Exxon Valdez Archives - Tulalip News

Low levels of oil pollution harm herring, salmon, study finds

Researchers find oil can harm herring and salmon at much lower levels than once thought. The work raises questions about Puget Sound pollution.

By Hal Bernton, Seattle Times

Federal scientists based in Seattle and Alaska have found that oil — by impairing heart functions — can cause serious harm to herring and pink salmon at far lower concentrations than previously documented.

The research, published Tuesday online in Nature’s Scientific Reports, could help unravel the mystery of why herring stocks in Prince William Sound collapsed after the 1989 Exxon Valdez oil spill. Their work also has implications about the effects of low levels of chronic oil pollution in Puget Sound and elsewhere in the world.

“What this study shows is that in very, very low concentration of oil, embryonic fish … get born with a mild heart defect,” said John Incardona, a National Oceanic and Atmospheric Administration toxicologist at a Seattle fisheries science center. He is one of 10 co-authors of the study.

Those fish may look OK on the outside, but the heart defect makes them less fit, so they can’t swim as fast. They may succumb to predators at higher rates than other fish and may be more vulnerable to infections, according to Incardona.

The findings reflect years of studies that explored the effects of polycyclic aromatic hydrocarbons, compounds released by crude oil spills, but also contained in many other forms of fossil-fuel pollution such as tailpipe emissions from Puget Sound motorists that condense and are carried into the water by runoff.

The research examined the effects on fast-growing zebrafish, and then replicated the heart damage in more complex experiments that exposed embryonic herring and pink salmon to oil.

The researchers found that oil’s effects are greatest in cold-water environments, where fish embryos are less able to metabolize the pollutants. And herring, with much smaller eggs than the pink salmon, suffered the most severe effects from the polycyclic aromatics.

In the aftermath of the 1989 Exxon Valdez spill that dumped nearly 11 million gallons of crude in Prince William Sound, Alaska became the first — and so far only state — to create a water-pollution limit for the polycyclic aromatics, according to Incardona.

That Alaska state limit is 10 parts per billion, but the researchers found herring embryos could be affected at levels 10 to 50 times lower than that. At those levels, herring that returned to spawn in Prince William Sound in 1989 as well as subsequent years could have produced offsprings with damaged hearts.

Those offspring would have hatched, but few may have survived long enough to reach spawning age. That could be a big reason spawning stocks of Prince William Sound herring crashed four years after the 1989 spill.

“The thresholds for developmental cardiotoxicity were remarkably low, suggesting that the scale of the Exxon Valdez impact in shoreline spawning habitats was much greater than previously appreciated,” the researchers wrote.

In the more than quarter century since the Exxon Valdez spill, Prince William Sound herring stocks have failed to recover even as oil pollution has declined to levels unlikely to affect them.

The study published Tuesday does not try to explain the herrings’ current problems, although Incardona says once fish stocks get knocked to a very low level, recovery can be very difficult.

The situation is very different in Puget Sound, which has the highest levels of polycyclic aromatics of any estuary due to ongoing chronic pollution, according to Incardona. The Puget Sound levels are not that far below those found to have effects in the aftermath of the Exxon Valdez, and raise questions about whether this pollution is harming Puget Sound’s struggling herring stocks.

Incardona, who said that federal researchers hope to work with Washington state biologists to try to answer that question.

EarthFix Conversation: 25 Years Later, Scientists Remember The Exxon Valdez

Killer whales swimming in Prince William Sound alongside boats skimming oil from the Exxon Valdez oil spill. Scientists report that orca populations there have not recovered and oil is still being found. | credit: (State of Alaska, Dan Lawn) | rollover image for more — Killer whales swimming in Prince William Sound alongside boats skimming oil from the Exxon Valdez oil spill. Scientists report that orca populations there have not recovered and oil is still being found. | credit: (State of Alaska, Dan Lawn)

By Ahsley Ahearn, OPB

25 years ago today the Exxon Valdez, an oil tanker bound for Long Beach, Calif., ran aground in Prince William Sound.

11 million gallons of oil spilled out, polluting 1,300 miles of Alaska’s coastline.

At the time it was the largest oil spill in U.S. history.

