Wild-harvested Marphysa madrasi for biosecure aquaculture: nutritional profiling, pathogen screening, and phylogenetic assessment

Abstract Polychaetes are widely used as high-value aquaculture feed, yet India continues to depend heavily on imported species despite the availability of locally abundant taxa. However, the nutritional potential, biosafety, and taxonomic clarity of indigenous polychaetes remain poorly characterized. This study addresses this gap by assessing the suitability of the underutilized speciesMarphysa madrasi Hutchings, Lavesque, Priscilla, Daffe, Malathi & Glasby, 2020 as a sustainable , locally sourced feed resource for aquaculture. Field observations were conducted across intertidal zones near Chennai to document harvesting activities, harvesting intensity and species occurrence. Morphological and molecular analyses confirmed the taxonomy of M. madrasi , and screening for major pathogens, including White Spot Syndrome Virus and Enterocytozoon hepatopenaei , showed no detectable infection. Nutritional profiling revealed a high protein content and a favourable fatty acid composition, including saturated, monounsaturated, and polyunsaturated fatty acids relevant to broodstock nutrition. Together, these results demonstrate that M. madrasi possesses desirable nutritional and biosafety characteristics, supporting its potential integration into Indian aquaculture value chains. These findings highlight opportunities to reduce reliance on expensive imported polychaetes, promote local livelihoods, and encourage sustainable harvesting and the development of future polychaete cultivation strategies.