Transcript Biodiversity of Fishes: Recent Trends in Global Fisheries Rainer Froese GEOMAR Kiel, Germany 24.01.2013 I gratefully acknowledge permission to use slides from Daniel Pauly, Boris Worm, Ram Myers,

Biodiversity of Fishes:
Recent Trends in Global
Fisheries
Rainer Froese
GEOMAR
Kiel, Germany
24.01.2013
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..
100
Percent
Fully exploited
Developing
50
Overfished
Collapsed
or closed
Undeveloped
10
0
1950
1960
1970
Years
1980
1990
2000
Froese and Kesner-Reyes, ICES 2002
Maximum catch and MSY are related
Froese et al. 2013
Trends in Global Fisheries
100%
Percent of World Fisheries
26%
22%
5.1 years
31%
80%
Collapsed
4.1 years
Overfished
5.0 years
Fully exploited
60%
38%
Developing
4.3 years
40%
20%
0%
1951
Undeveloped
?
1956
1961
1966
1971
1976
1981
1986
1991
1996
Years
Froese and Kesner-Reyes, ICES 2002
Out of Current Stocks in 2048 ?
Stocks (%)
Worm et al., Science 2006
2048 ?
More & More Collapsed stocks
Froese et al. 2013
Out of New Stocks in 2020
45
40
y = 24.27 - 0.4761 x
r2 = 0.4780
Number of new stocks
35
30
25
20
15
10
5
0
1970
1980
1990
2000
2010
2020
Year
Froese et al. 2008, Marine Policy
Reality Check in 2012
Froese et al. 2012, Marine Biology
Where Do Most of the Catches
Come From?
0
China grossly over-reported its marine
fisheries catches throughout the 1990s …
(b)
18
16
Constant catch
mandated
6
Chinese catch (t · 10 )
14
12
Overall marine
10
EEZ uncorrected
EEZ corrected
8
6
4
2
0
1970
1975
1980
1985
1990
1995
2000
(Watson & Pauly, Nature, 2001).
Impact of Over-reporting on
Global Catch Statistics
(a)
90
El Niño events
85
Global catch (t ·10 6)
80
75
70
65
El Niño
event
Uncorrected
Corrected
60
Corrected, no anchoveta
55
50
45
40
1970
1975
1980
1985
1990
1995
2000
Watson and Pauly (Nature), 2001.
(t/km2)
Biomass of Table Fish in 1900
Christensen et al. 2003
and in 2000….
Christensen et al. 2003
Catch per 100 Hooks
1952 - 1980
Blue Marlin
Swordfish
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.
Overfishing in Europe
B = B msy
1
0.8
B/Bmsy
75th percentile
0.6
Median
0.4
B = B pa
0.2
25th percentile
0
1970
1975
1980
1985
1990
1995
2000
2005
2010
2015
Year
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
4
75th percentile
3.5
3
F/Fmsy
2.5
Median
F = r max
2
1.5
1
25th percentile
F = F msy
0.5
0
1970
1975
1980
1985
1990
1995
2000
2005
2010
2015
Year
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.
Froese & Proelss 2010, Fish & Fisheries
Overfishing in Europe
1.6
1.4
1.2
B = B msy
B / Bmsy
1.0
0.8
0.6
0.4
B = B pa
0.2
0.0
16
14
12
10
8
6
4
2
0
-2
-4
Years to reach B msy
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.
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
before
after
Photos: Dr. K. Sainsbury, CSIRO
Area in NZ accessed by Scallop Trawlers
Before
Area in NZ accessed by Scallop Trawlers
Immediately after first trawling
Area in NZ accessed by Scallop Trawlers
Three years later (Dayton 1998)
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
Here: shrimp
trawlers off the
Texas Coast,
Gulf of Mexico
Photo courtesy of
Dr. Kyle van
Houten
(Duke
Ecosystem Effects of Fishing
4

10%
3
2
1
 10%
..
. . . . . . . 10%
. *. .*. .
*. . . *. . . . .
*
*. *. *. . *.
.
...
Fishing Down Food Webs
TL of landings
3.4
3.3
3.2
Marine
3.1
3.0
2.9
2.8
Freshwater
2.7
1970
1975
1980
1985
1990
Pauly et al. (Science, 1998)
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
8000
MSY
Catch in kg and Value/Cost in €
MEY
Cost of fishing
€ Growth
overfishing
6000
€
€
Economic
overfishing
4000
Fpa
Recruitment
overfishing
Flim
2000
?
†
0
0
20
40
60
Fishing Effort (hours)
80
100
EU Fisheries Management
8000
MSY
Catch in kg and Value/Cost in €
MEY
Cost of fishing
€
6000
€
€
4000
Subsidies
Flim
2000
?
†
0
0
20
40
60
Fishing Effort (hours)
80
100
Causes for Overfishing
• Crash course in fisheries management
– Three types of overfishing
– Subsidies increase overfishing
– Overfishing decreases mean size of fish
Catching Baby Fish
Babyfisch in Nordseefängen 2000 - 2004
100
90
82 %
Prozent Babyfisch im Fang (%)
80
70
61 %
60
54 %
55 %
Seelachs
Scholle
50
40
36 %
32 %
30
20
18 %
10
0
Makrele
Seezunge
Hering
Schellfisch
Kabeljau
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 Reduction
Eat Anchovies, Sardines, Mackerels…
Solution: MPAs
WPC: World Park Congress
CBD: Convention on Biological Diversity
Wood et al. (submitted)
Solution: Stop Subsidies
Subsidy amounts (USD billion)
60
50
40
30
Fuel
20
All except
fuel
10
0
FAO (1992)
This study
Milazzo (1998)
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
0.5 B msy
B msy
1.3 B msy
2 B msy
1
Fox
Y /MSY
0.8
Schaefer
0.6
0.4
0.2
0
0
0.5
1
1.5
2
B /B msy
Froese et al. 2011
Preventing Collapse of North Sea Herring
1,200
1.3 B msy
Landings (1000 t)
1,000
800
1960
1967
600
1962
1960
1962
400
1967
1977
1978
200
1978
0
0
500
1,000
1,500
2,000
2,500
Spawner Biomass (1000 t)
3,000
3,500
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.