Chumchal and colleagues hypothesize that increases in mercury contamination are related to the bottom-scouring effects of trawling operations, which churn sediments into the oxygen-rich upper levels of the ocean, making embedded mercury more accessible for easy uptake in the food chain.
Young snappers in heavily trawled areas may also have higher concentrations of mercury contamination due to differences in feeding strategies. The researchers suggest that small fish in these trawled areas may have the unusual opportunity to feast on fish and other organisms that have been killed or injured in the shrimping operations, thus providing a diet of organisms from higher up in the food chain where higher levels of mercury contamination may have accumulated.
"To our knowledge, this is the first study to document a relationship between the presence of trawling and fish Hg (mercury) concentration," the researchers conclude, noting that the findings are part of a growing body of evidence that man-made sediment disturbances often lead to increased contaminant concentrations in marine organisms.
'/>"/>
| Contact: Matthew Chumchal m.m.chumchal@tcu.edu 817-257-6440 Dick Jones Communications Source:Eurekalert |