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Undesirable substances in wild fish?

14.02.2014 // Since 1994, the National Institute of Nutrition and Seafood Research (NIFES) has been systematically monitoring the safety of seafood from the North Sea, the Norwegian Sea and the Barents Sea.

Monitoring was previously based on spot checks, but in the last three years additional comprehensive base-line studies have been conducted on important commercial fish species such as cod, saithe, mackerel, Norwegian spring-spawning herring, North Sea herring and Greenland halibut. Shellfish, too, are now subject to both programme-based and spot-check based monitoring.

Wild caught fish

In general, Norwegian seafood from all three marine areas contains low levels of contaminants. International food safety legislation defines upper threshold values for a number of different contaminants and, with few exceptions, Norwegian seafood complies with this legislation. Levels of metals and organic contaminants, generally below the EU threshold values, were found in the baseline study of mackerel from the North Sea, the Skagerrak, the Norwegian Sea and West of Scotland. Moreover, the base-line study of Norwegian spring-spawning herring shows that this species, which is the largest in volume in terms of fish caught in the wild for human consumption, does not contain elevated levels of contaminants.

As the Norwegian government aims for a seafood market free of products that may represent a health risk, risk-based analyses and assessments are targeted at fish species and contaminants with a specific potential for exceeding the threshold value. Results have shown that fillets from such fish species contain high levels of mercury and/or dioxins. This is a particular problem in long-lived species such as Greenland halibut, Atlantic halibut and tusk. Levels of mercury in tusk are higher in the southern part of the North Sea coastal current, whereas other factors define contaminant concentrations in halibut.

Fish liver is an important product in the Norwegian cod fishery industry and has a particular potential for elevated levels of dioxins and dioxin-like PCBs due to its high content of fat. Liver from cod caught in fjords and harbours, as well as in the Norwegian coastal current, generally contain organic contaminants in amounts that exceed the determined threshold values. Although cod liver from the Barents Sea has levels of dioxins and dioxin-like PCBs that are lower, their concentrations are close to the permitted maximum level.

The 2010 spot check monitoring of undesirable substances in cod fillet, polar cod, capelin and shrimps from the Barents Sea showed that these species does not exceed the threshold values for metals and organic contaminants.


A continued reduction in the level of potentially health-damaging substances in fish and other seafood is advisable. The effect of introducing restrictions on the discharge of contaminants will only be witnessed after an extensive period of time for wild-caught fish and seafood.  However, levels of organic pollutants such as dioxins and dioxin-like PCBs in farmed fish and cod liver oil may be influenced within a reasonable time frame.

Shellfish

In the case of shellfish, monitoring is required due to their ability to accumulate heavy metals and toxic algae. The levels of heavy metals found in shellfish in Norwegian marine areas are fairly low, though cadmium can sometimes be found in large amounts, for instance in brown meat from edible crab. These high levels appear to be independent of the geographical pollution situation.

 The Norwegian Food Safety Authority monitors the production and harvesting of live bivalve molluscs. Each year, samples are taken from production sites along the Norwegian coast. The sampling data are used to monitor the presence of toxin-producing algae and marine biotoxins in molluscs, as well as the presence of biological and chemical contaminants in harvesting areas. When harvesting, producers are also sampling for analysis of toxin producing algae and marine biotoxins to supplement the monitoring carried out by the competent authority. Based on the data from the monitoring programme, the NFSA issues weekly advice regarding the gathering of molluscs for own consumption along the Norwegian coast: See link in English on the site of Matportalen.no


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