Oceans full of Fish?
Small Steps in the Right Direction
Rainer Froese
GEOMAR, Kiel, rfroese@geomar.de
Webinar Alumni Portal, 26 April 2013
Overview
• Status of global fish stocks and fisheries
‚Stability‘ in world catches masks decline of fish stocks
3
Global Catches are Stagnating
Pauly and Froese, 2012
Global Effort Keeps Increasing
Pauly and Froese, 2012
Global Fish Stocks are Shrinking
If catches are stagnating
while effort is increasing
then fish stocks must be shrinking
Pauly and Froese, 2012
• The method to assess all global stocks proposed by Froese & Kesner-Reyes
(2002), subsequently used by others, including Worm et al. (2006) for their
2048 prediction, is sound
• Global overfishing continues
• FAO, by using a subset of well-researched stocks, severely underestimates
global overfishing
7
Status of Global Fish Stocks 2009
Neue Bestände
Undeveloped
Fully exploited
Overexploited
Developing
Collapsed
Zusammengebrochen
Froese et al. Marine Biology 2012
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Fisheries Can Provide More Protein Immediately
Carnivore Aquaculture is a Protein Sink
Four Terms
• Biomass (B) is the body-weight of all fish in
the water
• MSY is the Maximum Sustainable Yield
(= maximum catch) that can be taken from a
population of fish (= stock) indefinitely
• Bmsy is the biomass that a fish stock must
have, so that it can deliver the maximum
sustainable yield MSY
• Fmsy is the fishing rate (the proportion of fish
killed by fishing) resulting in Bmsy
MSY Is Good For You
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Below MSY Level
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If Stock Size is
Above MSY Level
Stressed ecosystems
Small fish
Small stock size
High fluctuations
Low, uncertain catch
High effort /cost
Low / no profit
Low impact impossible
MPAs problematic
Subsidies necessary
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•
•
•
•
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Healthy ecosystems
Large fish
Large stock sizes
Low fluctuations
High, certain catch
Low effort /cost
High profit
Low impact possible
MPAs unproblematic
Subsidies not necessary
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European Stocks and Fisheries
14
Status of all European Stocks
Undeveloped
Neue Bestände
Fully exploited
Developing
Overexploited
Collapsed
Zusammengebrochen
Froese et al. Marine Biology 2012
15
Status of European Fish Stocks
16
Landings from ICES 2010, MSY from Froese and Proelß 2010
Generic Harvest Control Rules for European Fisheries
Rainer Froese, Trevor A. Branch, Alexander Proelß, Martin Quaas,
Keith Sainsbury & Christopher Zimmermann (2011)
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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European Fisheries
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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Politics
News from Rio +20
Article 168 of the The Future We Want: Outcome
of the Conference deals with fisheries:
• Governments commit to intensify efforts to
restore stocks at least to MSY levels
• They commit to urgent measures, „including
by reducing or suspending fishing...“
• They commit to ecosystem-based fisheries
management
News from the CFP Reform
• The Commission (Maria Damanaki) has
presented a reasonable CFP reform proposal
(although less than Rio +20)
• The Council of Agriculture Ministers has
decided upon its ‚compromise‘ position
• The European Parlament has agreed on an
ambitious reform proposal
• Now a compromise has to be negotiated
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The Council Compromise
• Postpones sustainable fishing until 2020
• Proposes an administrative monster for
reduction of discards until 2020
• Introduces lots of loopholes for continued
overfishing, e.g. of not „significant“ species in
mixed fisheries
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The Fisheries Question
• How much can we safely take from a fish
population?
• How much mortality can we add without
destroying the stock?
The Answer
Principles of Ecosystem-based Fisheries
Management
• Never take more than all other predators
combined (typically 20% of stock)
• To avoid collapse with high certainty, take less
• Catch fish at the optimum size
Growth, Mortality and Reproduction
Froese & Pauly, 2013
Let them Grow and Multiply
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How about Data-Poor Stocks?
• Knowing the fraction of the stock that can be
fished is fine, but what about the many stocks
for which no abundance is known?
• New method (Martell & Froese 2012)
estimates the maximum sustainable yield
from catch data and resilience
Excellent Agreement
Plot of MSY estimated by the Catch-MSY method versus full stock assessments for 48 stocks
from the Northeast Atlantic. The broken line indicates the 1:1 relation while the dotted lines
indicate ratios of 0.5 and 1.5, respectively.
Seafood Labels to the Rescue
• Definitions of ‚overfished‘ and ‚overfishing‘ that are
compatible with international law
• 19% (FoS) to 31% (MSC) of certified stocks are
overfished and suffer from ongoing overfishing
• But 61% (MSC) to 81% (FoS) of stocks with data are
large enough and moderately exploited, which is
better than the 15% in uncertified stocks
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Just Out
• Mismanagement of North Sea Cod: rebuilding
was possible if scientific advice had been
followed (Froese & Quaas 2012)
• Taking Rio+20 seriously: 50 – 70% of European
stocks could be rebuilt to MSY-levels by 2015
(Froese & Quaas 2013)
• Is the costly European fisheries management
necessary? Much simpler managgement may
deliver better results (in prep).
Questions?
All paper PDFs are available from
www.fishbase.de/rfroese
Rainer Froese
GEOMAR, Kiel, Germany
rfroese@geomar.de