Biological characteristics of European hake (Merluccius merluccius) sperm

Very little is known on European hake's reproductive biology and especially on biological characteristics of its sperm despite a growing interest in its aquaculture potential. This study reports, for the first time some hake sperm characteristics. After activation, the swimming phase lasts 3 min (8 min when activated with 50% sea water (SW) but lower initial velocity). The initial flagellar beat frequency (BF), velocity and percentage of motile cells decreased after 100 s. After 2 days at 4 degrees C, the mean Adenylate Energy Charge (AEC) level was 0.71. Sperm stored at 4 degrees C still showed motility after 9 days for 2 individuals. When cryopreserved, the motility recovery index of thawed spermatozoa ranged from 11.8% to 29.6%.