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Gill lice parasite controversy taking on new form

Everybody Adventures
| Saturday, Nov. 17, 2018, 12:24 a.m.
Gill lice are a parasite that attach to the gills of trout. There is one species specific to brook trout, another to rainbows.
Gill lice are a parasite that attach to the gills of trout. There is one species specific to brook trout, another to rainbows.

A line in the sand has been erased.

How much that will do to resolve a potentially litigious debate around a parasite that may or may not be impacting wild brook trout populations remains to be seen.

A few months ago, Pennsylvania Fish and Boat Commission officials proposed a new rule saying that, as of Jan. 1, no one could knowingly introduce fish with gill lice into Pennsylvania waters. In late October it decided not to enact that, said Andy Shiels, director of the agency's bureau of fisheries.

Instead, it will meet with commercial hatchery operators – whom the commission remains convinced is tied to the parasite's spread — to look for ways to keep the parasite at bay.

Shiels believes the two sides should be able to find "common ground." But keep the parasite at bay they must, he added.

"We have to find a solution because we can't be introducing high loads of these things into our wild brook trout streams. We just can't do it," Shiels said.

Gill lice are a parasite that attach to the gills of trout. There is one species specific to brook trout, another to rainbows.

The commission found brook trout gill lice in Wolf Run in Centre County in 2016. Biologists determined those fish had come from a commercial hatchery.

Meanwhile, nine other streams stocked by the same sportsmen's club, using fish from the same hatchery, had gill lice, too.

Subsequent surveys of those waters, and others afterward found with gill lice, showed that wild brook trout populations took a dive after the parasite showed up, Shiels noted.

But most notably, the commission said each gill lice impacted stream had one "common denominator." Commercial hatcheries provided their fish.

As a result, this spring it attempted to "turn off the spigot."

It sent a letter to sportsmen's clubs applying for permits to buy and stock trout saying that they could only get fish from facilities certified as gill-lice free.

That set commercial hatchery operators off, for two reasons.

First, March is when the start shipping fish in earnest. Yet there was, at that time, just one person in the entire state qualified to do certifications.

Hatcheries with orders in and fish to ship couldn't do so.

So, in the short term, that "put our business at risk," said Adam Pritts of Laurel Hill Trout Farm in Somerset County.

"Take a month out of cash flow. It might be a slow month, but if you can't serve those customers, they go somewhere else," he said. "And they don't come back."

Second, and this is what commercial hatchery operators view as the longer-term problem, blaming them for gill lice is unfair and just wrong.

Gill lice evolved in conjunction with brook trout, said Carole Engle, a Pennsylvania native who spent 27 years as director of the Aquaculture/Fisheries Center of Excellence at the University of Arkansas at Pine Bluff. They've been around for centuries. And wherever there are brook trout there are gill lice, she said.

"If you stop all stocking programs in the state, you'll still have gill lice," Engle said.

The commission's finding of them does not constitute an emergency, she added.

"And there's really no justification to blame fish farms for their being here," Engle said.

Perhaps, Shiels said.

Gill lice are a native parasite to brook trout, he admitted.

"However, that doesn't mean that they are found everywhere that brook trout are found. Nor does it mean that they're found in high densities wherever brook trout are found, unless something else is going on," he said.

The commission surveyed 700 or more stream sections in the past two-plus years, he said. Yet it found fill lice in only a few places.

"And every one of those places can be tied to a co-op or commercial hatchery," Shiels said.

And what no one knows, he added, is what concentration of gill lice impacts brook trout on a population level.

Engle, though, said a number of factors impact gill lice infestations. They include water temperature and flow, among other things. In drought years, like 2016, gill lice will be more evident. In extremely wet ones, like 2018, they won't.

The commission's recent proposals are "fairly draconian" and an "over reach" based on some worst-case scenarios, she said.

It should step back, work with commercial hatcheries and monitor the gill lice issue to come up with rules that best serve everyone, she said.

"This is not a zero sum game. This is not a choice between protecting the resource and maintaining the stocking programs that are so vital to the quality fisheries that are known all around the United States," Engle said.

Charlie Conklin, operator of two fish farms in Montour County and a three-time president of the U.S. Trout Farmers Association, pleaded that same case.

He believes the commission has acted with the best of intentions on the gill lice issue. But it failed to gather input from all stakeholders, he added.

And that's got some in the commercial industry wanting to pursue legal action. Indeed, some fish farmers filed a notice of intent to sue the commission in October.

Conklin doesn't want things to come to that.

"The industry doesn't want this parasite. The Fish Commission doesn't want this parasite. The fishermen don't want this parasite. We all have the same goal here," Conklin said.

"But if this rule is going to put half the industry out of business, the industry can't accept it."

The rule – against knowingly introducing gill lice – is on hold, Shiels reiterated.

Commission staff met with members of the state's aquaculture advisory council, which includes fish farmers, to say so. Now it wants to set up a meeting, hopefully with a mediator, to go over how the commission and industry can work together.

"I think we can lay this out and find some common ground," he said.

Fish farmers hope so, too, said Liz Diesel-Pritts of Laurel Hill. It's just too bad that it had to get to this point, she said.

"So we've taken a pretty big black eye from the commission on this," she said. "It's been so beautifully mismanaged it's almost like it was intentional."

Bob Frye is the editor. Reach him at 412-216-0193 or See other stories, blogs, videos and more at

Article by Bob Frye, Everybody Adventures,

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