Seasonal variation of reproductive traits of the caramote prawn in the Gulf of Tunis

Abstract

The caramote prawn, Melicertus kerathurus , is a Penaeidae species inhabiting the Mediterranean Sea and the Est Atlantic Ocean. Caramote prawn represents a commercially important species in terms of both aquaculture and fishing; however, there is poor information on its reproductive biology in Mediterranean and, particularly, in Tunisian waters. To fulfil such a gap, monthly samples of caramote prawn were collected along the northern Tunisian coast throughout one year. Ovaries maturity data, obtained by histological analysis, together with reproductive and condition indices, indicated the main spawning season extends from April to August, with a clear peak in July–August. However, gonadic production still persists during September-December, although at lower levels. The seasonal patterns of somatic and gonadic conditions suggested that energy reserves, during the main spawning period, were invested both in gonadic and body production; but males and females appeared to devote differently such energy reserves. During the spawning peak, females revealed both good somatic and gonadic conditions simultaneously, while males displayed worse body conditions. Monthly sea surface temperature (SST) showed a high level of pattern correspondence with ovary maturity phase and gonadosomatic index (GSI); but a strong linear relationship between SST and GSI in the study area was observed only for males. Such results increased reproductive biology knowledge, therefore allowing to improve the management quality of both wild caramote prawn stocks and reared populations.