Tuesday, November 30, 2010

Northern Pike Enter Columbia River

Here is a piece I wrote about yet another invasive species, the northern pike, entering the Columbia River.

Predatory species moves into river

By Jim Bailey - Trail Daily Times
Published: November 18, 2010 5:00 PM

Northern pike ‘potentially’ trouble, says B.C. ministry

The Columbia River holds a variety of native and non-native species of fish but one particularly nasty predator has invaded, an ominous sign for the burgeoning trout fishery.

As their name suggests, northern pike are more at home in places like the Yukon, Northwest Territories and northern B.C., but within the last three years, have become familiar sights in the Columbia as well.

“Pike are native to B.C. but only in the northeast, Fort St. John country,” said Jeff Burrows, senior fish biologist for the Ministry of Environment. “They are an invasive fish (in the Columbia), they’re predators and competitors, and can also bring in new parasites so, yes, they are potentially a problem.”

The pike have infiltrated the Columbia from a number of reservoirs on the Pend d’Oreille and while not yet abundant, there are most likely to increase.

“I’ve talked to Washington state fish biologists and they’ve noticed quite an increase in Box Canyon, a reservoir (on the Pend d’Oreille) upstream from the border, so no doubt there will be more,” said Burrows.

The river has already suffered invasive predators such as walleye and smallmouth bass that threaten native species, so the presence of pike is an added menace.

Golder Associates’ fish indexing program for B.C. Hydro conducts annual fish sampling surveys in the spring and fall and have caught a number of pike during their studies.

Three years ago, the research crew thought they observed a northern pike but did not capture it and last year, they nabbed a juvenile pike in the upper section near Robson, said Golder biologist Larry Hildebrand.

“This past season, which just ended about three weeks ago, the crew captured, I believe it was five (northern pike),” he said.

While it is still early, the presence of a new top predator introduced into a system whose species have never had to evolve to adapt to the presence of that predator, will likely have some implications on certain species, he added.

As far as fishing for pike, some anglers have already hooked into the voracious invader including Freedom Fishing owner Ken Apps, who recently caught what he estimates to be a 10-pound pike.

“Between the squawfish, the walleye, the bass and now the pike, there is always concern not just for the rainbows but the sturgeon fry as well,” said the avid fly-fisherman.

The Trail man is not only worried about pike predating trout, he is also concerned about the increased competition for food sources.

And according to a bizarre fishing regulation, it is illegal to fish for bass or pike in the 50-kilometre stretch of river between the Hugh Keenleyside Dam and the international border. Any caught incidentally must be released.

“As good as the trout fishery is getting here, to have another predator introduced and leaving it just as a catch-and-release fish, all that’s going to do is allow it to establish . . . It has the potential to be an incredible detriment to the rainbow fishery which the Columbia River is known for,” said Apps.

According to Burrows, the regulation is meant to discourage people from moving alien species into native trout habitat in the first place. But if the pike population increases, the ministry may implement an exemption similar to the walleye quota of eight fish per day.

“I think our approach is we’re going to wait and see if it gets worse. Right now they’re not common enough to be more than a rarity and not of biological consequence.”