Sex organ extracts and artificial hormonal compounds as sex pheromones to attract broodfish and to induce spawning of Chinese black sleeper (Bostrichthys sinensis Lacepede).

摘要

Ovarian, testicular and seminal vesicle extracts of mature Chinese black sleeper (Bostrichthys sinensis Lacepede), synthetic steroids 17 alpha -progesterone (17 alpha -P), 17 alpha ,20 beta -dihydroxy-4-pregnen-3one (17 alpha ,20 beta -P) and prostaglandins PGE2 and PGF2 alpha were used in an attempt to attract broodfish and to induce spawning. Furthermore, 17 alpha -P, PGE2 and PGF2 alpha levels were determined in extracts, and PGE2 and PGF2 alpha levels were determined in holding and spawning waters. The results showed that ovarian extracts attracted more males than females to enter artificial nests, while testicular and seminal vesicle extracts attracted more females than males. The highest percentage of spawned nests were found when 17 alpha ,20 beta -P and PGE2 were administered to the nests, while the largest egg numbers and the mean highest fertilization rate were observed when PGE2 was added. In ovarian extract, 17 alpha -P level was higher than levels in testicular or seminal vesicle extracts. The PGE2 levels were significantly (P<0.05) higher than PGF2 alpha in the ovarian, testicular and seminal vesicle extracts. The PGE2 and PGF2 alpha levels in spawning waters were higher than those in holding waters. The PGE2 levels were greatly significantly (P<0.01) higher than PGF2 alpha in spawning and in holding waters. The results suggest that the sex organs of B. sinensis contain 17 alpha -P, 17 alpha , 20 beta -P, PGE2 and PGF2 alpha and that 17 alpha -P, 17 alpha ,20 beta -P and PGE2 may act as sex pheromones in this species, attracting both male and female conspesifics to spawning sites and inducing spawning. Among the compounds tested, PGE2 was the most effective sex pheromone for induction of spawning in B. sinensis..