Production of Penilia avirostris in Kingston Harbour, Jamaica

Abstract

The cladoceran Penilia avirostris is one of the more abundant and widespread members of the crustacean zooplankton in nearshore tropical and subtropical waters. Its abundance, biomass, fecundity, development rate and production were estimated in Kingston Harbour, Jamaica, during an 18 month period. Mean annual abundance of Penilia was 1821 m-3, while biomass (excluding eggs/embryos) was 2.87 mg ash-free dry-weight (AFDW) m-3 (43.1 mg AFDW m-2), accounting for 13% of the copepod community biomass. Fecundity increased with body size. There was no clear seasonal pattern of abundance, size or fecundity, nor were physical or biological variables correlated to these variations. Development time averaged 20.5 h for juveniles and 41.4 h for adult females during incubations; there was no clear evidence of a diel pattern to molting. Growth rate appeared to be exponential, with corresponding somatic growth rates, averaging 0.27 day-1 for juveniles, and 0.34 day-1 for somatic plus reproductive growth in adult females. Annual production was estimated as 173 kJ m-2 year-1, ∼10% that of the copepod community. Penilia avirostris production was similar to the third most productive copepod species. The importance of this species in tropical coastal waters would appear to be under-appreciated.