Ocean fish pathological changes may be caused by human pollution. fis.com. A team of researchers has found certain deep-water marine fish in the Bay of Biscay west of France may develop pathological issues as a result of human-caused pollution.
These scientists, from Oregon State University (OSU); the Centre for Environment, Fisheries and Aquaculture Science in the United Kingdom; and other agencies, analysed changes to the sex organs and livers of fish in the northeast Atlantic Ocean and suggested pollution from human activity may be causing liver pathologies and ‘inter-sex’ condition (a blend of male and female sex organs) in marine life inhabiting areas of up to a mile under the ocean.
“In areas ranging from pristine, high mountain lakes of the United States to ocean waters off the coasts of France and Spain, we’ve now found evidence of possible human-caused pollution that’s bad enough to have pathological impacts on fish,” pointed out Michael Kent, a professor of microbiology in the OSU College of Science, co-author on this research project and an international expert on fish disease.
Kent also explained: “Deep in the ocean one might have thought that the level of contamination and its biological impact would be less. That may not be the case. The pathological changes we’re seeing are clearly the type associated with exposure to toxins and carcinogens.”
However, these scientists consider that further chemical analyses before concluding these pathological changes are not caused by naturally-occurring compounds.
According to these researchers, this health survey is different from other studies that have looked only at the parasite fauna, not more internal biological problems such as liver damage. The issues are important, however, since there’s growing interest in these areas as a fisheries resource, as other fisheries on the shallower continental shelf become depleted.
These scientists believe that as the sea deepens along these continental slopes, it can act as a sink for heavy metal contaminants such as mercury, cadmium and lead, and organic contaminants such as PCBs and pesticides. Some of the “intersex” fish that have been discovered elsewhere are also believed to have mutated sex organs caused by “endocrine disrupting chemicals” that can mimic estrogens.
In this study, the health concerns identified were found in black scabbardfish, orange roughy, greater forkbeard and other less-well-known species, and included a wide range of degenerative and inflammatory lesions that indicate a host response to pathogens, as well as natural cell turnover. The fish that live in these deep water, sloping regions usually grow slowly, live near the seafloor, and mature at a relatively old age. Some can live to be 100 years old.
The study noted that partly because of that longevity, the fish have the capacity to bioaccumulate toxicants, which “may be a significant human health issue if those species are destined for human consumption.” Organic pollutants in such species may be 10-17 times higher than those found in fish from the continental shelf with the highest level of contaminants in the deepest-dwelling fish.
Nevertheless, most of those contaminants migrate to the liver and gonads of such fish, which would make their muscle tissue comparatively less toxic, and “generally not high enough for human health concern,” the researchers wrote.
This research has been published in Marine Environmental Research and was supported by the European Union (EU).

editorial@fis.comwww.fis.comMarch 27, 2015.