Steven A. Pothoven
John M. Dettmers
Jeffrey D. Holuszko
Charles P. Madenjian
2006
<p><span>The dreissenid mussel invasion of Lake Michigan during the 1990s has been linked to a concomitant decrease in the abundance of the amphipod </span><i>Diporeia</i><span>. We tracked the seasonal energy dynamics of alewife (</span><i>Alosa pseudoharengus</i><span>) in Lake Michigan during 2002–2004 and compared our findings with previously published results for years 1979–1981. Adult alewife energy density exhibited a pronounced seasonal cycle during both the pre-invasion and post-invasion periods, with energy density in October or November nearly twice as high as that in early summer. However, on average, adult alewife energy density was 23% lower during the post-invasion period compared with the pre-invasion period. This significant decline in energy density was attributable to decreased importance of </span><i>Diporeia</i><span> in adult alewife diet. In contrast, energy density of juvenile alewives did not significantly differ between the pre-invasion and post-invasion periods. To attain a weight of 8 kg by age 4, bioenergetics modeling indicated that a Chinook salmon (</span><i>Oncorhynchus tshawytscha</i><span>) in Lake Michigan would have to consume 22.1% more alewives during the post-invasion period compared with the pre-invasion period.</span></p>
application/pdf
10.1139/F06-017
en
Ingenta Connect
Changes in seasonal energy dynamics of alewife (<i>Alosa pseudoharengus</i>) in Lake Michigan after invasion of dreissenid mussels
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