LANDER — Two sauger spawning operations occurring this spring in the Wind/Bighorn River drainage will help recover populations in one area and in the other, improve the sport fishery and ensure genetic purity.
In the Wind River drainage, the operation will involve taking eggs from female sauger and raising offspring to 3-inch fingerlings for release into waters within the same drainage.
This is a cooperative effort between the Wyoming Game and Fish Department, the Wind River Reservation and the U.S. Fish and Wildlife Service.
Population estimates in the Popo Agie River and Little Wind River have shown a dramatic decline in sauger numbers since 2002. Monitoring of Boysen Reservoir has shown a similar decrease in the sauger catch.
“Poor spawning success and/or juvenile sauger survival are likely to blame for the decline,” Game and Fish Biologist Paul Gerrity said.
Multiple research projects are underway to determine the causes contributing to low sauger recruitment.
Overfishing is not thought to be contributing to the decline because a high percentage of the remaining fish are large, old fish. Cooperating agencies have decided not to propose more restrictive harvest regulations.
The stocking program will consist of capturing wild adult saugers and holding them in streamside tanks until they are ready to spawn.
Once the fish are in spawning condition, biologists will spawn them and send the fertilized eggs to the Dan Speas Fish Hatchery and Rearing Station near Casper.
Most eggs will hatch in 12 to 14 days.
After hatching, sauger fry will be transported to Garrison National Fish Hatchery in North Dakota to be raised in ponds until they are fingerlings.
The fingerling saugers will then be transported back to Wyoming and stocked into the Wind River drainage in July or August.
Most adult saugers spawn in the Popo Agie River and Little Wind River in May and June.
The cooperating agencies hope that supplemental sauger stocking will occur annually in the Wind River Drainage through 2017.
After 2017, the cooperating agencies hope numbers will be high enough to sustain the population and factors contributing to the decline will have been determined.
In the Bighorn drainage, the sauger population is doing well.
Because sauger are doing so well, the Wyoming Game and Fish Department and Montana Fish Wildlife and Parks are working together to collect eggs to enhance the Big Horn Lake sport fishery.
A major concern with sauger throughout their native range in the Missouri and Mississippi drainages is potential hybridization with walleye.
In waters where hybridization has occurred, fisheries managers have determined that hybrids known as saugeye have either been intentionally or unintentionally introduced into waters with both walleye and sauger, creating a reproductive bridge between the two species.
With the potential for hybridization between walleye and sauger in the Bighorn drainage, the Wyoming and Montana agencies are jointly studying whether stocking fingerling sauger to replace walleye could maintain the lake’s recreational fishery and reduce the likelihood of accidental saugeye introductions.
The most recent analysis of sauger in the Wind River and Bighorn River drainages found populations to be genetically pure.
The Bighorn River downstream from Worland and Big Horn Lake is considered the last stronghold of sauger in Wyoming and is among the few pure populations in the Missouri River drainage.
This year, the cooperating agencies’ goal is to provide enough eggs to produce 500,000 fingerlings to be released into Big Horn Lake.