Maria Vigo Fernandez

Academic year: 2018 -2019

MASTER OF OCEANOGRAPHY AND MARINE

ENVIRONMENTAL MANAGEMENT

SUPERVISORS: Joan Josep Navarro Bernabé, Joan Baptista Company Claret, Marta Carretón Salvador

DEPARTMENT: Renewable Marine Resources

INSTITUTION: Institute of Marine Sciences (ICM – CSIC)

UB SUPERVISOR: Creu Palacín Cabañas

Evaluation of the initial status of an overexploited

area before its fishing closure: the case of the

iconic fishery of the Norway lobster (Nephrops

norvegicus; Linnaeus, 1758) in the northwestern

Mediterranean Sea

Contents

Abstract …………………………………………………………………...…… 3

Introduction .....…………………………………………………………...……. 4

Aim of the study ………………………………………………………… 7

Materials and Methods ...………………………………………………………. 7

Study Area .……………………………………………………………...... 7

Sampling Design .….……………………………………………………... 9

Biological Sampling …...…………………………………………………. 9

Data Treatment ………………………………………………………….. 10

Statistical Analyses ……………………………………………………… 11

Results…………………………………………….…………………………... 12

Composition of the commercial species …………………………....…… 12

Biomass and diversity metrics ……………………………………….…. 14

Biological parameters of the target species, the Norway Lobster …….….17

Discussion ……………………………………………………………….……. 20

Description of the demersal community ..…………………….………… 20

Characteristics and biological parameters of N. norvegicus ……………. 21

Conclusions …………………………………………………………………... 23

Acknowledgements …………………………………………………………. . 24

References ……………………………………………………………………. 25

Supplementary Information………………………………………………....... 29

3

Abstract

An overexploited area located in the northwestern Mediterranean Sea has been established as a

no-take marine area (reserve) to recover one of the most important fishing resources in the

Mediterranean Sea, the Norway lobster (Nephrops norvegicus). Prior to its closure, in October

2017 within the framework of the project RESNEP from the Institute of Marine Sciences (ICM-

CSIC), two experimental trawl surveys were performed in the reserve and in an adjacent fished

area (control area) to analyse and compare the initial fish stock conditions. The biomass and

diversity of demersal communities did not show significant differences between the reserve and

the control area. The population of N. norvegicus differed significantly in terms of its abundance

and biomass between areas and surveys, although biological parameters of this overexploited

crustacean such as the distribution of sizes and sex-ratio did not differ between the reserve and

the control. The results of this study have provided us with the information of the initial

conditions of the reserve and enabled us to perform, in the future, a BACI (Before After Control

Impact) study design to assess the impact of the marine reserve establishment in this

overexploited area over time.

4

Introduction

Oceans provide important ecosystem services to human well-being as provisioning, cultural

and environmental education (Pikitch et al., 2012). Even so, marine resources are the main

benefit that humans obtain from this environment. The ocean provides 15% of the animal

protein consumed worldwide, which will tend to increase in the future at the expense of

overexploited populations (FAO, 2018; Jackson et al., 2007). For this reason, it is essential to

develop a sustainable exploitation of marine resources in order to ensure their future

availability.

In the last decades, there has been major concern about global overfishing which has a great

impact on target species and has altered marine ecosystems worldwide (FAO, 2018; see Figure

1). Most coastal ecosystems have suffered great loss of abundance and biomass of large animals

which are nowadays nearly extinct (Jackson et al., 2007). Moreover, over the last 50 years,

global landings have shifted from shallow to deeper water target species making deep water

species more vulnerable as they have less resilience to overfishing (Morato et al., 2006).

Figure 1. Global trend in the State of the World’s Marine Fish Stocks between 1974-

2015 from FAO (FAO 2018). In blue there are stocks biologically sustainable, and in

orange the area stocks biologically unsustainable.

The fishing activity of the Mediterranean Sea represents almost half of the total fishing of the

European Union (EEA, 2015). Fishing gears with great impact on the sea floor are now the

main cause of ecosystem modification in the Mediterranean Sea, regardless of the effects of

climate change or the pollution on the marine ecosystems (Danovaro et al., 2017; Puig et al.,

2012). One of the main fishing gears used in this area is bottom trawling, which has been proven

OVERFISHED

MAXIMALLY SUSTAINABLY

FISHED

UNDERFISHED

100

80

60

40

20

0

1975 1980

1975

1985

1975

1990

1975

1995

1975

2000

1975

2005

V

1975

2010

1975

2015

1975

5

to have negative effects for marine environment (Collie et al., 2000; Gianni, 2004), including

stock impoverishment, alterations of the sea-bottom morphology, sediment resuspension and

alteration of benthic biodiversity (Thrush & Dayton, 2002). Despite this fact, part of the

European fleet is focused on bottom trawl fishing and its use in deeper ecosystems which were

previously unreachable (Clarken et al., 2015). This situation has endangered some fishing

stocks in the Mediterranean (Smith et al., 2000; see Figure 2) and the profits of some iconic

species in the Mediterranean have been depleted (Farriols et al., 2017; Piroddi et al., 2015).

Figure 2. Percentages of stocks fished at biologically sustainable and unsustainable

levels from FAO Statistical Area (FAO 2018). The red arrow indicates the percentages

of the Mediterranean and the Black Sea.

A clear example of an overexploited iconic fishery in the Mediterranean is the case of Norway

lobster (Nephrops norvegicus Linnaeus, 1758) (Gibin et al., 2017; see Figure 3). This crustacean

has a high commercial value and is one of the main targets in the European fisheries (FAO,

2018; Sala & Giakoumi, 2018). The abundance of this species fishing stocks has been always

relatively high on muddy bottoms on the slope at depths between 400 and 600 m, being one of

the study priorities of the International Council for the Exploration of the Sea (Sardà, 1998).

However, during the last decade, the total catch in biomass of N. norvegicus has decreased, as

well as its economic profitability. This fact can be associated to the negative effects of the

bottom trawling.

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Mediterranean and Black Sea

Pacific, Southeast

Atlantic, Southwest

Tunas

Atlantic, Eastern Central

Atlantic, Western Central

Indian Ocean, Western

Atlantic, Southeast

Indian Ocean, Eastern

Atlantic, Norheast

Atlantic, Northwest

Pacific, Southwest

Pacific, Western Central

Pacific, Northwest

Pacific, Northeast

Pacific, Eastern Central

Unsustainable Sustainable

6

Figure 3. Evolution of the biomass fished in tons and total profits of N. norvegicus in

Catalonia (NW Mediterranean Sea) between 2000 and 2017 (A). Evolution of the

average biomass (kg) of N. norvegicus fished in Catalonia by year as a function of

the catch depth (B). Data obtained from the information in the Vessel Monitoring

System (VMS) and daily landings by vessel of Catalan harbours from the Government

of Catalonia between the years 2006 and 2016 (Fisheries Database of the Institute of

Marine Sciences, ICM-CSIC).

