Barataria Bay, La-- Scientists continue to be puzzled by high mortality rates of bottlenose dolphins in the Gulf of Mexico.
Through April 7 of this year, they count 47 strandings of cetaceans-- mostly dolphins-- in or near Louisiana, according to numbers from the National Marine Fisheries Service.
The figures, more than double the average mortality rate, actually represent some improvement.
Since early 2010, more than 600 dolphins have stranded themselves in what scientists refer to as an "unusual mortality event."
While the BP oil disaster might seem a likely suspect, the dolphin strandings started spiking in February of 2010, a full two months before the blow out of the Macondo well.
"Understanding the full extent of what this oil spill has done is going to take awhile," said Alisha Renfro, a coastal scientist with the National Wildlife Federation.
Environmentalists have raised concerns that oil could work its way from small creatures to dolphins and other species at the top of the food chain.
"When something eats that crab or eats that snail and that creature is, in turn, eaten by something, those toxins can be amplified up the food chain," said David Muth, Louisiana State Director for the NWF's Coastal Louisiana Campaign.
Last week, the NWF marked three years since the blow out with a new report on the health of six prominent species in the Gulf.
"Three years after the initial explosion, the impacts of the disaster continue to unfold," said Doug Inkley, NWF senior scientist.
The report, Restoring a Degraded Gulf of Mexico, rates the status of shrimp and brown pelicans as "good."
While Dolphins and deep sea coral are rated as "fair" in the report, it finds the major species in the most distress are bluefin tuna and sea turtles rated as "poor."
In both cases, the Gulf populations were in distress long before the BP spill.
The study notes the Atlantic bluefin tuna population has declined by 82% from the 1970s.
Recent studies estimated that the 2011 adult population of bluefin tuna was about 75% lower than the 2005 number.
The NWF report calls for channeling fines, including potentially billions of dollars in Clean Water Act penalties, into environmental restoration efforts.