SPERM CHARACTERISTICS OF PRECOCIOUS 1-YEAR-OLD MALE STRIPED BASS MORONE-SAXATILIS

Captive-reared, 10-mo-old, male striped bass Morone saxatilis were sam pled monthly for testicular development between February and June 1994 . One of the five males sampled in February showed precocious testicul ar development and had a gonadosomatic index (GSI) of 1.26%, while the other four fish had immature testes with a mean GSI +/- s(x) of 0.17 +/- 0.03%. Spermiating individuals were present from April to June. In April the average body weight (BW) of spermiating males was 65 +/- 4 g and their GSI reached a mean value of 4.75 +/- 0.52%. In June, milt collected from ten precocious males contained motile spermatozoa with a mean of 31 +/- 7% of the sperm showing forward movement. Mean milt v olume and sperm concentration were 1.67 +/- 0.41 mL/kg BW and 92.3 +/- 1.8 x 10(9) spermatozoa/mL, respectively. These data show that male s triped bass reared in captivity can reach sexual maturity during their first year. This is one year earlier than previously reported for str iped bass in mid-Atlantic regions.