Does maternal size affect red king crab, Paralithodes camtschaticus, embryo and larval quality?

Abstract

Stock assessment of Alaskan red king crab, Paralithodes camtschaticus(Tilesius, 1815), can be improved by incorporating reproductive output,which requires an understanding of maternal size effects on embryo andlarval quality. In June 2009 and 2010, we collected clutches of recentlyextruded red king crab embryos in Bristol Bay, Alaska, to assess embryoquality based on dry weight, carbon and nitrogen content. To assesslarval quality, we collected ovigerous females from Bristol Bay in 2007and reared them in the laboratory until larval hatching in 2008. Larvalquality based on dry weight, carbon and nitrogen content, and times to50% mortality under starvation conditions were assessed. All sampleswere collected in years that were colder than the 15-year average in theeastern Bering Sea. Among the measures of embryo quality, only nitrogencontent was significantly different, increasing with maternal size.Carbon and nitrogen content were significantly higher for embryos in2009 than in 2010, suggesting inter-annual differences in maternalinvestment. No effect of maternal size with larval quality was found.Our results indicate that maternal size does not have a biologicallysignificant effect on embryo and larval quality in colder-than-averageyears, and therefore maternal size effects on embryo and larval qualitydoes not need to be explicitly incorporated into reproductive outputestimates in stock assessments under these conditions. We are, however,cautious to extrapolate our results to years with differentenvironmental conditions. Further study is needed to fully resolve thepossible interaction of environment with maternal size effects on embryoand larval quality for red king crab.