The idyllic Pacific Northwest has long been a seafood-oriented place. Surrounded by water and mountainscapes, you can see its reliance on seafood running all the way back to ancient Native American ceremonies and totems. Today, Seattle is home to much of the Alaska fishing fleet, and Washington and Oregon are healthy producers of oysters, Dungeness crab, geoduck, and other prized seafood.
However, in the late 2000s, that way of life was called into question when ocean acidification turned up on the scene: causing massive die-offs of very young oyster larvae, called “seed.” While the ocean is alkaline, and will always be that way, ocean acidification is the term used to describe the process of the ocean gradually becoming more acidic due to absorption of carbon dioxide (C02) emissions. Nearly a third of carbon emissions released into the atmosphere are absorbed by the ocean. Once upon a time people thought that was a good thing: that the ocean was doing us a favor, and there would be no additional consequences. Well, that fantasy is over.
Since the beginning of the Industrial Revolution, the addition of C02 has been fundamentally changing the chemistry of seawater. These changes are illustrated twofold: first, the pH of the ocean is gradually decreasing. Healthy seawater has a pH of 8.1, but since the output of anthropogenic (human-caused) carbon emissions began, a .11 decrease in the global average pH of the surface ocean has been observed. The pH scale is logarithmic, which means a pH decrease of .11 is actually a 30% increase in acidity (a change more rapid than any observed in the last 300 million years). In some places, like the Pacific Northwest, the change to seawater has been even more dramatic, due to the upwelling of carbon-rich, deep ocean water to the surface each year, which exacerbates the effects of ocean acidification (OA). The pH can be as low as 7.5 in certain “hot-spots.”
Secondly, the addition of CO2 to the ocean causes a harmful chemical reaction. Carbon dioxide binds with water and carbonate ions to produce bicarbonate. For creatures that rely on plentiful carbonate to build their shells (like oysters, clams, shrimp, mussels, crab, and others), this change to the chemistry compromises their ability to do so.
Multiplying the effects of OA are other changing ocean conditions, such as warming, nutrient runoff, pollution, and disease. Known as multi-stressor scenarios, when these conditions combine – as they often do in the Pacific – it can create a domino effect of weakening marine foodwebs and organisms’ health. As Eric Sanford, professor of evolution and ecology at the University of California, Davis and lead author on a study of OA combined with other stressors, said, “You might decide to go to work if you had a toothache. But what if you had a toothache, the flu, and a broken leg? At some point, multiple stressors will cause natural systems to break down.”
Oysters Become the “Canary in the Coal Mine”
Before local seawater chemistry turned against them, most oyster farmers in estuaries along the coast of the Northwest relied at least partially on wild seed – the oysters in the estuary would spawn and the seed would settle on old shells and other rough surfaces, “set” there, and the growers would tend them until ready for harvest. Many growers also supplemented with seed from hatcheries, which pump in seawater to breed and sustain large tanks of oyster larvae, and then sell it in varying sizes and quantities to growers who want to boost their numbers.
While OA had been a subject of scientific study for some time, conditions were not expected to harm marine organisms until 2050, and back in 2007, the term “ocean acidification” was known to only a small circle.
That is, until something started happening at Whiskey Creek Hatchery, in Netarts Bay, Oregon, which had been farming oysters commercially for over 150 years, and provides over 3000 family wage jobs in rural areas along the coastline. After 30 years of consistent production of oyster larvae, in 2007 and 2008 they started experiencing losses that reduced production substantially and unsustainably. As hatchery manager Alan Barton says, “The bottleneck in supply always has been and always will be producing enough larvae to meet the needs of our growers. Now that we’re having problems producing larvae in our hatchery, it’s already had a pretty big economic impact on our industry, to the tune of tens of millions of dollars per year in lost harvested product.”
The usual suspects, like disease, were ruled out, and funding was collected to bring scientists in to identify the problem. They concluded that ocean acidification was to blame. The combination of carbon and nutrient rich deep ocean water upwelling along the west coast and carbon dioxide emissions absorbed from the atmosphere had caused a tipping point. Every year since this discovery, from California to British Columbia, monitoring systems have consistently documented water corrosive enough to dissolve fragile young larval shells, and it affects every grower and every hatchery along that coastline. At the same time, wild sets of oyster seed ceased to be available because they died in the first 48 hours of spawning. This made oyster farmers entirely reliant on hatcheries, and many growers had to invest in costly capital equipment like larval setting tanks, increasing expenses by 30% or more a year.
Before Barton experienced all of this for himself, he was the last person to call himself an environmentalist, and didn’t have a particular stance on climate change. The concepts, he says, are complicated to understand, but critical for his industry going forward. “It nearly drove us out of business in 2009, and continues to have a big economic impact on our industry. Thanks to monitoring we’re able to find times of years that are safer to spawn, and thanks to sophisticated water treatment systems, we can treat our hatchery water to maintain healthy production.”
