Journal of Experimental Agriculture International

The growing need for sustainable aquafeeds has accelerated the quest for alternative protein sources to substitute fishmeal, which is expensive and eco-unfriendly. Molluscan and crustacean byproducts such as snail and shrimp shell, clam, crab meal, and mussel shell and powder provide a good source of proteins, essential fatty acids, chitin, and minerals that support growth, immunity, and health of fish. These by-products, commonly viewed as waste, have the potential to drive the circular economy through minimizing environmental effects while enhancing feed efficiency. This review explores the nutritional quality, bioactivity, and processing of molluscan and crustacean by-products, highlighting their benefits and challenges in aquafeed formulation.  Despite differences in nutrient content and limitations in processing, their use in aquafeeds has enormous potential for encouraging low-cost and sustainable aquaculture. Further research is needed to refine processing methods, evaluate safety, and facilitate large-scale use in commercial feed manufacturing. Major challenges such as nutrient variability, contamination risks, and processing limitations need to be addressed for large scale adoption in aquafeeds.