|Document Type:||Journal Article|
|Title:||Variability in rockfish (Sebastes spp.) fecundity: species contrasts, maternal size effects, and spatial differences|
|Author:||Sabrina G. Beyer, Susan M. Sogard, C. J. Harvey, John C. Field|
|Journal:||Environmental Biology of Fishes|
|Keywords:||Sebastes spp., rockfish, fecundity, maternal size, spatial effects, multiple broods,|
We investigated the reproductive ecology of three rockfish species residing in the California Current System: chilipepper, Sebastes goodei, yellowtail, S. flavidus and speckled rockfish, S. ovalis. Females were sampled from four locations along the coast of California in the winter spawning seasons (November through March) of 2009, 2010 and 2011 to assess temporal and spatial effects on fecundity. Maternal size and age were positively correlated with relative fecundity ($rel, larvae per g somatic weight) for all three species and indicated a disproportionately greater reproductive output by older, larger females. Yellowtail rockfish had the highest absolute and $rel, the greatest maternal size effect, and produced the smallest eggs. Size-dependent $rel relationships were incorporated into published stock assessment models that originally assumed egg production to be directly proportional to spawning biomass. The updated models showed a reduction in larval output when large, old females were removed from the population by fishing for both chilipepper and yellowtail rockfish. In addition, fecundity varied spatially among sampling sites (chilipepper and yellowtail) and by year (chilipepper). Speckled rockfish lacked adequate sample size to assess spatiotemporal trends in fecundity. Chilipepper and speckled rockfish produced multiple broods annually in Southern California and to a lesser extent in Central California, complicating estimates of annual fecundity. Egg production was positively correlated with female condition, indicating environmental variability in oceanographic conditions and productivity may drive changes in fecundity and reproductive strategy (i.e. single verses multiple broods) in these species.
|Theme:||Ecosystem Approach to Management for the California Current Large Marine Ecosystem|
Characterize linkages between climatic conditions and biotic responses.