Natural Repro of Muskies in PA: North Branch Susky

[afishinado]

Recent article on Susky NB Muskies from the Times Leader:

There’s a big change coming for a big fish in the Susquehanna River.

Beginning in 2017, the Pennsylvania Fish and Boat Commission will no longer stock muskies in the North Branch of the river.

They don’t need to.

Sampling conducted by agency staff on the river throughout 2016 determined the musky population is supported through natural reproduction and the stocked fingerlings simply aren’t surviving.

Rob Wnuk, area fisheries manager for the PFBC’s Northeast Region, said there is a lot to like about the river when it comes to muskies.

“There is good nursery habitat in the river and a good forage base of suckers and young carp. Muskies grow really well in the river,” Wnuk said, adding both the catch rates during sampling and growth rates of muskies in the river were high.

“The North Branch of the Susquehanna River was right up there with some of the best musky rivers known in the country,” Wnuk said. “It was very impressive.”

Wnuk’s numbers back up the claim.

During 13 days of sampling on the river Wnuk and his crew captured 24 muskies, plus three more while sampling for other species for a total of 27. The adult muskies ranged in size from 14 to 44 inches in length.

Things are just as good for yearling muskies as well.

During 13 days of sampling in 2015, 31 wild young-of-the-year muskies were captured and six others were missed, for a catch rate of 2.85. The North Branch also has .48 young-of-the-year muskies per mile, exceeding the .24 figure Wisconsin uses to define a self-sustaining musky population in its lakes.

Not only are the muskies in the river numerous, they’re also growing rapidly.

Wnuk’s data shows that the mean length on wild one-year-old muskies in the river is 13.5 inches, greater than the 6 to 7-inch length of the fingerlings stocked by the agency.

And that’s one reason why the stocked muskies aren’t surviving in the river.

“The wild fish are 10 inches by the end of August, and 14 to 16 inches by the end of October. The stocked fish are six to seven inches by October, and muskies are known cannibals so when they are released and go to that nursery habitat, they’re being preyed upon by the larger muskies,” Wnuk said.

While natural reproduction will be the method of choice to sustain the musky population in the North Branch, what will happen to the hatchery fish that were previously earmarked to be stocked in the river?

Wnuk said the musky stocking program across the state is being revised and stocking rates will be cut.

But, he added, that decrease is designed to allow the hatcheries to produce bigger muskies to be stocked, a move that will help them survive. Considering that muskies are an apex predator that exists in low densities, Wnuk said it makes sense to cut stocking rates yet increase size.

“One reason why we want to stock bigger muskies is because of predation, particularly from bass,” Wnuk said. “The larger fish have a better chance, but if you stock them at too high of a rate they won’t grow above 30 inches. You have to give them space.”

Because the sampling was conducted in the spring, most of the fish captured on the river were males that instinctively wait at spawning areas for females to arrive. Wnuk said male muskies are smaller than females, yet his crew did capture a 44-inch female musky in Northumberland.

Wnuk said there’s evidence that wild musky populations increase following the termination of stocking, and both adult and young-of-the-year fish will be monitored throughout 2017. If the population unexpectedly decreases, he said, the agency can easily resume stocking to augment the fishery.

“It might take a few years for anglers to see the benefits of these changes, but I’m very impressed with the musky population on the North Branch,” Wnuk said. “As far as Pennsylvania being a musky state, I don’t think we’re on par yet with Minnesota, but we can get there.”

Growing up fast…

Muskies grow well in the Susquehanna River thanks to an abundant forage base of suckers and young carp. Here’s a look at the ages and lengths of the muskies captured by the PFBC on the river in 2016:

Age - mean length in inches

1 - 13.5”

2 - 24.5”

3 - 30.7”

4 - 34.5”

5 - 37.2”

6 - 38.8”

7 - 40.2”

Reach Tom Venesky at 570-991-6395 or on Twitter @TLTomVenesky

Link to source: http://timesleader.com/sports/618716/pa-fish-and-boat-commission-making-changes-to-muskie-management-on-the-susquehanna-river

 

[PACOFRANSICO]

Nature finds a way. There are smaller tribs to the Allegheny and Susquehanna that have natural repo. I've seen 6 to 7 inch musky fingerlings along shore. Ya have to remember historically this area is part of the musky natural home range. It extends as south a Tennessee.

