Observations on the ecology of Pleurobrachia pileus (Ctenophora) in the southern Benguela ecosystem
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Date
2003
Journal Title
Journal ISSN
Volume Title
Publisher
NISC (Pty) Ltd and Taylor & Francis
Abstract
The vertical distribution, abundance and size composition of a population of Pleurobrachia pileus was studied during a six-day drogue study conducted off the west coast of South Africa in February 1995. The population was centred in deep water, possibly because of the presence of a potential predator, Beroe sp., at shallower depths. The population of P. pileus failed to display clear patterns of migration, although nocturnal recruitment from deeper water resulted in a deepening of the depth of occupation then. The population was dominated by individuals <4 mm polar diameter, and large animals were confined to the upper water layers. These results are discussed with reference to possible spawning activities. Using published equations relating size to clearance rates, it was estimated that the population could remove up to 27% of integrated mesozooplankton standing stocks, and in excess of 100% (293%) at some depths.
Description
Keywords
Pleurobrachia pileus, Benguela upwelling ecosystem, Size structure, Vertical distribution
Citation
Gibbons, M.J. et al. (2003). Observations on the ecology of Pleurobrachia pileus (Ctenophora) in the southern Benguela ecosystem. African Journal of Marine Science, 25(1): 253-261