| Abstract: | The zooplankton populations in southeastern Lake Michigan underwent striking, size-related changes between 1954 and 1966. Forms that decline sharply were the largest cladocerans (Leptodora kindtii, Daphnia galeata, and D. retrocurva), the largest calanoid copepods (Limnocalanus macrurus, Epischura lacustris, and Diaptomus sicilis), and the largest cyclopoid copepod (Mesocyclops edax). Two of these, D. galeata and M. edax (both abundant in 1954), became extremely rare. Certain medium-sized or small species increased in numbers: Daphnia longiremis, Holopedium gibberum, Polyphemus pediculus, Bosmina longirostris, Bosmina coregoni, Ceriodaphnia sp., Cyclops bicuspidatus, Cyclops vernalis, and Diaptomus ashlandi.
Evidence is strong that the changes were due to selective predation by alewives. The alewife was uncommon in southeastern Lake Michigan in 1954 but had increased to enormous proportions by 1966; there was a massive dieoff in spring 1967, and abundance remained relatively low in 1968. The composition of zooplankton populations in 1968 generally had shifted back toward that of 1954, although D. galeata and M. edax remained rare.
The average size, and size at onset of maturity, of D. retrocurva decreased noticeably between 1954 and 1966 but increased between 1966 and 1968. |
| Genre: | Article |
| ProdID: | 1000408 |
| Citation Author: | Wells, LaRue |
| Citation Contributing Office: | Great Lakes Science Center |
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| Citation End Page: | 565 |
| Citation Issue: | 4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Limnology and Oceanography |
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| Citation Number Of Pages: | 9 |
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| Citation Phsyical Description: | p. 556-565 |
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| Citation Search Results Text: | Effects of alewife predation on zooplankton populations in Lake Michigan; 1970; Article; Journal; Limnology and Oceanography; Wells, LaRue |
| Citation Start Page: | 556 |
| Citation Volume: | 15 |
| Citation Year: | 1970 |
| Type: | citation/reference |
| Text: | Effects of alewife predation on zooplankton populations in Lake Michigan; 1970; Article; Journal; Limnology and Oceanography; Wells, LaRue |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Thu, 1 Jan 1970 00:00 -0600 |
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