July 29, 2014
MILWAUKEE - In a remarkable feat of distance swimming, tiny chinook salmon released in Lake Huron two years ago swam their way through the Straits of Mackinac and down through Lake Michigan into the waters off of Racine, according to newly released data gathered with the help of Wisconsin anglers.
Coded wire tags are attached to young fish before release and help DNR tack fish movements throughout the Great Lakes.
Brad Eggold, Lake Michigan fisheries supervisor for the Wisconsin Department of Natural Resources, said the 400 mile journey of fish released by the state of Michigan points to the benefits of coordinated management efforts given the mobility of species like salmon. Other fish caught at the Racine checkpoint originated from stocking efforts in Door County, western Michigan, Indiana and Illinois.
The study documenting the movement of fish throughout the lakes also indicates that natural reproduction of chinooks is picking up steam in Lake Michigan. For chinooks that are one year old, 55 percent of the population now comes from natural reproduction.
What makes these findings possible? Fish heads - containing tiny coded wire tags - that have been saved by attentive anglers and dropped off at key ports and collection points along Lake Michigan's shores.
The tags, which are embedded into the snouts of the young fish, include numbers identifying when and where the fish were stocked. The tags themselves are smaller than a fine sliver of pencil lead, yet when entered into a database maintained by U.S. Fish and Wildlife Service scientists, they provide a powerful narrative about the lives of these fish.
Tiny coded wire tags attached to fish provide important information about fish movements.
"We could not undertake this type of research without the support of an educated and dedicated group of anglers willing to save the fish heads and bring them in to our collection points," says Eggold. "The results continue to provide incredible insights into the movement and reproduction of Chinook salmon while demonstrating the benefits of interstate cooperation. For example, anglers harvesting fish in Racine are catching fish stocked everywhere in Lake Michigan and in some cases, fish stocked in Lake Huron."
While the natural reproduction data varies somewhat by year - in part due to inconsistences in the number of fish heads collected - a six-year time series dating from 2006 to 2011 indicates natural reproduction levels well above 50 percent. The results represent good news for anglers, whose license purchases have provided the funding to support biological research, as fisheries managers will continue to fine-tune stocking strategies based on the latest scientific data.
Eggold says state agencies with jurisdiction surrounding Lake Michigan as well as the U.S. Fish and Wildlife Service would like to encourage anglers to continue providing fish heads so the research can progress through additional years. While the tiny coded wire tags placed in the snout of the fish may be difficult to see, anglers can tell whether their salmon or trout carries a tag because the adipose fin on the fish's back, just in front of the tail, will be missing.
DNR appreciates the efforts of the more than 200 anglers who participated last year and the businesses that serve as collection points. These businesses have been given a supply of forms for anglers to fill out and bags to use for freezing the heads.
The forms ask anglers to include basic information such as the date of capture, capture location, fish species, length, weight and gender. Drop-off locations include:
For more information, visit dnr.wi.gov and search for "adipose missing fin."
FOR MORE INFORMATION CONTACT: Brad Eggold, Lake Michigan fisheries supervisor, 414-382-7921; Jennifer Sereno, communications, 608-770-8084