trends in global fisheries likely causes & possible solutions to overfishing rainer froese...

Trends in Global Fisheries

Likely Causes & Possible Solutionsto Overfishing

Rainer FroeseIFM-GEOMARKiel, Germany

Online Presentation for International Environmental Policy Potsdam Open University

5 November 2010

I gratefully acknowledge permission to use slides from Daniel Pauly, Boris

Worm, Ram Myers, and Villy Christensen

3

The Status of Global Fisheries

4

150 Years of Newfoundland Cod Fishery

5

A typical Fishery..

0

50

100

1950 1960 1970 1980 1990 2000Years

Per

cen

t

Fully exploited

Overfished

Collapsed or closed

Developing

Un-developed

10

Froese and Kesner-Reyes, ICES 2002

6

Trends in Global Fisheries

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

?

Froese and Kesner-Reyes, ICES 2002

7

Out of Current Stocks in 2048 ?Worm et al., Science 2006

Sto

cks

(%)

2048 ?

8

Catch

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Years

Pe

rce

nta

ge C

OF

FE

D

U

Froese et al. 2008, Marine Policy

2110

r2=0.975

Reality Check in 2008

9

Out of New Stocks in 2020

0

5

10

15

20

25

30

35

40

45

1970 1980 1990 2000 2010 2020

Year

Nu

mb

er o

f n

ew s

tock

s

y = 24.27 - 0.4761 x

r2 = 0.4780

Froese et al. 2008, Marine Policy

10

(t/km2)

Biomass of Table Fish in 1900 Christensen et al. 2003

11

and in 2000…. Christensen et al. 2003

12

Catch per 100 Hooks1952 - 1980

Blue MarlinSwordfish

Bluefin Tuna

Dolphinfish

13Source: Myers and Worm 2003.

Nature 423: 280-283


Nature 423: 280-283

42

The Failure of Management by Governments

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

Myers.

43

With thanks to Ram Myers and Boris Worm

The Failure of Regional Fishing Organizations

Recently confirmed by:Cullis-Suzuki & Pauly 2010. Failing the high seas: a global evaluation of regional fisheries management organizations. In press with Marine Policy

44

If Corrected for Over-Reporting, Global Catches are Declining Since 1988

Watson and Pauly (Nature), 2001.

40

45

50

55

60

65

70

75

80

85

90

1970 1975 1980 1985 1990 1995 2000

Glo

ba

l c

atc

h (

t ·1

06 )

Uncorrected

Corrected

Corrected, no anchoveta

El Niño event

(a)El Niño events

45

In Summary

• Global fisheries have drastically reduced the size of their target stocks, typically by 90% since 1950

• Global catches are declining since the late 1980s; this decline is masked by misreporting to FAO

46

Ecosystem Impacts of Fisheries

47

Impact on the Sea Floor

Photos: Dr. K. Sainsbury, CSIRO

before

after

48

Area in NZ accessed by Scallop Trawlers Before

49

Immediately after first trawling

Area in NZ accessed by Scallop Trawlers

50

Three years later (Dayton 1998)

Area in NZ accessed by Scallop Trawlers

51

Tracks of Trawls

courtesy F. Grassle

52

Shrimp Trawlers from Space

QuickBird satellite on 20 February 2003, off the coast of Jiangsu province near the mouth of the Yangtze River;

53

And More Trawling for Shrimps…

54

Not only in China, also in Texas

Photo courtesy of Dr. Kyle van Houten (Duke University)

Here: shrimp trawlers off the Texas Coast, Gulf of Mexico

55

Crash Course in Fisheries Management

56

What is a Stock?

• A stock is the exploited part of a population of fishes

• The total weight of the stock is called biomass (B)

• SSB is the Spawning Stock Biomass, i.e., the total weight of the adults

57

SardineBiscay and off Portugal

0

100

200

300

400

500

600

700

800

1975 1980 1985 1990 1995 2000 2005 2010

Year

Sp

awn

ing

Sto

ck B

iom

ass

(10

00 t

)

ICES 2010

58

What is MSY?

• MSY is the Maximum Sustainable Yield

• MSY is the maximum catch that the stock can deliver on a regular basis

• Catches above MSY shrink the stock

59

Cod, Eastern Baltic

0

100

200

300

400

500

600

700

800

900

1000

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

SS

B a

nd

Lan

din

gs

(100

0 t)

MSY

Froese & Proelß Fish & Fisheries 2010

60

What is BMSY?