 

[afishinado]

Here is the unabridged version of the PFBC Muskie plan written in 2012. A lot of good info on habitat and spawning contained in the plan.

PA Muskie Plan

 

[Dave_W]

It's interesting to ponder how certain fishes are native to some watersheds and not found in other ones nearby. In the case of muskies and smallmouth bass, they're native to the Ohio River watershed, but not the Potomac or Susquehanna. Now they are spawning in the Susky/Potomac successfully.

Think about places like Potter or Garrett counties where you have little continental divides that separate by just a hillside or ridge line streams that originally had smallmouth bass and muskies, from streams that didn't have them.

 

[afishinado]

Mike wrote:
How do angler's "know" that stopping stocking may not be the right idea? Electrofishing catch rates of naturally produced young Muskies substantially exceed, as I recall, those in one of the top Muskellunge states where fisheries are managed without stocking. Excessive Muskellunge stocking, if it occurs, not only wastes money, but keeps Muskelunge small(er).

Why increase the size limit statewide yet again when it is unlikely that harvest is limiting population abundance? Such higher size limits have not been shown to improve size structure or abundance in the study that I reviewed, but let's give the lesser 40 inch length limit a chance to show whether there is any measurable response in the Muskellunge populations in Pa lakes. Those studies have been underway for 5 years. When a length limit is higher than 40 inches it pretty much puts all of the harvest pressure, such as it is, on just the females. It is an uncommon male that exceeds 40 inches and it appears at the moment in present Pa studies that many males may never exceed 35-36 inches. If, however, one wishes to preserve high catch rates and one is not concerned about slow growth and perhaps only fish that are less than 35 inches long, a 45 inch length limit might be fine in some limited waters that could be called "action waters" for lack of a better term. In the past two years Leaser Lake has been an action water even without the 45 inch limit due to excellent survival of a single stocking combined with the new lake effect.

Frankly, from a personal viewpoint, I am growing more concerned by the poor handling techniques reported as being displayed by some anglers and the potential for delayed mortality as a result. I think that many angler's in large part are not geared up for or prepared to handle a fish of that size, strength, or sensitivity to handling stress, particularly when a muskellunge is a surprise catch. And it could even be that picture taking of an already stressed fish adds to the problem.

From the PFBC muskie plan 2016 to back up with Mike wrote above:

Harvest of Largest Fish: Further, changes to the population structure as a consequence of the increased minimum size limit could concentrate the harvest on the very largest of fish, which are also the least numerous. Thus, enhancement of the trophy element in the fishery may not occur.

Dunning et al. (1982) suggested that an overly high minimum size limit on northern pike in the St. Lawrence River could cause overharvest of fish above the proposed minimum size. Similarly, Cornelius and Margenau (1999) reported an initial increase in fishing pressure and exploitation of larger muskellunge in Bone Lake, Wisconsin following a minimum size limit increase. This change in regulation negatively impacted the Relative Stock Density in 1983. Later, the muskellunge population rebounded on that water. Countering this problem of concentrated harvest on larger muskellunge is the growing trend of catch-and-release of muskellunge, which should lessen the chances of this occurring (Fayram 2003).

Another potential problem with the elevated minimum size limit is that male muskellunge often do not reach 40 inches (1016 mm) in many waters such as the northern waters in Wisconsin (Hanson 1986) and in Canada (Casselman et al. 1999). Pennsylvania waters are in the more southerly part of the species range and therefore male muskellunge should be capable of growing to lengths of 40 inches or greater, in productive waters. However, if few male muskellunge reach the 40-inch minimum size limit then the new minimum size will likely be excessively targeting larger females for harvest. Therefore, it is important to know the percentage of male
muskellunge exceeding 40 inches, which provides justification to determine the sex of all fish ?30 inches.

