Fishing in National and International Waters: MSY and Beyond Rainer Froese GEOMAR, Kiel, Germany 2nd 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

Global Fisheries and Aquaculture

Fisheries Can Provide More Protein Immediately Carnivore Aquaculture is a Protein Sink

MSY Is Good For You 12

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 13

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., )

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: 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

2012

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.

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 22

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 23

References FishBase: AquaMaps: Froese, R. and A. Proelß Rebuilding fish stocks no later than 2015: will Europe meet the deadline? Fish and Fisheries 11: Froese, R., T.A. Branch, A. Proelß, M. Quaas, K. Sainsbury and C. Zimmermann Generic harvest control rules for European fisheries. Fish and Fisheries 12: Froese, R. and M. Quaas Three options for rebuilding the cod stock in the eastern Baltic Sea. Marine Ecology Progress Series 434: Martell, S. and R. Froese A simple method for estimating MSY from catch and resilience. Fish and Fisheries, doi: /j x Pikitch, E. et al 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 24

Thank You Rainer Froese GEOMAR, Kiel