A new method could help Washington shellfish farmers control a pesky shrimp
Our take
A new method developed through state-funded research at the University of Washington offers Washington shellfish farmers a promising solution to manage the pesky burrowing shrimp that threaten their crops. These shrimp, native to the region, create significant challenges for farmers by excavating sediments in marine environments. The burrowing activity leads to piles of material that can smother oysters and clams, jeopardizing both yield and quality. The innovative approach focuses on non-chemical strategies, which are crucial for maintaining the ecological balance of shellfish-growing areas while effectively controlling shrimp populations. By minimizing chemical interventions, farmers can work toward sustainable practices that protect not only their livelihoods but also the surrounding marine ecosystem. This research highlights the importance of collaborative efforts between academia and local industries, as it seeks to address real-world challenges faced by Washington's shellfish farmers. As these farmers navigate the complexities of their industry, staying informed about advancements in research and practical applications becomes essential. For those interested in how broader environmental factors influence local infrastructure, check out our related article, "Q&A: How evolution influences nature-based infrastructure," featuring insights from Marina Alberti, a University of Washington professor. This exploration delves into the intricate relationship between urban development and natural ecosystems, providing a deeper understanding of the challenges and opportunities we face in managing our resources.
The recent research led by the University of Washington offers a promising new method for controlling burrowing shrimp, a pesky threat to Washington's shellfish farmers. These shrimp, while native to the region, pose significant challenges by burrowing into marine sediments and creating piles of excavated material that suffocate oysters and clams. This issue highlights not only the delicate balance of marine ecosystems but also the economic implications for local farmers who rely on shellfish as a primary source of income. As the state continues to grapple with various environmental and socio-economic challenges—evident in discussions around topics like the ongoing Q&A: How evolution influences nature-based infrastructure and the complexities of national redistricting battles —innovative solutions in agriculture and aquaculture are vital.
The significance of this non-chemical approach to managing shrimp populations cannot be overstated. Traditional methods often rely on chemical treatments, which can have detrimental effects on surrounding marine life and ecosystems. By finding alternative solutions, researchers are not only addressing the immediate problem but are also fostering a more sustainable approach to shellfish farming. This aligns with broader trends in agriculture and aquaculture, where there is a growing recognition of the importance of ecological balance and sustainability. As we strive for a more responsible stewardship of our natural resources, the success of this research could serve as a model for other regions facing similar challenges.
Moreover, the implications of this method extend beyond just shellfish farming. It speaks to a larger narrative about the importance of local economies and the resilience of communities that depend on them. As Washington faces various economic pressures, including those highlighted in the recent Justice Department accuses Yale medical school of illegally using race in admissions case, supporting local industries like shellfish farming becomes increasingly critical. These small businesses not only provide jobs but also contribute to the cultural fabric of communities along the coast. A thriving shellfish industry can lead to increased tourism, better local food options, and a more robust economy overall.
Looking forward, the question remains: how can this innovative approach be scaled and adapted to other areas facing similar ecological challenges? As farmers and researchers collaborate, it will be essential to monitor the outcomes and share insights on best practices. Additionally, as Washington continues to confront environmental changes and pressures, the integration of such sustainable methods may pave the way for a new era of agriculture that prioritizes both productivity and ecological health. As we engage with these evolving narratives, it is crucial for the community—students, farmers, and policymakers alike—to remain connected and proactive in fostering solutions that benefit all.
Burrowing shrimp are small marine excavators native to Washington. They make their homes deep in the sediment by digging, turning the ground to Swiss cheese. This presents a problem for shellfish farmers, whose clams and oysters are often smothered under layers of displaced sediment.
The glass walls of this jar allow us to see what’s happening to the sediment as a shrimp (white) burrows. Jennifer Ruesink/University of Washington
Burrowing shrimp have been a nuisance for at least a century. In 1929, Belle Stevens, a University of Washington researcher, wrote: “Oyster growers have tried various means of defense against these persistent burrowers. But there seems to be as yet no really adequate and at the same time practical method of coping with the marine ‘crayfish.'”
Shellfish farmers used to use pesticides to kill the shrimp, but the chemicals also posed risks to other organisms, such as salmon and crabs, and could be transported in water outside the shellfish growing area. The Department of Ecology instructed farmers to stop using pesticides in 2018. Since then, family-owned shellfish farms have been losing large portions of their growing grounds to burrowing shrimp.