In this context of overexploitation, it is necessary to apply management actions focused on

the recovery and the sustainable exploitation of N. norvegicus population stocks. Marine no-

take zones where no fishing activity is allowed or where there are specific fishing regulations

have proved to be very effective in the restoration and preservation of marine ecosystems

(Kelleher et al., 2013). One of the main effects of no-take zones is the increase of the biomass

and abundance of the target species (Lester et al., 2009; Navarro et al., 2014; Sala &

Giakoumi, 2018). The benefits of the marine no-take zones have not only been observed

within protected areas, but also in adjacent habitats, where the no-take zone acts as a source

of adults and juveniles (named "spillover effect”) (Halpern et al., 2009). For crustaceans of

commercial interest, the use of marine reserves has been shown to benefit two lobster stocks

(Homarus gammarus and Palinirus elephas) in coastal areas (Goñi et al., 2010; Moland et

al., 2012). However, there is no evidence of the use of no-take zones to manage deep-sea,

such as the N. norvegicus, which in the Mediterranean Sea is mainly distributed at depths

between 300 and 450 metres (see Figure 4). N. norvegicus is a highly territorial and non-

migratory species, which makes it an ideal species to be managed through the use of no-take

marine areas (Smith & Jensen, 2008).

7

This study is an important part of one of the main aims of RESNEP project currently in

progress. RESNEP is a project financed within the Plan Nacional Retos del Gobierno de

España (REF: CTM2017-82991-C2-1-R, Marine Reserves of Fishing Interest as a

management tool to recover iconic Mediterranean fisheries). This project has already

achieved to establish a pilot no-take marine area at 400 m depth, in one of the areas of

maximum historical catch of this species in the northwestern Mediterranean Sea (Figure 4),

with a full closure to any type of fishing activity since October 2017. The agreement was

established between the fishermen's organisations of Roses and Palamós, two important

fleets working in Catalonia region (Figure 4).

Aim of the study

The aim of this study was to describe the baseline status of N. norvegicus stocks and the

entire demersal community before the implementation of the no-take area (from now on

called “reserve”) and of an equivalent area without any fishery regulation (named “control

area”). This information will be pivotal to evaluate the potential effect (positive or negative)

of this no-take area by comparing the baseline status of the reserve and the control area in

the near future (in 2020, 3 years after the implementation of the reserve) by applying a BACI

(Before After Control Impact) study design. Our hypothesis is that the implementation of the

no-take marine reserve as a management measure will help recover the overexploited

demersal community and the populations of N. norvegicus, while in the control areas, the

situation will be similar or worse in relation to the initial values or in comparison with the

no-take area.

Specifically, for the demersal community, our aim was to describe the richness, biomass,

abundance and biodiversity present in both areas. In relation to the population of N. norvegicus,

we aimed to describe biomass, abundance and the main biological parameters (sex ratio, size

frequency, stage of maturity) for reserve and control area.

Materials and Methods

Study Area

The study was conducted in the north of the Catalan coast (northwestern Mediterranean Sea)

during late summer and early fall (23th to 25th of August and on the 27th - 29th of September

2017) along N. norvegicus fishing grounds (Figure 4). The individuals of this species are caught

around 400 m depth in the upper slope with muddy bottoms of the continental shelf margin,

which is crossed by several submarine canyons. The study is located between Palamós Canyon

8

(also known as Fonera Canyon) and Cap de Creus Canyon. These submarine canyons are major

geomorphological structures of the northwestern Mediterranean Sea, together with Blanes

submarine canyon. The total length between these two submarine canyons is about 40 km and

the maximum depth is 1400 m for Cap de Creus canyon and 2200 m for Palamós. The influence

of these canyons affects the whole water column, being equally important for both demersal

and pelagic species (Fernández-Arcaya et al., 2017).

Figure 4. Spatial distribution of N. norvegicus catches along the Catalan coast (A),

and the location of the no-take marine area (green square) and the control area

(yellow square) where the experimental trawling has been performed (B). Fishing

hauls performed in both areas are indicated in black lines. The fishing effort was

obtained by combining Vessel Monitoring System (VMS) information and N.

norvegicus catches of each vessel.

Two areas were sampled in this zone (Figure 4; see latitude and longitude coordinates in Table

2 of the Supplementary Appendix), the first, the reserve area, is a fishing ground of 15 km2

where fishing activity was stopped in October 2017 and a second, the control area, with similar

dimensions of the reserve but where fishery activity was not stopped (control area). Both areas

were sampled before the establishment of the marine reserve.

A B

9

Sampling Design

Two surveys were performed both in reserve and control areas. The first survey was done during

late summer (23th to 25th of August) in the vessel Solraig from Palamos harbour and the second

survey was performed during early fall (27th - 29th of September) with Mèdan vessel from Roses

harbour. Both vessels fished with their own commercial otter-board trawl gear of a square mesh

size of 40 mm covered with an experimental net with a diamond mesh size of 12 mm (from

now on, cover net). The head line height of the trawl was around 1.3 m and the horizontal trawl

opening was around 22 m in Solraig and 28 m in Mèdan. The total wire of both fishing trawls

was between 850 and 950 m.

In all cases, the hauls were conducted during diurnal hours, coinciding with the activity period

of N. norvegicus (Aguzzi et al., 2015). In total, after performing the two surveys, 9 hauls were

conducted in the no-take marine reserve and 9 hauls in the control area. Towing speed was

maintained constant with some differences between the two vessels (speed = 2.4-2.5 kn in

Solraig and speed =3.4-3.6 kn in Mèdan). The duration of each haul ranged between 1h 44’ and

1h 31’in both sites.

Biological Sampling

The total catch was classified into four basic fishing categories: target species (N. norvegicus),

bycatch (other commercial species sold in the market), discard (species with no commercial

interest) and species present in the cover net. On board, all N. norvegicus individuals were

measured, weighted, and their sex and stage of maturation (1=immature; 2 = resting or

recovering; 3=maturing; 4=mature; and 5=spent or hatching; Company & Sardà, 1997; ICES,

2009; Rotllant et al., 2005; see Figure 5) was determined on board. All the individuals present

in the bycatch category were identified at species level, measured and weighted on board.

Discard and cover net content were frozen on board and identified at the Institute of Marine

Sciences (ICM - CSIC). In the laboratory, all specimens were identified at specific level as

possible and they were weighted (in g) and the standard body measures (in mm) were recorded

(Figure 6; mantel length ML in case of cephalopods, total length TL, standard length SL or anal

length AL in the case of fish species and carapace length CL in the case of crustaceans).

