Montana Fish, Wildlife and Parks Fisheries Biologist Ladd Knotek and Technician Will Schreck caught 24 smallmouth Thursday, May 5 on Seeley Lake. All smallmouth are being removed from the lake in an effort prevent them from spreading into the Chain of Lakes.
The trap net consists of a lead net set from shore (with the buoys) that guides fish into the frames and hoops. While only one end of the net is closed, fish get confused and are not able to return to the opening they first came through, like a minnow trap.
FWP fishery biologist Ladd Knotek and Technician Will Schreck work the fish towards the opening after removing the net Thursday, May 12.
SEELEY LAKE - Montana Fish, Wildlife and Parks (FWP) are continuing their mission to remove smallmouth bass, a non-native, illegally introduced species, from Seeley Lake.
After installing radio transmitters and tracking smallmouth's movement in 2014, they learned that the bass congregate in spring to spawn in the south bay of Seeley Lake. This is the third year they have set trap nets in the south bay in an effort to remove spawning smallmouth from the fishery.
Although there were unconfirmed reports, FWP received its first confirmed reports of smallmouth bass in Seeley Lake from anglers that caught the fish in the summer of 2013.
Smallmouth bass are not native to Montana and can add additional challenges when managing a fishery for trout and salmon in bodies of water such as Seeley Lake and its connected rivers and lakes.
FWP fisheries biologists assume they were illegally introduced by "bucket biologists."
"Their intentions are to make better fisheries but they are stressing an already complex system," said Region 2 FWP Fishery Biologist Ladd Knotek. "They should do well but they are usually stunted."
Knotek and FWP Fisheries Technician Will Schreck set four trap nets on Mondays through the month of May. They remove the nets on Thursdays to avoid the weekend lake traffic.
"We are removing specifically smallmouth. We feel it is our obligation so they don't spread down into the Blackfoot Watershed," said Knotek.
Smallmouth have high site fidelity. They learned from the telemetry study that they congregate in the south bay of Seeley Lake to spawn and then spread out into deeper water as the temperatures warm up. Since they spawn in the month of May it is easy to target them with the trap nets.
The trap nets are set from the shore and are four feet deep. The lead net funnels fish cruising the shoreline through a series of frames and hoops that are 15 feet long. The lead net length varies depending on the steepness of the shoreline.
Even though the one end remains open, most are unable to find their way out through the throats. Knotek said this is very effective for smallmouth because as the water warms up, they begin to swim the shoreline near their spawning beds.
"It's like a minnow trap," said Knotek. "The series of hoops confuses the fish and they travel deeper and deeper into the net, unable to find their way out."
Knotek and Schreck record species and length of everything caught in the net prior to releasing them. All smallmouth are kept and other fish they determine will not survive. The fish will be used as bear bait for the FWP grizzly project.
"We can look at the size and catch rate over time [for the other species]," said Knotek. "[For smallmouth] it allows us to see the size structure and track the abundance and size over time."
This technique is different than the gill net surveys FWP does in the spring. The gill nets are 125 feet long and can be set from seven feet to 30 feet deep. It gives them a much better representative sample of what is in the lake. While FWP release what they can, the surveys are much more lethal to the fish caught in the net. However, Schreck said that it is only a relative sample that is less than one percent of the fish population of the lake sampled.
The first week 24 smallmouth were removed including the four that were radio tagged in 2014. Knotek was impressed that they caught all four with the transmitters confirming for him that setting trap nets is an efficient way to remove smallmouth from Seeley Lake.
The second week only one, 12.5-inch smallmouth was caught and removed. Only two, of the nearly 50 fish caught, did not survive.
They will continue setting the nets through the end of the month as long as it is useful and continues to provide information.
"We hope to prolong the inevitable," said Knotek. "Smallmouth are on the ascending trend [versus northern pike that have long since been established]. People aren't seeing them in other lakes or in other parts of the lake. We are hoping we can protect the values that are here."
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