BIO

My name is Frederick Raftis, and I am undergraduate at Florida State University majoring in biology. I have a strong interest in zoological and ecological research, and generally have a love and knack for learning. I hope to one day be able to make a career through my research ideas, and wish to share any information I acquire with the world.

Physiological Effects of Pregnancy on Atlantic Stingray

Abstract

Elasmobranch reproductive strategies have largely been underrepresented in marine research over the last 50 years. A large proportion of ray species are viviparous and females nourish their offspring through lipid-rich fluids called histotroph. The nutritional costs of creating these fluids are unknown but thought to be the greatest form of maternal investment of all sharks and rays. This study quantifies the total maternal investment from mother to embryo in Hypanus sabinus, the Atlantic stingray, throughout their 4 to 4.5 month gestation. Embryos at various developmental stages were weighed (g), dried at 60℃, and incinerated at 550℃. The percent change in mass, (Final (g) - initial (g)/initial (g) x 100, was calculated for water, inorganic, and organic matter from initial fertilized zygotes and final full-term embryos. By investigating the contents of the embryonic digestive tract, liver, external and internal yolk sac, and surrounding body, we aim to identify how maternal histotroph secretions are being distributed to embryonic development and growth.
Future research will investigate the biochemical content of intrauterine histotroph secretions, as well as the effect of embryonic maternal investment on the physical performance of gravid females at different stages of gestation. This research aims to advance conservation efforts through knowledge of how maternal investment contributes to pup quality and survival and associated maternal costs.

Keywords: Elasmobranch, Stingray, Marine, Biology, Histotroph