The Bemidji Hatchery was established in 1915
Why was it established? The dam on the Mississippi River downstream of Lake Bemidji creating the Stump Lake reservoir was built for electric power generation in the early 1900’s. Fish hatcheries were often located below dams to take advantage of the gravity flow for a reliable water supply.
What is the general technology used for the hatchery? From establishment until recently (2010) little has changed in operating technology. Gravity flow from a reservoir is still the most dependable and efficient way to operate a hatchery, using no energy to pump water and not vulnerable to power failure. Additionally, surface water temperatures are often the most desirable incubation temperatures since they mimic natural conditions and timing of fry production.
Has the technology been modified since establishment? Why or why not? Some water treatment has been added using bubblers and/or agitators to reduce gas super-saturation which tends to float eggs out of the hatching jars. “Cannon” hatching jars (20-25 qt capacity) have been added to replace some of the original smaller “Mehan” type jars to increase incubation capacity. Compressed oxygen and diffusers have been added to hatching batteries and fry tanks to increase fry holding capacity.
Probably the most significant technological improvement to the Bemidji hatchery has been the addition of batch marking capability for freshly hatched walleye fry. This was initiated in 1999 as a tool to evaluate Red Lake recovery stockings and has since been utilized in Leech Lake, the Cass Lake Chain and numerous other smaller waters. While this additional marking procedure has had little effect on the actual hatching process it is proving to be invaluable as a fisheries assessment tool.
Unfortunately, the simple surface water gravity flow technology that has served this facility so well for nearly a century may no longer be feasible. We have been very fortunate in the Upper Mississippi watershed to have avoided most of the aquatic invasive species infestations that have occurred throughout the rest of the state. However, we cannot assume that we will be able to avoid an invasion indefinitely. Plans are being developed, and funding requested, for some significant modifications to filter and treat surface water before entering the hatchery. If an aquatic invasive does become established we will need to have controls in place to prevent spreading that invasive through our fry distribution process.
In general, fish management tools fall into one of four categories:
Lake surveys and research provide the information used to select appropriate management tools.
Minnesota has more walleye, walleye lakes, and walleye anglers than any other state. Each year, anglers harvest about 3.5 million walleye.
The best way to maintain walleye numbers where they are reproducing naturally is to protect critical habitats. Shore land zoning and related laws aid fish by controlling development and protecting spawning sites and aquatic plants that fish use for cover. Also important in maintaining natural reproducing populations is protecting spawning stock from excessive exploitation. Since hatching success in natural systems is relatively low it requires considerable egg production to produce the fry density necessary for a sustainable population.
Where spawning habitat or spawning stock is limited Sstocking is another management tool used to enhance walleye populations. Minnesota’s cool water hatcheries produce 2 - 5 million walleye fingerlings and millions of fry each year. Stocking can provide walleye fishing in lakes that lack successful or consistent reproduction but can otherwise support walleye. Stocking is also effective for lakes that have been “rehabilitated” or occasionally winterkill. Like any tool, stocking must be used appropriately. If misused, it will be ineffective or possibly harmful to existing fish populations. Stocked walleye may compete for food with other game fish.
Stocking a lot of small fish does not guarantee catching a lot of big fish. In fact, stocking too many fish can be counterproductive and result in fewer catchable fish. Of the five years that total fry density was estimated for the Red Lakes, the highest fry density (more than double any other year) resulted in the lowest eventual year-class strength. Most likely high density contributed to slower growth resulting in lower survival rate to catchable size.
Loss of habitat, pollution, and increasing fishing pressure continue to be the biggest issues in walleye management. Everyone must work to improve water quality, control runoff and waterfront development, and maintain aquatic vegetation. Anglers, in addition, will need to comply with regulations and harvest only what they intend to use, for Minnesota to maintain a quality fishery.
WALLEYE AND SUCKER PRODUCTION
Walleye egg sources for the Bemidji hatchery can be programmed from various spawning sites depending on the eventual fry destination. Most common sources are Big Lake Creek for stocking into the Upper Mississippi watershed, or Boy River for stocking into Leech Lake or connected waters. Pike River eggs from Lake Vermilion were supplied for the Red Lake recovery stockings. The Bemidji hatchery does have the ability to isolate unique strains with two sets of walleye batteries and fry tanks.
Annually, the Bemidji hatchery generally produces 20 to 30 million walleye fry, although 43 million were produced and marked for one of the Red Lake stocking events. Annual production is based on predetermined stocking quotas for rearing ponds, management lakes or special marking projects rather than simply maximizing hatchery capacity.
What types of research help with management decisions for this hatchery? Genetic research has guided our decisions on what strain of walleye to produce for each stocking destination. Generally a spawning site location from the same watershed as the stocking destination is preferred, especially when enhancing populations that have some successful natural reproduction. For the Red Lakes recovery effort, where egg supply was not sufficient from the parent lake, genetic analysis of numerous spawning locations was done to identify Pike River as the closest genetic match.
What other factors are involved with management decisions involving this hatchery? Fisheries management plans dictate the stocking quota for individual lakes, and hatchery quotas are programmed to produce the amount of fry needed to meet those needs.
What types of research or other science activities occur along with the activities in this hatchery?
Research involving contribution of stocked fry and estimates of wild fry has been possible due to techniques for batch marking walleye fry for later identification. Results of work on Red and Leech Lakes have revealed important information on egg to fry survival in natural systems, and the relation between spawning stock biomass and wild fry production. These and other marked fry studies are helping to identify optimal fry densities for sustainable recruitment, and provide useful information on early life history of walleye.
How does the data collected and/or research conducted at this hatchery inform/affect fisheries managers and fisheries habitats? While fish stocking can be an effective tool for fish managers, and is probably the most visible and popular management activity for anglers, it is important to understand that the stocking event is not the management objective. Continued evaluation of stocking efforts, including evaluation of natural reproduction in the absence of stocking, is necessary to insure that stocking programs are efficient (significantly enhancing the desired fishery). Inefficient stocking programs inflate production costs with minimal return to anglers, and divert production (fry or fingerlings) from lakes that could benefit from additional stocking.
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We are unable to give tours to casual visitors due to staffing limitations.