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Information gathering starts for Lake Elmo invasive Asian clam response

Aquatic Invasive Species

Fri May 01 14:34:51 MDT 2020

BILLINGS – Montana Fish, Wildlife & Parks is looking for comments and ideas on its proposal to remove invasive Asian clams from Lake Elmo in Billings Heights.

The public scoping – designed to gather information – is all online since directives in response to COVID-19 preclude a public meeting. A brief video about the invasive clams, history of the lake and potential alternatives for removal is on the FWP website at along with a poll and directions for submitting questions, comments and ideas.

The session is the first step in a required environmental assessment of alternatives for dealing with the invasive Asian clams. It will be followed by study of several alternatives and eventually a decision on action.

Asian clams were discovered in Lake Elmo during the summer of 2019 while FWP staff was training to look for invasive plants and animals in Montana waters. A subsequent FWP survey found both live and dead clams in the lake, but not in ditches and canals upstream or downstream from the lake.

It is unclear how the clams got into Lake Elmo, but possibilities include an aquarium emptied into the lake or introduction from an unclean out-of-state boat, waders or fishing equipment. Asian clams do not live elsewhere in Montana, though they are common in the Columbia River basin of Washington and Oregon.

Invasive Asian clams can multiply quickly and cause damage that includes clogging water intakes, outcompeting native organisms for food, promoting toxic algae growth and depositing sharp shells on the pond floor. Because the Asian clams were discovered early in their occupation of the lake, FWP biologists believe that they have a good chance of removing them before they get into adjacent waterways – including the Yellowstone River – or before the problem gets too expensive or physically expansive to address.

One alternative would involve draining the water out of Lake Elmo for the winter to starve and freeze the clams. The environmental assessment also would address the opportunity to make fisheries and park improvements if the lake is drained.

The information and comment session will remain online until May 17.