Seasonal variations of aliphatic hydrocarbons in Sardina pilchardus (Walb.) (Teleostei: Clupeidae) tissues

Aliphatic hydrocarbons from n-C15 to n-C30 were determined in some tissues of Sardina pilchardus (Walb.) collected during different seasons in the Adriatic Sea. The aim of this research was to evaluate the presence, origin (biogenic or fossil) and metabolic fate of these compounds. The highest amounts of total hydrocarbons were detected in June and September, the lowest in April, and intermediate levels were found in December. Among the tissues, the highest concentrations were found in mesenteric fat. n-C17, among the saturated hydrocarbons, and isoprenoid squalene, among the unsaturated, were, in general, clearly predominant. The distribution in the various tissues showed that hydrocarbons undergo limited metabolic change. In all the tissues and during all periods of the year the prevailing hydrocarbons are considered to be of recent biological origin. It is possible to exclude contamination of S. pilchardus (Walb.) by petroleum.