Quality changes in terms of nutritional value and pigmentation in pink salmon (Oncorhynchus gorbuscha) from the Barents Sea during sexual maturation

The invasion of pink salmon (Oncorhynchus gorbuscha) in northern Norwegian rivers has raised ecological concerns
and led to eradication fishing, primarily in freshwater systems. At present, most fish removed through
river-based fisheries are discarded, and the potential of river-caught salmon as a food resource has therefore not
been evaluated. This study investigated changes in food composition, fatty acid profile, fillet colour, and quality
during sexual maturation. Fish were classified into four maturation stages based on external characteristics, from
immature (MS 0) to fully mature individuals (MS 3). Advancing maturation was associated with a significant
increase in muscle water content from 72.8% to 76.9%, and corresponding decreases in protein, lipid, and ash
contents. Total fatty acid content declined from 2.47 to 1.38 g/100 g muscle during maturation, primarily due to
reductions in monounsaturated fatty acids. Fillet colour deteriorated noticeably at the spawning stage, with
substantial losses in redness and colour saturation. Despite reduced lipid content during maturation, pink salmon
remained a valuable source of high-quality protein and long-chain omega-3 fatty acids. These findings provide
essential food composition data and demonstrate that fish captured in river-based eradication fisheries may
represent an underutilised food resource.