Recruiting Help to Find Elusive Cisco in Green Bay
BY TED TRESKA, GREEN BAY FWCO
morphological measurements. Credit: Ted Treska, USFWS
Following up on an idea formulated in a coordination meeting of all agencies working on Green Bay, Green Bay Fish and Wildlife Conservation Office (FWCO) fisheries biologist Ted Treska worked to expand the network of participants to collect genetic samples of cisco (lake herring) from the bay for an ongoing study to determine the genetic make-up of remaining cisco stocks in Lake Michigan. In recent years, commercial fishers had been reporting the occasional encounter with cisco in their whitefish nets from various locations in the bay. Working with the area Wisconsin Department of Natural Resources biologist and conservation warden supervisor, Treska developed a protocol that asked commercial fishers to collect basic location information along with a fin clip for a genetic sample, while still keeping them within the regulations enforced by the department. The protocol provides a simple set of instructions along with cisco identification tips, and was provided with sample envelopes store the fin clip and record locational data.
Treska then contacted commercial fishers in the lake whitefish fishery of Green Bay that have cooperated with efforts in the past and asked them to participate in the effort and most were more than willing to help. Green Bay was historically the largest producer of commercial catches of cisco in the Great Lakes and a number of the current fishers come from families that grew up fishing cisco in generations past. Currently, nine fishers are participating in the collection effort and with whitefish season set to ramp up as fall and the whitefish spawning season approaches, we are hoping for more samples to be collected. To date, we have collected six samples for testing with a goal of 25 samples for genetic analysis. In addition to the genetic samples, any fish that are collected whole by government agencies are being photographed for morphological analysis, which compares lengths between different parts of the body to separate groups of fish out by body shape.
Also provides identification tips for similar species in Green Bay. Credit: Ted Treska, USFWS
Once fin clips are collected, they are sent to the U.S. Geological Survey’s Great Lakes Science Center in Ann Arbor, Michigan. Geneticist Wendy Stott tests them against other samples from the lake as part of a study initialized by Kevin Donner, a biologist with the Little Traverse Bay Band of Odawa Indians. The tests are used to determine if there are genetic differences between remnant populations in Green Bay and other small populations on the eastern shore of Lake Michigan, including those in Grand Traverse Bay and near Ludington. The samples will also be tested against a number of other samples from around the Great Lakes basin to define which existing stock they are most similar to. This information will likely play a significant role in efforts that are underway to examine the possibility of restoring this species as part of the native forage base in Lake Michigan, as ciscoes once played a very large part in the fish community of the lake. As consumers of plankton in the open water areas of the lake, they play a large role in transferring energy from the open lake environs to the predators, and at the same time, their high energy eggs that they deposit on shallow water reefs play a large part in bolstering energy reserves for a number of species that consume the eggs in preparation for the harsh times of winter.
Regardless of the outcome of the testing, many around the lake are hoping for a continued recovery of this species in the lake.