10

Figure 5. Stages of maturity of Nephrops norvegicus adapted from ICES (2009) and

Rotllant et al. (2005).

Data treatment

In all cases, the total number of individuals of each species and their biomass was estimated

taking into account the swept area, which is the area that the trawl net has towed, in km²

following this algorithm:

A = V x BT x H x 1852 / 106

Where V is the average speed of the trawls (in knots), BT is the towing time (in hours), H is the

horizontal opening of the net (in meters) and the constant 1852 is the equivalent of nautical

miles to do the conversion. The average biomass is calculated with these data.

The relative abundance of the four fishing categories (target species, bycatch species, discard

species and cover net) between areas was compared. In these analyses, the relative abundance

of “commercial species”, which englobes the target species and the bycatch, has also been

performed to observe and compare the proportion of targets species with other commercial

species. Biological data obtained for N. norvegicus has been analysed between the reserve and

the control area to study some biological parameters such as their size frequency, sex-ratio per

size class and proportion of maturity.

Stage 1 Stage 2 Stage 3 Stage 4 Stage 5

White Blue - Black Dark green -Blue Green Creme - Yellow

11

Statistical analyses

Abundance (total number of individuals per km²) and biomass (total weight in kg per km²) were

log-transformed (x+1) to normalize their distributions. Statistical analyses were performed in

R Software (R Core Team, 2013) with packages car (Fox & Weisberg, 2011), ggplot2

(Wickham, 2016), graphics and stats (R CoreTeam, 2013), HH (Heiberger, 2018) and vegan

(Oksanen et al., 2019).

To visualise a two-dimensional ordination of our biological data, four non-metrical

multidimensional scale representations were built: two representations carried out with

abundance data and the two others with biomass data of all species caught in the surveys. Before

the representation, distance matrices were built using Bray Cutis distances. The algorithm of

Kruskal I was used to build the diagrams, where a stable solution was obtained from random

starts, axis scaling and species scores. We looked for significant differences between the control

and reserve areas and between surveys for abundance and biomass obtained in each haul which

were represented in the diagram.

The abundance data (standardised) was used to estimate values of diversity metrics.

Specifically, Shannon diversity index (H) was used to characterise species diversity in the two

areas of study and surveys. Shannon diversity index values between control and reserve areas

were compared by using ANOVA tests. Previously, tests of normality and homogeneity of

variances were performed. ANOVA tests were also used to compare the biomass of the total

catch between areas and surveys.

Species richness was obtained from abundance data of the demersal community for both control

and reserve areas. To analyse the evenness of species in both areas the Index of Pielou was

calculated from Shannon index values.

In order to check for significant differences for N. norvegicus stocks between the two sites

(control and reserve) and between the different two vessels (Solraig vs. Mèdan), two analyses

were performed: for biomass and for abundance of N. norvegicus. A two-way ANOVA was used

as normality and homogeneity assumptions were met after a square-root transformation of

biomass and abundance data.

12

Bycatch29%

Discard17%

Cover Net45%

Target9%

Bycatch18%

Discard18%

Cover Net43%

Target21%

Helicolenus

dactylopterus

1%

Lepidorhombus

boscii

3%

Merluccius

merluccius

4%

Micromesistius

poutassou

41%

Nephrops

norvergicus

25%

Parapanaeus

longirostris

18%

Phycis blennoides

4%

Scyliorhinus

canicula

1%

Helicolenus dactylopterus

1%

Lepidorhombus boscii

4%

Merluccius

merluccius

3%

Micromesistius

poutassou

8%

Nephrops

norvergicus

53%

Parapanaeus

longirostris

18%

Phycis

blennoides

6%

Scyliorhinus

canicula

2%

Results

Composition of the commercial species

The percentages in terms of abundance of the different fishing groups present in the community

showed similar proportions in for both areas (Figure 6). In the case of N. norvegicus its

abundance was higher in the reserve compared to the bycatch, with a percentage of 29 % in the

control and 18% in the reserve. The other species have a similar relative abundance in catches,

with the exception of Micromesistius poutassou, which shows higher values in the control (41%

of the catch and only 8% in the reserve).

Figure 6. Percentages of catch in terms of abundance of species. Proportion of each

fishing category in the catches: target species, bycatch, cover net and discard (A and

B); Proportion of commercial species caught in the trawls (yellow: target; blue:

bycatch) (C and D); Control area (A and C); Marine Reserve (B and D).

B A

C D

13

Table 1. Individual size and abundances per species. Individual/km2: total number of individuals per species caught per swept area (km2); % is the proportion in

number of the total catches of commercial species (targets and bycatch); n: number of individuals caught; Min: minimum; Max: maximum; TL: Total Length; SL:

Standard Length, CL: Carapace Length: ML: Mantel Length. All measurements are in millimetres.

CPUE % n Min Mean Max Measure

Argentina sphyraena 185.44 0.19 32 115 14.,59 187 TL

Conger conger 80.30 0.08 16 362 527.69 830 TL

Gadiculus argenteus 4.62 0.00 1 93 93 93 SL

Helicolenus dactylopterus 1008.65 1.01 168 70 - 85 125.27 - 135.89 190 - 185 TL - SL

Lepidorhombus boscii 3349.35 3.35 635 42 - 85 134.48 - 128.04 266 - 215 TL - SL

Lophius budegassa 23.14 0.02 3 238 313 410 TL

Lophius piscatorius 58.81 0.06 8 145 424,5 920 TL

Merluccius merluccius 3551.66 3.55 667 140 - 220 283.07 - 298.79 440 - 435 TL - SL

Micromesistius poutassou 24465.98 24.45 4519 70 - 154 181.26 - 175.89 254 - 230 TL - SL

Molva dypterygia 113.44 0.11 22 218 - 227 240.6 - 243.67 375 - 275 TL - SL

Phycis blennoides 4224.24 4.22 832 110 -110 152.31 - 146 376 - 245 TL - SL

Symphurus nigrescens 4.87 0.00 1 115 115 115 TL

Trigla lyra 610.84 0.61 112 85 - 77 135.46 - 98.92 221 - 180 TL - SL

Trigla spp. 805.09 0.80 156 76 99.02 202 TL

Eledone cirrhosa 194.12 0.19 39 50 69 93 ML

Illex coindetii 48.18 0.05 9 79 115.27 155 ML

Rossia macrosoma 12.26 0.01 2 55 60 65 ML

Sepietta spp. 1094.93 1.09 70 15 23.7 35 ML

Todarodes sagittatus 55.50 0.06 9 85 149.33 225 ML

Todaropsis eblanae 21.14 0.02 4 115 120 125 ML

Goneplax rhomboides 4.74 0.00 1 13 13 13 CL

Liocarcinus depurator 93.93 0.09 15 16,8 23.13 29.4 CL

Macropipus tuberculatus 96.22 0.10 16 16,3 23.12 28.7 CL

Munida intermedia 48.78 0.05 6 16,6 17.34 17.9 CL

Munida iris 22.85 0.05 3 15,7 17.57 19.5 CL

Nephrops norvergicus 35373.88 35.36 6722 13,61 29.81 50.55 CL

Parapanaeus longirostris 16944.88 16.94 3136 23 31.17 43 CL

Raja spp. 3.73 0.00 1 375 375 375 TL

Scyliorhinus canicula 1157.19 1.16 216 219 415.76 515 TL

Size

Elasmobranchii

Abundance

Actinopterygii

Cephalopoda

Crustacea

Taxonomy Species

14

Biomass and diversity metrics

Non-metric multidimensional scaling (nMDS) was used to determine if there were two different

