The fate of animals in stream drift when carried into lakes

TitleThe fate of animals in stream drift when carried into lakes
Publication TypeJournal Article
Year of Publication1944
AuthorsDendy JS
JournalEcological Monographs

1. Special methods for sampling stream drift and stream and lake bottom are described. 2. A total of 71 kinds of macroscopic aquatic animals, distributed in seven phyla, have been recorded from drift in 3 streams. 3. Presence of animals in stream drift, although highly variable in quantity and quality, was the constant situation. Large quantities of drift material, including animals, are carried into Burt Lake by Carp Creek. 4. In general the same larger groups of animals were represented in all 3 streams, but there was considerable stream individuality as to species. With insignificant exceptions, all species which occurred in the bottom samples from Carp Creek were sooner or later found in the drift of that stream. 5. Most of the drift animals which entered Burt Lake settled to the bottom immediately lakeward from the margin of the delta, where a zone of concentration was established. Distribution of drift animals on the lake bottom beyond the zone of concentration was not dependent upon the distribution of creek water in the lake. 6. Fall of surface level of Burt Lake affected the drift animals in the following ways: (a) increased speed of the creek current and of bottom erosion for at least 85 meters upstream from the mouth; (b) altered quantity and probably quality of drift animals entering the lake; (c) caused lakeward extension of the delta; and (d) exposed drift animals, in concentration zone, to more vigorous wave action. 7. Observations and experiments showed that drift animals could maintain positions on the lake bottom during the absence of, or while protected from, wave action. 8. Wave action affected the drift animals inthe following ways: (a) prevented burrowing; (b) partially or completely depopulated the zone of concentration; (c) washed animals upon the beach near the creek; and (d) changed the position of the delta materials to form islands, spits, and sand bars upon which creek animals were stranded. 9. Creek animals on the beach met the following fates: (a) were buried in beach material; and (b) succumbed to desiccation. Predatory activities of fishes accounted for disappearance of only a minor portion of the drift animals which entered the lake. 10. Most of the animals drifting from Carp Creek into Burt Lake did not survive for extended periods of time. The major factor in the lake environment which determined the fate of drift animals was wave action.