15 MARCH 1999
CHARACTERISTICS OF SPERM OF CAPTIVE SEABASS IN RELATION TO ITS FERTILIZATION POTENTIAL
C. Fauvel, O. Savoye, C. Dreanno, J. Cosson, M. Suquet-1999
Journal of Fish Biology, 54: 356-639
Abstract:
Seabass Dicentrarchus labrax sperm concentration was high (up to 60 x10^9 spz/ml) but decreased significantly at the end of the reproductive season (mid-March) in monthly sampled fish. The spermiation period may be shortened by frequent stripping. Sperm can be prediluted up to 1: 128 in non-activating medium without loss of initial motility and motility duration. Immediately after activation by transfer to sea water, all the spermatozoa were motile for 10 s and then the number of motile cells decreased progressively but sharply to zero, so that the duration of sperm motility was very short (40 s). As a consequence, the fertility of seabass sperm decreased exponentially after 10 s following sperm activation and was zero by 1 min. The sperm requirements for optimal fertilization were c. 66 000 spermatozoa per egg. Scaling-up of the experimental insemination procedure yielded better fertilization rates while conserving the individual differences due to the breeder pairs.
(Station Experimentale d'Aquaculture, IFREMER, chemin de Maguelone, 34250 Palavas, France, tel: 33 467504106, fax: 33 467682885, e-mail: cfauvel@ifremer.fr)