New study finds Alaskans familiar with ocean acidification, not aware of risks to fisheries

New research published in Marine Policy from the first Alaska-focused study on public understanding and awareness of ocean acidification risk shows that Alaskans are three times more aware of ocean acidification than Americans in general.  However, Alaskans have difficulty seeing ocean acidification as an immediate risk, and the direct risks to Alaska’s fisheries are still not well understood. The research, “Gauging perceptions of ocean acidification in Alaska,” can be read online.

In Alaska, the impacts of ocean acidification have the potential to be even worse than “other coastal communities because of an accelerated rate of change in ocean chemistry, and statewide reliance on commercial and subsistence fishing. Accurately evaluating ocean acidification risk directly influences the ability to respond to change. The research builds on earlier NOAA-led research showing that communities in southeast and southwest Alaska are more at risk than other areas of the state because of their heavy reliance on fisheries expected to be impacted by ocean acidification.

“We wanted to learn the best way to provide Alaskans with the information they need to properly respond to ocean acidification,” said Lauren Frisch, who led the study and is a research associate at the University of Alaska Fairbanks Ocean Acidification Research Center. “The first step was to determine where there are gaps in the understanding of ocean acidification so that we can then work to fill them in.”

                      Crab fishing
A new study shows that Alaskans know about ocean acidification, but are not aware of the risk it poses to Alaskan fisheries. (NOAA)

Some 2000 Alaskans received a questionnaire in September, 2013. Questionnaires asked about each respondent’s role in the state's fishing industry as well as their belief in, understanding of, and concern about ocean acidification. The questionnaire’s response rate was 18 percent, which is high for studies of this nature. Results showed limited understanding of how Alaska will be uniquely impacted by ocean acidification. For example, only 28 percent of Alaskans believe that ocean acidification would have a greater impact on Alaska than other states in the United States.  Alaskans affiliated with the state’s fishing industry are not significantly more concerned about ocean acidification than those unaffiliated, and only 33 percent believe that ocean acidification will decrease revenue for fisheries. Finally, ocean acidification is perceived as a distant risk.  

“It can be difficult to think about ocean acidification as an immediate risk with all of the other challenges that we’re facing,” said Jeremy Mathis, who is the co-lead author on the paper describing the study’s results and an oceanographer at NOAA’s Pacific Marine Environmental Laboratory. “We really have to work harder to get the message out to stakeholders around Alaska that ocean acidification is something that they need to consider sooner rather than later.”

With a better idea of what Alaskans understand about this issue, the next step is to shape public education in a way that facilitates a long-term discussion of ocean acidification drivers and impacts, as well as mitigation and adaptation strategies.

“Moving forward, we need to figure out how to enhance this understanding that acidification is not uniform, and therefore adaptation plans will be more successful if they are local.  Educating communities with local examples about their specific risk could help foster this understanding.  The best thing we can do is provide vulnerable communities the toolset to evaluate risk themselves,” said Frisch.

Source: NOAA

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Dolly Varden are a species of char common in southeast Alaska. The fish shown is in spawning coloration.

Not all species may suffer from climate change. A new analysis shows that Dolly Varden, a species of char common in southeast Alaska, adjust their migrations so they can keep feasting on a key food source -- salmon eggs -- even as shifts in climate altered the timing of salmon spawning.

The resiliency of species to climate change may depend on how well they adapt to climate-driven changes in their food and habitat, such as altered growth of plants they feed on. A mismatch in timing between predators and the availability of prey could cause some species to lose access to food. But others such as Dolly Varden that successfully adjust to shifts in climate and prey offer a climate change story with a happy ending, according to the study published in Freshwater Biology.

Ignoring environmental cues may help this predator

The Dolly Varden's secret appears to be that instead of taking its migration cues from environmental variables such as water temperature or streamflow, the species cues directly off the presence of salmon the Dolly Varden depend on for food, the study found.

"Despite warming temperatures and shifting salmon migrations, Dolly Varden do a great job of following their food," said lead author Chris Sergeant of the National Park Service's Inventory and Monitoring Program in southeast Alaska. "Species that can handle a high degree of variability are the ones that should be most resilient to further changes associated with climate."

Dolly Varden get most of their energy over the course of each year by gorging themselves on salmon eggs, which are abundant in summer and rich in energy thanks to the same fatty acids that make fish healthy for humans. Eggs from any single species of salmon may be available during a narrow spawning window of two to six weeks. The Dolly Varden must follow salmon migrations closely to take full advantage of this annual salmon egg bonanza.

Sticking with salmon to find food

But salmon migrations are shifting as the climate warms. Previous research by the University of Alaska and NOAA Fisheries' Alaska Fisheries Science Center in southeast Alaska's Auke Creek has shown that pink and coho salmon now migrate to their spawning grounds 10 to 17 days earlier while sockeye salmon migrate eight days earlier.

