Title: Growth and reproduction performances of the Pacific oyster Crassostrea gigas in Algeria
École Nationale Supérieure des Sciences de la Mer et de l’Aménagement du Littoral,Campus Universitaire de Dely IbrahimBoisdesCars(ENSSMAL),Dely Ibrahim 16320, Algiers, Algeria
Sustainable oyster production of Crassostrea gigas in Algeria requires information about growing, condition and reproduction. This study documents growth rates, condition index (CI), and describes the reproductive cycle of oysters cultivated in open sea using plastic sacs suspended from long-lines. One experiment refers to growth and condition of juveniles (May 2011–February 2012), and a second experiment with adults (October 2012–October 2013), provides length and weight variation, CI and describes gametogenesis using oocyte cohort analysis. Juveniles showed exponential growth patterns of mean shell length (0.137 mm day–1) and total weight gain (0.141 g day–1). CI of juveniles was low during the cultivation period. Length and weight of adult oysters ranged from 93.9–109.1 mm and 64.1–132.3 g respectively, while CI was satisfactory (>50) most of the time. The reproductive cycle of C. gigas begins in December, with several oocytes cohorts growing during January-February, maturing in March-May and showing a main spawning in June when temperature was increasing. Spawning of less intensity were observed during July-October after the peak of temperature. Spring phytoplankton blooms seem to provide energy for gonad development. These results may serve as baseline data for the development of aquaculture programs in Algeria.