It has been found that the yelloweye rockfish is unable to detoxify mercury, which accumulates at toxic concentrations in their liver.
The yelloweye rockfish, which lives in the coastal waters of Alaska, can live up to 120 years. Over its lifespan, they are known to accumulate toxic chemicals in their tissues.
A study by researchers from McGill University sought to discover how much of those elements accumulate in sensitive sites within yelloweye cells. After catching eight yelloweye rockfish at Alaska's Inside Passage, the team analysed the fish's tissues at a subcellular level in the laboratory.
They discovered that the fish could immobilise some potentially toxic elements (like cadmium, lead and arsenic) within their liver tissues, thereby preventing them from interacting with the sensitive parts of the cell. But not so for mercury—it was found at toxic concentrations in the liver, and mostly in the sensitive sites (like mitochondria and enzymes) within the liver cells.
According to Benjamin Barst, a postdoctoral fellow at McGill University's Department of Natural Resource Sciences, "mercury from industrial activities can be transported over long distances and accumulate in sensitive sites within fish livers with dangerous results. [...] Now we know that mercury is not well detoxified by these fish. This adds another layer of evidence indicating mercury may be the cause of the problem."
The species is currently listed as listed as "threatened" in the Puget Sound-Georgia Basin in the United States. It is also a species of "special concern" in Canada, where there are conservation areas established to protect its habitat from commercial and recreational fishing.
The findings of the study has been published in the Environmental Pollution journal.