The Natural Resources Defense Council and dozens of Gulf Coast environmental groups called on the Obama administration today to bolster its testing of seafood in the wake of the massive BP PLC oil spill.

In letters to the National Oceanic and Atmospheric Administration and Food and Drug Administration, the groups request more data collection and strengthened protocols to determine whether fishing grounds should be reopened and whether seafood is safe to eat.

The letters come as the Gulf's fall shrimp season opens and federal officials begin reopening fishing grounds as spilled oil dissipates. About 22 percent of federal waters in the Gulf are closed to fishing -- down from a third at the height of the spill, which began with the explosion of an oil rig on April 20.

"With the opening of shrimping season and near-daily reopening of fishing areas, seafood safety is a major issue right now," said Gina Solomon, a senior scientist with NRDC. "The government needs to show it is putting strong safety criteria and testing standards in place to ensure that the seafood from the Gulf will be safe to eat in the months and years to come."

Before reopening fishing grounds, NOAA has relied on seafood tests and surveys and trajectory models of the oil spill to show areas are at low risk for future exposure.

Seafood assessments rely on testers using their sense of smell to sniff out defective food, a method that some have questioned but that federal officials say is very reliable.

Federal officials have repeatedly said Gulf seafood is safe and has shown no signs of oil or dispersants. President Obama has even come forward as the seafood-taster-in-chief, serving Gulf shrimp at his White House birthday party last week and eating seafood on his family's trip to Florida's Gulf Coast last weekend.

Fishermen faced severe reductions on their catch when fisheries were closed over the summer. And shrimpers lost the spring season, which runs from mid-May to July, to the spill and are hoping to capitalize on the fall season, which opened yesterday and extends through December.

But the environmental groups say NOAA should be more cautious before opening a fishery. The agency is relying on an FDA risk assessment that "fails to consider risks to the populations most vulnerable to seafood contamination," the letter states. Pregnant women, children and communities that rely on fishing may be more at-risk from chemical exposure.

Signatories to the letter include the Gulf Restoration Network, local chapters of the Sierra Club, the Louisiana Environmental Action Network and the Deep South Center for Environmental Justice.

Some physicians have also questioned the potential long-term health effects from seafood from the tainted waters. A commentary published yesterday in the Journal of the American Medical Association said the oil spill poses "indirect threats" to seafood safety.

Chemicals can accumulate for years in marine invertebrates, according to the article. The physicians are also concerned about trace amounts of cadmium, mercury and lead that occur in crude oil and can accumulate in fish tissues -- potentially increasing future health hazards in large fish.

Click here to read the letter to NOAA.

Click here to read the letter to FDA.