To address these hypotheses, we sampled the large aggregation of
round stingrays at Seal Beach, California, monthly for 16 months to
assess seasonal changes in reproductive physiology. Males were
assessed for plasma testosterone (T) and 11-ketotestosterone (11-KT)
concentrations, gonadal morphology, testicular apoptosis, and GSI. In
addition, we examined the influence of temperature on steroid hormone
concentrations in a subset of captive male round stingrays under
controlled laboratory conditions.