AN EXAMINATION OF THE STABLE ISOTOPE DYNAMICS OF CLEARNOSE SKATE (ROSTRORAJA EGLANTERIA) TISSUES

Abstract

Rostroraja eglanteria is a common, but under-researched elasmobranch species in the Delaware Bay. This study sought to elucidate the stable isotope dynamics, such as turnover rate and trophic discrimination factor, of R. eglanteria dermis, muscle, and blood plasma through a months-long diet-swap experiment with 12 fully-grown specimens in captivity. The results from this study indicate that R. eglanteria displays a remarkably slow turnover rate, as evidenced by strikingly high trophic discrimination factors ranging from 4.06 - 7.42, even after 5 months of experimentation. Potential explanations for this slow rate of isotopic incorporation include the lack of visible growth displayed by R. eglanteria in captivity, as well as the generally low metabolic rates of benthic species. These results have significant implications for future ecological studies into R. eglanteria and other similar organisms, suggesting the need for longer-term research. The methodologies presented in this study are broadly applicable to stable isotope analysis research in both laboratory and field settings, offering a viable approach to further explore the ecological role of under-studied species like R. eglanteria.