Distribution and abundance of copepod nauplii in the vicinity of a submarine canyon (NW Mediterranean)

Distribution and abundance of copepod nauplii in relation to oceanic features detected by in situ data in the vicinity of the Palamos Canyon (NW Mediterranean) was analyzed. Vertical trawls (60-μm mesh) and physical data (CTD and ADCP), were obtained in a spring period (May 1992). The vicinity of the canyon was dominated by the Liguro-Provençal-Catalan Current (slope current), influenced by the fresh water from of the Rhône River runoffs, and perturbations of its flow induced by the submarine topography. High abundance of copepod nauplii were associated with the slope current waters and its intrusions into the canyon, showing an offshore-nearshore abundance gradient. The highest concentrations of copepod nauplii were found at the eastern margin of the slope current along of a shallow salinity front. Results showed that the spawning of dominant copepod species in the offshore zone could be related to retention areas, such as the salinity front, and to the biological enrichment of the slope current influenced by Rhône river discharges during the rainy period and ice melting of the Provençal mountains.