Vertical distribution of Paracalanus crassirostris (Copepoda, Calanoidea): analysis by the general linear model

Abstract

The vertical distribution of each developmental stage of Paracalanus crassirostris was studied in a shallow water station at Ubatuba, SP, Brazil (23º30'S-45º07'W). Samples were collected monthly at the surface, 2m and near bottom levels . Salinity, temperature, dissolved oxygen, tide height, light penetration arid solar radiation were also recorded. Data were analysed by the general linear model. It showed that the amount of individuals at any developmental stage is affected diversely by hour, depth, hour-depth interaction and environmental factors throughout the year and that these effects are stronger in summer. All developmental stages were spread in the water column showing no regular vertical migrations. On the other hand, the number of organisms caught in a particular hour seemed to dependmore on the tide than on the animals behaviour. The results of the present paper showed, as observed by some other authors, the lack of vertical migration of a coastal copepod which is a grazer of fine particles throughout its life.