Geographical and seasonal differences in lipid composition and relative weight of by-products from gadiform species

The amount of available lipids and the lipid composition from gadiform species caught during three seasons in the Barents Sea, the Icelandic Sea and off the south coast of Ireland were determined. The size of the liver, constituting 1.3-6.9% of round weight, was affected by fishing ground. The fishing ground affected the lipid content in liver (30-78%) and viscera (2.2-7.1%). No significant effect of season was found on the lipid content of cod liver, while seasonal differences were found for other species and fractions. Polyunsaturated fatty acids (PUFAs) made up 21-45% and 34-63% of the total fatty acids in liver and viscera. Overall, effect of fishing ground and season were found on groups of fatty acid, and lower levels of PUFA were found in the liver of Icelandic cod. Depending on species and fishing ground, 550-1700 kg lipids can be obtained from the by-products from an average daily production of fillets (10 000 kg). The amount of available lipids was higher from gadiform species from the Barents Sea compared to the two other fishing grounds. All lipids extracted contained significant amounts of health-beneficial PUFAs.