Combining Science and Games to Advance Disease Research

The snow crab fishery in the Bering Sea once reliably brought in harvests worth $200 million or more — until 2022 when Alaska closed the fishery for the first time. Over the course of just a few years, the snow crab population plummeted more than 90%, devastating a lucrative industry and puzzling managers.

In the years since, scientists have put forward several explanations for the abrupt collapse. One possibility is disease. The Bering Sea’s rapidly warming waters seems to be facilitating the emergence and spread of diseases, leaving the population vulnerable to environmental changes.

That’s where Bigelow Laboratory’s Quantitative Marine Disease Ecology Lab comes in.

Led by Senior Research Scientist Maya Groner, the team is working to explain the causes and consequences of diseases that affect marine species and understand how they may proliferate in a changing ocean.

Postdoctoral Scientist Reyn Yoshioka has spent the last several years working specifically on snow crab diseases, using models, experiments, and field research — and, these days, creative outreach — to generate and share knowledge in disease ecology that could inform fisheries management.

Black eye syndrome, for example, was first observed in 2017. Even in the dark waters of the Bering Sea, crabs depend on vision, so the damage black eye causes may affect their ability to feed. It may also degrade an organ crabs have near their eyes that controls the production of critical hormones.

“We still don’t know much about it because it’s so new,” Yoshioka said of black eye syndrome, which still doesn’t have a known cause. “But there were all these environmental changes around the same time that it was first observed, like record low sea ice and a marine heatwave, that signaled maybe this emerging problem is related to those larger shifts.”

Meanwhile, another disease called bitter crab disease, named for the aspirin-like taste it imparts to infected crab, is known to be caused by a parasitic, single-celled organism. The bad taste causes economic losses for the fishery, but the infection is also known to be lethal for young individuals in other species in which it has been observed. As with black eye, scientists haven’t found any direct link between the disease and the collapse, but there was clearly an uptick in infections in the years preceding it.

“There are hints that bitter crab could be a contributing factor, but we just don’t have strong enough evidence yet,” Yoshioka said. “There’s certainly a concern, though, that having this lethal disease that affects young crabs will make it harder for the population to rebuild and recover.”

Part of the lack of evidence is driven by the fact that these conditions are simply hard to study.

Fatty acids, for example, can be a useful biomarker, but they need to be immediately cryopreserved, which is hard to do on a research vessel. The eye stalk that contains the organ that releases critical hormones can be degraded by black eye syndrome, making it hard to sample. And the visual cue that’s been used to diagnose bitter crab — the infected look almost baked — has been shown to miss almost 90% of infections.

Yoshioka and Groner are part of a team working to better understand these emerging diseases and develop new tools to study them with colleagues from the Virginia Institute of Marine Sciences, the University of Washington, and agencies, including NOAA, the USGS, and the Alaska Department of Fish and Game. They’re building models of how the diseases spread over space and time as environmental conditions change. They’re developing molecular tests to accurately diagnose bitter crab and catch early-stage infections, and tools to preserve fatty acids without freezers. And they’re running experiments to see how infections progress at different water temperatures.

Yoshioka is also spending much of his time communicating all of this research to a broader audience. Last year, he secured a grant from the North Pacific Research Board to develop a game — appropriately called Crabdemics! — to teach epidemiology, framed around crab diseases.

Yoshioka has been working on the game for several years. He’s built on an existing classroom activity to reflect principles like the SIR model — where individuals move between being susceptible, infected, and recovered — and the “disease triangle” — where diseases shift in the interaction between the environment, a pathogen, and a host. He’s added cards to represent those different components and dice rolls to reflect the probability of an infection and death.

Last winter, Yoshioka and Groner tested an early version with a high school fisheries class in Kodiak, Alaska. This past February, after several rounds of game testing with Bigelow Laboratory staff, Yoshioka returned to Kodiak to continue refining it.

“Interactive games like Crabdemics! are a compelling way to engage students with challenging, and potentially scary, topics in fisheries and public health and empower them by giving them ownership over a new tool,” Groner said. “This is taking outreach to the next level by combining art and science with fun and strategy.”

The hope is to create an activity that increases public health literacy in an accessible way that’s relevant for a fishing community. Yoshioka hopes that focusing on marine diseases also makes it less contentious, though the game’s lessons could easily be applied to humans. Once the game is ready in the coming months, they’ll be producing professional versions to share with the high school in Kodiak, as well as with partners at NOAA and Alaska Department of Fish and Game, and other outreach centers in Alaska.

Those partner agencies, Yoshioka said, aren’t just helping the game reach new audiences; they’ve been instrumental to these research projects and are critical partners for this kind of fisheries-related work. For example, Groner’s lab is similarly partnering with Maine’s Department of Marine Resources for experiments on shell disease in lobster here in Maine.

“When I first got into research, I didn’t recognize how incredible and important the science that was happening at these agencies was,” Yoshioka said. “The research they do is so important, but it’s also so valuable for us to work with them because they know what information is relevant to the management decisions and the needs of these fishing communities.”

Photo Captions:

Photo 1: Postdoctoral Scientist Reyn Yoshioka dissects a snow crab aboard a research vessel in the Bering Sea for a project looking at preserving fatty acid samples in the field (Credit: Nicole Charriere).

Photo 2: Researchers kept snow crabs at different temperatures to observe the progression of black eye syndrome at the Alaska Department of Fish and Game facility in Kodiak, Alaska (Credit: Reyn Yoshioka).

Photo 3: The Crabdemics! game features dice, cards, and 3-d printed figurines of crabs and pathogens to represent the “disease triangle” to teach players about marine disease principles.