baits at setting of the lines. To estimate the extent of this effect,

observational or experimental approaches on board vessels would be necessary.

However other factors may indicate an underestimation of the bait loss. It is unclear,

whether young and unexperienced birds have a lower average of baits in their stomachs

before they get entangled accidentally. Successful older birds may steal more bait

without being caught as often as young ones. It has been described that mainly young

non-breeding birds attend fishing vessels in the North Sea (Camphuysen et al., 1995).

43

Studies have shown that seabirds and especially northern fulmars rely on the fisheries,

as discards can be a major part of their summer diet (Phillips et al., 1999; Camphuysen

& Garthe, 2000). Another underestimation of bait loss which we cannot properly

account for, is that the model assumption of a ‘fixed’ group of birds around the vessel

is in fact not very realistic. We had to assume this for our ‘per trip’ modelling but in

fact it is more realistic to expect that birds come and go all the time. Thus substantially

more birds have stolen an average of 2.1 pieces of bait than the number of birds seen to

surround a vessel at a given moment.

There is concern regarding the contradictory estimates of population size and status of

northern fulmars in the North Atlantic. As mentioned in the introduction, published

qualifications for the status of fulmars range from “Least Concern” up to

“Endangered”. This might have to do with the lack of recent data of most northern

fulmar breeding populations and trends. As the population trends of northern fulmars

are under discussion at the moment, the high number of birds killed in longline

fisheries should be of concern to conservationists and policy-makers. As northern

fulmars are slow in reproduction and long-lived, Buckland (1982) indicates that 96%

adult survival is crucial to maintain the population stable. Therefore the estimation of

the MSC (2012) of 5% of northern fulmars being caught in saithe longline fishery on

the Faroe islands should be of serious concern. Changes in food availability, climate or

habitat shifts caused by policy changes (e.g. discard bans) will all have impacts on

seabird populations (Grosbois & Thompson, 2005). Therefore different effects can

influence the population size and then, bycatch can put accumulative pressure on

northern fulmars and other seabirds.

Economic loss calculations 5.2

As mentioned above, a lot of data is lacking to properly calculate the economic loss,

caused by seabirds. This might be in so far realistic, as there are many different factors

influencing the circumstances on board. Therefore a broad range of scenarios has been

provided with the least realistic minimum and maximum start and ending points, where

1,000 birds follow a vessel and the fishermen can catch a fish on literately every hook

deployed or the opposite only 70 birds that follow a vessel and a bad efficiency of the

44

hooked baits where only every tenth baited hook catches a fish. The real numbers will

be somewhere in this broad range of the loss calculated and are heavily dependent of

external circumstances as weather, season, fish availability, use of gear, habitat where

the lines are deployed, etc. The only other study that used stomach content analysis as a

tool to estimate bait loss (Gandini & Frere, 2012), used fisheries observer data in

addition to calculate the economic loss. However with the consideration of all

circumstances, this thesis might provide a useful tool for Faroese fishermen to calculate

their personal economic loss as they have a much deeper insight to the two variables

fishing efficiency and seabird abundance on a daily level.

Mitigation measures 5.3

From literature research it can be shown that there are several ideas and methods to

reduce bait loss and bycatch at the same time, some of them are still in their developing

phase, many have been tested under different circumstances and others have been

successfully implemented and enforced by policy makers.

Bird Scaring Lines have reduced the bycatch of seabirds reliably over various studies,

areas and species, especially in northern fulmars (Melvin et al., 2001; Løkkeborg,

2003). Problems with tangling of the scaring lines and the main fishing lines can be

avoided by increasing the distance of the Bird Scaring Lines and fishing lines by

increasing the height on where the Bird Scaring Line is fixed (Brothers et al., 1999).

Being relatively cheap in purchase and maintenance, they do not have any negative

influences on the target species. In Norway, fishermen used old fishing gloves to hang

on lines above the baited longlines. Their movement in the air and on the water surface

resembles the traditional tori lines and seem to have a deterrent effect on northern

fulmars that constantly stayed behind the gloves. The costs of this method are

negligible and might be a cheap and convenient alternative to other bird scaring lines

(M. Langset, personal information).

