Biological assessment and metals concentration in blue shark (Prionace glauca) caught in the southeast-south coast of Brazil

Sharks are suffering from fishing industry pressure, mostly by human consumption of meat and fins, causing a great impact on its population. These top predators can bioaccumulate metals in its tissues, which brings risks to human health and indicates aquatic pollution. The objective of this work is to determine metallic trace elements as chromium, copper, zinc and aluminium in Prionace glauca, while studying the biological aspects such as fork length and approximate age to indicate if there is a metal accumulation in shark tissues evaluated. Nine specimens were obtained through commercial fishing in the Southeast and South regions of Brazil, using pelagic longline fishing. On arrival at the port, specimens were weighed and sexed in its commercial weight (headed, finned and gutted). About 100 g of muscular flesh from dorsal region between the dorsal and caudal fin was removed. Metal determination in muscle tissue (wet weight basis) was performed through acid digestion (mixture of HNO3 and H2O2). After the acid digestion, the metals concentration was determined by means of inductively coupled plasma optical emission spectrometry (ICP-OES). The results indicated that Prionace glauca capture during the winter in the Southeast-South regions of Brazil, consists mostly by small adult males. Copper, zinc and aluminium concentration was well below de maximum limits permitted by Brazilian and international agencies. Chromium average (0.14 mg/kg) was above the limits permitted by Brazilian legislation (0.10 mg/kg). A significant positive correlation was found between some metals (Al, Cr and Cu) and sharks fork length. These results corroborate the bioaccumulation of some metals in Prionace glauca, showing the need for more studies about metal determination in shark tissues