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The University of Massachusetts Amherst

Trends in the Reproductive Phenology of two Great Lakes Fishes

Authors:

John Lyons

Andrew Rypel

Paul Rasmussen

Thomas Burzynski

Bradley Eggold

Jared Myers

Tammie Paoli

Peter McIntyre

Publication Type:
Journal Article
Year of Publication:
2015
Secondary Title:
Transactions of the American Fisheries Society
ISSN:
1548-8659
DOI:
10.1080/00028487.2015.1082502
Pages:
1263-1274
Volume:
144
Year:
2015
Date:
03-Nov-2015
URL:
https://onlinelibrary.wiley.com/doi/abs/10.1080/00028487.2015.1082502

Abstract

To assess potential effects of climate change on Great Lakes fish populations, we evaluated trends in the reproductive phenology of Yellow Perch Perca flavescens (spring spawner) and Lake Trout Salvelinus namaycush (autumn spawner). For Yellow Perch in Lake Michigan, the estimated reproductive midpoint date (50% of mature females ripe or spent, 50% not yet spawned) took place 6.2 d/decade earlier in the spring near Milwaukee from 1988 to 2012 and 1.8 d/decade earlier in Green Bay from 1980 to 2012. At both locations water temperatures at the spawning sites on the midpoint date showed no trends, but mean water temperatures during the spring at the spawning site and midlake increased over the study period. This suggests that Yellow Perch spawning areas were warming sooner in the spring and that Yellow Perch were spawning earlier to maintain a consistent spawning temperature. Lake Trout phenological patterns were more complex. For Lake Trout in Lake Michigan near Milwaukee, there was a marginally significant trend for spawning to take place 2.1 d/decade later in the autumn from 1983 to 2006. However, water temperatures at the spawning site at the midpoint date did not change and autumn temperatures at the site and at midlake did not show a warming trend. For Lake Trout in Lake Superior near the Apostle Islands, the midpoint date did not change from 1988 to 2012. Water temperatures at the spawning site on the midpoint date and during the autumn also showed no trends, but midlake summer and autumn water temperatures increased significantly. Overall, Yellow Perch in Lake Michigan have shifted reproductive timing in a manner consistent with a warming climate, but the relationship of climate change to reproductive phenology remains unclear for Lake Trout in Lake Michigan and Lake Superior.