Tracking down the pike: Fish and Game goes high tech to monitor invaders

Posted: Sunday, February 14, 2010

The Department of Fish and Game's Sport Fish Division is at war with a piscatorial enemy, sort of.

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Massengill prepares the radio equipment he uses to track pike. The department planted transmitters in 30 of the fish that were caught in the long, narrow body of water.

That's how Rob Massengill, a fisheries biologist with the division, describes his activities on Stormy Lake in Nikiski.

While the battles haven't begun in earnest, Massengill is leading the charge against invasive northern pike on the Kenai Peninsula by gathering intelligence on their movements and habits.

Last September, he and his colleagues recruited 30 involuntary spies from Stormy by implanting radio transmitters into 30 captured pike and releasing them back into the lake.

"What we're trying to do is identify some primary spawning locations in this lake that we might be able to go into with nets or other control methods and target those areas," he said in his prevalent mid-western accent. "We don't know if these pike spawn every year or every other year, and we might get a surprise that shows us some vulnerabilities or some new insight we're not even expecting."

This is one of the first tracking programs launched in almost a decade according to Massengill, who's been working on the pike problem on the Peninsula since 2006.

"If we could nail down some of the areas where the majority of fish spawn we could really knock them down and let these native rainbow (trout) and arctic char have a fighting chance," he said.

The transmitters, which Massengill described as being about the diameter of a roll of nickels and about half as long, are implanted near the anal fin of the fish, and trail a 10 inch antennae out the back of the slender ambush predators.

A spaghetti tag is attached to the pike's back so the fish can be identified if caught.

Massengill said the department doesn't mind if someone catches one of the fish, but asked that they bring it by the department's office so the transmitter can be retrieved.

The batteries in the transmitters should last up to two years, or the duration of the study, he said.

While 30 fish had transmitters put in them in the fall, 10 have since died.

Massengill was on the lake this past Thursday, cruising its 500 ice clad acres on a snowmachine rigged to carry a small antennae, a receiver, a GPS unit to mark locations and headphones.

When the ice goes out later this year, he'll step up his twice-monthly visits aboard a boat.

Massengill starts his trips by buzzing down to a stationary monitoring site set up near the lake's woody outlet.

Here, a 20-foot antenna with a small solar panel stands guard, recording if any tagged pike try to enter the shallow stream.

Massengill brings a replacement 12-volt battery for the station and a laptop to download any data.

So far, he said not a single one of the spy fish has come close enough to get picked up, a hopeful sign for now.

With a fresh battery in place, he sets up his smaller mobile tracking unit.

He sets the receivers on the snowmachine and flips it on so it will sound audibly without a pair of headphones to see how many tagged fish are hanging around in the shallow two- or three-acre bay near the lake's outlet.

Immediately, the quiet winter landscape that had only been punctuated by the occasional gust of moist inlet air comes alive with chirping patterns that resemble those of crickets on a late summer evening.

Massengill scans through the different frequencies and counts a total of seven different fish in the shallow bay.

"It doesn't take much to get us biologist types excited," Massengill said, as he went through his chart.

Each implanted transmitter emits a unique pulse code, so Massengill can individually identify the seven tagged fish in the bay from his other 30 spies, even though he can't see them just a few feet below.

The transmitter also signals that the fish might be dead if a pike sits still for four hours.

Pike tend to hold in one spot while they wait for their unsuspecting prey to swim by though, so Massengill said that on more than one occasion he'll walk up on a fish that the receiver says is dead, only to have it suddenly jump back to "life," spooked by the noise he makes above.

He won't mark a fish as officially dead unless he comes back and finds it in the same spot on his next visit.

To actually pin-point a pike's location is somewhat like a game of electronic Marco Polo.

Donning headphones, Massengill waves the handheld antenna back and forth in a wide arc, picking up which direction a chirp is the loudest. He'll move toward that spot, guided by the increasing or decreasing volume of the chirps.

When they become almost overbearing, he's on top of it.

The snowmachine set-up allows him to cover the lake's surface pretty quickly.

In recent weeks he's been able to find all 30 of his spies, even the dead ones. If the fish dive below 30 feet in the deeper parts of the lake however, they go out of range.

Fortunately, pike are shallow water hunters.

As he finds a fish, he'll mark the spot with GPS coordinates, note the approximate location from shore and the estimated depth of the lake at that spot.

The lake has been split into six zones to help keep track of each fish's movement.

Thursday saw one of the biggest fish movements yet, with a somewhat unnerving push toward the outlet.

As to why, Massengill said he could only speculate. Though he'll usually see one or two fish that have moved all the way across the lake since his last visit, most of the time they stay in the same area.

He guessed that food, oxygen or even the approaching breeding season could be drawing the fish.

It's the latter activity, Massengill said, he's particularly concerned about.

A war begun

The reason Fish and Game has honed in on Stormy is simple.

The lake's meandering and sometimes dry outlet stream is just three quarters of a mile from the Swanson River, a system that's presently pike free. It's a system that Massengill described as being a strong producer of silver salmon and rainbow trout.