Instead of falling out of synch with salmon, though, seagoing Dolly Varden in Auke Creek have accurately adjusted their annual migrations from the ocean back to freshwater to stick with the salmon. The adjustment has maintained their access to egg meals, according to the new research that includes coauthors from the University of Wyoming and NOAA Fisheries' Northwest Fisheries Science Center.

Researchers rely on long record of fish migration data

The research depended on a wealth of fish data from a weir on Auke Creek maintained primarily since 1980 by NOAA Fisheries' Alaska Fisheries Science Center Auke Bay Labs, supported by collaborations with the University of Alaska Fairbanks and Alaska Department of Fish and Game. From 1997 to 2006 crews counted and measured Dolly Varden migrating from the ocean, past the weir and into Auke Creek, providing an unusual long-term picture of fish migration times.

"We're really indebted to the people who kept that record going for so long," said Eric Ward of the Northwest Fisheries Science Center. "It turns out to be very valuable in understanding how species are responding to the changing climate."

Researchers in the new study used the weir data to examine the relationship between migrations of salmon and Dolly Varden from year to year. They found the timing of Dolly Varden migration more closely related to the presence and timing of the salmon than on environmental variables such as temperature and precipitation that are often seen as driving animal migrations.

In short, the Dolly Varden are shifting their migration to follow their food instead of following temperatures or other environmental cues that, as the climate changes, might otherwise lead them to migrate at a different time than the salmon that provide their most important food.

The researchers cautioned that it's unclear whether other salmon predators could adjust their timing to follow salmon as effectively as Dolly Varden do, apparently by watching salmon passing by or detecting salmon eggs through smell. But the adaptability of Dolly Varden suggests that at least some species may be more resilient to climate-induced changes in migration timing than ecologists might assume.

Source: NOAA Fisheries West Coast Region

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Climate change projected to drive species northward

Coho salmon are among the species anticipated to shift northward with climate change. Credit: NOAA Fisheries

Anticipated changes in climate will push West Coast marine species from sharks to salmon northward an average of 30 kilometers per decade, shaking up fish communities and shifting fishing grounds, according to a new study published in Progress in Oceanography.

The study suggests that shifting species will likely move into the habitats of other marine life to the north, especially in the Gulf of Alaska and Bering Sea. Some will simultaneously disappear from areas at the southern end of their ranges, especially off Oregon and California.

"As the climate warms, the species will follow the conditions they're adapted to," said Richard Brodeur, a NOAA Fisheries senior scientist at the Northwest Fisheries Science Center's Newport Research Station and coauthor of the study. "We're going to see more interactions between species and there will be winners and losers that we cannot foresee."

The study, led by William Cheung of the University of British Columbia, estimated changes in the distribution of 28 near-surface fish species commonly collected by research surveys in the northeast Pacific Ocean. The researchers used established global climate models to project how the distribution of the fish would shift by 2050 as greenhouse gases warm the atmosphere and, in turn, the ocean surface.

Brodeur cautioned that like any models, climate models carry uncertainty. While they provide a glimpse of the most likely changes in global climate, they may be less accurate when estimating more fine-scale, local changes.

"Nothing is certain," he said, "but we think we have a picture of the most likely changes."
Some species shifts are already being documented as West Coast waters are warming: predatory Humboldt squid from Central and South America have invaded the West Coast of North America in recent years, albacore have shifted to more northerly waters and eulachon have disappeared from warming waters at the southern end of their range.

"Thinking more broadly, this re-shuffling of marine species across the whole biological community may lead to declines in the beneficial functions of marine and coastal ecosystems," said Tom Okey, a Pew Fellow in Marine Conservation at the University of Victoria and a coauthor of the study. "These declines may occur much more rapidly and in more surprising ways than our expected changes in species alone."

The study anticipates warm-water species such as thresher sharks and chub mackerel becoming more prominent in the Gulf of Alaska and off British Columbia. Some predators such as sea lions and seabirds, which rear their young in fixed rookeries or colonies, may find the fish they usually prey on moving beyond predators' usual foraging ranges.

"If their prey moves farther north, they either have to travel farther and expend more energy to get to them, or find something else to eat," Brodeur said. "It's the same thing for fishermen. If it gets warmer, the fish they depend on are going to move up north and that means more travel time and more fuel will be needed to follow them, or else they may need to switch to different target species. It may not happen right away but we are likely to see that kind of a trend."

El Nino years, when tropical influences temporarily warm the eastern Pacific, offer a preview of what to expect as the climate warms.

Shifts in marine communities may be most pronounced in high-latitude regions such as the Gulf of Alaska and Bering Sea, which the study identifies as "hotspots" of change. Cold-water species such as salmon and capelin have narrower temperature preferences than warmer water species, making them more sensitive to ocean warming and likely to respond more quickly.

An intrusion of warm-water species into cooler areas could lead to significant changes in marine communities and ecosystems. The diversity of northern fish communities, now often dominated by a few very prolific species such as walleye pollock, may increase as southern species enter the region, leading to new food web and species interactions.

Source: NOAA Fisheries West Coast Region

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