A casual day of bass fishing on the Columbia River near Paterson turned up a bizarre, slimy surprise for two Yakima anglers last month.
Jerry Wilken and Randy Swanson couldn’t reel in any bass — they did catch one catfish — but a fish bite on Swanson’s line led to an unexpected reward. He reeled in a stick with a translucent, brownish spotted blob attached that Wilken said was as big around as it was long, with a diameter he estimated to be 18 inches.
“We wouldn’t touch it,” Wilken said. “It scared the hell out of us. We had no idea.”
They snapped a picture and showed their discovery to the local Washington Department Fish and Wildlife office the next day. Nothing resembling the strange mass can be found on the department’s website and it mystified regional fish program manager Marc Divens until he looked online, then eventually contacted the Washington Department of Ecology.
Those efforts led to information on the magnificent bryozoan, an aquatic invertebrate made up of hundreds or even thousands of micro-organisms known as zooids. But while other, smaller freshwater bryozoans attach to the algae or other plants from which they feed, multiple bryozoans come together to form a magnificent bryozoan, a sort of gelatinous blob comprised of 99 percent water and capable of breaking into smaller clusters, attaching to objects or floating freely.
Another one of the strange creatures attracted attention from the The Tri-City Herald last September, when Bill Smith found it in the Columbia near Kennewick’s Columbia Park.
Wilken wondered whether his discovery on July 10 represented only the second sighting in Washington, but the U.S. Geological Survey’s website revealed reports of magnificent bryozoans in the state date back 20 years and include 16 different areas, mostly in Western Washington lakes.
The floating colonies easily mistaken for amphibian eggs are native to freshwater areas east of the Mississippi River, in part because they can’t survive in water colder than 60 degrees. They’re generally seen mid-summer or sometimes washed ashore and broken apart when waters begin to cool in September or October, according to Ian Walker, a biology professor at the University of British Columbia.
He developed an interest in bryozoans after first learning about them from one found in a Canadian lake in 1991. He began to see and hear more reports over the years, including one found at Vancouver’s Stanley Park that attracted attention from National Geographic and several other publications last fall.
Bryozoans eventually break apart each year and split into small seedlike statoblasts, which can reproduce asexually and attach themselves to plants or animals. Some biologists theorize migrating birds brought the statoblasts to the Pacific Northwest, where they’re growing more common thanks in part to climate change and warming water temperatures, but Walker suggested another possibility.
“Some people have suggested they’re an invasive species that has recently been introduced to the area but I’m not sure that’s true,” Walker said. “It may be one of those things that has been around a long time but people just generally overlook.”
Fossil records provide evidence of bryozoans existing in some form for close to 500 million years, although most species never grow to more than a few millimeters, especially in freshwater.
The unique magnificent bryozoan — scientific name Pectinella magnifica — can be found only in calm lakes and rivers, since Walker said a strong current would likely cause it to break apart.
He questions fears that bryozoans could negatively affect ecosystems, since they don’t seem to last long in large colonies or develop significant populations. The state’s Department of Ecology also doesn’t consider bryozoans an invasive species or an organism worth tracking.
However, they could potentially clog drains and pipes by attaching to them in some lakes. Walker said it’s possible bryozoans could create clearer water, since they act as a filter by extending tentacles to pull in their food.
They’re non-toxic and pose no known risk to humans, other than leaving behind a somewhat sticky substance on anyone brave enough to hold them. Wilken and Swanson chose to leave the magnificent bryozoan on its stick and return it back to the water, but it’s an experience they won’t soon forget.
“I kind of consider it a privilege to be one of the very few people around to see one,” Wilken said. “It was awesome to look at, you just didn’t want to touch it.”