Bay science: Trying to unlock shrimp biology with baking soda
Published 4:48 pm Sunday, January 25, 2026
Burrowing shrimp are a well-documented native pest species in Willapa Bay that have been a nuisance to bottom-culture shellfish farmers for over a century. Methods for controlling shrimp populations have varied over the years, including mechanical and chemical controls.
Most notably, carbaryl — widely used in pet flea collars — was the control method of choice because of its effectiveness at ridding the mudflats of burrowing shrimp, once again making land viable for shellfish farming. Carbaryl is no longer used in Willapa Bay due to a series of environmental and health concerns that came up in the mid-2010s, leading to a legal settlement. Since then, an alternative method for farmers has been a focus of research in the bay.
Pushing the shrimp
Emma Guerrini Romano, a Ph.D. student at the University of Washington, is a new player in the field of burrowing shrimp control but presents a novel angle — leveraging the existing conditions of burrows to make the environment too extreme for burrowing shrimp to live. Essentially, push the shrimp to their physiological limits.
The burrow environment is innately challenging — low oxygen and high toxic ammonia buildup make it so shrimp need to be great at managing their behavior to survive. For example, to combat low oxygen, shrimp will ventilate their burrow by beating pleopods, disk-shaped features on the underside of their body. On a cellular level, burrowing shrimp are not well studied, so the basic adaptations they have evolved to persist in the burrow and dominate mudflats have yet to be uncovered.
Guerrini Romano’s entire doctoral thesis is focused on understanding the basic biology of burrowing shrimp at a deeper level. The hope is that a greater understanding of their biology will unlock the key to a control method that can be used by farmers.
Burrowing shrimp are classified as crustaceans — more specifically, decapods. Crustaceans include animals like amphipods and barnacles, and decapods, more specifically, encapsulate crustaceans with 10 of their many appendages considered legs. Examples of decapods include lobsters, crabs, and crayfish. Often, decapods will have an enlarged pincer that is sexually dimorphic (specific to the sex of the animal). Burrowing shrimp males have one large claw that falls in this category.
There is a lot of research on the physiology of decapods, such as crabs and lobsters, which can be looked at to surmise some of the more basic functions of burrowing shrimp.
Some of the adaptations burrowing decapods have include specialized pumps to regulate internal ion concentrations, which can be thought of as parts of salt, and water movement. Ions include chloride (Cl-), sodium (Na+), potassium (K+), and others, and these play large roles in the function and survival of the animal. These pumps are present in many types of marine animals but vary in amounts and concentrations depending on the environment. Some specialized pumps specifically regulate the movement of an ion called ammonium, which is built up in the body naturally as waste, but can be converted to a super toxic form, called ammonia, when pH increases, or becomes more basic. Ammonium, the non-toxic form, builds up in burrows naturally as shrimp eat and excrete sediment.
When thinking about creating a targeted chemical treatment, researchers at UW thought to shift the already present ammonium into toxic ammonia by making the water more basic. The way to do this? Add baking soda!
‘Hard’ science ahead
Baking soda dissolves into two major ions, Na+ (sodium) and HCO3- (bicarbonate), when added to water. The bicarbonate shifts the pH of the water to be more basic (higher). Researchers initially thought that this change in pH would be powerful enough to make the toxic ammonia amount in the burrow increase, and therefore kill shrimp. But they found that the introduction of baking soda did not kill the shrimp because of ammonia, but because of the inherently unbalanced salts present in the solution. “Unbalanced” salts represent the addition of TONS of HCO3- ions and Na+ ions, but no addition of Cl- ions, which are naturally present in similarly concentrated Na+ in regular, “balanced” sea salts.
This unbalanced environment causes failure of pumps throughout the shrimp’s system. In the lab, shrimp experienced 100% mortality when exposed to high amounts of baking soda. This was an exciting find, especially when considering the non-toxic nature of baking sod and the inherent aspect of the burrow that could isolate the treatment from non-target organisms on the surface of the mud.
Guerrini Romano, the lead on this project, obtained funding from the USDA Western SARE grant to scale this work up to field trials in Willapa Bay. Working with Taylor Shellfish, Guerrini Romano went out to the mudflats to see if baking soda was a viable option for farmers to use.
Nope to baking soda
The answer? Baking soda isn’t the key to a chemical control method. The sheer amount needed is too great. The current project relies on the density of baking soda to replace the porewater within burrows over the span of a four-hour low tide, meaning that the application doesn’t require spraying, pumping, or injecting. Interestingly, during field trials, burrowing shrimp were in lower abundances in buckets with baking soda applied but were not dead.
More trials will continue in the spring and summer of 2026 to get more definitive results, but there is a possibility that baking soda is a deterrent, essentially causing shrimp to leave to avoid dying from changed conditions.
Other scientists, such as Dr. Jen Ruesink and Alan Trimble, are working on mechanical control methods, including compaction and vibration of sediments. Scientists in the private sector, including those at the Invasive Species Corporation, are utilizing biologicals in the form of microbes to tackle the shrimp problem, too.
Multiple approaches and options are being tested, and baking soda is just one of the recent endeavors to find a control option. The uniqueness of this project is the targeted physiology that baking soda leverages. Though baking soda may not necessarily be the key to the burrowing shrimp problem, it unlocks new ways of thinking about the animal, its function, and how it interacts with the burrow.
The more we learn about its physiology, the closer we can get to not only finding a viable chemical option, but explaining exactly how and why it works to kill shrimp.