Metal composition of arrow squid (Nototodarus sloanii [Gray 1849]) from the Chatham Rise, New Zealand: implications for human consumption

Trace element concentrations, including Cd and Hg, in long-finned pilot whales (Globicephala melas edwardii) mass stranded on the New Zealand coast

The Southern Hemisphere long-finned pilot whale (Globicephala melas edwardii) is a top predator in the New Zealand pelagic food web, feeding predominantly on arrow squids. This study quantified trace element concentrations (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Mn, Pb, Se, V, Zn) in four tissues (blubber, kidney, liver, muscle) from 21 individuals from stranding sites in New Zealand. Maximum Cd and Hg concentrations were measured in liver and kidney, respectively. Selenium had a positive correlation with Cd and Hg, suggesting the involvement of Se in Cd and Hg detoxification. Arrow squids from the whales' stomach contents were DNA barcoded and identified as Nototodarus sloanii. Trace element concentrations were measured in squid samples from the whale stomach contents. The significant correlation for Hg between the squid tissue and the whale tissue suggests that arrow squids play a major role in trace element uptake by G. m. edwardii.

Regional assessment of trace element concentrations in arrow squids (Nototodarus gouldi, N. sloanii) from New Zealand waters: Bioaccessibility and impact on food web and human consumers

The New Zealand arrow squids, Nototodarus gouldi and N. sloanii, play an important role in the marine food web, and are both economically important fishery species. This study compares trace element concentrations (As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Mn, Pb, U, and Zn) in these animals from different fishing locations within New Zealand's Exclusive Economic Zone (Auckland Islands, Chatham Rise, Dunedin, Golden Bay, Taranaki, and West Coast of the South Island). Muscular mantle (the tissue usually consumed by humans) and digestive gland tissue (the primary organ for trace element accumulation) concentrations were compared among regions, revealing size, species, and sampling location effects. Overall, N. gouldi had higher concentrations of As and Zn. The Taranaki region had the highest concentrations for Cd, Co, Cu, and Zn in both tissues analysed. To assess the bioaccessibility of these trace elements to humans, an in-vitro digestion simulation experiment was conducted, revealing bioavailable concentrations overall below the maximum levels presently considered tolerable for human consumption. However, the in-vitro digestion had no observable effect upon Cd concentrations in arrow squid mantle tissue (implying that the measured concentrations are bioaccessible to humans), and revealed that Cd had the highest potential impact on marine food webs and human health. Digestive gland concentrations in particular indicate that arrow squids can be considered important vectors for trace element transfer to top predators (mean concentration for Cd: 123 ± 148 μg g^-1 dw), with region-specific differences.

Possible food safety hazards of ready-to-eat raw fish containing product (sushi, sashimi)

It is undeniable that with the popularity of sushi and sashimi over the last decade the consumption of raw fish has extremely increased. Raw fish is very appreciated worldwide and has become a major component of human diet because of its fine taste and nutritional properties. Possible hazards concerning fish safety and quality are classified as biological and chemical hazards. They are contaminants that often accumulate in edible tissue of fish and transmit to humans via the food chain affecting the consumer's health. Although their concentration in fish and fishery products are found at non-alarming level of a daily basis period, they induce hazardous outcome on human health due to long and continuous consumption of raw fish. Regular sushi and sashimi eaters have to be aware of the contaminants found in the other components of their dish that often add up to acceptable residue limits found in fish. Hence, there is the urge for effective analytical methods to be developed as well as stricter regulations to be put in force between countries to monitor the safety and quality of fish for the interest of public health.

Trace element analysis reveals bioaccumulation in the squid Gonatus fabricii from polar regions of the Atlantic Ocean

The boreoatlantic gonate squid (Gonatus fabricii) represents important prey for top predators-such as marine mammals, seabirds and fish-and is also an efficient predator of crustaceans and fish. Gonatus fabricii is the most abundant cephalopod in the northern Atlantic and Arctic Ocean but the trace element accumulation of this ecologically important species is unknown. In this study, trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn) were analysed from the mantle muscle and the digestive gland tissue of juveniles, adult females, and adult males that were captured south of Disko Island off West-Greenland. To assess the feeding habitat and trophic position of this species, stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N) were measured in their muscle tissue. Mercury concentrations were positively correlated with size (mantle length) and trophic position. The Hg/Se ratio was assessed because Se has been suggested to play a protective role against Hg toxicity and showed a molar surplus of Se relative to Hg. Cadmium concentrations in the digestive gland were negatively correlated with size and trophic position (δ¹⁵N), which suggested a dietary shift from Cd-rich crustaceans towards Cd-poor fish during ontogeny. This study provides trace element concentration data for G. fabricii from Greenlandic waters, which represents baseline data for a northern cephalopod species. Within West-Greenland waters, G. fabricii appears to be an important vector for the transfer of Cd in the Arctic pelagic food web.