Application of the Seawater Medaka Oryzias melastigma (McClelland) for Marine Ecotoxicology

This chapter summarizes the general features and basic biology of Oryzias melastigma. This small fish, often referred to as the “marine medaka,” completes its whole life‐cycle in seawater. It exhibits fast and uniform growth, the generation time is relatively short (2‐3 months) and females can produce eggs daily, hence providing a variety of developmental and reproductive endpoints for whole life‐cycle and multigeneration assessments. It is very important to maintain optimal conditions for mass culture of marine medaka in order to ensure a high hatching rate, reduce larval mortality during development, and allow rapid and uniform growth into adulthood. Three established Standard Operating Procedures are presented here to illustrate the cost‐effectiveness and high‐throughput application of marine medaka for environmental toxicology studies. These include protocols for immunotoxicity assessment, fish dissection for the whole adult histology array, and the embryo chip