Date of Award

Spring 2013


© 2013 Bianca Prohaska

Document Type


Degree Name

Master of Science in Marine Sciences


Marine Science

First Advisor

James Sulikowski

Second Advisor

A. Christine Brown

Third Advisor

Paul Tsang


Currently, circulating concentrations of plasma steroid hormones are used as one means to assess reproductive maturity and reproductive cycles in elasmobranchs. However, obtaining blood non-lethally from large and/or endangered species can be problematic because of difficulties involved with specimen handling. Thus, there is a need to develop new approaches and techniques to study the reproductive biology of elasmobranchs. Previous work conducted on other classes of vertebrates has demonstrated that steroid hormones can be successfully extracted from muscle tissue. The process of collecting muscle tissue samples is quick, minimally invasive, and may be conducted without removing the animal from the water, facilitating its use on larger, and/or endangered species of elasmobranchs. Thus, the objective of the current study was to develop and validate a method for extracting steroid hormones from the skeletal muscle tissue of the lecithotrophic aplacental viviparous spiny dogfish (Squalus acanthias), the oviparous little skate (Leucoraja erinacea), and the placental viviparous Atlantic sharpnose shark (Rhizoprionodon terraenovae). The results suggest that concentrations of progesterone [P4], testosterone [T], and estradiol [E2] present in skeletal muscle of the three aforementioned species can be successfully quantified by radioimmunoassay. Additionally, there were significant correlations between plasma and muscle E2 concentrations in S. acanthias, as well as plasma and muscle P4, T and E2 concentrations in R. terraenovae and L. erinacea. Furthermore, concentrations of muscle P4, T and E2 were determined to be statistically significant indicators of reproductive status. The results of the current investigation demonstrated that skeletal muscle, which can be non-lethally harvested, is a viable and practical alternative to collecting blood samples for studying the reproductive biology of elasmobranchs.


Master's thesis