The effects of breeding season and habitat on the biochemical composition and energy content of the Liza aurata fillet (Teleostei: Mugilidae)

The present study was conducted to examine the relationship between the biochemical composition and energy content of the golden gray mullet (Liza aurata) fillet and its breeding season and habitat in the southern coast of the Caspian Sea. A total of 100 adult golden gray mullet were caught from 10 sites in various coastal areas (wetland and deltaic) during the spring and fall. The fish bioassay results showed the highest weight and total length to have been detected in Anzali (the eastern part of the wetland mouth) and the lowest in Hojanepes (before Gorganroud delta). A significant increase was noticed in the protein content of the fish in the eastern regions of the delta's and wetland's mouth compared to the west coast. Based on the results, the season and the living environment affect the total length, weight, protein, fat and water content of the fish, and the differences in these variables are significant. The fat content of the fish body is highly influenced by the changes in the breeding season. The mean protein, fat, water, ash and energy content of golden gray mullet of the southern coast of the Caspian Sea was 22.33, 3.08, 77.76, 1.40% and 649.71kJ per 100g of fillet respectively. Golden gray mullet fillets contained lower amounts of fat, protein and energy during the fall (i.e. the breeding season) than during the spring.