Lake Whitefish continue to be captured in Detroit River

[Spiel]

Lake Whitefish continue to be captured in Detroit River

After an Absence of Almost a Century

 

January 28, 2008

Great Lakes Sport Fishing Council

 

USFWS Fisheries Biologists James Boase and Jim McFee, in conjunction with United States Geological Survey (USGS), completed a third year of pre-assessment lake whitefish survey work on the Detroit River. Sampling was conducted from mid-October through early December in both US and Canadian waters focusing particular attention on areas near Fighting Island and at the mouth of the Detroit River where it empties into Lake Erie. The location near Fighting Island will be the site of an artificial spawning reef to be constructed in 2008.

 

The first whitefish adults were captured in the river in the fall of 2005 but we were unable to capture adults in the river in 2006 despite an increase in sampling effort. During the same period Lake Whitefish eggs were collected throughout the river using a combination of egg-mats and by sucking the eggs off of the bottom using a diaphragm pump. In the spring of 2006 and 2007 larval whitefish were collected after they hatched from eggs and began drifting in the water column.

 

These findings helped identify locations in the river to focus effort to capture more adults in the fall of 2007 and as a result we were able to capture 13 spawning adult lake whitefish.

 

All eggs and larvae captured each year have been incubated and reared by researchers at the USGS Great Lakes Science Center. In the fall of 2006 and 2007 they were released back into the Detroit River in ceremonies commemorating the positive changes that have been taking place on the Detroit River and have been attended by such dignitaries as Congressman John D. Dingell (MI 15), Congressman John Conyers (MI 14), Member of Canadian Parliament Jeff Watson, Canadian Consul General Robert Noble, along with number of local, state and municipal politicians.

 

Whitefish are currently the most sought after commercial species in the Great Lakes and at one time they were harvested in huge numbers in Lake Erie. Historically the Detroit River supported a very large spawning population of Lake Whitefish and it has been almost a century since Lake Whitefish spawning has been documented in the river. The fishery collapsed for a number of reasons but spawning habitat loss and pollution were identified as primary reasons for the decline. At the turn of the century the Detroit River supported huge numbers of spawning whitefish because at that time the river was composed of many braided, shallow channels. Those historical channels were composed primarily of limestone bedrock, rock and gravel, habitats that are needed for successful spawning by not only whitefish but also many other species of native fish like lake sturgeon and walleye.

 

Construction of the artificial reef at Fighting Island is one of the first international efforts directed at replacing some of that lost habitat in the river. The amount of pollution in the river has slowly declined since the U.S. Clean Water Act and U.S. – Canada Great Lakes Water Quality Agreement were both signed in 1972. Ultimately the goal is to clean up the river and provide adequate habitat that will eventually lead to the re-establishment of species like whitefish and lake sturgeon.