Lake Pend Oreille: State of the Lake 2013

On Wednesday, Feb. 19th, Idaho Fish and Game held their annual State of the Lake meeting in Ponderay, Idaho. 2013 was a very productive and promising year for the lake. The past year saw the highest kokanee salmon spawning success in the past 40 years with over 1.2 million mature kokanee surviving to spawn. Anglers were able to fish for kokanee for the first time since the fishery was closed in 2006. Anglers are reporting significantly better success for trophy Gerrard Rainbow trout in the lake with several over 20 pound fish reported.

2013 marked the eighth year of netting for predatory lake trout and much of the improved angling can be attributed to the success of the netting effort along with the Angler Incentive Program that rewards anglers for catching lake trout. These programs have reduced the lake trout population to a point where predation no longer limits the size of the kokanee population. The goal moving forward is now to find ways to maintain the lower population of lake trout while reducing the netting effort.

As reported earlier, the boom in the spawning kokanee numbers has also resulted in a dramatic increase in the bald eagle visitation around the lake as the birds gather to feast on the easily-accessible shallow-spawning fish.

Somewhat complicating the kokanee boom in 2013 was a complete crash of the Mysis shrimp population in 2012. The Mysis population in Pend Oreille has historically  averaged just over 800 shrimp per square meter. In 2012, that population dropped dramatically to only 45 mysis/square meter. 2013 saw a slight rebound to 135 per square meter, but still well below historic levels. Biologists are stumped as to what caused the crash, but continue to study the population in hopes of finding answers.

Mysis shrimp are important because their abundance directly affects the survival of juvenile lake trout. With fewer Mysis, fewer juvenile lake trout will survive to adulthood to prey on kokanee. So, it is likely that some of the rebound in the kokanee population is tied to fewer Mysis in the lake.

The good news is; fewer Mysis will mean stronger year-classes of kokanee for the time being and also, the drastic drop in the population will give biologists a unique opportunity to study the lake trout/kokanee/mysis interaction if, and when, the Mysis population rebounds.

Numbers of native bull trout, as indicated by spawning redd counts in the tributaries, have remained stable throughout the netting effort showing that activities to reduce lake trout have not resulted in any significant bycatch mortality. Our sister chapter, the Panhandle Chapter of Trout Unlimited is working closely with IDFG to determine limiting factors affecting westslope cutthroat trout survival in, and around the lake, to hopefully find ways to increase numbers and size of those native fish.

As part of the program to increase kokanee numbers in Pend Oreille, IDFG had also placed a $15 bounty on the famous rainbow trout in the lake. That bounty has been removed and there seems to be a rebound in the trophy rainbow population with several fish over 20 pounds being reported this past year.

Probably the most important activity that will take place on the lake in 2014 will be an exhaustive year-long creel survey to estimate fishing effort and angler harvest that is occurring on the lake. The survey will inform upcoming regulations and management for Pend Oreille.

So, overall it has been a very good year for the Lake Pend Oreille fishery with the expectation of better things to come. Many other exciting and ongoing management activities continue in Northern Idaho. You can see the complete Panhandle Annual Fisheries Report on the IDFG website.