The Status of World Fisheries The Status of World Fisheries

byby

Daniel PaulyDaniel Pauly

Fisheries Centre, Fisheries Centre,

University of British ColumbiaUniversity of British Columbia

Vancouver, CanadaVancouver, Canada

United Nations University United Nations University

Fisheries Training ProgrammeFisheries Training Programme

Institute of Marine ResearchInstitute of Marine Research

Reykjavik, December 16, 2002Reykjavik, December 16, 2002

Everywhere one looks, fisheries are in trouble…

Martell (1999)

Bluefin tuna in the Atlantic …

Lingcod in British Columbia …

…and I could go on with hundreds of those…

We can generalize this by using simple definitions of stock status:

Status of fishery Criteria applied to 932 species (groups) in FAO’s global catch statistics

Undeveloped Year before maximum year and value less than 10% of maximum value.

Developing Year before maximum year and value 10-50% of maximum value.

Fully exploited Value larger than 50% of maximum value.

Overfished Year after maximum year and value 10-50% of maximum value.

Collapsed Year after maximum year and value less than 10% of maximum value.

Definitions by R. Froese, IfM, Kiel, Germany

...and applying these to FAO’s marine catch data (1951-1998).This shows a steady erosion of fisheries worldwide. Thus, fisheries are in crisis, and the problem is growing rapidly.

0%

20%

40%

60%

80%

100%

1951 1956 1961 1966 1971 1976 1981 1986 1991 1996

Undeveloped Developing Fully exploited Overfished Collapsed

Analysis by R. Froese, IfM, Kiel, Germany

And yet, the global catch statistics assembled by FAO so far did not seem to add up to a globally declining catch …

Indeed, global catches appeared to increase in the 1990s.

Based on the FAO FISHSTAT database (with approximations for discards and unreported catches).

To deal with anomalies of this sort, we usually plot things on a graph, and look for patterns, and deviations from the patterns. However:

• Except for tuna, fisheries data are usually not presented in spatially disaggregated form;

• Data on who caught ‘what and where’ usually exist only for fisheries with on-board observers, tend to be confidential, and cover only a small part of the world fisheries;

• Hence, to place fisheries catches on maps, we must use other things we know.

Taxon (what) FAO Area (where)Country (who)

Taxon distribution database

Spatial referencedatabase

Fishing accessdatabase

Common spatial cells?

Assign catch rate to common cells

YES

This algorithm now assigns over 99 % of FAO global marine catches to ½ degree spatial cells, and we are still improving the underlying databases …

NOImprove databases

Thus, we used a ruled-based algorithm…

The global map we got was not very exciting, except for the anomalies (red)…. 0

We had no problem with Peru and Chile. But China?

So we used a statistical model to try to reproduce the catch map, using depth, primary production, etc., to predict catches...

It worked everywhere, except for Chinese waters, where the discrepancies were huge….

This allowed us to identify and quantify over-reporting of marine catches by China throughout the 1990s …

0

2

4

6

8

10

12

14

16

18

1970 1975 1980 1985 1990 1995 2000

Ch

ine

se

c

atc

h (

t ·

106 )

Overall marine

EEZ uncorrected

EEZ corrected

(b)

Constant catch mandated

(Watson and Pauly, Nature, Nov. 29, 2001).

Correcting for this resolved the global conundrum:

… in reality, global marine fisheries catches have been decreasing since the late 1980s (Watson and Pauly, Nature, 2001).

40

45

50

55

60

65

70

75

80

85

90

1970 1975 1980 1985 1990 1995 2000

Glo

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l c

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h (

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Uncorrected

Corrected

Corrected, no anchoveta

El Niño event

(a)El Niño events

Now to the ecological processes underlying Now to the ecological processes underlying overfishing. overfishing. Fisheries exploit resources embedded within Fisheries exploit resources embedded within ecosystems …ecosystems …

wherein each organism has its own trophic level …

Now consider that ecosystem fluxes move up ‘trophic Now consider that ecosystem fluxes move up ‘trophic pyramids’ …pyramids’ …

Turning this around, we can use global catches to estimate how much primary production is required to support the fisheries …

Tro

ph

ic le

vel

Phytoplankton

Top predators

Prey fish

Zooplankton

. . ... .. .. .. .. .. .. .. *.*. .. .... . ..*.*.*.*.*.*.

*.*. *.*.*.*.*.*.

. . . . . . 10% 10%

10% 10%

10% 10%

*.*.

4

3

2

1

Terrestrial average: 35-40%

Non-tropical shelves: 35%

Open ocean: 2%

Tropical shelves: 35%

Upwelling: 25%

Rivers/ lakes: 24%

Pauly and Christensen, Nature 1995

And we can estimate the percentage of total marine And we can estimate the percentage of total marine primary production that is appropriated by humans…primary production that is appropriated by humans…

Pauly et al. Science March 1998

2.7

2.8

2.9

3.0

3.1

3.2

3.3

3.4

1970 1975 1980 1985 1990

TL

of

lan

din

gs

MarineMarine

FreshwaterFreshwater

Similarly, we can estimate (from catch data and the Similarly, we can estimate (from catch data and the trophic level of all species caught) the mean trophic trophic level of all species caught) the mean trophic level of global fisheries landings. This is declining…level of global fisheries landings. This is declining…

In a critique, Caddy et al. (1998. Science 282:183a.) wrote we overlooked several sources of bias, notably:

1. The composition of landings does not necessarily reflect relative abundance on underlying ecosystem;

2. Trophic levels change with size or age;

3. Over-aggregated catch statistics may bias results.

Ad (1) - landing trends vs. ecosystem trends.