groups associated to each sampling area (Figure 7). Four matrix of distances have been obtained from

the biomass and the abundance of the demersal community. In the case of the abundance values, the

stress value is about 0.146 which indicates that has been well adjusted and there was no grouping

(nMDS, F1.18 = 1.17, P = 0.28). About the biological distance matrix of biomass values, there were

neither differences among the sampling areas with a stress value of 0.141 (nMDS, F1.18 =0.87,

P=0.48). The nMDS have been performed for the group area (control and reserve) and for surveys

(first and second surveys).

Figure 7. Diagrams for non-metric multidimensional scaling. Biomass obtained from control

(yellow) and reserve (green) (A); Abundances obtained from control (yellow) and reserve

(green) (B); Biomass obtained from first survey (pink) and second survey (blue) (C);

Abundances obtained from first sampling (pink) and second sampling (blue) (D).

A B

C D

B

15

Shannon index values did not differ between areas or surveys (ANOVA tests; Between areas, F1.18 =

0.09, P = 0.78; Between surveys, F1.18 = 1.06, P = 0.32; Figure 8-A). Biomass of the catches did not

differ between areas or surveys (ANOVA tests; Between areas, F1.18 = 0.01, P =0.97; Between surveys,

F1.18 = 0.07, P = 0.44); see Figure 8-B).

Figure 8. Boxplot of the biomass values (A) and the diversity (B) of the demersal community.

In the X axis there are the two surveys of the surveys. A: The biomass values are standardised

by swept area; B: Diversity is expressed in Shannon index values. Green boxes represent the

reserve area yellow boxes represent the control area.

The most diverse group in both areas was Actinopterygii (Shannon values = 2.56 and 2.13, reserve

and control area respectively; see Figure 9), followed by Crustacea (Shannon values = 1.78 and 1.98)

and Cephalopoda (Shannon values = 0.91 in both areas), Gastropoda (Shannon values = 1.78 and

0.38), Tunicata (Shannon values = 0.86 and 0.81). Control area had diversity values for Echinoderma

(Shannon value = 1.17), while reserve had diversity values for Elasmobranchii (Shannon value

=0.01).

The species richness, considering all fishing categories showed richness that ranged between 40-45

and Pielou index values between 0.70-0.75 (Figure 10). Both areas showed similar values in density

of species and in frequency of dominant species.

A A B

Survey Survey

16

Figure 9. Bar plots of the diversity of the demersal community. Control area (A); Reserve

area (B).

Figure 10. Bar charts about the species richness (A and B) and the Index of Pielou’s (C and

D). In A and B, the X axis represent the number of species and the Y axis the density. In bar

plot C and D, the X axis show the index of equitability and the Y axis the frequency.

A B

C D

0

0,5

1

1,5

2

2,5

3

Shan

no

n v

alu

es

B A

0

0,5

1

1,5

2

2,5

3

Shan

no

n v

alu

es

A

17

12

-13

13

-14

14

-15

15

-16

16

-17

17

-18

18

-19

19

-20

20

-21

21

-22

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-23

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-24

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-25

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-26

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-28

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-29

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-30

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-31

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-32

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-33

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-34

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-35

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-36

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-37

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-38

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-39

39

-40

0

500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

4.500

5.000

Carapace length (mm)

Ab

un

dan

ces

(N/k

m2 )

Reserve

Control

Biological parameters of N. norvegicus

Biomass of N. norvegicus was significantly higher in the reserve (ANOVA test, F1.18 = 5.59, P= 0.03).

There were not differences between surveys (ANOVA test, F1,18 = 4.11, P= 0.06). Regarding the

abundances of N. norvegicus, significant differences were found between areas (ANOVA test, F1,8=

7.44, P = 0.02) and surveys (ANOVA test, F1,8 = 9.48, P = 0.01) being higher in the reserve and in the

second survey (Figure 11).

Figure 11. Vioplots of biomass (A) and abundance (B) of the population of N.norvegicus.

Most of the individuals of N. norvegicus caught showed a size between 24-30 mm CL (Figure 12-A).

There were less individuals with larger than small sizes. Distribution of size frequency was similar in

both areas and surveys (Figure 12-B).

A B

A

survey survey

18

Figure 12. Abundance of N. norvegicus per size frequency (A); Size distribution of the

population of N.norvegicus indicating the mean with a black dot, and in green the sizes in

the reserve and in yellow indicates the control (B)

No significant differences in body size of N. norvegicus were found between the two areas (F1,18=

0.01, P = 0.91). Also, both areas showed a similar proportion of males and females in the

intermediate size classes (Figure 13). The control and the reserve showed similar sex ratio

proportions (60% of males and 40 % of females; Figure 14).

Figure 13. Sex-ratio per size class of N. norvegicus. Control (A); Reserve (B). The males are

shown in blue, the females in red

8 6 4 2 0 2 4 6 8

12-13

15-16

18-19

21-22

24-25

27-28

30-31

33-34

36-37

39-40

42-43

45-46

Proportion (%)

7 2 3

12-13

15-16

18-19

21-22

24-25

27-28

30-31

33-34

36-37

39-40

42-43

45-46

48-49

Proportion (%)

Size

cla

ss (

mm

)

B A

B

survey

19

111%

277%

33%

49%

50%

Figure 14. Sex-ratio of N. norvegicus. Both graphics show the proportion of females and

males. The males are shown in blue, the females in red.

The analysis of the maturity of the females showed more individuals in the stage 2 in both areas.

Immature (stage 1) individuals were not recorded in any area, and the number of reproductive

individuals or hatching eggs from stages 3-5 was very low (Figure 15).

Figure 15. Reproductive stages of N. norvegicus females in the control area(A) and the

reserve (B)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Control Reserve

13%

286%

35%

46%

50%A B

20

Discussion

In the present study, fishing stock conditions of two fishing areas located in an overexploited habitat

of the northwestern Mediterranean Sea have been described. The data available was obtained prior to

the establishment of one of the areas as a no-take marine area. The results of this study have provided

information on the initial conditions of the reserve before its closure, and they can serve as a baseline

to evaluate its effect over time on the iconic fishery, the Nephrops norvegicus.

