New Tools for Management of Data-Poor Stocks Rainer Froese, GEOMAR, Kiel, Germany Pew Fellows Meeting, Gamboa, Panama, Workshop on Options for the Management of Data-poor Stocks

Of all the possible r-k pairs in the rectangle, only the displayed ones did not collapse the stock or overshoot carrying capacity.

All r-k pairs under the bold line result in the same value of MSY. The outer lines contain 95% of the possible MSY estimates.

Reported catches with overlaid MSY estimate and 95% confidence limits.

From MSY to Management If MSY and mean catch over several years are known, then equilibrium biomass can be obtained from a Schaefer model: B/Bmsy = f(Catch/MSY)

Catch of 37 ICES stocks in 2010 after 6 years of MSY management, relative to actual catches

Biomass of 37 ICES stocks in 2010 after 6 years of MSY management, relative to actual biomass

Length Frequency Analysis North Sea flounder,

Length Frequency Analysis North Sea flounder,

Length Frequency Analysis Absolute slope = total mortality (Z). If Z is larger than r, then fishing mortality F exceeds natural mortality M.

References Martell, S. and R. Froese, A simple method for estimating MSY from catch and resilience. Fish and Fisheries, doi: /j x R-code ICES_Data RAM_Data PDFR-codeICES_Data RAM_DataPDF Froese, R. and A. Sampang Proxies for estimation of relative fishing mortality when biomass is unknown. ICES CM 2012/G:15, 1-17 DOC XLS Stocks Flounder MustelusDOCXLSStocksFlounderMustelus Froese, R Putting the Catch-MSY method to a test: preliminary insights. Report from the WKLIFE workshop, February 2012, IPIMAR, Lisbon, Portugal. DOCDOC Froese, R., A. Stern-Pirlot, H. Winker and D. Gascuel Size Matters: How single-species management can contribute to ecosystem-based fisheries management. Fisheries Research 92: , PDFPDF

Summary Catch-MSY method has been applied now to many stocks and seems to work satisfactorily MSY-only management worked well in most ICES stocks Additional information on stock development (e.g. from length frequencies) is important to check assumptions and confirm trends