Of men and Mussels

Red-sided shiner: a mussel step-parent.

Red-sided shiner: a mussel step-parent.

One of the best things about Environmental Studies 120 is the field excursions. Each Thursday we venture to some environmentally relevant site—some depressing, others inspiring. Ice Harbor Dam. Hanford. River restoration projects.

Last week my 24 students and I descended upon the tribal lamprey and mussel restoration laboratory located at the Walla Walla Community College Water Center.

This tidy, high-ceilinged room of recirculating pumps, water filters, and clear, blue fish tanks, each bearing a single, lonely minnow that kept company with its reflection, would hardly seem a place for epiphany.

But it was.

The students, who have been practically brainwash about the lore and value of lamprey, had hoped to see one. But there were no adults this time of year. Instead, they got a quick peak at a batch of tiny, nocturnal lamprey larva who all liked to be in the dark and would be traumatized if enough light was let into their tank for a clear view. Students were disappointed. Lamprey lost some of their glamor.

“And over here,” said Alexa Maine, fisheries biologist and tour guide, “is our brood mussel. She is a brown pearlshell mussel. Her name is Lucy.” Alexa pointed to a clear tank that contained what liked like a white coffee cup with a dark mussel shell propped up inside. The shell exuded a network of delicate filaments that waved with each of Lucy’s watery exhalations.

“How long do mussels live?” one student asked, probably hoping that the answer would be pretty ordinary and we could all go home.

“About 200 years.” Alexa said.

You could have heard a pin drop, and Lucy’s exhalations seemed palpable.

Two Hundred Years?!! We were hooked. These small, unprepossessing, innocuous , ugly brown shellfish lived long enough that some might have actually seen the real live Lewis and Clark wade through their streams.

Mussels, it turns out, are not only long-lived, but also play important roles in the early lives of lamprey and salmon. They filter algae and remove contaminants from streams. (You wouldn’t want to eat a really old mussel”, Alexa noted. “They’ve been filtering and concentrating pollutants for a very long time.” ) They transform industrial fertilizers into ecosystem/fish-friendly and tasty nutrients. Lucy’s species, Margaritifera margaritifera, the brown pearlshell mussel, is the longest lived. Others, that may live only 75 – 100 years, include Anodonta –a lighter colored and slightly larger mollusk.

But mussels are vanishing. A shellfish survey compiled over the last 15 years of walking river bottoms on the Umatilla Reservation, (CTUIR) has found only 73 (seventy three) Margaritifera mussels (the dark brown, long lived species) in the entire river. There may be others in the headwaters of tributaries. No-one knows.

So the tribal (CTUIR—Confederated Tribes of the Umatilla Reservation) program at the Water Center is an effort to change this. To bring mussels back, along with their companion species—lamprey. Lucy was evidently fertilized by another, unknown male (Single mothers should not be disparaged.) Her every exhalation now pumps out eggs that will grow rapidly to a tiny larva. Those tiny larvae will use the clamping power of their shells to attach themselves to fish—generally to its gills. In the real world, the fish would transport them to new places, sites where a future mussel colony might flourish. There is more adventure in a young mussel’s life than you might imagine.

But here in the lab, instead of their preferred host–a juvenile salmon–the mussel larvae will be offered a much more limited ride on a lonesome dace or red-sided shiner in a blue aquarium tank. Then, after 6 or 7 months, they will drop off the fish, and establish a new home in a gravelly or sandy stream bottom. Conveniently, this timing also lets them exit their quarters before the host salmon gets serious about its migration to the Pacific. At least the baby mussels who hitch a blue-aquarium-bound-ride on a dace or shiner have little to worry about in this respect.

To count only 73 of these long-lived mussels in an entire river, from head to mouth, is appalling. It suggests –or maybe demonstrates — that we are not paying attention to the little things that hold our ecosystems together. Hopefully, that is changing, thanks to the Umatilla Reservation tribal fisheries. I’m rooting for all of Lucy’s descendants.

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