DIF&W netting Pushaw pike

Fisheries technicians have netted and killed 78 northern pike in inlets and outlets of Pushaw Lake this spring. Pike were illegally introduced into the lake and first documented in 2003.
Photo courtesy Maine Department of Inland Fisheries & Wildlife
Fisheries technicians have netted and killed 78 northern pike in inlets and outlets of Pushaw Lake this spring. Pike were illegally introduced into the lake and first documented in 2003.
Posted April 22, 2011, at 11:28 p.m.
Last modified April 25, 2011, at 3:01 p.m.
Joshua Kuester, a temporary biology technician with the Maine Department of Inland Fisheries & Wildlife, holds a 17-pound northern pike that was trap-netted in an outlet of Pushaw Lake recently. The DIF&W has netted and killed more than 75 pike at Pushaw this spring. The species was illegally introduced into the lake several years ago.
Photo courtesy Maine Department of Inland Fisheries & Wildlife
Joshua Kuester, a temporary biology technician with the Maine Department of Inland Fisheries & Wildlife, holds a 17-pound northern pike that was trap-netted in an outlet of Pushaw Lake recently. The DIF&W has netted and killed more than 75 pike at Pushaw this spring. The species was illegally introduced into the lake several years ago.

Gordon “Nels” Kramer says that eradicating northern pike from Pushaw Lake, where they were illegally stocked and eventually discovered in 2003, isn’t a realistic option. But that doesn’t mean the fisheries biologist for the Maine Department of Inland Fisheries and Wildlife is ignoring the Pushaw pike situation.

Far from it, in fact.

For the sixth straight year the DIF&W, in collaboration with the Maine Department of Marine Resources and with help from the Maine Atlantic Salmon Federation, is trap-netting Pushaw and its inlet and outlet in order to learn as much as possible about the fish population.

“We have no expectation that we will control or contain the population,” Krame said on Thursday. “Right now we’re just trying to document what the population is and how it’s expanding and trying to remove all the fish that we can.”

Seasonal fishery technicians Josh Kuester and Chris West have been deploying and checking trap nets since late March, and as of Thursday they had caught and killed 78 pike. During 2006 just 14 pike were caught. A year ago, 38 were caught. Kramer said using more traps this year has contributed to the higher total.

 

A snapshot of this year’s trap-netting effort: The 78 fish have averaged 26.7 inches long and 4.9 pounds. The largest fish caught weighed 17 pounds. All of the fish were killed.

“We’ve trapped a number of fish in the inlet this spring. Most of them have come from that,” Kramer said. “Of the 78, probably 65 have come from Pushaw Lake, the inlet. The rest of them have been in the outlet, either down by Hirundo [Wildlife Refuge] or the rips,” where Route 43 crosses Pushaw Stream five miles downstream from the lake.

Complicating efforts is the life cycle of the northern pike, Kramer said. Maine’s fisheries biologists target those spawning fish for their trap-netting efforts, figuring that finding pike when they move into the shallows is most efficient.

But pike spawn early in the spring. Too early to catch, in some cases.

In most trap-netting efforts for other species, the catch total shows up on a graph as a bell-shaped curve, with a clear peak of spawning activity. With pike in Maine, the graph peaks at the beginning of the trapping process. The reason: Technicians can’t get to the spawning ground to set nets until the spawning period is well under way.

“Early on is when we get most of our encounters, back in the end of March and the beginning of April,” Kramer said. “But the ice, in some cases we have to set traps on top of the ice, wait for the ice to go out, and I suspect that some of these fish are down there and spawning before the ice goes out.”

The most recent female pike trapped — those caught between April 18 and April 20 — had already laid their eggs. Females trapped earlier had yet to lay their eggs.

Kramer’s crew pushes the season as much as possible and does a lot of work in advance so that they can deploy traps as early as possible.

“This year they hauled nets and anchors and all the gear, put them in a boat and then dragged them in by snowmobile and unloaded all the gear in anticipation of the ice starting to go,” Kramer said. “Even [doing] that, you can see from the numbers, we started out high and then it drops off.”

On April 2, technicians caught 28 fish. They caught 10 more on April 4. More recent catches dropped to 4, 5, 4, 2 and eventually 3 fish.

Kramer said that biologists were learning a lot about the movement of pike. Some of the things the data reveal, however, seem to go against popular theories.

“[One theory is that] they don’t tend to move until the habitat is saturated, in other words, when the population gets to a certain density,” Kramer said. “Then individuals will start to move out of the system, down the outlet, and when they find suitable habitat they will take up residence there. When that habitat becomes saturated, fish keep dropping down.”

Biologists can track that density by determining how likely anglers are to catch a pike. If a “dense” population existed, anglers would reasonably expect to catch a pike or two in an average day of fishing. That hasn’t occurred with Pushaw, he said.

Another complication: Biologists would expect the migrating fish to be younger, smaller fish looking for their own territory. The biggest fish would remain where they’d set up housekeeping, and where they could out-compete others. That, too hasn’t been the case.

The 17-pound fish was caught in the lower section of the netting area, in the outlet. For some reason, it had moved out of the lake, and Kramer suspects it’s one of the larger pike in Pushaw and its tributaries.

“That 17-pounder may be one of the original fish that was moved into Pushaw,” Kramer said. “We don’t know that, but it’s probably old enough that it could have been.”

Biologists have heard anecdotal reports of anglers catching northern pike in the Stillwater and Penobscot rivers in recent years but have yet to document those incidents. They encourage anyone who catches a northern pike in the Penobscot watershed to kill the fish and report it immediately by calling 732-4131 or 441-5409.

A clarification to this story was made on April 25 to reflect that not all trapped female pike had laid their eggs.

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