An examination of reproductive senescence and parental effects in the Caribbean spiny lobster, Panulirus argus

The harvest or conservation of particular size and age classes of fished species can significantly affect their reproductive potential. Management strategies, such as maximum size limits, can help rebuild depleted spawning stocks, but both positive and negative effects of parental size on reproductive success should be considered. Positive parental effects on offspring fitness relative to increasing parent size or age have been documented in several marine species. Likewise, reproductive senescence, the reduction in reproductive fitness relative to size or age, also has been documented in a number of taxa. The Caribbean spiny lobster, Panulirus argus (Latreille, 1804), supports one of the Caribbean region's most valuable fisheries, but lobster catch and their average size in most areas has decreased over the last 30 yrs. Large lobsters produce more eggs per clutch and more clutches per season, thus contribute disproportionately to a population's reproductive capacity. In the present study, we tested the relationship between lobster size, gamete production, and larval quality over multiple mating events to examine the possibility of reproductive senescence and positive parental effects. Rather than a decline in offspring quality with female size over successive clutches, we found that eggs and larvae in the second and third clutches produced by large females were generally of higher quality. Similarly, spermatophores deposited by large males were heavier and thicker with no decline in sperm number or quality with size. Thus, we found no evidence of reproductive senescence in P. argus, and instead some positive parental effects-important considerations for their future management.