Biologists keep close eye on bull trout

NACHES – Michael Mizell has favorite fish.

Not fish species. Favorite fish – as in, this one and that one.

Not as dinner on a plate or as eye candy in an aquarium, either. These fish are alive and swimming in rivers.

For two years, they have consumed his thoughts, his conversations, nearly his every waking moment and, for that matter, even the non-waking ones. “At this point,” he said with a grin, “I dream fish.”

Specifically, about bull trout working their way through various river systems in the upper Yakima Basin – the Rattlesnake, the Naches, the American, the Ahtanum and others. Mizell has been hands-on with so many of these fish, knows them so intimately, that … well, he has favorites.

“One-twenty-five and 129 are my favorite fish,” he said without a trace of irony.

Those numbers refer to the codes on radio tags that Mizell installed in those fish nearly two years ago as part of a study by the state Department of Fish and Wildlife in cooperation with the U.S. Fish and Wildlife Service and, more recently, the Bureau of Reclamation.

There have been nearly five dozen others, but the fish bearing tags 125 and 129 were among the first bull trout tagged during the study. They’ve moved around a lot in the time since, so Mizell, a state biologist and telemetry expert, has a lot of data on them. And he knows he will soon be losing touch with that favorite twosome, because the tags have a battery life of, at most, 21/2 years.

“That,” Mizell said, “a pretty good chunk out of the life history of a fish that lives about three times that long.”

And, as Mizell knows from his studies of the bull trout in the Yakima Basin, that life history gets an annual jump-start in mid-May. That’s when they really get on the move.

So Mizell and his assistant, Eiko Urmos-Berry, are on the move, too. Wherever the fish go, they go.

Until this study, where the bull trout in the Yakima Basin went was essentially a mystery.

But then, it was only six years ago that the entire species was listed as threatened, and thus mandated for protection under the Endangered Species Act. That political distinction opened the federal purse strings and helped the state obtain funding and support from the Fish and Wildlife Service for the study.

The reasoning behind the project, in a nutshell: Only by knowing as much as possible about the Yakima Basin’s estimated 2,000 bull trout can state and federal agencies adequately protect them.

Do the fish travel between different creek systems? Do they intermingle with seemingly separate populations? Are they all able to reach their spawning sites every year? Do they always winter in the same places? Besides the need to spawn, do other influences trigger their movement from one area to another?

“The more we know about those kinds of things – where the fish are and what they’re doing and why they’re doing it – then we can make better decisions,” said state fish biologist Eric Anderson, Mizell’s Yakima-based boss and the man behind the study.

“Decisions about what to do with, say, a river flow, or an angling regulation. Or if it’s a low-water condition in a stream that’s caused by man, we can make some decisions about protecting the fish … or not protecting it.

“Whatever that decision is, it’s going to be a better-informed decision.”

So Anderson and Mizell began capturing and inserting tags into bull trout wherever they were known to exist in the basin.

“My boss is Eric Anderson, but my real bosses are” – Mizell paused and waved toward the river – “out here. The fish dictate to me what the study’s going to do to my schedule. It’s kind of neat having my big boss as a fish.”

Neat, maybe, but not convenient – at least, not for someone who lives west of the Cascades, as Mizell does.

Many has been the dinner at home in Olympia when he has gotten a call that another bull trout had been trapped, and thereby available for a radio-tag implantation. Because the longer the fish is out of water, the more stress its system undergoes, Mizell would quickly begin the seven- to nine-hour round-trip drive to wherever the fish was being held. All for a 20-minute operation.

And it really is an operation – a surgical procedure, complete with surgical scrub, a catheter (to help insert the tag), sutures and surgical glue.

The survival rate of tagged fish has been outstanding – “haven’t lost a fish on the table yet,” Anderson noted – largely due to two reasons:

* The biologists were able to perfect the procedure by practicing on rainbow trout, which are in no danger of extinction.

* Mizell does what might best be called surgical follow-ups.

Mizell knows all about snorkeling in river water so frosty that the water freezes on his snorkel mask whenever he surfaces. That kind of cold is when he can best check certain things – like how each fish’s surgical wounds have healed, what kind of water temperatures and flow speeds the fish are holing up in.

Because only in that glacial cold can he can do it from extremely close quarters.

“You can swim right up and touch them. You could pet them,” Mizell said. “It’s almost like a marmot hibernating. All they’re doing is storing up their energy and generating gametes. Basically, their entire life cycle is survival and spawning. They’re just keeping the species going.”

Mizell presented many of the early findings of the telemetry study – what the basin’s bull trout are doing and when – in a Yakima Basin management conference at Central Washington University.

But perhaps even more interesting, if not from a scientific vantage point, are his anecdotal observations about bull trout.

“They’re very social. You don’t usually find them single,” Mizell said. “If you find five of them in a pool, they’re together. They’re not territorial in that sense.

“And not only are they social, but they pair up male and female. The problem with that is that it’s not a spawning pair. We could have a female that spawns in the Rattlesnake with a Rattlesnake that spawns in Union Creek. They’ll hang out together, but they’ll go off to different places to spawn. I don’t think they’re mated couples. They’re just very social.”

And they’re voracious.

“They’ll eat anything,” Mizell said. “If you would put your finger in the water in front of them, they might go for that. They’re very aggressive. They’re like the wolves of the water.”

For now, those wolves in Yakima waterways are being staked out. The study is designed to go into 2006, and possibly longer – as long as there are radio tags with any battery life remaining.

“As long as they’re still beeping,” Anderson said, “we’re going to track them.”