Transcript F msy - FishBase

Pathways Towards Sustainable
and Profitable Fisheries
Rainer Froese
IFM-GEOMAR, Kiel, Germany
[email protected]
FC-UBC, 08 March 2011
1
Overview
•
•
•
•
•
•
Some definitions
Global status of stocks
European Stocks and Fisheries
Current Work
Conclusions
Discussion
2
Some Definitions
• Stocks are the exploited part of populations
• Biomass (B) refers to the sum of body weights of
mature individuals (= spawning stock biomass)
• MSY is the maximum sustainable yield or catch
• F is the fraction of the stock dying from fishing (=
fishing mortality)
• Fmsy is the F that produces MSY at the stock size
Bmsy (less if the stock is smaller, more if it is larger)
• TAC is the total allowable catch per year per stock
3
Global Status of Fish Stocks
4
• Global catches can increase 40% under
effective management
• Subsidies (27 billion) exceed value added
• Commercial stocks are headed towards
collapse under current management
5
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
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Froese and Kesner-Reyes, ICES 2002
Out of Current Stocks in 2048 ?
Stocks (%)
Worm et al., Science 2006
20487 ?
Rainer Froese
Amanda Stern-Pirlot
Kathleen Kesner-Reyes
• The global number and percentage of stocks producing
less than 10% of their maximum landings continues to
increase
• New stocks are getting less, approaching zero after 2020
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9
Froese et al. Marine Policy 2009
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Froese et al. Marine Policy 2009
European Stocks and Fisheries
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Rainer Froese, IFM-GEOMAR
NO RELATIONSHIP BETWEEN FECUNDITY
AND ANNUAL REPRODUCTIVE RATE IN BONY FISH
Rainer FROESE, Susan LUNA
ACTA ICHTHYOLOGICA ET PISCATORIA (2004) 34 (1): 11–20
Maximum annual reproductive rate versus mean (solid dots) and minimum
(open dots) annual fecundity.
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Fish and Fisheries, 2004, 5, 86–91
Keep it simple: three indicators to deal with overfishing
Rainer Froese
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• Reducing catch to Fmsy is good but insufficient
• Stock size may increase seven-fold if fish are caught
after multiple spawning, at around 2/3 of their maximum
length
• Large stock size means low cost of fishing
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Age-structure of North Sea
Cod, with same catch but
different minimum size
Fmsy & Lopt
Fmsy
Current
For a given catch, the impact
on the stock is least if fish
are caught at Lopt
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Same catch, better
age structure
Stock size can increase
seven-fold
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• The Law of the Sea (UNCLOS 1982) requires
stock sizes that can produce the maximum
sustainable yield (MSY)
• Johannesburg (2002) gave the political goal of
2015
• With ‘business as usual’ Europe will miss this
goal by more than 30 years
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Rebuilding European Fish Stocks
Precautionary
Target
1
Mean stock size
0.8
Overfished
0.6
0.4
Trend
0.2
0
1970
Unsafe
1975
1980
1985
1990
1995
2000
2005
2010
2015
Year
Average size of 54 European fish stocks (bold blue line). The upper arrow indicates the path, if 75% of the
stocks were to reach the internationally agreed target in 2015. The lower arrow shows the current trend. 18
Froese et al. Fish & Fisheries 2010
Fishing Pressure on European Fish Stocks
4.5
UNCLOS
CFP
FAO/UNFAS
JPOI
Damanaki
Fishing pressure (F /Fmsy )
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3.5
3
Threatening the stock
Trend
2.5
2
1.5
Overfishing
1
Precautionary
Target
0.5
0
1970
1975
1980
1985
1990
1995
2000
2005
2010
2015
Year
Average fishing pressure on 54 European fish stocks. The lower arrow indicates the path if 75% of the stocks
were to be fished at the maximum sustainable rate in 2015. However, with the current trend that target will be
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missed by more than 30 years.
