Change of Plasma Chemistry Values in Captive Breeding Loggerhead Turtles (Caretta caretta)

Loggerhead turtles, Caretta caretta, have been laying eggs in an indoor artificial beach since 1995, at the Port of Nagoya Public Aquarium (PNPA). Two males and four females were mated and those four landed and laid eggs several times during the breeding period in 1996. In 1998 egg laying was observed from April to July and mating was one or two months prior to the nesting season. Blood samples from these individuals were collected monthly in the previously mentioned years in order to investigate the changes in sex steroid hormones (testosterone, estradiol, and progesterone). Moreover, blood chemistry values (total protein, albumin, triglyceride, total cholesterol, total calcium, and inorganic phosphorus) were investigated. In 1998, for the two males, changes in testosterone levels were additionally examined. Blood chemistry values of each turtle changed periodically as sex steroids did based on the breeding period and laying cycle. Data from a completely artificial environment such as the one at the PNPA provide elucidation of the reproductive physiology in these endangered species.