Observations on Metal Concentrations in Three Species of Shark (Deania calcea, Centroscymnus crepidater, and Centroscymnus owstoni) from Southeastern Australian Waters

Abstract

Deep sea dog sharks (Deania calcea, Centroscymnus crepidater, and Centroscymnus owstonii) were captured from the waters off western Victoria, Australia, in April and May 1998. The elements As, Ca, Cd, Cu, Fe, Hg, K, Mg, Mn, Na, Sr, and Zn were detected in the muscle tissue. The concentrations of Al, Ba, Be, Cr, Mo, Ni, Pb, and V were below the detection limits of the instrumental techniques employed (ICP-ES and GF-AAS). However, significant concentration differences between species were detected for As, Cd, Hg, and Zn. C. owstoni contained the highest concentrations of each of these elements. The concentrations of Cu, Pb, and Zn in each species were below the maximum levels permitted in food by the Australian Food Standards Code. The maximum permitted concentrations of As and Hg were exceeded in all species, and weekly consumption of 400 g of any of these sharks would result in intake of more than the FAO's provisional tolerable weekly intake. Although C. crepidator and D. calcea have strong relationships between length and mercury concentration, C. owstoni does not. Placing C. crepidator and C. owstoni in the same genus, therefore, is worth re-examination as the mechanisms for controlling mercury in C. owstoni appear to differ from that used by both C. crepidator and D. calcea.

Mercury in 16 demersal sharks from southeast Australia: Biotic and abiotic sources of variation and consumer health implications

“…This pattern has been extensively exhibited in previous studies of sharks (Forrester et al, 1972;Walker, 1976Walker, , 1988Taguchi et al, 1979;Hueter et al, 1995). For C. crepidater analysed in this study, comparable Hg levels and a similar relationship between size and Hg levels was observed by Davenport (1995) and Turoczy et al, (2000). The accumulation of mercury with increasing size (fundamentally age) is likely to also reflect other ecological and physical factors, such as differential feeding ecology, and slow and inefficient elimination of mercury from deeper dwelling species (Trudel and Rasmussen, 1997).…”

“…Results of several studies around southeastern Australia (Walker, 1988;Davenport, 1995;Turoczy et al, 2000) show similar mean mercury levels in the muscle tissue to those reported in this study. Comparable elevated levels are also documented in several demersal sharks, globally (De Pinho et al, 2002;.…”

“…For comparisons with this study, only for the genera Centrophorus, Etmopterus, Squalus, Dalatias, Deania and Chimaera are some published data available (e.g., De Pinho et al, 1989;Hornung et al, 1993 ;Davenport 1995;Turoczy et al, 2000;Storellii et al, 2002; and reviewed by Cossa and Coquery, 2005). Results from the present study are the first published for dogfish, Etmopterus baxteri, Proscymnodon plunketi, chimaeras, Rhinochimaera pacifica, and Chimaera lignaria, and deepwater catshark, Apristurus sp (A and C) and Figaro boardmani.…”

Mercury and Selenium in Muscle and Target Organs of Scalloped Hammerhead Sharks Sphyrna lewini of the SE Gulf of California: Dietary Intake, Molar Ratios, Loads, and Human Health Risks

“…This finding is well illustrated by the strong associations between body length and muscle Hg concentrations that have been observed for several shark species (Turoczy et al 2000;Gelsleichter and Walker 2010;Storelli et al 2011;Hurtado-Banda et al 2012;Maz-Courrau et al 2012;Delshad et al 2012). In the current study, although all scalloped hammerhead sharks were juvenile with relatively low variation in body size, significant correlations were found between total length and weight and Hg concentration in muscle and liver, but it was found that Hg in muscle increased and Hg in liver decreased as total length and weight incremented.…”

Improved Squalene Production via Modulation of the Methylerythritol 4-Phosphate Pathway and Heterologous Expression of Genes from Streptomyces peucetius ATCC 27952 in Escherichia coli

“…Squalene has a chemopreventive effect on colon cancer (14). Moreover, squalene has wide applications in fine chemicals, magnetic tape, and low-temperature lubricants and as an additive in animal feed (1).The use of shark liver oil is limited, due to the presence of environmental pollutants, such as polychlorinated biphenyls, heavy metals, and methylmercury residues, as well as an unpleasant fishy odor and taste (17,19). Moreover, the presence of similar compounds, such as cholesterol, in the oils from marine animal liver can make squalene purification difficult.…”