Gamete Viability, Fertilization, and Embryonic Development of Gracious Sea Urchin Tripneustes gratilla Under Varying Temperature Ranges

Abstract

The Gracious Sea Urchin Tripneustes gratilla is a model organism for invertebrate marine animals and an economically important marine resource. This study investigated the effects of varying temperature ranges 29-30°C, 34-35°C, and 39-40°C on the reproductive capacity of T. gratilla. Under these temperature treatments, gamete viability was determined through the resazurin reduction test and quantified through resazurin absorbance at 630 nm, while fertilization and embryonic development were investigated through in vitro experiments. With increasing temperature, there was a significant decline in the viability of both sperm and egg cells. Gamete death was highest at 39-40°C followed by 34-35°C temperature ranges. Successful fertilization was highest at 29-30°C (92.26%) followed by 34-35°C (20.83%) and 39-40°C (11.05%) temperature ranges for the two batches. Normal embryonic development from 2 cells up to 2 arm echinopluteus was observed at 29-30 °C while abnormalities including apoptotic body formations, cell fragmentation, cell lysis, and embryo arrest were observed at 34-35°C and 39-40°C temperature ranges. This study confirmed the deleterious effect of increased temperature (34-40°C) on the reproductive potential of T. gratilla.