NAPHTHALENE-INDUCED ATRESIA IN THE OVARY OF THE CRAYFISH, PROCAMBARUS-CLARKII

Female crayfish, Procambarus clarkii, were exposed to 10 ppm naphthale ne to determine its effect on ovarian development. Ovaries were remove d for examination after 1, 2, 4, 6, 8, 10, 12, and 15 days of exposure to the naphthalene. Crayfish that had been exposed to naphthalene for 15 days were then returned to clean freshwater for 1, 2, 4, 5, 7, 10, and 15 days to determine whether the ovaries would recover from the n aphthalene exposure. The ovarian index, which reflects the weight of t he ovary, decreased gradually over the 15-day naphthalene exposure per iod. The previtellogenic and vitellogenic oocytes degenerated. Intense atresia along with yolk resorption led to this decrease in the ovaria n index. In contrast, the ovaries of the control crayfish developed in to ripe gonads. However, immature oocytes reappeared in the ovaries of the crayfish subjected to depuration, which suggests that the ovary o f P. clarkii can recover from naphthalene-induced atresia. (C) 1995 Ac ademic Press, Inc.