Word of the day: bioturbating.
That’s what sand aka ghost shrimp and blue mud shrimp are doing in their little burrows in estuaries up and down the Northwest Coast 24/7/365.
Bioturbating the holy hell out of all that mud and silt and decaying plant matter and whatnot that collects on the tideflats, making it that much richer.
All that free labor’s great for the health of the ecosystems our salmon and other critters depend on. By one estimate, burrowing shrimp filter as much as 80 percent of the water in bays.
And here you thought sand skrimps just existed to adorn a 2/0 hook with some eggs on the side!
But it’s not so good if you’re an oyster in Nahcotta or Newport. All that mucking around kills the valuable shellfish, which are hugely important for coastal economies. The oysters can sink into veritable “quicksand,” quickly suffocate and die.
So in effect, the shrimp have become the northern pikeminnows of our rich bays, a native species that has to be controlled so other more financially and culturally desirable ones may thrive in the altered environments.
In Washington pesticides have been used to kill them off, but that’s caused a big stir in recent years. A state permit to use imidacloprid was issued in 2015 but then almost immediately withdrawn at the request of the oyster industry after public outcry.
A subsequently “reduced scope” application for a five-year permit to annually spray up to 500 acres of Willapa Bay and Grays Harbor by hand and boat instead of helicopter is now out for public comment.
I have to admit that when I learned about the spraying, it really, really bugged me.
It wasn’t so much the self-righteous indignation of Seattle chefs, more like, should we be using that stuff in the environment, let alone to kill off key actors in it?
On the flip side, in a Seattle Times video, you can hear the frustration voiced by a Washington State University extension agent tasked with helping oyster growers figure out a different solution.
“We beat our heads against the wall,” says Kim Patten, “and nobody has come up with any ideas. So at this point I have no idea, and I don’t think anybody else does.”
Someone might, however.
A recently posted blog by the Northwest Fisheries Science Center on these “estuarine engineers” details research into figuring out where they do well in the bay, in essence attempting to learn if it’s possible to reverse engineer things to benefit shrimp and farmers.
“If it’s an area where we would anticipate the population going down, having weak reproduction, or growing slowly—perhaps, for aquaculture, that would be a good location, because you’d minimize the interaction between the shrimp and the oysters,” Dr. Katelyn Bosley of the Oregon State University’s Hatfield Marine Science Center, a stone’s throw or two from Yaquina Bay, told author Al Brown.
“Or conversely, you’ll identify areas where there are fast-growing shrimp because of the high-quality, high-food environment,” she added. “Clearly, by assessing the nutritional status of the environment and knowing that shrimp live there—maybe that’s not a good place to grow juvenile oysters at certain times.”
These are the kind of solutions we should be finding.
It’s also important because burrowing shrimp, particularly blue muds, are being wiped out by an invasive isopod carried here in ship ballast that turns them into zombies that can’t breed.
Usually stopping zombies from breeding is a good thing, but it’s unclear what happens if the shrimp disappear for good — it’s possible systems will become overloaded with nutrients and experience algae blooms, posits Bosley .
With how important the shrimp are — “a key part of their environments,” writes Brown — we should be looking for ways to keep them healthy instead — and bioturbating the bays.