Both marine areas showed similar abundance, biomass and diversity indexes, indicating that the initial

conditions of the demersal communities in the control and the reserve are similar. However, the results

related to the population of N. norvegicus, the target species, differed in abundance and biomass

between the two areas. In contrast, some biologic parameters of the species such as the size frequency,

sex ratio and percentages of maturity showed similar values in the two studied areas. Despite that

there are some differences between both marine areas, the fact of knowing their initial conditions

before the closure of the no-take marine reserve will allow us to perform future design studies (BACI)

about the correlation of changes of the environment and fisheries. All variables analysed (sex ratio,

size, abundance and biomass) are considered appropriate to compare the control area and the reserve

over time (Smith, 2014) .

Description of the demersal community

The relative abundance of the different fishing categories (target species, bycatch species, discard

species and cover net) was similar in both areas, with a higher proportion of individuals present in

the cover net category, followed by the bycatch, discard and, in the lowest proportion, the target

species (N. norvegicus). However, in the control area, the catch of N. norvegicus was lower than in

the control area. Regarding to the commercial fishing categories (bycatch and target species), the

percentages of N. norvegicus were clearly higher in the reserve than in the control area. Our results

are therefore around the average of the usual commercial catches of these crustaceans.

N. norvegicus fisheries in the Mediterranean Sea are multispecific (Santurtún et al., 2014). For this

reason, even though their activity is focused on this crustacean, this fishery regularly catches other

important commercial species such as blue whiting (Micromesistius poutassou), some cephalopods

(Rossia macrosoma and Sepietta spp.), other crustaceans (deep rose shrimp Parapanaeus

longirostris) and some elasmobranchs (Scyliorhinus canicula and Raja spp.) (see Table 1). Some of

these species have a minimum allowed size (ANNEX III and ANNEX IV European Council, 2006).

In our case, the mean size of commercial species was close to their minimum commercial sizes in

some species such as Merluccius merluccius which has a minimum size of 200 mm and the majority

of the catches were about this size (mean 283 mm). Even in the case of N. norvegicus, with a minimum

21

commercial size of 20 mm CL, some individuals fished were below this size. These results provide

evidences of how this area is overexploited not only for N. norvegicus, but also for other species of

the demersal community.

Both vessels had a square mesh of 40 mm which is considered more selective and is the minimum

mesh size allowed in Europe (Bahamon & Sard, 2006; The Council of the European Union, 2006).

Even if it is a very selective mesh, the discard consisted in one third of the catch including commercial

species smaller than the Minimum Conservation Reference Size (Official Journal of the European

Union, 2006)and species without commercial value. The average diversity value of 2.75 showed in

the present study is considered intermediate according to the available literature (Pla, 2006; Shannon

& Weaver, 1948). Even for the diversity analysed in each taxonomic category for both areas, similar

values of diversity with an average of species richness of 45 species were found. Pielou’s evenness

index (J’) is another measure of biodiversity which refers to how dominant in number the species are.

This index is comprised between 0 and 1, being 0 the lowest evenness value (Mulder et al., 2004).

Our resulting values of 0.75 mean that the dominance of particular species is high.

In the analyses, we considered two factors of the surveys which may influence the results: different

season of sampling and different vessel trawl. The fact that there were no differences demonstrates

that there is no variability over seasons nor over possible different fishing effort of the vessels because

of vessel size or equipment. Control and reserve showed no differences in the composition of the

stock fishery in terms of abundance and biomass, which make these variables suitable to compare

results in the future and to observe possible changes.

Characteristics and biological parameters of the population of N. norvegicus

The population of N. norvegicus was analysed concerning its abundance and biomass for both areas

and surveys. The results indicated an abundance of around 2,000 individuals/km2, with higher values

in the reserve. Differences in the abundance and biomass of N. norvegicus between areas may be

caused by its high variability in catch over time, as it is deeply affected by factors such as light

intensity, which modulates the diurnal emergence of individuals that inhabit the slopes and peaks at

noon (J. Aguzzi et al., 2013). Successive fisheries in the same area may also have affected catches

(Sardà, 1998; Thomas & Figueiredo, 1965). Despite these possible causes, the reason of higher

abundances in the reserve may be simply because in this area, due to natural reasons, N. norvegicus

is most frequent. Regarding surveys, the month of sampling may had an effect as in spring-summer

the light intensity is higher and this influence in the emergence of N. norvegicus (Aguzzi et al., 2004).

Another factor which could have leveraged more catch differences may have been the equipment or

size of trawl vessels. Different electronic technologies (positioning, detection, trawl controls) or

22

engine powers in Mèdan vessel may have made a difference in the catchability of N. norvegicus

(Sardà, 1998). In fact, the results showed a higher abundance of N. norvegicus in surveys performed

with Mèdan vessel in September. However, we cannot identify which factor had influenced these

differences in catches, we can only speculate on this matter, as velocity and towing time of both

vessels were similar, and there were no differences in catches of other species.

The average individual size found in the population of N. norvegicus was about 28 mm CL in both

areas with no differences in the individual size distribution between areas. The resulting mean size is

lower than the sizes measured in close areas 20 years ago (Sardà, 1998) where the average size was

about 31 mm CL. This result suggests a reduction of size over time, probably due to fisheries

overexploitation. Also according to Sardà (1998), the length maturity was about 30 mm CL, whereas

the individuals in our catches had sizes about 24-28 mm CL and most of them were maturing (stage

2) suggesting a reduction of size of first maturity as well.

The distribution of the sex-ratio was similar between control and reserve, with larger males than

females. Males were not only larger, but also more abundant with a percentage of 60% and females

being only 40%. Previous studies show that females tend to be more overexploited than males, which

may explain why there are fewer females in the population of this crustacean (Sardà, 1998b).

In the analyses of maturity in N. norvegicus, in both areas the stage 2 of maturity, where individuals

are resting or recovering, was the dominant stage. This result matches with the reproductive cycle of

N. norvegicus. Female reproductive cycle lasts for a year and in late August, when the sampling was

conducted, most of the females are in the early stage of maturation until February when they hatch

the eggs (Orsi Relini, Zamboni, Fiorentino, & Massi, 1998; Rotllant et al., 2005).

23

Conclusions

Both areas of study, the reserve and the control, showed similar biological conditions concerning the

community of fishes except for biomass and abundance of Nephrops norvegicus.

The biomass and abundance of N. norvegicus differed in both areas and surveys.

The biological parameters of the population of N. norvegicus (sex ratio, size frequency, stage of

maturity) are equal for both areas.

The relative abundance of species of demersal community in both areas was similar.

