Utilization of fish waste extraction as organic fertilizer for crop growth and yield improvement. A review

The fishing sector in Sri Lanka plays a crucial role in the national economy and food security, providing approximately 50% of the animal protein consumed and supporting the livelihoods of over a million individuals. However, fish processing generates substantial quantities of waste—up to 30–40% of the total catch, which poses environmental and public health challenges. Fish Amino Acids (FAA), derived from the fermentation of fish by-products such as heads, bones, skins, and viscera with sugar, have emerged as a promising organic fertilizer and plant growth enhancer. This review synthesizes the available literature on the production, nutrient composition, extraction methods, and agricultural applications of FAA. Relevant studies were identified through systematic searches of published literature, including reports, journal articles, and case studies focusing on fish waste valorization, fermentation technologies, and the impact of FAA on crop growth, soil health, and environmental sustainability. The review highlights that FAA is rich in macro- and micronutrients, enhances soil fertility, stimulates microbial activity, improves nutrient bioavailability, and promotes vegetative growth and yield in a wide range of crops, including cereals, vegetables, and fruits. Furthermore, FAA contributes to environmental sustainability by reducing reliance on synthetic fertilizers, mitigating nutrient runoff, and facilitating the circular economy in fisheries and agriculture. Despite its potential, challenges such as odor, storage stability, nutrient variability, and regulatory concerns must be addressed to optimize its adoption. Overall, FAA represents a sustainable, eco-friendly, and economically viable solution for improving soil health, crop productivity, and the management of fish processing waste in Sri Lanka.