state of the marine environment rainer froese leibniz institute of marine sciences, kiel ifm-geomar...

State of the Marine Environment

Rainer FroeseLeibniz Institute of Marine Sciences, Kiel

[email protected]

Acknowledgements

• Sea Around Us provided data

• FishBase provided data

• EEA provided data

• Daniel Pauly, Boris Worm and Ian Payne shared slides

• DG Development and DG Research supported previous research

Overview

• Major Threats to European Seas

• Paradox of Fishing

• Myths about Fishing

• Common Sense Fisheries Policy

Europe‘s Regional Seas

Major Threats to Europe‘s Seas

1. Fishing (NE, North Sea, Mediterranean, Baltic, Black Sea)

Fishing Down Marine Food WebsPauly et al. 1998 Science 279:860-863

5

4

3

2

Tro

phic

Lev

el

Watson and Pauly In: Atlas of the Ocean

Fishing Down the Food Webin the North Sea

(Source: Froese and Pauly 2003)

3

3.1

3.2

3.3

3.4

3.5

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Years

Mea

n Tr

ophi

c Le

vel

0

0.5

1

1.5

2

2.5

3

3.5

4

Mill

ion

Tonn

es /

year

Catch

Trophic Level

Trends in mean trophic level of annual landings from the North Sea



2. Pollution (North Sea, Baltic, Black Sea)

PollutionRegional trends of hazardous substances in fish from north-east

Atlantic and Baltic regions (Source: EEA)




3. Eutrophication (Black Sea, Baltic, North Sea)

EutrophicationChlorophyll-a concentrations in transitional, coastal and marine waters (Source: EEA)





4. Climate change (NE, North Sea)

Climate changeObserved European annual average temperature deviations (Source: EEA)





4. Climate change (NE, North Sea)

5. Invasive species (Black Sea, Mediterranean)

6. Local threats: Coastal developments, Mariculture, Shipping accidents

Paradox of Fishing

• Reducing pollution, eutrophication, green house gases, and ballast water introductions are ‚common sense‘ solutions that seem to work.

• Fishing less to get more fish is not ‚common sense‘

• Fishers and boats are less but fishing effort has increased

• Focus only on reducing fishing effort has not worked in the past 100 years and is unlikely to work in the future.

Time Series of Abundance and Fishing Mortality

Trends from ‘Working Group’ reports by fisheries scientists in government agencies (NMFS, DFO, DIFMAR, IFREMER, etc.), compiled by R. A.

Myers.

Myths about Fishing

• There are enough fish...

FAO Marine Catches 1951-1998(Source: Froese and Pauly 2003)

0%

20%

40%

60%

80%

100%

1951 1956 1961 1966 1971 1976 1981 1986 1991 1996

Years

Pe

rce

nt

of

Wo

rld

Fis

he

rie

s

26%5.1 years

38%

4.3 years

31%5.0 years

22%4.1 years

Undeveloped

Developing

Fully exploited

Overfished

Collapsed

?

The Northeast Atlantic, ICES (Source: Froese and Pauly 2003)

0%

25%

50%

75%

100%

1974 1978 1982 1986 1990 1994 1998

Years

Per

cen

t o

f IC

ES

Fis

her

ies

43%3.9 years

28%5.1 years

Undeveloped

Developing

Fully exploited

Overfished

Collapsed

Geographic expansion of fisheries (Source: Sea Around Us)

Years at and after maximum catch in half-degree cell

Myths about Fishing


• It is the climate...

Source: Myers and Worm 2003.

Nature 423: 280-283

Myths about Fishing



• It is the pollution...

Biomass of table fish in 1900

(t/km2)

(Christensen et al. 2003, Fish & Fisheries)

and in 2000….

Myths about Fishing




• Size does not matter...

Size Does Matter!

1. Size at first maturity: fish caught below that size could not spawn;

2. Size at maximum yield: fish caught below that size have not yet reached optimum weight;

3. Mega-spawner size (many eggs, high egg survival, good genes): fish caught below that size have no chance to become Mega-spawners

EC Minimum Size LimitsCouncil Regulation No 2555/2001

Species EC Minimum Size

Size at first maturity

Size at maximum yield

Atlantic cod 41 cm 60 cm 85 cm

American plaice

25 cm 20 cm 25 cm

Yellowtail flounder

25 cm 26 cm 29 cm

Greenland halibut

30 cm 58 cm 72 cm

Myths about Fishing




• Size does not matter...

• Recruitment can be predicted...

• Stocks will recover...

• Aquaculture is the solution...

Aquaculture is Part of the Problem

• 3-4 kg of wild fish to culture 1 kg of salmon

• 5 kg of wild fish for 1 kg of cod

• 20 kg of wild fish for fattening of 1 kg of tuna

• More Aquaculture means less wild fish for human consumption

Three Simple Steps from CFP to Common Sense Fisheries Policy

1. Let them spawn– Size at first maturity is known for all stocks

2. Let them grow– Size of maximum yield per recruit is known for all

stocks and is slightly beyond size at maturity

3. Let some live– Old, large fish produce more eggs, have better

genes, and provide an insurance against recruitment failures

CSFP

Commercial Landings of Nile perch in 1982

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180 200 220

Length (cm)

Nu

mb

ers

CSFP


0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180 200 220

Length (cm)

Nu

mb

ers

LinfLoptLm

CSFP


0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180 200 220

Length (cm)

Nu

mb

ers

LinfLoptLm

Actual catch:1,218 fish9,171 kg

Potential catch:541 fish12,556 kg+ 29%

Common Sense Fisheries Policy

• Agree on biology of stock: maturity, spawning time and area, productivity

• Agree on percentage of first-time spawners to be caught (10 – 50 %)

• Determine annual number of first time spawners by survey on spawning grounds

• Allow fishing of first-time spawners after spawning season

• Provide strong incentives for catching only fish of the desired size (mix of Policy Instruments)

• Only import mature fish

Don‘t Eat Babies

Herring, Clupea harengus, Lm = 24 cm TL

Rainer FroeseIfM, Düsternbrooker Weg 20

24105 Kiel, [email protected]

As a result of overfishing, most fishes are now caught before they had a chance to reproduce. This results in low catches (growth overfishing) and very small spawning stocks (recruitment overfishing). We suggest that fish of a given suitable stock are only caught after the first and before the second spawning in order to obtain maximum biomass and at the same time rebuild and maintain strong spawning stocks including large, fit ‘mega-spawners‘. The percentage to be taken from this cohort will depend on the species and on the status of the stock, and should be agreed between all parties involved. As the size of the cohort can be easily determined through surveys before and during first spawning, the total allowed catch in a given year can be determined quite accurately and transparently. We suggest that such simple regulations can be easier communicated and enforced than traditional management tools. Preliminary size at first maturity can be obtained from www.fishbase.org for all commercial fishes of the world. This size is shown below for some commercial fishes of the North Sea. Similar posters can be used to educate fishers, fish dealers, and consumers.

European Sprat, Sprattus sprattus, Lm = 10 cm TL

Atlantic cod, Gadus morhua, Lm = 50 cm TL

European plaice Pleuronectes platessusLm = 28 cm TL

Atlantic mackerel, Scomber scombrus, Lm = 30 cm FL

Thank You

More information:

• Froese, R. 2004. Keep it simple: three indicators to deal with overfishing. Fish and Fisheries 5:86-91

• Froese, R. 2004. Keep fishery management simple. ICES Newsletter 41:9-10

Copies available from

[email protected]

state of the marine environment rainer froese leibniz institute of marine sciences, kiel ifm-geomar...

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