The biomass and abundance of the total catch were similar in both areas and surveys.

The diversity of the two areas of study and the diversity in their taxonomy categories were similar

in both areas.

We have obtained a good basis to perform a good BACI design to correlate possible changes

because of the absence of fisheries in the future.

24

Acknowledgements

I would like to thank my supervisors Joan, Batis and Marta for helping me so much with this master

thesis, and not only that, you have taught me so many other things. I'm lucky to be able to count on

you not only for this master but also for the next few years. Thank you very much. To Creu Palacín,

my inner supervisor in UB, thank you once again! I really appreciate all you support, since when I

was doing my bachelor’s final thesis until now with this master thesis. Thank you so much for

everything! To my friends in Barcelona, Chubbies, you have made everything easier and lighter for

me this year, even in the worst situation you made me laugh. I really think that if you weren’t there,

I wouldn’t present my thesis now. Thank you girls! There are so many more people which I am

thankful. In middle of a campaign, few weeks before the presentation of this thesis, so many of you

help me. Alba, Nixon, José Antonio, Guiomar, Ari, Anabel, Ricardo, Joan, Mireia and all the people

working at the R/V García Del Cid, it was a great experience and you made all the stress disappear. I

really had a great time, thank you! Claudio, you are the responsible for me being in the ICM in the

first place. In fact, thanks to you I could apply to this Master Course! I could never thank you enough

for everything you have done for me. This year I have known new people thanks to this master, really

nice people. I want to thank all you to made this year amazing. Marian, we have been living together

now for one year! Thank you to cheer me up all the time I need it and to make me feel really at home.

And finally, to my family, thank you to always support me!

25

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29

Supplementary Information

Table 2. Coordinates of each haul performed in the study areas (C = control area; R = reserve)

ID Harbour Area Date Hour Latitude Longitude Velocity

(knots)

Depth

(m)

Swept

Area (km2)

P01 Palamós R 23/08/2017 8:26 41.98 3.5 2.5 329 1.4

P02 Palamós R 23/08/2017 10:57 42.02 3.52 2.4 329 1.45

P04 Palamós C 24/08/2017 8:27 41.98 3.5 2.4 311 1.42

P06 Palamós C 24/08/2017 10:40 42.1 3.55 2.4 335 1.62

P07 Palamós R 25/08/2017 6:12 41.98 3.5 2.4 320 1.43

P08 Palamós C 25/08/2017 8:28 42.05 3.53 2.4 322 1.42

P09 Palamós R 25/08/2017 11:00 42.02 3.52 2.4 326 1.53

R01 Roses C 27/09/2017 5:43 42.1 3.55 3.5 362 1.25

R02 Roses R 27/09/2017 6:35 42.02 3.53 3.5 355 1.25

R03 Roses R 27/09/2017 8:32 41.97 3.52 3.5 364 1.47

R04 Roses C 28/09/2017 5:39 42.1 3.55 3.6 373 1.32

R05 Roses R 28/09/2017 7:42 42.02 3.53 3.5 368 1.17

R06 Roses R 28/09/2017 9:33 41.98 3.52 3.4 355 1.2

R07 Roses C 28/09/2017 11:40 42.03 3.55 3.4 355 1.33

R08 Roses C 29/09/2017 5:39 42.1 3.55 3.5 346 1.33

R09 Roses R 29/09/2017 7:35 42.02 3.53 3.5 364 1.3

R10 Roses C 29/09/2017 9:31 41.97 3.52 3.4 388 1.35

R11 Roses C 29/09/2017 11:30 42.05 3.53 3.4 318 1.52

30

Species P01 P02 R02 R03 R05 R06 P07 P09 R09 Total

Actinopterygii 3713.29 1711.27 5932.64 4611.11 4235.85 4935.29 3812.50 5233.08 2437.50 36622.53

Arctozenus risso 62.18 17.65 79.82

Argentina sphyraena 83.92 28.17 10.36 18.52 9.43 35.29 85.94 203.01 474.64

Argyropelecus hemigymnus 55.94 321.24 13.89 169.81 211.76 57.69 830.34

Capros aper 30.08 30.08

Ceratoscopelus maderensis 125.00 38.46 163.46

Chauliodus sloani 104.90 7.04 111.94

Chlorophthalmus agassizi 10.36 18.87 29.23

Coelorinchus caelorhincus 27.97 14.08 72.54 9.26 37.74 29.41 125.00 120.30 436.30

Conger conger 20.73 9.26 9.43 29.41 46.88 9.62 125.32

Engraulis encrasicolus 9.26 9.26

Epigonus denticulatus 83.92 9.43 31.25 60.15 28.85 213.60

Gadiculus argenteus 867.13 133.80 797.93 439.81 320.75 488.24 796.88 2120.30 96.15 6061.00

Gaidropsarus biscayensis 55.94 145.08 46.30 103.77 276.47 93.75 115.38 836.70

Helicolenus dactylopterus 132.87 98.59 93.26 83.33 42.45 11.76 85.94 112.78 14.42 675.42

Lampanyctus crocodilus 41.45 9.26 86.54 137.25

Lepidopus caudatus 18.52 9.43 9.62 37.57

Lepidorhombus boscii 307.69 204.23 1948.19 1162.04 1240.57 1335.29 140.63 315.79 711.54 7365.95

Leptocephalus (larva) 17.65 17.65

Lestidiops jayakari 15.63 38.46 54.09

Lophius budegassa 20.98 28.17 18.52 78.13 52.63 9.62 208.04

Lophius piscatorius 6.99 7.04 7.81 21.85

Merluccius merluccius 183.10 243.52 203.70 75.47 147.06 164.06 75.19 168.27 1260.38

Micromesistius poutassou 195.80 176.06 880.83 1597.22 250.00 617.65 156.25 240.60 115.38 4229.79

Mictophidae 279.72 140.85 238.34 1132.08 617.65 150.38 269.23 2828.24

Molva dypterygia 27.97 41.45 83.33 28.30 76.47 31.25 120.30 19.23 428.31

Notoscopelus elongatus 349.65 14.08 859.38 96.15 1319.26

Peristedion cataphractum 92.59 92.59

Phycis blennoides 615.38 147.89 595.85 504.63 523.58 382.35 359.38 639.10 485.58 4253.74

Spicara sp. 15.04 15.04

Table 3. Abundances of species per swept area (n/km2) in the reserve. There are the abundances per each haul identified for their ID.

