Fish Lake - Answers About Weeds

By Bruce R. Schmidt

The February 16th issue of Utah Fishing Magazine contained two interesting letters to the editor raising points which deserve to be answered.

Mr. Johnny Appleseed discussed various topics, but was primarily concerned about the weed problem at Fish Lake. I tried to call Mr. Appleseed to discuss some of the finer points with him personally, but he apparently has an unlisted phone number so I will have to address the issue here.

Mr. Appleseed is correct that a new species of aquatic vegetation has been identified in Fish Lake. It is Eurasian water milfoil, an exotic pest weed originating in Europe and Asia. It is an aggressive species which can take over vast areas of a lake and is exceedingly difficult to control. Coincidentally to Mr. Appleseed's letter, Louis Berg, our research biologist in Cedar City has prepared a short article discussing the finding of water milfoil in Fish Lake. That article appears in this issue and should answer some of the specific questions about this finding.

Undoubtedly, this latest discovery will lead to the commonly asked question "What are you going to do about it?" Ever since the weed problems became evident at Fish Lake we have been asked this question. Unfortunately, the answer has to remain unchanged. The Utah Division of Wildlife Resources has no legal authority over vegetation, either aquatic or terrestrial, in the State of Utah. Fish Lake is part of the Fish Lake National Forest, and generally speaking the Forest Service exercises control over both aquatic and terrestrial habitats on lands that they administer.

There are also private land holdings around Fish Lake, but I don't know what authority landowners would have to control the problem.

In addition, noxious weeds are usually controlled by county governments, but I am not aware of this applying to an aquatic situation. To further complicate the matter, there is probably very little that can be done to change the situation once a pest species as virulent as Eurasian Water Milfoil is already well established.

Fish Lake is too large to treat chemically with weed killers, most of which are toxic to fish anyway. Mechanical harvesting of weeds provides only temporary relief and is so expensive that it is usually relegated to clearing out specific areas around docks or boat launching areas. Biological controls such as the use of grass carp would be very slow to take effect due to the cold temperatures at Fish Lake, and would also be prohibitively expensive. The number of grass carp necessary to effect weed control in a lake that size would be staggering, and at a price tag of from $5 to $8 apiece for grass carp, nobody could afford it. They are a logical solution to weed problems only in small waters.

In spite of the difficulties with controlling this pest weed and the fact that we have no legal authority or mandate to deal with the problem, we would be willing to work cooperatively with the Forest Service, the county and any individuals to discuss what possible control options are available. I do not expect, however, that a simple solution exists or that we would be able to make a dent on the problem at any time in the near future.

The only lucky thing about the finding of milfoil at Fish Lake is that the lake is deep enough so that the weeds will probably not spread much beyond where they presently exist around the shoreline. That situation, however, might be different at many other waters in the state. Now we have to be concerned about the potential for the weed to spread to other popular fishing waters. This weed reproduces by a variety of methods, including seeds and shoots from leaf or stem fragments, making it extremely easy to transport when trailering a boat to other waters. We urge all boaters at Fish Lake to carefully remove weeds from their trailer or the bilge inside the boat when they leave the lake. This weed has the potential to completely take over shallower bodies of water which would cause major problems for anglers, boaters and irrigators.