Nutrient allocation in the gonads of the sea urchin Arbacia dufresnii in different stages of gonadal development

Abstract

This study reports nutrient allocation in different stages of gonadal development for two populations of the sea urchin Arbacia dufresnii off the Patagonian coast of Argentina (Nuevo Gulf and San Jorge Gulf). The biochemical composition of gonads was used to assess nutrient allocation by measuring ash, soluble protein, lipid and trichloroacetic acid-soluble carbohydrate concentrations, and absolute contents over a 24-month period. Reproductive output in terms of energy was calculated for females. Results were correlated with histological stage of the gonads. Soluble proteins were the main component for the Nuevo Gulf population while unmeasured organic material (i.e. insoluble proteins and nucleic acids, especially in testes) was prevalent in gonads from San Jorge Gulf. Soluble protein and lipid concentrations followed the gonadal cycle, while carbohydrate concentration was almost negligible, especially in the Nuevo Gulf population. The different patterns in the gonadal cycle in the two populations were reflected in the biochemical composition of gonads. Concentrations and contents of the biochemical components and reproductive output were higher in the population from San Jorge Gulf owing to the larger size of gonads and gametes. These findings contribute to the better understanding of the plasticity of the reproductive biology of A. dufresnii in different environments.

Keywords:

• Echinodermata
• Echinoidea
• biochemical composition
• gonadal stages

Acknowledgments

We would like to thank Lic. Javier Tolosano, Belén Reartes, and Soledad Pérez-Gallo for collection and sample processing in SJOG. We also want to thank the divers from Master Diver for the assistance during the sampling in NG. We would like to thank Dr John Lawrence for reading of earlier versions of this manuscript.