31

Stomias boa boa 41.96 42.25 120.30 204.51

Symphurus nigrescens 27.97 9.43 125.00 162.41

Trachurus trachurus 27.97 27.97

Trigla lyra 342.66 471.83 409.33 273.15 169.81 388.24 421.88 676.69 19.23 3172.81

Trisopterus capelanus 55.94 14.08 62.50 132.53

Trigla spp. 75.47 241.18 48.08 364.73

Notoscopelus spp. 11.76 180.45 192.22

Nezumia sclerorhynchus 18.52 18.52

Bivalva 19.23 19.23

Bivalva 19.23 19.23

Cephalopoda 2139.86 725.35 357.51 268.52 306.60 482.35 2187.50 2240.60 158.65 8866.96

Abralia veranyi 146.85 654.93 62.18 18.52 75.47 82.35 593.75 421.05 38.46 2093.57

Eledone cirrhosa 6.99 10.36 13.89 17.65 39.06 7.52 19.23 114.70

Illex coindetii 7.81 14.42 22.24

Neorossia caroli 15.04 15.04

Rossia macrosoma 14.08 7.81 21.90

Scaeurgus unicirrhus 31.25 31.25

Todarodes sagittatus 10.36 5.88 7.81 22.56 46.61

Todaropsis eblanae 6.99 14.15 21.14

Sepietta spp. 1979.02 56.34 274.61 236.11 216.98 376.47 1500.00 1774.44 86.54 6500.51

Cnidaria 15.63 15.63

Actinia spp. 15.63 15.63

Crustacea 7482.52 3260.56 8595.85 6106.48 6226.42 5558.82 6023.44 5729.32 4899.04 53882.46

Alpheus glaber 62.18 23.15 28.30 35.29 62.50 48.08 259.50

Aristeus antennatus 4.63 4.63

Calocaris mecandreae 19.23 19.23

Chlorotocus crassicornis 55.94 72.54 37.74 35.29 62.50 48.08 312.09

Dardanus arrosor 7.04 18.52 15.63 135.34 176.52

Deosergestes corniculum 27.97 27.97

Eusergestes arcticus 223.78 20.73 4.63 103.77 31.25 384.15

Goneplax rhomboides 4.63 18.87 23.50

Liocarcinus depurator 27.97 41.45 18.52 17.65 23.44 135.34 9.62 273.98

Macropipus tuberculatus 6.99 28.17 41.45 55.56 37.74 35.29 7.81 97.74 19.23 329.99

Macropodia longipes 18.52 18.52

32

Meganyctiphanes norvegica 62.18 47.17 17.65 126.99

Monodaeus couchii 6.99 10.36 4.63 18.87 31.25 19.23 91.33

Munida intermedia 27.97 28.17 124.35 23.15 37.74 94.12 31.25 67.31 434.05

Munida iris 6.99 28.17 41.45 4.63 9.43 35.29 85.94 210.53 57.69 480.13

Munida tenuimana 18.52 18.52

Nephrops norvergicus 1629.37 1690.14 6362.69 4500.00 2589.62 2723.53 2109.38 1330.83 2764.42 25699.98

Pagurus alatus 15.04 15.04

Pagurus excavatus 11.76 15.04 26.80

Pagurus prideaux 6.99 11.76 18.76

Pandalina profunda 9.43 9.62 19.05

Parapanaeus longirostris 657.34 760.56 886.01 902.78 599.06 888.24 1031.25 1308.27 826.92 7860.43

Pasiphaea multidentata 37.04 37.04

Pasiphaea sivado 3916.08 514.08 269.43 41.67 1735.85 547.06 906.25 1308.27 432.69 9671.39

Philocheras echinulatus 10.36 35.29 45.66

Plesionika acanthonotus 13.89 13.89

Plesionika heterocarpus 405.59 190.14 393.78 134.26 198.11 323.53 781.25 751.88 250.00 3428.55

Plesionika spp. 166.67 166.67

Pontocaris lacazei 103.63 4.63 94.34 88.24 31.25 19.23 341.31

Pontophilus spinosus 7.04 32.41 18.87 29.41 19.23 106.96

Solenocera membranacea 314.69 7.04 41.45 27.78 188.68 123.53 343.75 240.60 96.15 1383.67

Processa spp. 167.83 51.81 46.30 452.83 505.88 468.75 180.45 192.31 2066.16

Echinoderma 15.63 19.23 34.86

Astropecten spp. 15.63 19.23 34.86

Elasmobranchii 783.22 471.83 2129.53 388.89 679.25 1305.88 1218.75 1849.62 543.27 9370.24

Scyliorhinus canicula 769.23 471.83 2129.53 388.89 679.25 1305.88 1218.75 1849.62 543.27 9356.26

Raja spp. 13.99 13.99

Gastropoda 196.89 27.78 56.60 281.27

Aporrhais spp. 10.36 9.26 19.62

Cymbulia peronii 186.53 56.60 243.13

Euspira fusca 18.52 18.52

Scaphopoda 9.62 9.62

Dentallium sp. 9.62 9.62

Tunicata 14.08 62.18 52.94 62.50 255.64 86.54 533.88

Ascidia 14.08 15.63 15.04 44.75

33

Species R01 P04 P06 R04 R07 P08 R08 R10 R11 Total

Actinopterygii 3488.38 7869.92 10900.71 3385.37 25659.22 2968.89 2555.56 2511.85 3466.42 6286.31

Arctozenus risso 16.26 16,.26

Argentina sphyraena 48.78 226.95 29.27 27.93 248.89 4.44 4.74 591.00

Argyropelecus hemigymnus 104.80 28.37 156.10 139.66 40.00 203.79 44.78 717.50

Bathophilus nigerrimus 9.48 9.48

Benthosema glaciale 9.48 9.48

Capros aper 32.52 32.52

Ceratoscopelus maderensis 406.50 794.33 43.90 13.33 1258.07

Ceratoscopelus sp. 40.00 40.00

Chauliodus sloani 16.26 14.18 17.78 18.96 67.18

Chlorophthalmus agassizi 16.26 27.93 4.74 48.93

Coelorinchus caelorhincus 26.20 65.04 28.37 19.51 97.78 13.33 23.70 55.97 329.90

Conger conger 8.73 32.52 78.01 19.51 61.45 17.78 35.56 4.74 29.85 288.16

Echiodon dentatus 8.73 8.73

Engraulis encrasicolus 18.96 18.96

Epigonus denticulatus 8.73 29.27 26.67 18.96 33.58 117.21

Gadiculus argenteus 314.41 634.15 1333.33 268.29 418.99 995.56 186.67 203.79 302.24 4657.43

Gaidropsarus biscayensis 165.94 32.52 85.11 58.54 307.26 71.11 80.00 52.13 179.10 1031.71

Glossanodon leioglossus 28.37 28.37

Helicolenus dactylopterus 56.77 130.08 56.74 19.51 72.63 75.56 23.70 7.46 442.44

Lampanyctus crocodilus 126.83 56.87 183.70

Lepidopus caudatus 9.48 9.48

Pyrosoma atlanticum 62.18 67.31 129.48

Salpa sp. 52.94 46.88 240.60 19.23 359.65

Total general 14118.88 6183.10 17274.61 11402.78 11504.72 12335.29 13335.94 15308.27 8173.08 109636.67

Table 4. Abundances of species per swept area (n/km2) in the control. There are the abundances per each haul identified for their ID.