Research led by the UW, and funded by the state, has yielded a non-chemical, proof-of-principle method for killing shrimp in targeted areas. The method, borrowing from the construction industry, uses a custom-built platform to apply vibration and pressure to a 50-square-foot region of sediment. This compacts the sediment and effectively traps shrimp in their burrows. Starved of oxygen, the shrimp die after a few days.
The researchers tested this method at four sites around Willapa Bay, Washington. It worked just as well as pesticides, reducing the number of live shrimp by between 72% and 98%.
“The challenge of managing burrowing shrimp on private tidelands has many dimensions. There still need to be enough shrimp to serve as food for gray whales and sturgeon, and the whole shrimp population is connected by a long larval phase in the ocean,” said senior author Jennifer Ruesink, UW professor of biology. “Once back in the estuary though, these shrimp can live for up to 10 years. Even a moderately sized shrimp, about four inches long, can bring a handful of sediment to the surface every day, dropping that on top of everything. We’re trying to find the balance — how to keep them out of shellfish beds, but let them grow elsewhere.”
The team published this research May 12 in the Journal of Shellfish Research.
“Burrowing shrimp have decimated our farm,” said Ken Wiegardt, a fifth-generation oyster farmer and head of Jolly Roger Oysters in Willapa Bay. “We’ve lost 75% of our nursery ground and, as a result, the farm’s carrying capacity has fallen from 265,000 bushels of market-ready oysters to 75,000 bushels. Last month I had to lay off three oyster shuckers, each of whom had been with me for many years, because I just don’t have the oysters to process. The health of the Willapa Estuary as well as my business and all of my employees depend on finding an effective tool.”
Over the years farmers and researchers have toyed with the idea of trying to “mechanically” control shrimp populations.
“The idea was, ‘Let’s crush them underground, or crush them when they come to the surface,'” Ruesink said. “There are old photographs that show people using vehicles, such as repurposed tanks and snow crawlers, to try to target the shrimp.”
This idea resurfaced at a recent conference. Over lunch, Ruesink and shellfish growers decided to codesign an experiment to test whether driving a tracked vehicle called a MarshMaster over sediment would actually affect the shrimp. After careful analysis, the method proved ineffective.
Ruesink’s co-author, Alan Trimble, who was previously a research scientist at UW and is now volunteering on this project, had an idea for why the “crushing” experiment had failed.
“He told me, ‘You’re thinking like a dirt farmer and you need to start thinking like a concrete engineer instead,'” Ruesink said. “That’s when he mentioned these concrete vibrators in construction. When you pour concrete, if you don’t get all the bubbles out of it, it won’t be as strong. This is a consolidation technique for a wet slurry of particulates, which is exactly what a mud flat is.”
Ruesink and Trimble ran three experiments to test whether a concrete vibrator, a hand-held metal tube with a motor powered by a generator, could kill the shrimp. For each experiment the team compared sediment cores from treated plots to cores from untreated plots. The researchers took core samples on multiple days after treatment and counted live versus dead shrimp.
In an earlier experiment, the team tried using the vibrator while standing in the water. This method was successful in killing shrimp, but also not practical for scaling up. Jennifer Ruesink/University of Washington
The best option was a custom-built floating platform with six vibrators mounted through a hollow part in the middle. Ruesink and Trimble added weights near each vibrator head to provide pressure in addition to vibration, a winning combination that compressed the sediment and killed the shrimp. The specific cause of death was asphyxiation, not the vibration.
While this proof-of-principle experiment seems promising, there’s more work to do before shellfish farmers can implement it. Right now it’s a time-consuming and labor-intensive process because everything is manually operated. Also, more studies need to be done to determine the long-term impacts to the ecosystem, from the shrimp in neighboring non-shellfish farm mudflats to other creatures living in the area.
“What we’ve done so far is introduce a novel control mechanism. No one had thought that you could trap the shrimp underground,” Ruesink said. “But this research wouldn’t have happened without the investment from the state and the private landowners and growers. I have such a deep appreciation for the opportunity to work with folks on something that is clearly affecting their lives.”
The researchers performed field trials on the private tidelands of Pacific Shellfish, Bay Center Farms and John Heckes. This research was funded by the Washington State Department of Agriculture.
For more information, contact Ruesink at ruesink@uw.edu. For more information about Jolly Roger Oysters, contact Wiegardt at oysterman73@hotmail.com.
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