Abstract
Red gurnard, Chelidonichthys kumu, were sampled by long-lining and from a fish processing factory to investigate the seasonal cycle of reproduction in a population from north-eastern New Zealand. Female red gurnard showed changes in gonadosomatic index (GSI) and frequencies of stages of ovarian development consistent with spawning from spring (September) until autumn (May). Peak GSI (approximately 6%) occurred in late spring or early summer, and minimum GSI (approximately 1%) occurred in winter (June). Blood samples were taken from live fish caught on long-lines, and seasonal changes in plasma concentrations of oestradiol-17� (E2) and testosterone (T) were measured by radioimmunoassay. Plasma E2 and T reached maximum concentrations of 1.99 ng mL-1 and 2.06 ng mL-1, respectively, as GSI levels peaked, and then declined as GSI decreased over summer. Plasma E2 and T increased again as GSI began to increase prior to the next spawning season. Maximum hepatosomatic index (HSI) occurred in association with gonadal recrudescence. HSI decreased significantly as the spawning season progressed and showed a significant but irregular increase as recrudescence occurred prior to the following spawning season.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