Gary Shigenaka and Alan Mearns responded to the Exxon Valdez, and they’ve been studying oil spills ever since. They’re scientists with the National Oceanic and Atmospheric Administration in Seattle.

They told EarthFix’s Ashley Ahearn about their experience responding to the Exxon Valdez all those years ago.

Alan Mearns: Some places we’d go ashore and you’d see starfish that looked like they were sick, they were just kind of drifting around in the surf. And you could smell the oil too, in the places where there was plenty of it. It smelled like benzene, like you’re pumping gas at the gas station and you sniff that little bit of benzene as you pull the hose out of your car.

EarthFix: Gary, how were orcas impacted by the spill?

Gary Shigenaka: Two groups that frequent Prince William Sound crashed immediately after the spill. So since the time of the oil spill those populations have continued to be monitored and we can follow the trends and for the AB pod — the resident pod – there’s been a slow recovery. For the AT1 group, which is the transient pod, it’s been declining ever since the spill and the orca specialist for Prince William Sound, Dr. Craig Matkin, has predicted that that particular group is going to go extinct. It continues to decline with time. So it’s an unfortunate longterm legacy from the spill.

EarthFix: Some people thought the orcas would swim away, would avoid the oil spill itself, but that wasn’t actually the case, was it?

Shigenaka: What we all thought was that orcas are so smart. They will simply avoid the oiled waters. But we’ve got very good photographic evidence that shows that indeed they did not.

One photograph, an aerial photograph, shows orcas cutting through a slick and you can see where they’ve come to the surface right through the oil. There’s another shot of a pod of orcas right at the stern of the Exxon Valdez, right at the tanker.

EarthFix: What creatures were the most impacted or most harmed by the Exxon Valdez spill?

Mearns: Oh, birds. We’re talking about 200 to 300,000 I think, Gary.

Shigenaka: Yeah.

Mearns: Seabirds, mainly seabirds and some shorebirds. And of course that was the big thing you’d see in the news almost every day: pictures of an oiled bird, somebody picking it up, taking it to a wildlife rehabilitation station where they’d clean them and then hold them until they could be released.

Birds killed as a result of oil from the Exxon Valdez spill. Credit: Exxon Valdez Oil Spill Trustee Council.

EarthFix: SO for people who weren’t alive, weren’t reading the paper when the Exxon Valdez spill happened, what were those animals going through? What happens to a bird when it interacts with an oil slick?

Mearns: Well, first of all, even though it’s in the spring and summer it’s still cold up there. If it’s not killed by being smothered by gobs and gobs of oil, if it’s a little bit of oil, it will succumb eventually to things like pneumonia-type diseases and things like that, so it suddenly causes birds that had good insulation not to have insulation and start suffering the effects of cold conditions.

Shigenaka: And the same holds true for another of the iconic wildlife species in Prince William Sound: the sea otters. They insulate themselves with that nice thick fur pelt and they are affected in the same way by oil disrupting their ability to insulate themselves during a spill.

EarthFix: 25 years later, how is Prince William Sound? What species have recovered, how does the place look?

Mearns: Well, 14 or 15 species or resource values have recovered. The recovery started a few years after the spill with things like bald eagles. A number of them were killed off but their population rebounded. The most recent recovery was just announced was of the sea otters that we were just talking about. So between 1991-92 when we started seeing reports of recovery of a few bird species and now we’ve had about 14 or 15 species recover but there’s still some others that haven’t yet.

EarthFix: Which ones are you most concerned about, Alan, or scientists are following most closely with concern?

Mearns: The orcas are really the ones we’re most concerned about now.

EarthFix: Is the oil gone?

Mearns: No. There are still traces of oil in the shorelines. When you go out at low tide and go into some of these back bay areas with gravel and sand overlying bedrock and dig down maybe a foot sometimes you’ll hit spots with oil that is still actually fairly fresh. We’ve encountered that at a few sites that we’ve monitored over the past 25 years.

Shigenaka: That’s been one of the 25-year surprises for us is that there are pockets of relatively fresh oil remaining both in Prince William Sound and along the coast of the Alaska Peninsula and that’s something that I don’t think any of us expected 25 years later.

