trends in global fisheries likely causes & possible solutions to overfishing rainer froese...
Post on 23-Jan-2016
216 Views
Preview:
TRANSCRIPT
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
14Source: Myers and Worm 2003.
Nature 423: 280-283
15Source: Myers and Worm 2003.
Nature 423: 280-283
16Source: Myers and Worm 2003.
Nature 423: 280-283
17Source: Myers and Worm 2003.
Nature 423: 280-283
18Source: Myers and Worm 2003.
Nature 423: 280-283
19Source: Myers and Worm 2003.
Nature 423: 280-283
20Source: Myers and Worm 2003.
Nature 423: 280-283
21Source: Myers and Worm 2003.
Nature 423: 280-283
22Source: Myers and Worm 2003.
Nature 423: 280-283
23Source: Myers and Worm 2003.
Nature 423: 280-283
24Source: Myers and Worm 2003.
Nature 423: 280-283
25Source: Myers and Worm 2003.
Nature 423: 280-283
26Source: Myers and Worm 2003.
Nature 423: 280-283
27Source: Myers and Worm 2003.
Nature 423: 280-283
28Source: Myers and Worm 2003.
Nature 423: 280-283
29Source: Myers and Worm 2003.
Nature 423: 280-283
30Source: Myers and Worm 2003.
Nature 423: 280-283
31Source: Myers and Worm 2003.
Nature 423: 280-283
32Source: Myers and Worm 2003.
Nature 423: 280-283
33Source: Myers and Worm 2003.
Nature 423: 280-283
34Source: Myers and Worm 2003.
Nature 423: 280-283
35Source: Myers and Worm 2003.
Nature 423: 280-283
36Source: Myers and Worm 2003.
Nature 423: 280-283
37Source: Myers and Worm 2003.
Nature 423: 280-283
38Source: Myers and Worm 2003.
Nature 423: 280-283
39Source: Myers and Worm 2003.
Nature 423: 280-283
40Source: Myers and Worm 2003.
Nature 423: 280-283
41Source: Myers and Worm 2003.
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
Froese & Proelß Fish & Fisheries 2010
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
Froese & Proelß Fish & Fisheries 2010
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
Froese & Proelß Fish & Fisheries 2010
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
Froese & Proelß Fish & Fisheries 2010
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
Froese & Proelß Fish & Fisheries 2010
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
Fishing Effort (hours)
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
Fishing Effort (hours)
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
top related