Scientists Examine Oil Spill’s Impact on Oysters

More than three years since the BP oil spill, an LSU AgCenter scientist is working to determine how oil impacted oysters, which have been struggling to recover since 2010.

(From / by Nikki Buskey / The Houma Courier) — The Houma CourierJerome La Peyre, a scientist who specializes in oyster diseases in the LSU AgCenter School of Animal Sciences, is studying the effect of oil by evaluating biomarkers that are used to assess oyster health.

These biomarkers include looking at the whole oyster performance down to its cells, proteins and genes.

La Peyre’s research is part of a multi-national research initiative studying the impact of the oil spill. The work is being paid for by research money set aside by BP and administered independently through the Gulf of Mexico Research Initiative.

La Peyre’s three-year research project is receiving about $183,000 in grant money.

A variety of issues can impact oyster populations, making it difficult to discern the impacts of oil on oysters in local estuaries, La Peyre said.

“Fluctuating temperatures, changes in water salinity and diseases can have an effect on oyster populations,” he said. “All of these make it difficult to unravel the effects of oil.”

La Peyre’s research has two components. He is examining the effects of oil and evaluating chosen biomarkers in caged oysters kept at oiled and non-oiled sites. He’s also exposing oysters to oil-contaminated sediment in the lab to measure the effects on them, allowing him to control the experiment.

In the lab, La Peyre uses different combinations of salt and fresh water and different concentrations of oil. This will allow him to discern the effects of the oil independently of water salinity. It can also help him note the combined effects.

A problem with studying oysters after the spill is the lack of significant previous research in estuaries along the Gulf Coast,  “In many ways we are creating a database for the Gulf region that will be useful in future events such as another major oil spill,” La Peyre said.

Because of oil and gas activities in Barataria Bay, some data was available from before the 2010 oil spill that looked at the presence of oil hydrocarbons in oysters. Six months after the BP spill, he found that hydrocarbon levels in oysters had returned to those seen before the spill.

“Oil was found but only at background level,” he said.

But the level of oyster reproduction and survival has still been low since the oil spill.

Al Sunseri, owner of P&J Oyster Co. in New Orleans and a member of the state’s Oyster Task Force, said tag sales, which indicate how many oysters are landed in the state, are down 40 percent since the spill.

It’s hard to say whether that’s because of the spill itself. La Peyre said other events typically associated with low reproduction and survival have also occurred, making it difficult to discern exactly how responsible the oil is for the low numbers.

In 2010, freshwater diversions along the Mississippi River opened to keep oil from reaching the coastline. Large amounts of freshwater can have a negative effect on oysters by lowering the salinity levels they prefer for reproduction, La Peyre said.

Oystermen say low reproduction has been devastating for the industry. Even if new growth is successful, it still takes 2 1/2 to three years for oysters to grow to marketable size under good conditions.

La Peyre hopes his work discerning how oysters respond to these events can help.
“Interpreting our oyster field data is sometimes challenging, but this research needs to be conducted to give us a better understanding of how oysters respond to specific events,” La Peyre said.

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