Warm Gulf water raises eyebrows
Scientists haven’t spotted any disasters related to warm water in the Gulf of Alaska just yet, but they’re keeping their eyes peeled.
The National Oceanic and Atmospheric Administration, or NOAA, is keeping a close watch on a series of strange environmental events in the North Pacific related to an unusual patch of Gulf of Alaska water referred to as “the blob” by researchers and media.
The blob has not yet been directly connected to any damaging environmental effects, though anecdotal evidence points to a dramatic spike in paralytic shellfish poisoning, or PSP, levels in the Aleutian Islands resulting from an algae bloom creeping into Alaska water.
Presently, most researchers see the blob an interesting and useful tool to study the effects of warm waters on ocean biology, rather than a harbinger of the North Pacific’s impending doom. The question of what happens when ocean water is warmer could find answers in the North Pacific’s blob.
“We’re kind primed to answer this complex question as it plays out,” said Kris Holderied, NOAA’s science lead at its Kasitsna Bay laboratory. “This warm blob is a big thing that might be giving us a foretaste of what’s happening in the future.”
The blob was originally noticed and its nickname coined by Nicholas Bond, a research meteorologist at the University of Washington.
Bond first noticed the blob in late 2013, the result of “a naturally occurring, short-term perturbation in the atmosphere and ocean climate of the North Pacific.”
Warmer and drier climates in the western U.S. combined with Pacific Ocean currents to cause a patch of water stretching along the West Coast and into the North Pacific with an average surface temperature of 2 degrees centigrade, or 3.6 degrees Fahrenheit, warmer than the historical mean.
“Basically there are two things going on,” said Holderied. “There’s this North Pacific weather shift happening, and the continuation and intensification of El Nino, and they’re combining to make the water warmer.”
Researchers and fishermen haven’t positively connected anything sinister to the warm water, but there’s no lack of troubling episodes in the Gulf of Alaska. Dead whales have cropped up near Kodiak, Chignik, Katmai, Seldovia, and False Pass during the summer, along with dead sea lions in Dutch Harbor and Amalik Bay. Dead puffins and other seabirds abound along the Gulf, as well as washes of dead bait fish including sand lances and herring.
NOAA has not made any direct causal connection between warm water and the deaths of various marine mammals and seabirds. According to initial reports, Holderied said, the birds appear to have starved to death, suggesting food competition is a likely culprit.
Sampling the whales, however, proved more difficult. The expenses due to the carcasses’ remoteness precludes sample collection, and the decaying remains would be difficult to draw useful samples from anyway, according to Aleutians Pribilof Island Association senior scientist Bruce Wright.
Less ominously, warm waters could be attached to host of strange, but relatively benign, fish behavior in the Gulf.
Salmon are unpredictable at best, but Alaska’s stocks showed odd behavior attributable to side effects of warmer than average temperatures.
Early Gulf of Alaska sockeye salmon came in undersized. Many factors influence returning salmon size, brood year first among them.
Alaska Department of Fish and Game biologists from Bristol Bay, Cook Inlet, and Prince William Sound, however, said the fish have been smaller for their respective age brackets, and that a possible explanation the food competition and metabolic variation warm water could cause.
Further, fishermen and biologists in Prince William Sound and Cook Inlet have reported the signs that warmer than average temperature forcing sockeye beneath drift nets, whose depths are regulated, in order to find cooler water.
“That was a theory proposed by fishermen, that they were never able to find a concentration of fish,” said ADFG Kenai area commercial management biologist Pat Shields. “They claim this year the fish were running deeper. I have no data to show that, but usually drifters know how to catch fish. If they can’t catch them, there’s a reason why.”
Typically, the drift fleet catches 53 percent of the total sockeye harvest in Shields’ management area, he said. This year, it only caught 40 percent.
Even stranger, four mola mola, or ocean sunfish, were spotted by the Oil Spill Recovery Institute in Prince William Sound in August. Sunfish are tropical, and rarely venture farther north than British Columbia. This follows a 2014 sighting of the same fish, as well as a rarely northbound skipjack tuna, which had not been previously seen in Alaska water since the 1980s, according to NOAA’s Joe Orsi.
Rising PSP concentrations
Most visibly, the warm water is conducive to certain kinds of pseudo-nitzschia or phytoplankton, types of algae, creeping into the Gulf of Alaska from farther south.
Bruce Wright said first and foremost on the list of possible scares is rising concentrations of paralytic shellfish poisoning, or PSP, in Gulf of Alaska shellfish, the sampling for which he is currently waiting.
The algae moving into the Gulf carries the risk of both domoic acid, a neurotoxin which causes amnesic shellfish poisoning in humans, as well as PSP.
Earlier in the year, domoic acid levels prompted the state of Washington to prematurely shut down its Dungeness crab fishery for safety concerns. The Alaska Department of Environmental Conservation, or DEC, has been monitoring domoic acid levels of shellfish and algae samples from the Aleutian Islands and Southeast Alaska. The results came back negative.
Both domoic acid and PSP occur naturally, and are widely seen across Alaska in small enough concentrations as to make little difference in human consumption. Wright is keeping an especially vigilant eye after getting a troubling PSP reading from Sand Point, where PSP is common enough but not in this concentration.
When Wright sent samples to be measured for PSP levels, however, he found a darker story. From butter clams taken from Sand Point, Wright said the DEC measured 2,580 micrograms of PSP on June 8.
The Food and Drug Administration declares anything over 80 micrograms unsafe for human consumption.
“That might have been a record breaking level if it were mussels,” said Wright. “I think this bump we had in Sand Point in June was huge, kind of a game changer.”
Beyond bivalves, Wright looks for evidence that PSP has entered into the larger food chain to affect other animals, which he said could partially explain seabird and sea mammal deaths. The dead herring and sand lance, which are bait fish, could be the mechanism by which PSP is creeping into sea bird and mammal diet.
Wright took samples from two dead sea lions, which came back positive for PSP levels.
The U.S. Fish and Wildlife Service researchers are reexamining the samples of dead birds, whose deaths are currently attributed to starvation.
PSP or not, Wright said starvation merits another look. Typically, starved birds turn up in winter and early spring, not in summer when there’s ample opportunity to scavenge the runoff from salmon processors and hunt fish returning to spawn. PSP, he said, could be affecting their feeding habits by means of cerebral deterioration, a symptom of the toxin.
Wright clarifies that the evidence is only anecdotal. Along with the birds, Wright is waiting for 40 shellfish samples to be analyzed by DEC researchers. The results should come later in the week.