Patrick Lehodey

Influence of temperature and ENSO events on the growth of the deep demersal fish alfonsino, Beryx splendens, off New Caledonia in the western tropical South Pacific Ocean

Abstract This paper deals with the influence of temperature on the growth of alfonsino, Beryx splendens , caught in New Caledonia at 23–25°S and 165–171°E. The mean temperature of the 0–500 m water layer was cross-correlated with the Southern Oscillation Index after the seasonal cycles were removed. It is shown that the interannual fluctuations of temperature are influenced by ENSO (El Nino-Southern Oscillations) events with a time-lag of several months. The growth study is based on the reading of annuli on sagittal otoliths. In order to show fluctuations in otolith growth, an index of increase variation I va was defined. Superposition of the I va series on temperature series suggests the growth of alfonsino to be strongly related to temperature fluctuations in intermediate-depth water masses and consequently by ENSO events which appear further north at low latitudes in the equatorial Pacific. “El Nino” events would increase growth rate whilst “La Nina” events would reduce it.