biodiversity of fishes: recent trends in global fisheries rainer froese geomar kiel, germany...

Biodiversity of Fishes:Recent Trends in Global

Fisheries

Rainer FroeseGEOMAR

Kiel, Germany24.01.2013

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

Ram Myers, and Villy Christensen

Overview

• The status of global fisheries

• Ecosystem impacts of fisheries

• Causes for overfishing

• Possible solutions

The Status of Global Fisheries

150 Years of Newfoundland Cod Fishery

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

Maximum catch and MSY are related

Froese et al. 2013

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

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

Sto

cks

(%)

2048 ?

More & More Collapsed stocks

Froese et al. 2013

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

Froese et al. 2012, Marine Biology

Reality Check in 2012

Where Do Most of the Catches Come From?

0

China grossly over-reported its marine fisheries catches 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 & Pauly, Nature, 2001).

Impact of Over-reporting on Global Catch Statistics

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

(t/km2)

Biomass of Table Fish in 1900 Christensen et al. 2003

and in 2000…. Christensen et al. 2003

Catch per 100 Hooks1952 - 1980

Blue MarlinSwordfish

Bluefin Tuna

Dolphinfish

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Source: Myers and Worm 2003. Nature 423: 280-283

Overfishing in the North Atlantic

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

Myers.

0

0.2

0.4

0.6

0.8

1

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Year

B/Bmsy

Median

25th percentile

75th percentile

B = B msy

B = B pa

Fig. 1. Time series of biomass B relative to the biomass Bmsy capable of producing maximum sustainable yield, for 54 stocks of the Northeast Atlantic. Bpa is the biomass below which the reproductive capacity of the stock may be reduced. The arrow indicates the trajectory if 75% of the stocks were to reach Bmsy by the internationally agreed deadline of 2015.

Froese & Proelss 2010, Fish & Fisheries

Overfishing in Europe

0

0.5

1

1.5

2

2.5

3

3.5

4

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

Year

F/Fmsy

Median

25th percentile

75th percentile

F = F msy

F = r max

Fig. 2. Time series of fishing mortality F relative to the fishing mortality Fmsy associated with maximum sustainable yield, for 54 fish stocks of the Northeast Atlantic. If F is larger than the intrinsic rate of population increase rmax, stocks will shrink below safe biological levels. The arrow indicates the trajectory if 75% of the stocks were to reach Fmsy at the internationally agreed deadline of 2015.

Overfishing in Europe

Froese & Proelss 2010, Fish & Fisheries

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

-4-20246810121416

Years to reach Bmsy

B /

Bmsy

B = B msy

B = B pa

Fig. 3. Time to reach the biomass Bmsy capable of producing maximum sustainable yield, for 54 fish stocks of the Northeast Atlantic. Bpa is the biomass below which the reproductive capacity of the stock may be reduced. Stocks in the green box have reached the target, stocks in the yellow box may reach Bmsy in 2015 if fishing is halted in 2010. Stocks in the red box are unlikely to reach Bmsy until 2015.

Overfishing in Europe

Froese & Proelss 2010, Fish & Fisheries

In Summary

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

Ecosystem Impacts of Fisheries

Impact on the Sea Floor

Photos: Dr. K. Sainsbury, CSIRO

before

after

Area in NZ accessed by Scallop Trawlers Before

Immediately after first trawling

Area in NZ accessed by Scallop Trawlers

Three years later (Dayton 1998)

Area in NZ accessed by Scallop Trawlers

Tracks of Trawls

courtesy F. Grassle

Shrimp Trawlers from Space

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

And More Trawling for Shrimps…

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

Ecosystem Effects of FishingT

rop

hic

leve

l

Phytoplankton

Top predators

Prey fish

Zooplankton

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

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

. . . . . . 10% 10%

10% 10%

10% 10%

*.*.

4

3

2

1

Pauly et al. (Science, 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

Fishing Down Food Webs

Fisheries-induced Unnatural Selection

• Fishing removes large, old, highly fecund, ‘fit’ fishes before they can reproduce

• Reductions in size and age at first maturity are visible in most stocks

• Stocks adapted to fishing become less well adapted to their natural environment

• Recovery will take long, leaving a ‘Darwinian debt’ to future fishers and consumers

Diekmann et al. 2009, ICES Insight

In Summary…

• Global fisheries have severe negative impact on the marine ecosystem

Causes for Overfishing

• Crash course in fisheries management– Three types of overfishing

Fisheries Management Basics

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

EU Fisheries Management

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

?

Flim

†

Subsidies

Causes for Overfishing

• Crash course in fisheries management– Three types of overfishing– Subsidies increase overfishing– Overfishing decreases mean size of fish

Catching Baby FishBabyfisch in Nordseefängen 2000 - 2004

82 %

61 %

55 %54 %

36 %32 %

18 %

0

10

20

30

40

50

60

70

80

90

100

Makrele Seezunge Hering Seelachs Scholle Schellfisch Kabeljau

Pro

zen

t B

abyf

isch

im

Fan

g (

%)

Quelle: ICES Report on the Assessment of Demersal Stocks in the North Sea and Skagerrak 2005

Causes for Overfishing

• Mismanagement

• Subsidies

• Misinformation

The Fecundity Myth

“In theory, one pair of cod is enough to replenish the North Sea cod stock…”

Fact 1: No relationship between fecundity and reproductive success

No Relationship between Fecundity and Reproductive Success

Froese and Luna, ACTA 2004

The Fecundity Myth

“In theory, one pair of cod is enough to replenish the North Sea cod stock…”

Fact 1: No relationship between fecundity and reproductive success

Fact 2: ICES estimates critical spawning stock biomass for North Sea cod at 70,000 t

(10 million pairs…)

The ‘Juveniles Die Anyway’ Myth

“Catching juveniles is good because it let’s the old, productive fish live. Many juveniles would have died anyway.”

Facts: 1. Causes for mortality do not substituted,

they add up. 2. Juveniles are the adults of tomorrow. 3. A given catch kills 10 times more

juveniles than adults.

Possible Solutions

Solution: Reduce ReductionEat Anchovies, Sardines, Mackerels…

Solution: MPAs

Wood et al. (submitted)WPC: World Park CongressCBD: Convention on Biological Diversity

Solution: Stop 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)

Solution: Work With Consumers and Retailers

• Fish Rulers

• Fisch im Handy

• Marine Stewardship Council

• Sonderwirtschaftszone westliche Ostsee

• More Research

Harvest Control Rules

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5 2

B /Bmsy

Y/MSY

B msy0.5 B msy 1.3 B msy 2 B msy

Fox Schaefer

Froese et al. 2011

Preventing Collapse of North Sea Herring

0

200

400

600

800

1,000

1,200

0 500 1,000 1,500 2,000 2,500 3,000 3,500

Spawner Biomass (1000 t)

Lan

din

gs

(100

0 t)

1960

1960

1962

19621967

1967

1977

1978

1978

1.3 B msy

Conclusions

• Fish stocks are declining worldwide• Overfishing is drastically changing the marine

ecosystems • Overfishing is driven by mismanagement, myths

and subsidies• Top down solutions (MPAs, no subsidies, better

management (HCR)) are needed but slow• Involving retailers and the public seems most

promising

Exercise

Go to www.ices.dk, Latest Avice

For herring, cod, or plaice:•Which stock is of sufficient size (B > Bmsy)

and fished sustainably (F < Fmsy)?

Note: use 2 * Bmsy-Trigger (or 2 * Bpa) as proxy for Bmsy. Ignore stocks where Fmsy is not known.