King and pink salmon can also be found in the river, along with char.

"If pike get a foothold in there, it's going to forever change it," he said.

Pike are native to the state, but until people began to introduce them to lakes and streams in Southcentral, they were never found south of the Alaska Range.

What's happened at Stormy is typical of many of the lakes the voracious predators have been dumped into through a process biologists refer to as "bucket biology."

Hardly 10 years ago, the lake was flush with native rainbows and char, as well as long nose suckers and sticklebacks.

In 2001 however, following up on angler reports, Fish and Game confirmed pike were living in the lake.

That summer they netted extensively near the outlet, Massengill said, and 50 pike were caught.

Since then, the lake has become well known as a local hot spot for big pike.

"We did see one guy who came in with one that broke the 20-pound mark, and a few others that have been close to that," he said.

The pike got fat off the abundant native fish, which have since become extremely scarce.

This past summer, Massengill said Fish and Game netted hard for several weeks and only caught two char and a few suckers.

Perhaps most notable was the fact that not a single rainbow was caught in the entire effort.

"If you back up a couple decades ago, this was considered a really good rainbow fishery," he said.

Right now all that separates the pike in Stormy and the Swanson is a "fyke net," a thin meshed web that's been stretched across the outlet since 2001.

While summer flows out of the lake are often so meager that no fish could escape anyway, at times of high water, Massengill said the net is an insufficient blockade.

Over the years, muskrats, otters and even a bear have wreaked havoc on it, requiring innumerable repairs.

And while the net might be keeping the pike trapped in the lake, it's also keeping other fish like juvenile silvers out, which used to rear in the lake, limiting their available habitat.

Fish and Game has taken a few opening shots at pike living in other Peninsula water bodies in the last two years, chemically treating two lakes with rotenone. The chemical is highly toxic to gilled creatures.

The two treated lakes, Scout Lake in Sterling and Arc Lake in Soldotna, were small and landlocked, though. Stormy presents a greater challenge with its size and connection to a productive wild fishery.

"We don't know, with a lake this size, if we can successfully treat it," Massengill said of Stormy.

Fish and Game has had an engineering firm provide estimates on building a permanent blockade at the outlet, but that could cost $400,000 to $700,000.

They also had the firm look at the cost of draining the lake and letting it refill naturally, an undertaking that ranged in price from $1-3 million.

Fighting with knowledge

What's learned through the study on Stormy however, might help Fish and Game consider their battle options in other infested systems like the Soldotna Creek drainage, which connects to the Kenai River.

Massengill said pike have already made an impact on other major salmon systems in Southcentral.

"Look at the Susitna Valley right now, they've got systems up there where they're scratching their heads like what happened to our sockeye. There's a lot of pike in those lakes now," he said. "It's very suspicious, some of these systems where the productivity has dropped."

Massengill said he thinks pike have played a key role in bringing down Susitna sockeye runs.

While parts of the Kenai River aren't conducive for pike -- the deep sockeye rearing waters of Skilak and Kenai Lake for example don't offer much in the way of habitat for them -- the slow moving headwaters of the Moose River offer pike an all-they-can-eat buffet.

"We probably wouldn't see sockeyes drop off the map decades from now if pike expanded, but we could probably see a pretty good dent in the coho and rainbow fishing, especially in spots like the Swanson and the Moose River," he said. "Twenty to 40 percent of the total Kenai River drainage coho smolt population comes out of the Moose River, and that's just ideal pike habitat."

Massengill said he heard news Thursday morning that someone had recently reported a pike in a lake off of the Moose.

"That's going to be really bad news if that's the case. Even though we've had reports of pike in the Moose River, it's been a long time since we've confirmed a pike there," he said. "We're really hoping there's not a reproducing population."

He said that while most people seem to be getting the message about how dangerous the fish are to the Peninsula's aquatic ecosystems, the easiest battle the department can wage is one of public knowledge.

Even in the last week, Massengill said he was tipped off that an angler found some youth with a cooler full of pike planning to "stock" a central Peninsula lake.

"There's a contingent of people that love pike fishing and don't realize the damage they can do," he said of people who continue to introduce the fish to new waters. "Not only is it illegal, but the consequences are huge."

Massengill said Fish and Game will continue its efforts to spread the word on pike, and have meetings planned later this winter to garner more public awareness on the problem and the potential solutions they're considering.

"The bucket biology thing has caused a lot of problems here and I don't know if that's sinking in," he said.

For more information on northern pike in Southcentral including a list of systems with confirmed and suspected infestation visit Fish and Game's Web site at http://www.sf.adfg.state.ak.us/Statewide/InvasiveSpecies/index.cfm/FA/pike.about. Anglers who catch pike in a lake or river system where the fish are not already confirmed by Fish and Game are encouraged to report it to officials as soon as possible.

Dante Petri can be reached at dante.petri@peninsulaclarion.com.



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