Natural Mortality Fishing Mortality Immigration Emigration Population Numbers Recruitment Spawning Potential Ratio SPR Number of lifetime eggs produced by an average recruit when fished ID: 602084
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Slide1
Stock-Recruitment
Natural Mortality
Fishing Mortality
Immigration
Emigration
Population
Numbers
RecruitmentSlide2
Spawning Potential Ratio (SPR)
Number of lifetime eggs produced by an average recruit when fished divided by the number of lifetime eggs produced by an average recruit
when unfished. Compares the spawning ability of a fished stock to the spawning ability of
the unfished stock. Stock-Recruitment2Slide3
Spawning Potential Ratio (SPR)
Stock-Recruitment3
Proportion mature
Mean fecundity
Survival to age iSlide4
Spawning Potential Ratio (SPR)
Use in managementPrinciple: enough fish have to survive to spawn and replenish the stock.
Benchmark: not well-defined for most speciesMarine pelagic -- >20% (Goodyear 1993)Marine pelagic -- >30% (Mace & Sissenwine 1993)Channel catfish -- >10% (Slipke
et al. 2002)Shovelnose sturgeon -- >40-50% (Quist et al. 2002)Stock-Recruitment
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