34

Lepidorhombus boscii 807.86 130.08 234.04 878.05 2335.20 244.44 742.22 786.73 1108.21 7266.83

Leptocephalus (larva) 27.93 27.93

Lestidiops jayakari 13.33 13.33

Lophius budegassa 32.52 14.18 8.89 13.33 28.44 11.19 108.56

Lophius piscatorius 32.52 4.44 36.96

Merluccius merluccius 318.78 666.67 49.65 156.10 296.09 151.11 253.33 132.70 328.36 2352.78

Micromesistius poutassou 751.09 97.56 49.65 385.37 20223.46 168.89 271.11 165.88 305.97 22418.97

Mictophidae 87.34 1707.32 3588.65 585.37 391.06 142.22 106.67 56.87 414.18 7079.67

Molva dypterygia 30.57 81.30 56.74 34.15 83.80 75.56 28.44 111.94 502.48

Myctophum punctatum 9.48 9.48

Notoscopelus elongatus 2910.57 3687.94 195.53 53.33 61.61 6908.99

Ophichtus rufus 11.19 11.19

Phycis blennoides 384.28 195.12 361.70 463.41 569.83 146.67 386.67 308.06 186.57 3002.31

Sarda sarda 3.73 3.73

Stomias boa boa 14.18 13.33 4.74 32.26

Symphurus nigrescens 26.20 32.52 4.88 11.19 74.79

Trigla lyra 387.95 308.94 170.21 107.32 307.26 400.00 133.33 56.87 100.75 1972.63

Trisopterus capelanus 243.90 71.11 201.49 516.51

Trigla spp. 173.18 40.00 208.53 18.66 440.37

Notoscopelus spp. 106.67 13.33 120.00

Cephalopoda 515.28 5626.02 4340.43 409.76 597.77 3459.56 328.89 236.97 152.99 15667.64

Abralia veranyi 8.73 2926.83 411.35 19.51 27.93 631.11 53.33 56.87 22.39 4158.06

Bathypolypus sponsalis 32.52 27.93 60.45

Eledone cirrhosa 17.47 16.26 56.74 4.88 33.52 4.44 22.22 9.48 18.66 183.66

Heterotheutis dispar 26.67 26.67

Illex coindetii 4.88 72.63 17.78 14.22 109.50

Rossia macrosoma 4.44 9.48 13.92

Todarodes sagittatus 8.89 8.89

Sepietta spp. 489.08 2650.41 3872.34 380.49 435.75 2810.67 208.89 146.92 111.94 11106.49

Crustacea 5503.06 4170.73 4560.28 5585.37 6949.72 4604.44 7173.33 5009.48 3649.25 47205.67

Aegaeon lacazei 17.78 17.78

Alpheus glaber 61.14 85.11 19.51 55.87 40.00 33.18 11.19 305.99

Aristeus antennatus 14.63 14.63

Calocaris mecandreae 9.48 9.48

35

Caridea sp. 27.93 22.39 50.32

Chlorotocus crassicornis 113.54 32.52 113.48 165.85 167.60 35.56 306.67 4.74 67.16 1007.11

Crangonidae 8.73 8.73

Dardanus arrosor 27.93 35.56 80.00 14.93 158.41

Eusergestes arcticus 19.51 9.48 28.99

Goneplax rhomboides 8.73 27.93 17.78 4.74 59.18

Isopoda 27.93 27.93

Liocarcinus depurator 113.82 17.78 40.00 4.74 176.34

Lophogaster sp. 9.76 27.93 37.69

Macropipus tuberculatus 16.26 39.02 83.80 17.78 26.67 9.48 193.01

Medorippe lanata 17.78 17.78

Monodaeus couchii 8.73 48.78 17.78 26.67 4.74 106.70

Munida intermedia 34.93 81.30 141.84 43.90 167.60 53.33 26.67 23.70 33.58 606.86

Munida iris 113.54 28.37 82.93 279.33 17.78 93.33 615.27

Munida rugosa 34.93 34.93

Munida tenuimana 29.27 29.27

Nephrops norvergicus 2781.66 772.36 1170.21 2107.32 1687.15 1053.33 1080.00 3682.46 682.84 15017.33

Pagurus excavatus 14.18 14.18

Pagurus prideaux 17.47 14.18 31.65

Pandalina profunda 34.93 19.51 55.87 9.48 119.79

Parapanaeus longirostris 930.13 1577.24 1049.65 790.24 1268.16 902.22 1306.67 388.63 1619.40 9832.33

Pasiphaea sivado 296.94 471.54 453.90 648.78 837.99 977.78 1893.33 236.97 111.94 5929.18

Philocheras echinulatus 9.48 9.48

Plesionika heterocarpus 542.36 959.35 1078.01 409.76 921.79 977.78 960.00 80.57 973.88 6903.49

Plesionika narval 4.74 4.74

Pontocaris lacazei 52.40 16.26 28.37 111.73 22.39 231.15

Pontophilus spinosus 17.47 58.54 13.33 28.44 11.19 128.97

Solenocera membranacea 244.54 97.56 269.50 658.54 698.32 302.22 826.67 94.79 33.58 3225.72

Processa spp. 200.87 32.52 113.48 419.51 474.86 142.22 453.33 369.67 44.78 2251.24

Echinoderma 8.73 28.37 58.54 71.11 13.33 22.39 202.47

Asteroidea 28.37 13.33 41.70

Brissopsis lyrifera 58.54 58.54

Astropecten spp. 71.11 22.39 93.50

Spatangus purpureus 8.73 8.73

36

Elasmobranchii 910.48 1398.37 1106.38 580.49 2837.99 648.89 284.44 127.96 466.42 8361.43

Scyliorhinus canicula 910.48 1398.37 1106.38 580.49 2837.99 648.89 284.44 127.96 462.69 8357.70

Raja spp. 3.73 3.73

Gastropoda 17.47 48.78 83.80 150.05

Aporrhais spp. 17.47 17,.47

Cymbulia peronii 48.78 83.80 132.58

Porifera 14.63 14.63

Porifera 14.63 14.63

Tunicata 43.67 14.18 55.87 8.89 9.48 132.09

Diazona violacea 14.18 14.18

Pyrosoma atlanticum 27.93 9.48 37.41

Salpa spp. 43.67 27.93 8.89 80,.49

Total general 10487.07 19113.82 20950.35 10034.15 36184.36 11761.78 10355.56 7895.73 7757.46 134540.28