Meeting Abstract
The Atlantic sea urchin, Arbacia punctulata, is a unique invertebrate and a primeval species of the phylum Echinodermata. Natural phenomena such as water temperature and moonlight act as external cues that stimulate the reproductive activity of aquatic organisms. In order to acquire a better understanding of the correlation between gonadal maturity, lunar reproductive rhythm and spawning season in the economically and environmentally important marine species, the focused objective of our study was to determine the annual and lunar reproductive rhythms of the Atlantic sea urchin in the southern waters of Texas in the Gulf of Mexico. Sea urchins were collected monthly from July 2016 to June 2017 and sampled weekly in accordance with the lunar cycle from May to July in 2017 in South Padre Island, Texas. The gonadosomatic index (GSI, a biological indicator of isometric growth in gonads) of each sea urchin was calculated as the percentage of gonad weight/total body weight measurements. Gonadal tissues were sectioned and stained with hematoxylin-eosin. Subsequent histological examination of ovaries and testes was performed: maturity levels and spawning phases were determined quantitatively by calculating the percentage of oocytes (immature egg) and ova (mature egg) for each female and the production of sperm for each male. Collectively, our histological analysis suggests that Atlantic sea urchin spawns synchronously according to the lunar cycle and could spawn several times for the following summer months in the southern Gulf of Mexico.