Harvest of Female Muskellunge: To accurately assess growth rates in any study it is necessary to identify the sex of all sexually mature muskellunge that are sampled. These data are especially important since growth rates in muskellunge are sexually dimorphic (Casselman and Crossman 1986) with male muskellunge growing more slowly and having generally shorter lives than females (Casselman 2007). In Pennsylvania, muskellunge typically reach sexual maturity around 30 inches (762 mm), but problems with consistent sampling of muskellunge

 

[troutbert]

Dave_W wrote:
It's interesting to ponder how certain fishes are native to some watersheds and not found in other ones nearby. In the case of muskies and smallmouth bass, they're native to the Ohio River watershed, but not the Potomac or Susquehanna. Now they are spawning in the Susky/Potomac successfully.

Think about places like Potter or Garrett counties where you have little continental divides that separate by just a hillside or ridge line streams that originally had smallmouth bass and muskies, from streams that didn't have them.

It is interesting that the smallmouth and muskies were found in the Ohio system, but not the Susquehanna and Potomac. They did not cross the divides.

But brook trout were found in the Ohio and system, throughout much of western PA. How did they get there? Did they move from the Gulf of Mexico up the Mississippi? That seems unlikely because that is so far south, and a warm climate. Although it would have been much colder than now in the ice ages.

Or did the brook trout cross the divide(s) at one or more points from the Susquehanna, Potomac, or St. Lawrence River drainages?

 

[Dave_W]

troutbert wrote:

Dave_W wrote:
It's interesting to ponder how certain fishes are native to some watersheds and not found in other ones nearby. In the case of muskies and smallmouth bass, they're native to the Ohio River watershed, but not the Potomac or Susquehanna. Now they are spawning in the Susky/Potomac successfully.

Think about places like Potter or Garrett counties where you have little continental divides that separate by just a hillside or ridge line streams that originally had smallmouth bass and muskies, from streams that didn't have them.

It is interesting that the smallmouth and muskies were found in the Ohio system, but not the Susquehanna and Potomac. They did not cross the divides.

But brook trout were found in the Ohio and system, throughout much of western PA. How did they get there? Did they move from the Gulf of Mexico up the Mississippi? That seems unlikely because that is so far south, and a warm climate. Although it would have been much colder than now in the ice ages.

Or did the brook trout cross the divide(s) at one or more points from the Susquehanna, Potomac, or St. Lawrence River drainages?

Interesting indeed. I suppose we could chalk it up by saying "the Ice Age worked in mysterious ways."

 

[troutbert]

Go to Acmemapper and search for "Honeyoye Creek, PA".

This is a trib to Oswayo Creek, which is a trib to the Allegeheny, so in the Ohio system.

If you follow Honeyoye Creek to its origin in NY state, you see that it originates in a flat wide, glaciated valley.

Very close to there, in the same flat valley, a stream called Marsh Creek originates and it is a trib to the Genessee River, which flows north, and is in the St. Lawrence River drainage.

The "divide" isn't just low, it's almost imperceptible. The valley floor is almost table flat. Brook trout could easily have crossed the divide there.

There is another similar very low "divide" which you can see by putting "Wellsboro Junction" into the search bar on Acmemapper. This is just north of the town of Wellsboro. The Pine Creek drainage and Tioga River drainage are very close here, little streams in the floor of the same flat valley.

There may also be some other very low divides in that glaciated area in the NY/PA border region.

The brook trout likely crossed the low divides because they are cold water fish that exist as far upstream as there is water.

The smallmouth probably did not cross the divides because they are not found in the tiny streams in the far headwaters, they are found further downstream where the streams get somewhat warmer and larger.