Experimental Manipulation of Sculpin (Cottus cognatus) Populations in a Small Stream
| Autor: | Neil H. Ringler, Charles R. Morgan |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Journal of Freshwater Ecology. 7:227-232 |
| ISSN: | 2156-6941 0270-5060 |
| Popis: | We examined movement and age distribution of experimentally manipulated natural populations of slimy sculpin (Cottus cognatus) in streams having open and closed vegetation canopies. Densities were estimated in three treatments: reference populations (no transfers), reductions (fish removed from the sites), and additions (fish added to the sites). Biweekly replenishment of addition sites raised sculpin densities to over 10/m2 in the open canopy, at least 3 times that of reduction and reference populations. In closed canopy habitats, densities of addition populations (6/m2) were twice as great as reference populations (3/m2), although reduction populations (41m2) did not differ from either. Addition sites showed a net increase of numbers of sculpin over four summer months, in spite of a decline in older sculpin (age III-V years). Reduction sites showed no differences from reference sites regarding sculpin numbers, indicating that recruitment of fish to reduction sites did occur. However, more than ... |
| Databáze: | OpenAIRE |
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