A couple of weeks ago, I highlighted a status report featured on the North Dakota Game and Fish Department’s weekly webcast, “Outdoors Online,” relating to the Missouri River-Lake Oahe walleye fishery. This week, I’ll summarize the webcast’s recent Devils Lake walleye population update featuring biologist Todd Caspers.
Todd Caspers: The overall walleye numbers are pretty close to average, just a little bit above average. In terms of size distribution, right now most of the size groups of walleyes are right around their long-term averages, except for 15- to 20-inch size group, which is the ones anglers really like to keep. Those are a little bit below average, and the reason for that is that from 2013 to 2015, we had lower reproduction each of those three years, which is not typical on Devils Lake.
The good news moving forward is that from 2016 to 2018, we had pretty good walleye reproduction, and coupled with stocking efforts in 2016 and 2017, we should again see more “keeper”-size walleye for anglers in the next couple of years.
Our overall walleye mortality rates on Devils Lake are on the low end of what is considered average, meaning anglers are not harvesting too many fish. So, additional regulations (size restrictions) really would have no impact in improving size structure of the fishery.
Game and Fish also gets questions on protecting walleyes running up the coulees (Channel A, Mauvais Coulee) in the spring.
Caspers: At current (harvest) levels, we do not believe it is really impacting the population really at all. A good example of that would be in 2009, when we had good coulee fishing that spring, but we also saw really good natural reproduction that year, our highest reproduction event we have ever seen on Devils Lake. If the anglers were really tough on those spawning fish, you obviously would not have observed a huge year-class in a year like that. And walleyes are a species that have a high reproductive capacity. It does not take a lot of females to be able to produce a good year-class if environmental conditions are favorable for those eggs to hatch and then the young fish to survive well.
Additionally, the majority of walleye that are caught in the coulees north of Lake Irvine and Lake Alice are probably residents of those two lakes, not Devils Lake itself. Springtime walleye harvest from these coulees is not likely to harm the walleye population since Lake Irvine and Lake Alice are relatively lightly fished lakes since access conditions are currently poor on Lake Irvine, and Lake Alice is a national wildlife refuge where no open-water fishing is allowed. The most serious threat to the walleye population in these two lakes is probably declining water levels, which may lead to winterkill if dry conditions continue.
There is a full section of questions and answers on various versions of walleye size restrictions and the year-round open fishing season on the Game and Fish website at https://gf.nd.gov/fishing/faq.