A mile deep, ocean fish facing health impacts from human pollution
CORVALLIS, Ore. – Deep-water marine fish living on the continental slopes at depths from 2,000 feet to one mile have liver pathologies, tumors, and other health problems. These may be linked to human-caused pollution. One of the first studies of its type has found this connection.
The research, conducted in the Bay of Biscay west of France, also discovered the first case of a deep-water fish species with an “intersex” condition. This condition is a blend of male and female sex organs. The sampling was done in an area with no apparent point-source pollution. It appears to reflect general ocean conditions.
The findings have been published in Marine Environmental Research. The authors are scientists from Oregon State University and the Centre for Environment, Fisheries and Aquaculture Science in the United Kingdom. Other agencies also participated. It was supported by the European Union.
Significant Pollution on Ocean Floor Affecting Male Fish to Give Birth
The research is of particular interest, OSU researchers said, as it sheds light on critical environmental issues affecting local ecosystems. This interest becomes evident when contrasted with studies done several years ago in the American West’s national parks. Those studies highlighted the pervasive nature of pollution. They also found significant pollution and fish health impacts, including male fish that had been “feminized” and developed eggs. This indicates serious disruptions in wildlife due to contaminants. This ongoing research underscores the persistent threats posed by environmental pollutants. Moreover, it emphasizes the urgency for continued monitoring. It calls for protective measures to safeguard aquatic habitats and restore ecological balance in these regions.
“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. It’s bad enough to have pathological impacts on fish,” said Michael Kent. He is a professor of microbiology in the OSU College of Science, a co-author on both research projects, and an international expert on fish disease.
Highest Level of Pathological Changes due to Toxins and Carcinogens
“Deep in the ocean, one might have thought that the level of contamination and its biological impact would be less,” Kent said. “That may not be the case. The pathological changes we’re seeing are clearly the type associated with exposure to toxins and carcinogens.”
The researchers noted that linking these changes in deep water fish to pollution is still early. The complexities of marine ecosystems can often produce a variety of responses to environmental shifts. These changes could also result from natural compounds, such as variations in oceanic currents or temperature fluctuations that occur seasonally. Such factors can affect fish populations in unforeseen ways. Further chemical tests would help clarify the connections between the changes and human activities. Researchers should focus on identifying specific pollutants and their concentrations. Additionally, they should assess the potential long-term impacts on marine biodiversity and the food web. This is crucial for understanding the health of deep water ecosystems. It also has implications for commercial fishing and human consumption.
Fish on Continental Slopes Most Toxic
Few, if any, health surveys of this type have been done on fish living on the continental slopes, the researchers said. Most past studies have looked only at their parasite fauna. They did not address more internal biological problems, such as liver damage. The issues are important because there’s growing interest in these areas as a fisheries resource. Shallow continental shelf fisheries are becoming depleted.
As the sea deepens along these continental slopes, it’s known to act as a sink for heavy metal contaminants, such as mercury, cadmium, and lead. Additionally, organic contaminants like PCBs and pesticides are present. Some “intersex” fish discovered elsewhere are believed to have mutated sex organs. These mutations are caused by endocrine-disrupting chemicals that can mimic estrogens.
Generating Degenerative and Inflammatory Lesions
In this study, the report identifies health effects across various demographic groups and environmental conditions. It highlights the importance of considering multiple variables when assessing public health impacts. These effects include both short-term and long-term consequences. This demonstrates a complex interplay between lifestyle factors and overall health outcomes. Furthermore, the collected data emphasizes the necessity for ongoing research. It aims to better understand the implications of these health effects on different communities. Researchers seek to develop targeted interventions that address the specific needs of those affected.
1.black scabbardfish
2. orange roughy
3. greater forkbeard and other less-well-known species.
The concerns included a wide range of degenerative and inflammatory lesions. These lesions 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. They live near the seafloor and mature at a relatively old age. Some can live to be 100 years old.
Partly because of their longevity, the fish can bioaccumulate toxicants. The researchers state in their report that “this may pose a significant human health issue if those species end up in human consumption.” Organic pollutants in such species may reach levels 10-17 times higher than those found in fish from the continental shelf. The study notes that the deepest-dwelling fish contain the highest levels of contaminants.
Most Contamination in Liver and Gonads of Fish
However, most of those contaminants migrate to the liver and gonads of such fish. This would make their muscle tissue comparatively less toxic and “generally not high enough for human health concern,” the researchers wrote.
The corresponding author on this study was Stephen Feist at the Centre for Environment, Fisheries and Aquaculture Science in Weymouth, England, where he has been conducting significant research for over a decade. His work focuses on the intricate relationships between marine ecosystems and the impacts of environmental changes, making substantial contributions to our understanding of fish health and aquatic biodiversity. Under his guidance, the Centre has published numerous influential papers that address critical issues affecting fisheries management and sustainability in the face of climate change.
In their previous research in the American West, scientists discovered toxic contamination from pesticides, the burning of fossil fuels, agriculture, industrial operations, and other sources. These pollutants mainly entered high mountain lakes through air pollution. Pesticide pollution, in particular, remained pervasive.
Together, the two studies suggest that fish from some of the most remote parts of the planet, from high mountains to the deep ocean, may be impacted by toxicants, Kent said. This alarming discovery highlights not only the vulnerability of aquatic ecosystems in isolated regions but also raises questions about the broader environmental implications as these toxic materials may be carried by air or water currents, affecting species far from their original sources. Furthermore, the research indicates that even the most pristine habitats are not immune to human activity, emphasizing the urgent need for global awareness and action to mitigate pollution in these untouched areas.
Source: OSU College of Science
3-25-15, http://bit.ly/1CPn6xP