The measures proposed range in the low cost level and therefore promise an economic

gain especially on a longer term. Bird Scaring lines have been described as “cheap” by

45

BirdLife International (2014) or as initial cost of 1,500 Australian Dollars (ca. 7,600

DKK; Brothers et al., 1999) but low in ongoing costs. Even cheaper is the version of

scaring lines proposed by Norwegian fishermen, the “gloveline”. Thus using the costs

of 7,600 DKK that has been paid in Australia, even with a lowest bait loss rate

calculated here (616 DKK per trip) might pay off almost immediately after only 12

trips and much faster when seabird abundance or fishing efficiency increases.

Strategic offal discard does not create any costs (e.g. McNamara et al., 1999) and

therefore should be considered as a very cheap measure that can be implemented

immediately. The strategic discard of offal could be considered for the Faroe Islands as

it is a cheap and convenient method to reduce seabird bycatch. Different options of

either completely retain offal on board or to distract seabirds during the deployment by

discarding offal on the opposite side of the fishing operation on board are some of the

options. The first option could create problems regarding storage space and additional

weight of the boats. Distraction at the same time as deployment has been discussed

controversially, as it might attract more seabirds in general. However, it might be an

option to restrict offal dumping to times when there is no setting or hauling, not

compromising operations on board. Hooks however should be removed in any of the

options.

Weighted lines have shown good results in areas with low abundance of deep-diving

seabirds and are especially suitable for demersal longline fisheries as weight plays a

minor role in deploying the lines. Robertson et al. (2006) estimate the costs of weighted

longlines at being 14-23% higher than conventional lines, but they expect lower costs

when the demand and therefore industrial production increases. Løkkeborg (2011)

calculated that increased sinking rates not only reduce bait loss, but the time of the lines

they need to reach the bottom is much shorter than in conventional unweighted lines.

As the smell of the bait attracts most fishes during the first two hours, the short sinking

time increases the attraction of the bait to fishes and therefore the fishing rates have

been observed to be increasing.

Dyed bait showed a variable outcome in reducing bait loss to seabirds. The method

seems to be less efficient compared to other mitigation measures (Gilman et al., 2007)

and reduction in target species catch has been observed (Minami & Kiyota, 2004). This

46

method has been tested for pelagic fisheries but not in demersal, due to the higher

number of hooks used (Bull, 2007) and might therefore not be a suitable mitigation

measure for the Faroese longline fisheries.

The laser deterrent is a new method, therefore more independent trials are necessary to

test it under various circumstances. Producers claim that the system operates on its

optimum in darkness, twilight, fog and rain as the laser becomes more visible to the

birds. This could be suitable for Faroe weather circumstances, especially during the

long-lasting winters. In clear daylight weather the producers suggest spraying seawater

in the laser line to increase its visibility. However it needs to be researched whether

habituation of birds can take place after a period of time and how harmful the effects of

the lasers are to the eyes of seabirds.

Underwater setting tubes could be a good protection against bait stealing birds, even

though the literature shows varying results in efficiency. A lower efficiency was caused

by diving seabirds and these birds are not commonly known as bait scavengers around

the Faroe Islands. However the initial construction prices for the tubes are high and

procedures can get slower, decreasing the fishing efficiency.

The relative high initial costs are also apparent in side setting, laser deterrents and

weighted lines. Side setting would need some construction work and the crew members

would have to adapt to the new situation, however, Gilman et al. (2003) observed an

increased catch of the target species and after habituation by the crew, side setting did

not create any ongoing costs or discomfort for the crew.

While the line shooter seems not to be realistic because of its low efficiency, other

measures are also high in costs. For example substantial or additional temporal and

spatial closures have been recorded as being very efficient in reducing bait steal,

however, it might diminish the economic gain as attractive fishing grounds and seasons

might become restricted (Løkkeborg, 2003; Brothers et al., 1999) and the incentive to

comply with such regulations might be low (Boyce, 1996). However, as bycatch rates

are higher in breeding areas during the breeding season, this mitigation measure should

be considered, especially because northern fulmars are particularly vulnerable during

the breeding season. Mate-fidelity is strongly developed in northern fulmars. Both

partners share incubation and chick rearing (Mallory, 2006) and operate on the limit of

47

their capacities (Furness, 1987). When one of the partners is removed during the

breeding season the other partner is forced to temporarily leave the nest unattended in

order to find food or to abandon the nest to ensure its own survival, which in both cases

increases the chance of breeding failure (Chaurand and Weimerskirch, 1994). The

surviving partner may attempt to rear the chick solely which consequently has a

negative impact on its own condition. Also the chick can be in a less favourable

condition when fledging. Therefore the mortality of one mature northern fulmar can

impact the outcome of at least two other individuals during breeding season.

