Coastal Conversation: Harmful algal bloom forecasting in Alaska

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HOST: This is the NOAA Ocean Podcast. I’m your host, Allison Burrell. In this special coastal conversation episode, we’re turning things over to our guest host, Max Brown, from the National Ocean Service’s National Centers for Coastal Ocean Science, or NCCOS. NCCOS plays a key role in supporting our nation’s coastal stewardship and resource management by providing the scientific information necessary to protect environmental resources and safeguard public health. One example is the production of ecological forecasts for harmful algal blooms. A harmful algal bloom occurs when colonies of algae, or simple plants that live in both marine and freshwater, grow out of control and produce toxins that can affect fish, shellfish, marine mammals, birds, and even humans. NOAA’s forecasting tools predict the location and severity of these blooms and help environmental managers in local communities to take early steps to minimize impacts, especially on seafood and tourism. 

In this episode, you’ll hear from Kasey Jo Wright, an environmental technician from the Kodiak Area Native Association (KANA), and Steve Kibler, an oceanographer from the National Ocean Service, about the effects of harmful algal blooms on shellfish in Alaska, which is a food staple in many Indigenous Alaskan communities. Now, let’s dive in.

GUEST HOST: The Kodiak Archipelago is a group of more than 30 islands covered in forest and glaciers on the northwestern edge of the Gulf of Alaska. For thousands of years people are known to have lived on the islands fishing and hunting. These activities continue to this day. Harvested shellfish are an important part of the culture, diet, and economy of the communities across Kodiak, particularly among the Indigenous peoples. 

But according to the State Public Health Division, Alaska has one of the highest rates of paralytic shellfish poisoning in the U.S. and within Alaska, Kodiak has the highest rate of poisoning. Paralytic shellfish poison is a naturally occurring marine biotoxin that is produced by certain species of microscopic algae. Shellfish that eat these algae can retain the toxin, making it harmful to people who consume the shellfish. Scientists use the term harmful algal bloom to describe the occurrence of toxic algal species in high enough concentrations to harm people and the environment. The human illnesses caused by these blooms, though rare, can be debilitating or even fatal.

NOAA’s National Centers for Coastal Ocean Science, or NCCOS, is working to solve this problem by developing a seasonal forecast that can predict harmful algal blooms in the Gulf of Alaska. NCCOS leads NOAA’s efforts to advance the scientific understanding and ability to detect, monitor, assess, and predict bloom events as directed by Congress in the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998. 

I’m Max Brown and in this episode we will learn how NCCOS is working with the Kodiak Area Native Association, or “KANA,” and the Aleutiiq Pride Marine Institute to provide shellfish harvesters with an early warning system — or forecast — of when and where toxins may be present. Let’s have a coastal conversation.

Outbreaks of paralytic shellfish poisoning, or PSP, are specifically caused by neurotoxins produced by a toxic, single-celled species of marine algae known as Alexandrium catenella. Shellfish like clams, mussels, and crabs eat microscopic algae including Alexandrium. During a bloom of Alexandrium, the concentrations of neurotoxins can reach dangerous levels in the tissues of these shellfish, making them unsafe to eat.

In many Indigenous communities on the Alaskan coast, shellfish have traditionally made up a significant portion of people’s diets. KANA is a Tribal health and social services organization serving Alaska Native and American Indian people in the Koniag region, with many services also available to the wider community. They have been working to monitor and track PSP in the area. Kasey Jo Wright is an environmental technician working with KANA. We spoke to them nearby Kodiak island, where they help monitor Alexandrium.

WRIGHT: So the Native people of Kodiak, the Alutiiq/Sugpiaq people, have lived on this island for almost ten thousand years. Until now they have been able to rely on traditional knowledge of when to harvest. Those Indigenous ways of knowing are passed down generation to generation and accumulated and really enhanced with each person.

GUEST HOST: Alexandrium, the organism that causes PSP, is extremely sensitive to temperature changes. It blooms historically during summer months; however, rising temperatures year round have increased the likelihood of PSP in spring and fall as well. 

WRIGHT: There are people that previously have harvested their whole lives who grew up harvesting and now are in their later years and won't do it anymore because of this fear of it…because the toxin is showing up earlier in the spring and later in the fall. And whereas this was a more winter-time source of subsistence for the communities on our island, in the colder months of spring and fall, people were not expecting, based on years of traditional knowledge, for it to show up. So our goal is not to replace this traditional knowledge, but to adapt with it to a changing ecosystem and support the gaps where we can.

GUEST HOST: Intertwined with the cultural tradition of shellfish harvesting is the role that shellfish harvesting plays in providing a degree of economic independence for some communities. 

WRIGHT: It's a difficult process to get food and groceries out to the villages. They don't always have their pick of what's available, and there may be surcharges for the extra distance that is gone. Or supplies needed immediately might have to be flown out and paid with extra fees. So there's the economic resilience of these communities is enhanced by partaking in their traditions of subsistence, of being in the cycle with the land and the ocean. 

GUEST HOST: One way to prevent outbreaks of PSP is to test samples from shellfish in a laboratory to determine if PSP toxins are present. Another method to protect against PSPs is to check the coastal waters near shellfish for and Alexandrium cells. This can be done using a microscope, or by checking to see if Alexandrium’s DNA is present in water samples. 

WRIGHT: So our part at KANA is doing a lot of the monitoring along the Kodiak road system, while also accepting samples from the villages and any other subsistence harvesters. And then we also will be doing multiple HAB cell samplings, so that will look like phytoplankton tows and whole water grabs where we're going to be taking qualitative and quantitative data about the phytoplankton that are present there. Now that serves as an early warning system for if and Alexandrium is sighted in the waters. And then we will follow that up the same week doing shellfish toxin sampling to see how much is actually in the shellfish at that time of harvest. 

