ROBERT SIEGEL, HOST:
Five years after the BP oil spill, a massive scientific effort is underway to figure out how the disaster harmed the Gulf of Mexico. It was an unprecedented blow to Gulf wildlife at the time, killing shorebirds, marine mammals and fish. But the lasting damage is not as dire as originally feared. Still, researchers say it's too soon to know what the long-term impacts might be. NPR's Debbie Elliott reports.
DEBBIE ELLIOTT, BYLINE: Wetzel Wood casts his fishing line into the rough surf of the Gulf of Mexico. He pulls his bait, a cigar minnow, through the water just beyond where the waves break for shore near his hometown of Orange Beach, Ala.
WETZEL WOOD: On a good day, you'd catch king mackerel, Spanish mackerel.
ELLIOTT: Wood is at the Gulf State Park Pier. It's where he first learned to fish with his grandfather in 1969.
WOOD: I've seen a lot of different things out here. It's been wonderful.
ELLIOTT: But one of the worst was five years ago when oil was spewing from BP's out-of-control well for nearly three months. From this pier, Wood watched as mats of oil hit the Alabama coast.
WOOD: I was kind of thinking, you know, I don't know if we'll ever be able to come out here and fish again. It was kind of a lonesome feeling, you know? I had no idea when it would come back if it came back.
ELLIOTT: Wood says today you don't see oil, and fishing appears to be on the rebound, but it's not as good as it once was. He still worries about the future. Scientists are trying to find some answers. The results so far are mixed. Kenneth Heck with Alabama's Dauphin Island Sea Lab says fish population studies in the Gulf show one picture, but a different one emerges when researchers look at individual fish in controlled lab studies.
KENNETH HECK: Almost without exception, those studies find negative impacts - OK - at the level of the individual organism. However, all the studies that I know of that have been done to-date at the population level out in nature have not found those impacts. So there's a mismatch between what we have seen in the laboratory and what we've seen in the field.
ELLIOTT: BP points to those population studies as evidence of a strong recovery for a resilient Gulf - far better than the ecosystem collapse some people predicted during the spill. BP Senior Vice President Geoff Morrell.
GEOFF MORRELL: There is not what many people had feared, a lost generation of Gulf species.
STEVE MURAWSKI: I think the homework is incomplete.
ELLIOTT: Steve Murawski is a marine scientist at the University of South Florida.
MURAWSKI: This is a large, complex ecosystem that's difficult to sample. You're talking about cryptic things that we're trying to, you know, get a handle on. We know that there's impacts in certain areas. And some species - sure, they're capable of rebounding, and they did. But to basically make a blanket statement is way too premature.
ELLIOTT: Murawski says migrating fish with a shorter lifespan, such as Spanish mackerel, appear to be doing OK. But ones that live longer and don't move around as much - red snapper and tilefish, for instance - show more problems like tumors and oil in their organs.
Other studies indicate that dolphin in certain areas have suffered and endangered sea turtle nests have declined. Murawski says more than 3 million barrels of oil is going to have an impact.
MURAWSKI: People need to acknowledge this was a massive oil spill. This stuff, by-and-large, doesn't just disappear. It has consequences. And so we would expect a certain level of consequence to happen in a spill of this magnitude.
ELLIOTT: Murawski says because the BP spill was unprecedented, there's little historical data to provide clues about the long-term prognosis for the Gulf, and those answers will only come with time. Debbie Elliott, NPR News, Orange Beach, Ala.