Three counter-arguments:1. Fish are nowadays exploited everywhere they are

abundant;2. All trawl survey data so far tested for this (e.g.,

Gulf of Thailand, Cantabrian Shelf, Guinea, etc.) show TL trends similar to those of the landings;

3. Work by Pinnegar et al. (Lowestoft) for the Irish Sea shows that decline of TL in landings is less pronounced than in survey data (i.e., skippers try to maintain catches of high TL fishes).

Ad (2) – ontogenic changes in TL.

Trophic level tends to increase with size/age; as ‘fishing down’ is associated with high F, TL decline is faster when ontogenic changes in TL are considered.

From Pauly et al. (2001; Can. J. Fish and Aquatic Sci.)

Item (3) came up because much of the world’s catch is reported in very coarse categories…

However, over-aggregating catch statistics has the effect of masking the fishing down effect.

FAO Area 27 (NE Atlantic)

Indeed, there is another masking effect, overlooked by Caddy et al. (1998), illustrated by FAO Area 31 (West Central Atlantic). There, fishing down did not seem to occur, which we first attributed to the crude statistics from many countries of that region.

However, after separating the USA (‘South Atlantic’ and Gulf of Mexico) from the rest of the region (Mexico, Caribbean, NE South America), we get:

Disaggregating the tuna and billfishes group from the others in the FAO global database also shows the fishing down effect to occur in oceanic areas…

This had so far been missed because we had pooled these fishes with others in our analyses by FAO areas.

The ‘fishing down’ effect is strong and

everywhere.

This is why we now see increasing emphasis on products such as this. (indeed, Western companies are now beginning to export jellyfish to East Asia).

There is also a notion that some parts of the world still have large fisheries resources, thus making it superfluous to deal with ‘fishing down marine food webs.’ However, the fish wealth of West Africa has long attracted distant water fleets from other continents …

Number of ‘country access years’by area, 1960-1969

Number of ‘country access years’by area, 1980-1989

… and these have increased tremendously over the years …

… finally reaching the present, staggering levels.

Number of ‘country access years’by area, 1990-1999

What is the impact of all this fishing on the resource base?

• We quantified this impact for the countries of the Northwest African sub-region using a methodology previously applied to the North Atlantic

• This methodology is based on maps of catch data, combined with ecosystem models, as documented at the website of the Sea Around Us Project (see ‘Reports’ at above address).

Fish biomass in 1950(excluding small pelagics)

Fish biomass in 1975(excluding small pelagics)

Fish biomass in 1999(excluding small pelagics)

The reason for this is fishing intensity, which was low in 1950 …

… but increased tremendously over time …

… finally reaching the very high present levels of fishing intensity.

Thus, we have in summary…

0.0

0.5

1.0

1.5

2.0

2.5

1950 1960 1970 1980 1990 2000

Bio

mas

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atch

(m

illio

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on

nes

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Fis

hin

g in

ten

sityCatch

Biomass

Fishing intensityBiomass

Thus, we can assume that globally, caught seafood per person will continue to go down…

Seafood per person

6

8

10

12

14

16

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020

kg

per

pers

on

R. Watson and P. Tyedmers, 2001

0

Projection

Less than half the seafood per person available at the peak in 1988

0

Aquaculture can counter the fisheries trends only if it is based on organism low in the food web…

2.00

2.20

2.40

2.60

2.80

3.00

3.20

3.40

3.60

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997

Tro

ph

ic L

evel

India

Japan

China

2.00

2.20

2.40

2.60

2.80

3.00

3.20

3.40

3.60

1970 1973 1976 1979 1982 1985 1988 1991 1994 1997

Tro

ph

ic L

evel

Norway

UK Chile Canada

USA

France

Trophic level trends of aquaculture production in selected countries: Left: major Asian producers; right: major non-Asian countries.

Here is an example of a herbivore , which can add to the global fish supply.

Nile tilapia, Oreochromis niloticus

Other fishes, such as salmon (Salmo salar), do not add to world fish supply, because they (must) consume more than they (can) produce….

Our somewhat pessimistic conclusions:

• Fisheries resources, throughout the world, are under tremendous pressure, as are the ecosystems within which they are embedded, and we are losing stocks and increasingly, species;

• There is a strong tendency for these pressures to increase, i.e., we do not have mechanisms in place to control the growth of fishing effort. Indeed, most fisheries work is still devoted to various forms of ‘development;’

• Aquaculture cannot replace the losses that are due to overfishing.

The next lectures will address some of these issues. Thank you.

Acknowledgements…

• Thanks to the Pew Charitable Trusts, Philadelphia;

• Fisheries Centre, Faculty of Graduate Studies, UBC;• Members of the Sea Around Us project;

and many others.