Barataria Basin, Louisanna -- Barataria Basin fisherman are now calling this thick patch of BP oil in Bay Jimmy, "The Black Sea."

The fumes are overwhelming and the sludge is toxic to the fragile marshes between Grand Isle and Lower Lafitte, south of New Orleans.

Tuesday, Louisiana Wildlife and Fisheries agents discovered dead fish floating in the oil.

The fish were later identified as gulf menhaden, also know as pogey fish along the Louisiana coast.

"If you found dead fish, that's not good at all," said Lafitte fisherman Lindberg Santini.

Sanitini has fished these waters for the past 39 years. He said seeing the smaller fish die can only mean one thing for his livelihood on the water.

"Nobody really knows how long it's going to last," said Sanitini. "I don't think I'll be back fishing no more at my age."

So far, fish kills related to the oil spill have been few and far between. Local leaders fear this is just the beginning, as thick oil pops up in the marsh.

"The dispersants caused a lot of this oil to sink," said Jefferson Parish Councilman John Young. "We're told as the water gets warmer then the oil will rise to the top, and that's why it has that dark black crude look and feel to it."

Researchers at the Audubon Aquarium of the Americas are now studying the effects of the oil spill on the local fisheries.

Marine Biologist John Hewitt said when the base of the food chain suffers, effects can be felt up the chain as well.

"The species, the populations of redfish and speckled trout are dependent upon those things at the bottom end of the scope for their existence," said Hewitt.

Hewitt also said it's hard for smaller fish to survive in oil polluted water.

"There is the potential for oil ingestion, particularly in a fish like a gulf menhaden that's a filter feeder," said Hewitt. "They swim around with their mouths open, filtering out plankton and such. It wouldn't take much oil to adversely effect an animal like that."

Fishermen expect to feel effects from the oil spill for years to come.

"They're going to have to get it cleaned up and don't know how long it will take to get it back," said Sanitini.

Local leaders hope new plans to reduce the amount of oil now flowing into Barataria Bay will lessen the impact on the environment.