Some Recent Work on Fish and Fisheries
Rainer FroeseGEOMAR, Kiel, [email protected]
Taking Stock: Journalism Conference on European Fisheries Issues
25 October 2012, Lübeck
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
6
Status of Global Fish Stocks 2009
7
Neue Bestände
Zusammengebrochen
Undeveloped
Developing
Fully exploited
Overexploited
Collapsed
Froese et al. Marine Biology 2012
Below 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
Above MSY Level
• 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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If Stock Size is
Status of all European Stocks
13
Neue Bestände
Zusammengebrochen
Developing
Fully exploited
Undeveloped
Overexploited
Collapsed
Froese et al. Marine Biology 2012
Generic Harvest Control Rules for European FisheriesRainer 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%
15
Harvest Control Rule Schema
0
0.2
0.4
0.6
0.8
1
0 0.5 1 1.5 2
Biomass / B msy
Ca
tch
/ M
SY
B msy0.5 B msy 1.3 B msy
DepletedZone
OverfishingZone
BufferZone
TargetZone
MSY
0.91 MSY
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European Fisheries
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
Cat
ch /
MS
Y
B msy0.5 B msy 1.3 B msy
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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 recently decided upon its ‚compromise‘ position
• The European Parlament will present its position in in the next months, then a new compromise has to be negotiated
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The Council Compromise
• Postpones sustainable fishing for stocks without Fmsy estimates 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 General Problem
• Over 4,000 species of fishes are harvested from the wild globally (FishBase 02/2012)
• Full stock assessments are available for only a few hundred species
The Solution
• General principles combined with incomplete knowledge are sufficient for reasonable management
(Lessons learned after 30+ years of managing the
Great Barrier Reef, Josh Gibson, pers. comm., 21.6.2012)
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
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 stocksfrom the Northeast Atlantic. The broken line indicates the 1:1 relation while the dotted lines indicate ratios of 0.5 and 1.5, respectively.
• 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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Stuff to Come
• Mismanagement of North Sea Cod: rebuilding was possible if scientific advice had been followed (in press)
• Taking Rio+20 seriously: 50 – 70% of European stocks could be rebuilt to MSY-levels by 2015 (accepted)
• Is the costly European fisheries management necessary? Much simpler managgement may deliver better results (in prep).
Thank You
All paper PDFs are available fromwww.fishbase.de/rfroese
Rainer FroeseGEOMAR, Kiel, Germany