GUEST HOST: Local testing and monitoring is an important tool for addressing the risk of PSP. However, Alaska’s coastline is longer than the lower 48 states combined. Because of this lengthy coastline and the widespread distribution of largely rural communities along the coast, it is very difficult to effectively monitor more than a small number of shellfish beds that are harvested. All of the methods for testing and monitoring require access to laboratory facilities, which are sparsely located in Alaska. This results in an increased likelihood that people collecting and consuming shellfish could be exposed to the toxins that cause PSP. We spoke to Steve Kibler, an Oceanographer at NOAA’s National Centers for Coastal Ocean Science, aboard a busy NOAA research vessel.

KIBLER: Right now the options are not great in Alaska for getting shellfish tested. There are some regional locations, laboratories that our Tribal partners run, that can do the testing for us. The state laboratory in Anchorage, Department of Environmental Conservation can do the testing as well, but it's relatively expensive and it requires collecting the shellfish, sending them in to see if they're safe and waiting for the results to come back. So many times it can take almost a week before you get your results back. So it's not a good option if you decide to harvest to hang on to the shellfish for several days before deciding to eat them.

GUEST HOST: NCCOS currently manages several HAB forecasts throughout the country. For example, in the Gulf of Maine, NCCOS predicts concentrations of and Alexandrium cells in the coastal environment, producing maps that inform people when and where it is safest to harvest shellfish. NCCOS is aiming to use this methodology in Alaska by collecting samples of Alexandrium cells in coastal waters.

Audio clip from research vessel: Bridge, you are free to maneuver, we got a good sample. Bridge copies, congratulations.

GUEST HOST: In order to develop a forecast in Alaska, scientists are collecting measurements related to the life cycle of Alexandrium cells. These cells respond to environmental stimuli by moving through the water column. When conditions are not ideal, Alexandrium cells can form dormant cysts and rest until conditions improve. Temperature changes have been shown to regulate this process. For instance, when water temperatures rise in the spring, Alexandrium cells can awaken and form the next bloom, potentially causing shellfish toxicity. Understanding where resting Alexandrium cells- or cysts- accumulate in the sediment during the winter can help predict where they will “wake up” to form blooms in the spring. Scientists at NOAA are working with local partners to map out where Alexandrium cysts are located. This information can be combined with meteorological and oceanographic data to model where blooms are most likely to occur. Steve explains:

KIBLER: NOAA uses several different approaches for doing forecasts for harmful algal blooms. Typically, there's first a bunch of laboratory and field work done, oftentimes for years, to establish what the linkages between changes in the environment and the regulation of blooms, and what makes them reproduce rapidly or what time of year that they tend to reproduce. How the toxins get into the seafood products and how long they stay there. All of these can be approximated using mathematical models and a lot of environmental data. So what we try to do is figure out these relationships. Now mathematically and then use that to predict what the future is going to hold. In the short term, we're trying to come up with a seasonal forecast that will say, well, next year is going to be worse or better than it was this year, and then try to build on that to make it a little more useful to the residents. And this similar approach is used in other parts of the world, in other parts of the country rather. Probably the one that's run the longest is in the Gulf of Maine in the New England states. We have the Gulf of Maine harmful algal bloom forecast that's been running for arguably twenty to thirty years now, where we have a seasonal forecast product that says how bad this year is going to be compared to last year, and then we also have a weekly Nowcast that comes out during the spring and summer months that gives a projection of where the blooms are going that particular week, and how severe they're going to be.

GUEST HOST: Mapping the locations of Alexandrium cyst beds and their abundance, and then combining these measurements with environmental data, allows scientists to forecast where the risks of PSP may be highest. Over time, the models are calibrated more precisely to produce increasingly accurate predictions of where blooms will occur. This information can then be provided to communities, shellfish farmers, health organizations, and coastal managers to avoid PSP outbreaks.

Audio clip from research vessel: Permission to deploy core? You may deploy the core. Copy, deploying.

GUEST HOST: Last spring, NOAA worked with scientists from KANA and the Alutiiq Pride Marine Institute to collect water quality and sediment core samples at 78 sites in the Gulf of Alaska, around and adjacent to the Kodiak Archipelago and the lower Kenai peninsula. This was the first step in creating a regional HAB forecast in Alaska. Before the forecast is fully operational, more data will need to be collected.

KIBLER: Well, the current effort that we have underway now is a five year project. What we're trying to do is put the building blocks together to produce a forecast to try to do a small scale forecasting to see how that develops. To come up with some effective communication methods to provide month forecasting information to the individual communities around the region and to try to build toward a larger forecast for the future.

GUEST HOST: When completed, the Gulf of Alaska HAB forecast would regionally predict which years are more likely to have high risks for shellfish harvesting in places like Kodiak. Harmful algal blooms are a naturally occurring phenomenon, but they are likely to increase in frequency across the Alaskan coast due to rising ocean temperatures. NOAA is proudly working with its local partners to inform coastal communities of the changing risks of PSP in their shellfish harvest. 

HOST: Thanks to Max Brown for guiding this coastal conversation. I’m Allison Burrell with the NOAA Ocean Podcast. For helpful resources related to this episode, or to check out all our episodes, please visit oceanservice.noaa.gov/podcast. You can also subscribe to the NOAA Ocean Podcast at this link or on your favorite podcast platform. Thanks for listening. Let’s keep making waves.