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Abstract: A one year long monthly sampling series at a fixed station was combined with a high-spatial resolution survey (May 2003) to investigate factors controlling zooplankton distribution in the south-eastern corner of the Bay of Biscay. Species abundance and gonad maturity for Calanoides carinatus and Calanus helgolandicus were estimated to clarify whether the observed spatial patterns were attributable to increased population growth or to mechanical accumulation. The two studies included distinct oceanographic regimes. The eastern corner of the grid was characterized by Adour river plume waters and the Cap Breton canyon, and the rest of the area by an alternating pattern of physical convergences and divergences. In the river plume, the zooplankton community diversity and abundances were highest in response to the nutrient enriched river plume waters and the submarine canyon. In the rest of the area, distribution and abundance patterns were the result of a combination of behaviour and physical transport. [Copyright &y& Elsevier]

The effect of the parasite Ellobiopsis sp., on the fecundity of Calanus helgolandicus and Calanoides carinatus in the Bay of Biscay, was investigated in May 2003. An average of 6.8% of C. helgolandicus females were infected with Ellobiopsis sp., whereas none of the C. carinatus were found to be infected. An objective method of estimating gonad development was applied to quantitatively measure the effect of the parasitism on the reproduction of the copepod. Parasitism by Ellobiopsis sp. has the potential to reduce the fecundity of C. helgolandicus females. [ABSTRACT FROM AUTHOR]