According to Barton, Whiskey Creek installed automatic buffering systems in 2011 in order to maintain a constant pH in the hatchery. But even he admits it’s only a short term fix. “Every year we can see it getting harder to fix the water. And every year our production changes as a result of that,” he says. “We want to work in the hatchery and produce larvae. But we’re forced to start thinking about the global problem of CO2 emissions, because we have no other option. Some of you guys might not like oysters, but food webs that affect salmon, cod, crab, shrimp, and lots of other important seafood is also at risk.”
The life-long oysterman reiterates that he’s not an environmentalist, but the problems facing his industry require action on a larger scale. “If we continue down the road that we’re on, in terms of emissions, there won’t be oyster farmers by the turn of the century,” he says. “We have often been referred to as the canary in the coal mine, but if you’re familiar with the history of that phrase, the canary has to die so that everyone else can make it out safe. We don’t want to be the canary in the coal mine. It’s time to make some hard decisions that can keep us going in the future.”
For now, west coast hatcheries use expensive real-monitoring water monitoring systems that detect when seawater conditions are harmful, and add sodium carbonate to buffer it sufficiently to protect delicate larvae. But as Barton mentioned, it is becoming more difficult each year and none feel confident of a long-term future. For family-owned businesses in their fourth and fifth generations, this is a real blow. For them, oyster farming is a way of life and they can’t imagine spending their days any other way.
King Crab on the Hook
Another iconic seafood, the red king crab, looks to be vulnerable to OA, and stakeholders are scrambling to find a solution. One group is looking to hatcheries as a partial fix. Now for the first time, hatchery-reared juvenile red king crab have been released into the wild, and results are back on the viability of restocking areas where populations have been devastated, or where future OA hot-spots may kill young red king crab, which have proven to be particularly susceptible to OA conditions.
A 2013 report shows that red king crab juveniles experience 100% mortality rates when exposed to pH 7.5 for 95 days. While the Pacific Northwest regularly experiences such conditions, Alaskan waters are still generally in the healthy range of 8.0 pH, for now. But Robert Foy, one of the authors of the report, predicts natural breeding and successful survival of red king crab to fail within 20-30 years of Alaskan waters reaching pH 7.8 (expected within 30 years). The Seattle Times reported on the study and its implications last year in their award-winning Sea Change series.
These potentially dangerous conditions, however, might not be as far in the future as we thought. Jeremy Mathis, a well-known OA researcher for the National Oceanic and Atmospheric Administration (NOAA), found disturbing evidence about current conditions: “What we actually found is that in certain times of the year, the [pH] conditions near the bottom in the Bering Sea were actually worse than the conditions that Bob was raising his crabs under [in the lab].” Fortunately, there’s no evidence that OA is currently affecting wild populations; the critical times when Mathis’ study found the sea to be most corrosive happen during a part of the crab life cycle when they are not as vulnerable. However, there’s no denying that stocks are dwindling and have been for some time – even in places where fishing has been banned -but a specific cause has yet to be isolated.
Red king crab is a lucrative fishery, and many fortunes have been built on it over the last century. You see its iconic image reflected all over the Northwest and Alaska, and real estate investments born from king crab money abound today in both areas. At Seattle’s famous Pike Place market, king crab can command as much as $39.99 a pound. In addition to its delicious flesh, the fishery itself became hugely popular through the reality TV show “Deadliest Catch,” which exposed audiences to the dangerous nature and the emotional highs and lows of crab fishing. But for those who rely on healthy king crab stocks for their living, particularly those who own quota and fishing vessels, the look at the future predicted by this OA research is troubling. For many multi-generational fishing families, there’s a strong chance that their children and grandchildren will not be able to carry on the crab fishing legacy. Adding that in some places king crab stocks are already down from historic levels, as well as threatened by other issues like warming seas, some in the industry felt compelled to act by forming new partnerships. Others are diversifying to other fisheries, while still others are continuing with business as usual. Jim Stone, co-owner of a Bering Sea crab vessel, the F/V Arctic Hunter, told the Seattle Times, “We’re scared to death, but we’ve heard a lot of horror stories before.”
Seeking to get ahead of the curve is the Alaska King Crab Research, Rehabilitation and Biology program (AKCRRAB), a joint program supported by industry, natives, Alaskan communities, and state and federal programs. Their attention turned to an experiment led by Alutiq Pride Shellfish Hatchery, which had already been underway for some years, to restock crab populations around Kodiak Island where levels had crashed forty years ago. That experiment took on a new meaning and garnered new attention with the threat of ocean acidification.
Alutiq Pride Shellfish Hatchery is at the center of rearing crab larvae, they’ve spent years learning how to do it as part of the Kodiak restocking effort. Along with producing stocks of oysters, geoducks, abalone, butter clams, and sea cucumbers, they also raise juvenile red and blue king crab larvae. Crab fishing vessels help the hatchery collect pregnant females, and Alutiq Pride raises broodstock on site. Now the result of years of experimentation is coming to fruition, with the successful outplanting of hatchery-reared crab into the wild.
