Thursday, September 16, 2010

Large Lake Sturgeon Found at Petoskey's Bay Harbor Resort


If you’ve ever been walking along the shoreline of Lake Michigan and noticed the remains of a fish that looks like it could have lived in prehistoric times what you saw could well have been a Lake Sturgeon. That was exactly what construction workers working near Petoskey saw when they arrived at a job site last week.


Early last week biologists at the Michigan Department of Natural Resources and Environment (MDNRE) fisheries station in Charlevoix received a call about a very large dead fish found on the rocky shore of the Bay Harbor Resort. Turns out that the fish was a five foot eight inch long Lake Sturgeon.

MDNRE biologist at the Charlevoix station Randall Claramunt says it is not particularly uncommon to find dead Sturgeon along the Lake Michigan shoreline especially in the later half of the month of August or the beginning of September but it is uncommon to find one this large or in this good of condition.

Sturgeon like this one seem to have become an unwitting victim of one of the hundreds of invasive species that now inhabit the Great Lakes. Samples from this fish will be sent to different agencies to help determine its age and the exact cause of death but fisheries personnel feel the likely culprit is botulism. “The majority of the ones we’re finding died from botulism.“ said Claramunt. The theory is that the fish acquire the disease by eating Zebra Mussels.

In a twist of fate only mother nature could come up with the invasive Zebra Mussel is thought to indirectly create the conditions for the botulism to develop and then ingests the disease and passes it on to the Sturgeon.

     * Zebra Mussels filter lake water removing their food from it leaving the water much clearer.

     * clearer water allows algae to bloom in far greater quantities then normal (if you’ve noticed an increase of large clumps of algae floating on the surface or building up along the shoreline this is likely a result of Zebra Mussels.)

     * large amounts of dead and decaying algae allow the botulism bacteria to grow and disperse into the water.

     * Zebra Mussels, that are immune to the bacteria, filter the lake water and absorb the botulism bacteria.

     * Sturgeon eat the Zebra Mussels and contract the deadly disease.

“There’s no expert who would have predicted that the botulism mechanism would do this.” said Claramunt. “Nobody would have predicted that because it’s so complex. With any invasive species its impossible to predict all the interactions that they will have with native life.”


MDNRE Biologost Randy Claramunt (left) and MDNRE Tribal Coordinator
Nick Popoff hold a measuring tape up to the frozen carcass of a Lake
Sturgeon that recently washed ashore in Little Traverse Bay.

Sturgeon are a very long lived fish. It is believed that Lake Sturdeon can live to be well over a hundred years old. They are part of the diverse Great Lakes ecology and different Sturgeon varieties, including Lake Sturgeon, are a part of the cultural history of many native American tribes throughout the United States. Not only has the Sturgeon been a source of food but it is also an important part of tribal art and history according to the Charlevoix stations tribal coordinator Nick Popoff.

There are several co-operative studies currently underway to help understand the Lake Sturgeon and breeding programs are being developed to help sustain the population. Part of these studies include the electronic tagging of fish that are caught in survey nets. When possible, netted fish have a Passive Integrated Transponder (PIT) tag inserted underneath the third skew (pointed armor like plate) on their backs. The PIT tag is an electronically coded device that can be read using a special computer wand. The tag contains an identification number that can be checked to see when and where the fish was first tagged and if it has been caught more than once. In some cases it can also identify the sex and age of the captured fish.

Since the Lake Sturgeon is listed as a threatened species by the State of Michigan if you do happen to come upon a Sturgeon carcass there are several different organizations that might be interested in your discovery. On a state level you can contact the local MDNRE field office. If you are close to a fisheries station you can contact them or your local conservation officer. Many tribal governments also have a conservation department that might be conducting or participating in studies about Sturgeon so they will most likely be interested in any find. “We definitely want people to call” said Claramunt. “If its dead we definitely want to scan it to see if its been PIT tagged.”

Other sources for information on Lake Sturgeon in Michigan include:

http://www.michigan.gov/dnr/0,1607,7-153-10370_12145_12203-33009--,00.html

http://www.sturgeonfortomorrow.org/

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