Froese et al. Fish & Fisheries 2010
In Press
• CFP contains over 600 regulations, some contradictory,
without efficient control
• CFP aims for smallest instead of optimal stock size
• Annual horse-trading leads to overfishing and uncertainty
• The precautionary principle is perverted
• Subsidies waste taxpayers money and create and
maintain overcapacity
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Harvest Control Rules for
Future Fisheries
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Rainer Froese, IFM-GEOMAR
Under review
Generic Harvest Control Rules for European Fisheries
Rainer Froese, Trevor A. Branch, Alexander Proelß, Martin Quaas,
Keith Sainsbury & Christopher Zimmermann
• Rules
for sustainable and profitable fisheries based on
1) economic optimization of fisheries
2) honoring international agreements
3) true implementation of the precautionary principle
4) learning from international experiences
5) ecosystem-approach to fisheries management
6) recognizing the biology of European fish stocks
• If these rules were applied, catches could increase by 63%
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Harvest Control Rule Schema
0.5 B msy
B msy
1.3 B msy
MSY
1
0.91 MSY
Depleted
Zone
Catch / MSY
0.8
Buffer
Zone
Overfishing
Zone
Target
Zone
0.6
0.4
0.2
0
0
0.5
1
Biomass / B msy
1.5
2
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Fisheries in 2007
0.5 B msy
B msy
0.5
1
1.3 B msy
1.6
1.4
Catch / MSY
1.2
1
0.8
0.6
0.4
0.2
0
0
Biomass / B msy
1.5
2
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North Sea Herring 1960 - 1978
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
3,000
3,500
Spawner Biomass (1000 t)
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North Sea-Herring 1979 - 2008
1,000
1.3 B msy
1987
Landings (1000 t)
800
1985
600
2003
1985
2003
1987
2008
400
2008
200
1979
0
0
1983
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
Spawner Biomass (1000 t)
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Critique of Planned
F-based Management
• Fmsy is taken as target, not limit, thus violating
UNFSA and the precautionary principle
• Fishing at Fmsy is less profitable than at Fmey
• Fishing at Fmsy results in substantially smaller
stocks, violating the ecosystem approach
• Fishing at Fmsy results in strongly fluctuating
catches with high uncertainty for the industry
• Fishing at Fmsy provides strong incentives for
overcapacity
• Fishing at TAC = 0.9 MSY solves these
problems
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ICES F-based Mangement
B pa
2
Catch
B msy
1.8
F / Fmsy or Catch / MSY
1.6
1.4
1.2
F
1
0.8
0.6
0.4
0.2
0
0
0.2
0.4
0.6
0.8
1
1.2
Biomass / B msy
1.4
1.6
1.8
2
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North Sea Herring Once More
B msy
800
Landings (1000 t)
1966
600
F -based HCR
1971
1960
1967
1977
400
1978
Proposed HCR
200
1978
0
0
500
1,000
1,500
2,000
2,500
3,000
3,500
Spawner Biomass (1000 t)
F-based Management would not have prevented the collapse of herring.
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Profits in Fisheries
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Making a Miracle Come True: Three Options for
Rebuilding the Cod Stock in the Eastern Baltic Sea
Submitted as Point of View (AISI) to MEPS
Rainer Froese and Martin Quaas
• Due to several lucky coincidences, the
eastern Baltic cod stock is recovering
• Here we look at options for management
to fully rebuild the stock and make the
fishery highly profitable
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Simulated catches for the eastern Baltic cod resulting from four different
management options. The dotted horizontal line indicates the maximum
sustainable yield (MSY).
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Simulated spawning stock biomass (SSB) of the eastern Baltic cod, resulting
from four different management options. The dotted horizontal line shows the
biomass that would produce the maximum sustainable yield (Bmsy).
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Simulated profits for the eastern Baltic cod resulting from four different
management options.
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Current Work
• Regarding not-taken catches as highly
profitable investment in the resource
• Evaluating status of MSC-certified stocks
• Practical approaches to data-poor stock
assessment and management
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Conclusions
• Rebuilding healthy stocks and fisheries is
possible, sometimes even without pain for the
fishers
• Reducing fishing effort alone is not enough,
mean size in catch needs to be increased in
addition
• Profits from healthy fisheries can be much
higher then currently, making subsidies
unnecessary
• `Pain-less´ paths towards profitable fisheries
exist
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Thank You
Questions?
Rainer Froese
[email protected]
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