Distribution of mesopelagic decapod Crustacea in and around a warm-core eddy in the Tasman Sea

Abstract

Nocturnal distributions of mesopelagic penaeid, sergestid, and carid crustaceans were determined in the upper 300 m inside, outside and at the edge of warm-core eddy F in December 1978. The 3 sites sampled represent 3 different domains within the Tasman sea water mass. Twenty-five species (2025 specimens) were caught. Systellaspis debilis, Funchalia villosa and Sergestes stimulator were most abundant inside the eddy, whilst Sergestes disjunctus was most abundant outside. Acanthephyra quadrispinosa, Gennadas gilchristi, Sergestes armatus, S. disjunctus , and Sergia prehensilis were more numerous in cold (< 16 degree C) water, while Funchalia villosa was more numerous in warm water. The abundance of Oplophorus spinosus, S. debilis, S. armatus , Sergestes corniculum, S. disjunctus and S. prehensilis increased with depth. Three communities, corresponding to the outside, inside, and edge domains, were found. O. spinosus, S. prehensilis , and S. debilis were the dominant species in this study (72.2% of the total individuals) and all had evidence of population differences across the eddy boundary.