Blue proteins: Marine-derived alternatives for sustainable nutrition and climate-resilient food systems.

The accelerating global demand for high-quality protein, coupled with escalating ecological pressures from terrestrial livestock systems, has intensified the search for sustainable alternative protein sources. Marine resources denote a promising frontier in addressing global protein security while reducing ecological footprints. This review explains the potential of alternative proteins derived from marine ecosystems, macroalgae (seaweed), fish protein hydrolysates, including microalgae, marine invertebrates, and low-trophic organisms. These resources offer great nutritional value, including balanced essential amino acid profiles, omega-3 fatty acids, vitamins, bioactive peptides and minerals, while generally requiring fewer land and freshwater inputs compared to conventional livestock production. Advances in green extraction technologies, biorefinery approaches, fermentation, and controlled enzymatic hydrolysis have enriched the functional and techno-economic viability of marine-derived proteins for food and nutraceutical applications. Furthermore, innovations such as sustainable harvesting frameworks, integrated multi-trophic aquaculture, and circular bioeconomy strategies strengthen environmental resilience and biodiversity conservation. Despite their promise, challenges remain regarding scalability, regulatory frameworks, allergenicity risks, and consumer acceptance and contamination concerns. Strategic research, policy support, and responsible commercialization pathways are important to unlock the full potential of marine alternative proteins. Overall, marine-based protein systems offer emerging solutions for climate mitigation, sustainable nutrition and resilient food systems in the context of a growing global population.