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US Fish & Wildlife Service FieldNotes

2019 Alpena Fish and WIldlife Conservation Office surveys

Region 3, February 21, 2020
A thin section of a burbot otolith that has an estimated age of 16.
A thin section of a burbot otolith that has an estimated age of 16. - Photo Credit: n/a
A thin section of a lake whitefish otolith that has an estimated age of 27.
A thin section of a lake whitefish otolith that has an estimated age of 27. - Photo Credit: n/a
A thin section of a lake trout maxilla with an estimated age of 21 (left) and a zoomed in picture of the maxilla (right).
A thin section of a lake trout maxilla with an estimated age of 21 (left) and a zoomed in picture of the maxilla (right). - Photo Credit: n/a

During the 2019 field season, the Alpena Fish and Wildlife Conservation Office conducted surveys in Lake Huron for juvenile lake whitefish, adult lake whitefish, spawning lake trout, and spawning lake herring.

During these surveys, a suite of biological data is collected from fish including hard structures, like otoliths, spines, and maxillae, for estimating ages. Otoliths are used to age lake whitefish, lake herring, burbot, and large lake trout. Maxillae are used to age lake trout, whereas dorsal spines are used to age walleye and yellow perch.

These structures are similar to trees in that they have rings or annuli that we count to estimate ages of fish. This winter over 1,000 fish were aged from fish collected. Some of the oldest fish aged were lake whitefish and lake trout with the oldest estimated age for each species being 27 and 24, respectively. Additionally, the oldest estimated ages for burbot, lake herring, and walleye were 22, 18, and 13, respectively. Estimated ages from Alpena, Michigan Department of Natural Resources, and tribal agencies are then included in population models which are used to set harvest limits and make other management decisions for Lake Huron.

Contact Info: Benjamin Leonhardt, 989-356-5102, benjamin_leonhardt@fws.gov