Oil spill stil impacting fish growth
Scientists from the University of Miami recently completed a study of the potential effects of the Deepwater Horizon oil spill on marine life in the Gulf of Mexico. Their findings suggest that local fish populations, including cobia and mahi-mahi, could be experiencing stunted growth.
Researchers at the university worked with the National Oceanic and Atmospheric Administration (NOAA)’s Northwest Fisheries Science Center and the University of North Texas to study the effects of toxic elements from the oil spill on developing fish.
Their experiments involved exposing fertilized eggs, fish embryos and hatchlings to toxic compounds, and found reduced hatch rates, along with impaired cardiac development in the fish that did hatch and survive. The study also found evidence of photo-enhanced toxicity, or that sunlight enhanced the effects of the toxins.
“We found that in more sensitive species the photo-enhanced toxicity could account for up to a 20-fold higher sensitivity,” said Dr. Martin Grosell, one of the University of Miami researchers. “This is an important part of the equation because it means that traditional toxicity testing performed under laboratory conditions will tend to underestimate the toxicity that might have occurred in the natural environment under the influence of sunlight.
Fish that did survive, the study found, swam only about 70 percent as fast as fish raised in clean water.
“The severely reduced swimming performance we saw could impact the ability of these fish to catch sufficient prey, avoid predation, or travel the long distances that some migratory species require for survival,” Grosell said.
The studies were funded as part of the National Resource Damage Assessment and findings were presented at the recent Society of Environmental Toxicology and Chemistry annual meeting. The team is currently working on publication of the findings of the investigation.