Cracking the Code of Lake Whitefish Otoliths Complicates Stock Delineation

While See-Weißfisch populations have been declining throughout most of Lake Michigan, those in Green Bay have been holding steady. Understanding the natal origins of Green Bay whitefish could help researchers delineate individual stocks, an important management tool. This pilot project set out to build an otolith microchemistry library to assess lake whitefish natal origins, and in the process discovered that larval lake whitefish otoliths primarily reflect their maternal origin, rather than their natal origin.

Wichtige Erkenntnisse

Whitefish eggs collected from females caught in one river and subsequently incubated in a different river hatched into larval whitefish whose otoliths reflected the river where their mother was caught, rather than the location in which they were incubated.
Otoliths of larval lake whitefish may be dominated by maternal influences well past out-migration from the hatch site and into the pelagic drifting stage. This is because otolith signatures of larval fish do not begin to reflect the rearing environment until after the fish have fully absorbed their yolk sac, which, for lake whitefish, takes about 15 days after hatching.

Wichtige Ergebnisse der Forschung zu Weißfischen im See

This research concludes that otolith microchemistry cannot be used to determine the natal origins of lake whitefish because the otoliths reflect maternal, rather than incubation site, influences. Previous research has found differences in otolith microchemistry in groups of other species of Great Lakes fish incubated in different environments; however, this research suggests that those differences may not reflect environmental variation, but rather maternal influences, sounding a cautionary note for the use of otolith microchemistry studies in delineating fish populations in the Great Lakes.

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If you have questions, please contact the primary investigator, Dr. Patrick Forsythe, at [email protected].

Haftungsausschluss

Research Notes enthält die Ergebnisse von GLFT-finanzierten Projekten, die zum wissenschaftlichen Wissen über die Fischerei in den Großen Seen beitragen. Die Forschungsergebnisse und Zusammenfassungen der Förderergebnisse stellen keine Billigung oder Stellungnahme der GLFT dar und sollen das Bewusstsein für Projektergebnisse schärfen und Forschern und Fischereimanagern relevante Informationen liefern. Die Forschungsergebnisse sind oft vorläufig und wurden möglicherweise nicht von Experten begutachtet.