The Reproductive Biology of the Finetooth Shark, Carcharhinus isodon, in the Northwest Atlantic Ocean

Publication Year:
2015
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Repository URL:
https://digitalcommons.unf.edu/etd/564; https://digitalcommons.unf.edu/cgi/viewcontent.cgi?article=1594&context=etd
Author(s):
Brown, Amanda; Brown, Amanda Nevada, 1984-
Tags:
Thesis; University of North Florida; UNF; Dissertations; Academic -- UNF -- Master of Science in Biology; Dissertations; Academic -- UNF -- Biology; reproduction; endocrinology; morphology; sharks; fisheries; Thesis; University of North Florida; UNF; Dissertations, Academic -- UNF -- Master of Science in Biology; Dissertations, Academic -- UNF -- Biology; reproduction; endocrinology; morphology; sharks; fisheries; Animal Sciences; Aquaculture and Fisheries; Biology; Endocrinology; Marine Biology
thesis / dissertation description
Shark fisheries are a multimillion dollar industry in the United States and have significant contributions both recreationally and commercially. In order to maintain this industry, fisheries must be properly managed. An understanding of life history and reproduction is crucial in order to adequately manage shark fisheries. The finetooth shark, Carcharhinus isodon, is a member of the small coastal shark (SCS) fishery complex. It is found in Atlantic waters from South Carolina to Florida and throughout the Gulf of Mexico. This species has recently come under increased fishing pressure and has previously been overfished. New data is needed in order to properly assess the reproductive capacity of this species so that healthy populations can be sustained. This study evaluated the overall reproductive cycle of northwest Atlantic populations of C. isodon using composite variables of morphology, histology and endocrinology. Atlantic C. isodon were found to display seasonal reproduction with biennial reproductive periodicity with a 12 month gestation period and litters of 2-6 pups. E2 and T displayed similar patterns and were highest during gametogenesis. P4 did not show any discernible patterns. Estrogen receptors were found in developing follicles of gravid and non-gravid females, in the oviducal glands of non-gravid and early pregnant females and in the uterus of pre-ovulatory females. P4 was found in the oviducal glands in all reproductive stages and in the uterus of pre-ovulatory females. Androgen receptors were found in Sertoli cells and mature spermatozoa as well as epididymal epithelial cells.