EarthFix: What did this spill mean for your careers? You guys were both young bucks when this happened. And now, 25 years later, when you look back, what did it mean, the Exxon Valdez?

Shigenaka: I think overall, just the notion that we have a responsibility, both as responders and as scientists to try to communicate what we do and what we know in a way that’s understandable to the people who are affected.

EarthFix: There is more oil moving through this region now – more oil coming from the tar sands of Alberta and coming from the Bakken oil fields of North Dakota to refineries here in Washington state. If I talk to you guys 25 years from now, what do you hope we’re talking about?

Mearns: One thing that I worry about and I think Gary has some other things that he worries about is a lot of this new oil is going to be going through the Aleutian Islands, the great circle route, more and more tankers leaving here or in Canada and heading across. And in the Aleutian Islands, we thought Prince William Sound was remote, well the Aleutian Islands are even more remote. Getting equipment there, getting staff, we’ve had a few experiences with spills. I guess I’m concerned that there will be more spills in that region from this increased traffic out there.

EarthFix: Or elsewhere.

Mearns: Yeah.

Shigenaka: 25 years from now I’m hoping that we have a much better handle on how these novel new oils like the tar sands oil and the Bakken crude oil from North Dakota, how they behave in the environment and what their potential impacts are to exposed organisms because frankly right now we don’t really know how the stuff behaves, both types of oil, once it gets loose in the environment and we’re only beginning to understand what potential impacts there might be for the exposed communities.

Gary Shigenaka and Alan Mearns are scientists with the National Oceanic and Atmospheric Administration in Seattle. They responded to the Exxon Valdez spill 25 years ago.

Mink will be trapped to right the wrongs of Exxon Valdez

By John Upton, Grist

Nearly a quarter of a century after the Exxon Valdez crashed and spewed 11 million gallons of crude into Prince William Sound, one species of seabird still has not recovered from the disaster. To help it recover, the federal government is proposing to get rid of lots of American minks. Allow us to explain.

Thousands of pigeon guillemots were killed by the Valdez disaster — some coated with oil, others poisoned by it for a decade afterward. The guillemots are the only marine bird still listed as “not recovering” from the accident; the local population is less than half what it was before the spill.

The birds used to flourish on the Naked Island group in the middle of the sound, but fewer than 100 remain there now. To boost that number back up to the pre-spill level of 1,000, the U.S. Fish and Wildlife Service is proposing to trap most of the islands’ American minks — aquatic ferret-like creatures that feast on the birds’ chicks and eggs. If trapping doesn’t work, shooting the minks is the backup plan.

The minks are native to the region, but nobody knows for sure whether they are native to the islands in question. What scientists do know is that the islands’ mink populations skyrocketed in the immediate aftermath of the 1989 spill. “[T]he increase in mink caused pigeon guillemots and other bird species (whose nests are susceptible to mink predation) to decline significantly,” the FWS wrote in a draft environmental assessment detailing its proposal.

From the Alaska Dispatch:

Figuring out how many mink to remove is “the hard part,” [FWS seabird coordinator David] Irons said, as the exact number inhabiting the cluster of islands is unknown, although their numbers are estimated to range roughly from 200-300.

By removing the mink, several other species of birds that nest on the islands would benefit as well, Iron said. Parakeet auklets, tufted puffins and horned puffins have also been on the decline in the past decades, but those birds are not on the [Exxon Valdez oil spill] Trustee Council’s list of affected animals.

“Right now Naked Island is a desert of birds — it used to be a hot spot,” Irons said, adding that the Prince William Sound used to be home to 700 parakeet auklets, whereas now only around 40 remain.

It’s hard to imagine how an oil spill would cause a mink population to explode. But Irons points out that that’s not the main concern — what’s important to the Exxon Valdez oil spill Trustee Council is that the birds “were affected by the oil spill” and it is therefore the council’s responsibility to do what it can to help them out, drawing on $900 million in civil penalties paid by Exxon.

This map shows the Naked Island group. The Exxon Valdez ran aground bear Bligh Island.

Prince William Sound — U.S. Fish & Wildlife Service