Abstract
Growth and secondary production of pelagic copepods near Australia's North West Cape (21° 49′ S, 114° 14′ E) were measured during the austral summers of 1997/1998 and 1998/1999. Plankton communities were diverse, and dominated by copepods. To estimate copepod growth rates, we incubated artificial cohorts allocated to four morphotypes, comprising naupliar and copepodite stages of small calanoid and oithonid copepods. Growth rates ranging between 0.11 and 0.83 day−1 were low, considering the high ambient temperatures (23–28°C). Calanoid nauplii had a mean growth rate of 0.43±0.17 day-1 (SD) and calanoid copepodites of 0.38±0.13 day-1. Growth rates of oithonid nauplii and copepodites were marginally less (0.38±0.19 day−1 and 0.28±0.11 day−1 respectively). The observed growth rates were suggestive of severe food limitation. Although nauplii vastly outnumbered copepodite and adult copepods, copepodites comprised the most biomass. Copepodites also contributed most to secondary production, although adult egg production was sporadically important. The highest copepod production was recorded on the shelf break (60 mg C m-2 day-1). Mean secondary production over both shelf and shelf break stations was 12.6 mg C m-2 day-1. Annual copepod secondary production, assuming little seasonality, was estimated as ~ 3.4 g C m-2 year-1 (182 kJ m-2 year-1).
Published Version
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