Broodstock collected from Alitak Bay in fall of 2013 was reared until August 2014, when 11,250 red king crab juveniles were released into experimental 5×5 meter plots in Trident Basin, near Kodiak, Alaska. Their survival in the wild has been carefully tracked since the time of release, with varied trial crab densities and predator density monitored. At the last reporting, AKCCRAB found that after 65% die-off in the first 24 hours (similar to losses in other hatchery-reared animals released into the wild) survival rates of hatchery-reared crab are about the same as that of wild juveniles – supporting the theory that artificially restocking the area is ecologically viable. After that initial mortality, the loss rate of hatchery crab and wild populations equalized, indicating that outplanting works and that future releases of juveniles could be made in higher numbers.
Three more outplantings took place this year, and mortality and efficiency are increasing with each attempt. Alutiq began the year with 400,000 red king crab larvae and 15,000 blue king crab larvae in March, when larvae hatching was underway. Such large numbers are necessary to start, because cannibalism is rampant among hatchery reared juveniles – as many as 50% are lost with each molting. Larvae from numerous females are being utilized to preserve genetic diversity in the stock. They can also do full parental genotyping, so progeny can always be traced back to the mother. Larvae are fed on algae until they molt into the first juvenile stage. In each round of outplanting, AKCCRAB experimented with variables to increase survival: like releasing crabs of different sizes, and releasing at night when the threat from predators could be lower. NOAA teams will continue to monitor all of the released juveniles through the winter, until March 2016.
These experiments indicate significant progress for Alutiq Pride and AKCCRAB. The project has brought together collaborators from across the board: the fishing industry, tribal interests, Alaskan communities, and organizations from both state and local government. At long last the project is bearing fruit, and there’s some hope in the use of hatchery-reared king crab to support natural stocks. Hatchery manager Jeff Hetrick says, “The big picture is reestablishing stocks, but we’re also learning techniques and technology that are pretty amazing.”
Now that multiple experimental releases have proved successful, Hetrick says, “Alutiq Pride can start ramping up production, releasing a couple hundred thousand next year.” That will be the final year of experimentation. After that, they will be using the technology to take the project to the next level and actively reestablish crab stocks.
But nobody believes that hatcheries can fully replace wild populations of red king crab. The amount of juveniles needed to populate the Bering Sea alone boggles the mind. “We’re hoping that it never gets to the point that they rely on the hatchery for that kind of work,” Hetrick says. “If we get to that point I think we’re in trouble. But it is a possibility.” However, perfecting the science might help restock populations in devastated areas, and the industry can be ahead of the curve in hatchery-rearing king crab as the pH continues to drop in ocean waters around the world. Hetrick adds, “With what we’ve learned in the last few years, ocean chemistry is changing rapidly for the worse, and the work that we’re doing is vital for sustaining crab populations.”
Just as oyster growers in the Pacific Northwest now rely solely on hatchery-reared oyster seed while the rest of the world can count on wild sets, it might be that future Alaskan OA hot-spots will need some help from hatcheries to support crab populations. While AKCCRAB is hoping that we never see that future, they are leading the fishing industry by getting the heavy lifting of the science perfected before mortality events catch them off guard.
A Strand of Hope
The Washington State Blue Ribbon Panel on Ocean Acidification was formed by Governor Christine Gregoire in 2012 to identify potential OA adaptation, mitigation, and remediation actions. One of the most promising is the use of vegetation, like eelgrass and kelp, to help “sweeten” the water. When plants photosynthesize, they absorb carbon dioxide from the water, and cause the seawater’s pH to go up. This action is called phytoremediation. A lot of research is currently underway to investigate its efficacy in creating “OA refugia.” The idea of an OA refuge is that certain small geographical areas could, through the use of naturally occurring materials, create a small halo area where OA is reduced or even eliminated.
Betsy Peabody, of the Puget Sound Restoration Fund, speaks about a recent grant they received from the Paul G. Allen Family Foundation to investigate the use of kelp for OA remediation. When asked if she believes that the seaweed project will produce enough of a change to seawater chemistry to create an OA refuge, Peabody said: “Everyone on the project team feels like if there is an effect it will certainly be localized, but the important point is that it is replicable. It can be used to help mitigate OA hot-spots. Hopefully, we’ll see that a kelp cultivation array will reduce nitrogen and carbon locally, plus provide other ecosystem services. The concept of refuges is really important, we have to find ways to improve and maintain conditions for important calcifiers [oysters, clams, crab, mussels].”
At the same time, the Washington State Department of Natural Resources and the University of Washington have been investigating the changes in pH that the presence of eelgrass creates. They established experiments at five sites, and found that while photosynthesizing, eelgrass raised the pH at a rate of .05 units per hour. Areas with eelgrass also maintained a higher pH at night (when not photosynthesizing).
This gives some promise for the hope of mitigating the effects of OA in the short term, in the areas that need it most – economically and ecologically valuable sites, or in certain “hot-spots.” But until carbon emissions are drastically reduced globally, seafood is on a slippery slope. Ocean acidification legislation has been lucky to find bipartisan support in a way that climate change generally does not, and seven coastal states have now addressed OA through expert panels, task forces, or other state legislation. In the big picture though, seafood producers are left wondering if there will be a future for the next generation.