fishing in national and international waters: msy and beyond rainer froese geomar, kiel, germany...
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Fishing in National and International Waters: MSY and Beyond
Rainer FroeseGEOMAR, Kiel, Germany
[email protected] Sustainable Oceans Conference: Reconciling Economic Use and Protection
New York, 13th July 2012
Overview
• Existing Knowledge: FishBase and AquaMaps• Global Fisheries and Aquaculture• MSY is good for you• How to implement MSY fisheries?• What about ecosystem-based fisheries?• Conclusions
Knowledge Bases
www.fishbase.org
www.fishbase.org
www.fishbase.org
www.fishbase.org
www.fishbase.org
www.futureoceanatlas.de
www.aquamaps.org
Global Fisheries and Aquaculture
Fisheries Can Provide More Protein ImmediatelyCarnivore Aquaculture is a Protein Sink
MSY Is Good For You
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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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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 AnswerPrinciples of Ecosystem-based Fisheries Management:•Take account of species interactions•Never take more than what all other predators combined are taking•To avoid collapse with high certainty, take less than the other predators
– For regular fish, take ¾ of natural mortality– For forage fish, take ½ of natural mortality
Pikitch et al. 2012
How to Estimate Natural Mortality?
• From decrease of numbers by age class (only about 200 studies in FishBase; Z = F +M)
• From growth parameters • From longevity• From maximum size
How about Data-Poor Stocks?
• Knowing the fraction of the stock that can be fished sustainably (about 20%) 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
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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.
Conclusions
• We know more than we know
• Carnivore aquaculture is a problem and not a solution
• The MSY concept is good and binding
• MSY can be estimated for all stocks
• Ecosystem-based fisheries management is doable right now
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Main Conclusion
• Compared with other Ocean problems, Overfishing can be fixed within a few years at low cost with high gains
• Rio+20 (Article 168) provides an excellent basis
• Europe could take the lead
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References• FishBase: www.fishbase.org• AquaMaps: www.aquamaps.org, www.futureoceanatlas.de • Froese, R. and A. Proelß. 2010. Rebuilding fish stocks no later than 2015: will
Europe meet the deadline? Fish and Fisheries 11:194-202• Froese, R., T.A. Branch, A. Proelß, M. Quaas, K. Sainsbury and C. Zimmermann.
2011. Generic harvest control rules for European fisheries. Fish and Fisheries 12:340-351
• Froese, R. and M. Quaas. 2011. Three options for rebuilding the cod stock in the eastern Baltic Sea. Marine Ecology Progress Series 434:197-2011.
• Martell, S. and R. Froese. 2012. A simple method for estimating MSY from catch and resilience. Fish and Fisheries, doi:10.1111/j.1467-2979.2012.00485.x
• Pikitch, E. et al. 2012. Little fish, big impact. Managing a crucial link in ocean food webs. Lenfest Ocean Program. Washington, DC. 108 pp.
This presentation will be available for download at www.fishbase.de/rfroese
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