Bioaccumulation and biomagnification in elasmobranchs: A concurrent assessment of trophic transfer of trace elements in 12 species from the Indian Ocean

What Is in Your Shark Fin Soup? Probably an Endangered Shark Species and a Bit of Mercury

“…Evidence from fins collected and analyzed throughout the world indicates that the presence of toxic elements in sharks is a global phenomenon, not restricted to specific bodies of water. Studies from the Atlantic, Indian, Pacific, Caribbean, South China Sea and Australian waters all find high levels of lead, arsenic and mercury in shark products, frequently exceeding safe advisory levels [ 20 , 21 , 22 , 23 , 24 , 26 , 45 , 46 , 47 ], and many of these tainted products enter human food chains, especially shark fins, via soups.…”

“…Studies show that children and adults who consume shark products once a week are exposed to three times more mercury than what is recommended by the United States Environmental Protection Agency (U.S. EPA) [ 24 ]. While the majority of studies generally report mercury and levels of other toxic elements in muscle tissue, the liver or from vertebrae where they readily accumulate [ 20 , 24 , 25 ], it is important to note that fins can contain higher levels of mercury and other toxic elements, such as lead and cadmium, in comparison to muscle and other non-fin tissues [ 23 , 26 ]. Additionally, work performed in Hong Kong and China shows that the total amount of mercury found in shark fins regularly exceeded the prescribed Hong Kong and China legal limit of 0.5 ppm [ 22 ], and the 1 ppm legal limit used for predatory fish in Singapore [ 27 ].…”

Heavy Metals Concentration in Muscle Tissue of Threatened Sharks (<i>Rhizoprionodon acutus</i>, <i>Sphyrna lewini</i>, and <i>Squallus hemipinnis</i>) from Binuangeun, Lebak Banten, Indonesia

“…Another factor is the migratory pattern of the shark while in the juvenile and adult stages or during the nurseries stage [29][30]. Pb, Cd, and Ni concentration in R. acutus and S. lewini from Binuangeun show a lower trend than the previous result on Ong and Gang [21] from Kuala Terengganu, Malaysia, Boldrocchi et al [27] from Djibouti, Indian Ocean areas, and Adel et al [20] from the Persian Gulf. This study's Cd, Ni, and Pb concentrations were lower than Hauser-Davis et al [31] on blue sharks (Prionace glauca) from the Western North Atlantic Ocean.…”

“…Differences in these findings in this species may be related to differences in As availability at different sites and biological parameters involved in As metabolism (length, age, weight, reproductive stage) [19]. Feeding behavior and the food sources of the shark species were other factors that metals can uptake in shark metabolism [19] and trophic position on the food web [27]. S. lewini has been classified as a general opportunistic predator [16], directly relating to the abundance of prey in the study area [19,28].…”

“…Titanium concentration showed a significant positive relationship with total length and weight (Pearson correlation, (TW) r = 0.40, p = 0.028, n = 28; (TL) r = 0.43, p = 0.016, n = 28) if analysis based on habitat (coastal/pelagic vs demersal/deep-water), while lead showed a significant negative relationship with TW and TL (TW r = -0.58, p = 0.0016, n = 25; TL r = -0.61, p = 0.0008, n = 25). In habitat, many factors influence the uptake of metals in sharks, such as a variety of food diets [2,19], the abundance of food sources [19], anthropogenic activities [7,26], and different trophic positions while juvenile stage vs. adult stage [27,29].…”