• BMSY is the stock size that can produce the maximum sustainable yield

• BMSY is the central reference point of the Law of the Sea and UNFSA (1995) with regard to fisheries

Stock biomass B Depleted Unfished

BMSY Can produce MSYCan not produce MSY

61

Cod, Eastern Baltic

0

100

200

300

400

500

600

700

800

900

1000

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

SS

B a

nd

Lan

din

gs

(100

0 t)

BMSY

MSY


62

What the hell is F?

• F is the rate by which fish are removed from the stock by fishing (fishing mortality)

• F can be translated into the percentage of the stock that is taken by the fishery

F 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

% 10 18 26 33 39 45 50 55 59 63

63

What is FMSY?

• FMSY is the fishing mortality that will lead to BMSY

• F < FMSY leads to stock sizes above BMSY

• F > FMSY shrinks the stock below BMSY

FMSY 0.11 0.24 0.43

% 10 21 35

Greenlandhalibut

Cod, herring Sandeel


64

Cod, Eastern Baltic

0

100

200

300

400

500

600

700

800

900

1000

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

SS

B (

1000

t)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Fis

hin

g m

ort

alit

y F

FMSY

BMSY


65

Legal Considerations

66

Is Overfishing Legal?

• The Law of the Sea defines the “biomass that can produce the maximum sustainable yield” (Bmsy) as reference point

• Stocks that are smaller than Bmsy need to be rebuilt

• Harvest levels that reduce the stock below Bmsy are incompatible with the Law of the Sea

• The USA have adopted this in national law: Fishing with F > Fmsy is illegal.

67

How about Overfishing in Europe?

68

0

0.2

0.4

0.6

0.8

1

1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

B/B

msy

B = B msy

B < B msy

B << B msy

75 percentile

25 percentile

Median

Biomass of European Stocks


69

What is the fishing mortality of European stocks relative to FMSY

70

Fishing Pressure on European Stocks

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

F/F

msy

Median

25 percentile

75 percentile

F = F msy

F >> F msy

F > F msy


71

What are the landings relative to MSY?

72

Landings and Biomass of European Stocks in 2007

Froese et al., submitted

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 0.5 1 1.5 2

Biomass / B MSY

Lan

din

gs

/ M

SY

B MSY

MSY

73

Main Causes for Overfishing

• Greed

• Mismanagement

• Subsidies

74

Fisheries Economics

0

2000

4000

6000

8000

0 20 40 60 80 100

Fishing Effort (hours)

Cat

ch i

n k

g a

nd

Val

ue/

Co

st i

n €

MSY

Cost of fishing

€

€€

MEY

Fpa

?

Flim

†

Economicoverfishing

Growthoverfishing

Recruitmentoverfishing

75

EU Fisheries Management

0

2000

4000

6000

8000

0 20 40 60 80 100


Cat

ch i

n k

g a

nd

Val

ue/

Co

st i

n €

MSY

Cost of fishing

€

€€

MEY

Fpa

?

Flim

†

68% EU stocksbeyond Fpa

EU 2008: 88% of stocks MEY and MSY overfished

Subsidies ?

76

Possible Solutions

77

Solution: Phase out Subsidies

All except fuel

Fuel

0

10

20

30

40

50

60

FAO (1992) This study Milazzo (1998)

Subs

idy

amou

nts

(USD

billi

on)

Khan et al. (2006)

78

Removing Subsidies Rebuilds Stocks and Increases Catches in the Mid-term

0

2000

4000

6000

8000

0 20 40 60 80 100


Cat

ch i

n k

g a

nd

Val

ue/

Co

st i

n €

MSY

Cost of fishing

€

€€

MEY

Fpa

?

Flim

†

79

Rebuilding Stocks Pays Off

• A recent study shows that European fisheries can produce 60% higher catches if they were managed properly and precautionary (at 0.9 MSY)

Froese et al. 2010. Generic harvest control rules for European fisheries. Fish and Fisheries

80

0.9 MSY Harvest Control Rule

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 0.5 1 1.5 2

Biomass / B MSY

Lan

din

gs

/ M

SY

B MSY 1.3 B MSY

MSY

0.9 MSY

Move stocks here.Landings may then be 60% higher and stocks 4-times larger

Froese et al. 2010. Generic harvest control rules for European fisheries. Fish and Fisheries

81

Conclusions

• Fish stocks are declining worldwide

• Overfishing is drastically changing the marine ecosystems

• Overfishing is driven by mismanagement and subsidies

• Fisheries can produce more food, livelihood, profit and taxes if done properly

82

Thank You

Rainer FroeseIFM-GEOMARKiel, Germany

trends in global fisheries likely causes & possible solutions to overfishing rainer froese...

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