Efficacy of animal anti-fertility compounds against sea lamprey (Petromyzon marinus) spermatozoa

Sterile-male-release technique is currently used to control the sea lamprey (Petromyzon marinus) population in the Great Lakes. The chemosterilant (bisazir) used in this program is extremely hazardous; special safety measures are necessary when handling this chemical. Therefore, replacement of bisazir with safer agents is desirable. In this study, we examined the effects of low-toxicity compounds with previously described spermicidal activity (mainly against mammalian sperm) on motility and fertilizing ability of sea lamprey spermatozoa. Nonoxynol-9, benzalkonium chloride, zinc acetate, cupric chloride, cysteamine, tannic acid and propranolol were able to inhibit both sperm motility and fertilizing ability. Effective concentrations of these spermicides ranged from 0.15 to 1%. Therefore, they can be potentially used in further study directed at in vivo sterilization of male sea lampreys.