Night setting as a special type of temporal restrictions seems to be very efficient in the

Southern Ocean toothfish fisheries, however, on the Faroe, northern fulmars are the

major species attending longline vessels and these birds are known to also forage at

night (Furness & Todd, 1984). Most Faroese longline vessels are small and often only

go out for day trips, a change in the routine would impact the life and safety of

fishermen tremendously. Furthermore, in high latitudes this measure would affect

fishermen a lot during summer and again decrease fishing efficiency (Løkkeborg, 2011;

Bull, 2007).

48

49

6 Conclusions

This research was done in order to answer three questions. The first question was about

possible pitfalls of using the approach of stomach content analysis of bycaught seabirds

to estimate bait loss rates and whether this approach can be improved. The results and

the discussion show, that stomach content analysis can be a good addition to fishery

observer’s data, as the by-catch rate does not equal the number of bait that is lost to

seabirds. Therefore to calculate the economic loss, this data is crucial to collect, as

earlier research by Gandini and Frere (2012) also has emphasised.

The second research question addressed the economic loss that a fisherman on the

Faroe Islands might experience due to bait loss to seabirds. The data collected for this

research was not enough to calculate damage in detail, but did provide a simple model

to estimate the potential losses against which fishermen can balance costs of mitigating

measures.

The third research question focused on the suitability of mitigation measures to reduce

seabird bycatch and bait stealing and the economic loss. In this thesis a broad range of

possible scenarios shows the variability of economic impact the northern fulmars can

have on longline fisheries as costs can increase a lot (616 up to 88,000 DKK). However

this study also shows that there is a range of mitigation measures that are efficient and

affordable. Therefore the implementation of one or more of these measures can result in

a higher fishing efficiency with the higher economic benefit to the fisherman and at the

same time seabird populations could benefit as well.

This study highlights the lack of, and great need for on-board observations and at sea

trials of mitigating methods. Nevertheless, with the data provided a tool was

established that can easily be used by fishermen to calculate their own financial risk.

Even though exact numbers for costs of mitigation measures could not be revealed for

many of the mitigation measures presented, this thesis showed options that are low in

costs and are still capable in reducing bait loss and seabird mortality.

The Bird Scaring Lines seem to be the most convenient primary mitigation measure

that could be supported by other, secondary measures as strategic discard and weighted

50

lines. If these measures do not lead to the expected increase in fishing efficiency other

option should be considered as temporal and spatial closures. Those should be

implemented carefully to maximise seabird (and bait) protection but not compromise

the fishing options too much. In this case especially the breeding season and the space

around colonies should be considered for closures as research (including this one) has

shown higher numbers of bait stealing by seabirds during the breeding season. To

evaluate the success rates, again fisheries observers are an essential way to gather data

on:

a. the fishing efficiency with or without mitigation measures

b. factors contributing to different bycatch rates (weather, daytime,

seasons, etc.)

Together with such data, scientific-based improvements could be realized and tested. It

is important to bear in mind that implementation and compliance are easier, when

scientists, industry and government collaborate (Cox et al., 2007). A good stakeholder

involvement and the guidance throughout the process are crucial to make sure that

fishermen and nature both can benefit from mitigation measures to avoid bait loss. In

the Southern Ocean, the Commission for the Conservation of Antarctic Marine Living

Resources (CCAMLR) has been successful in implementing several mitigation

measures to reduce seabird bycatch. This shows that international cooperation, even on

a very large scale can improve the situation and should be motivating Faroese policy

makers to stimulate fishermen to use mitigation measures. Funding selected options of

mitigation with associated research on economic and ecological efficiency could prove

rewarding for the future Faroese fishing fleet.

51

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