STREAMS 425 © Copyright by the American Fisheries Society 1998 Coho Salmon Populations in the Karst Landscape of
Abstract.-Karst topography is a unique and distinct landscape and its geology may have important implications for salmon productivity in streams. The relationship between salmonid communities and water chemistry and the influence of habitat was examined in a set of streams on north Prince of Wales I...
| Main Authors: | , , , , , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.157.7110 http://www.fs.fed.us/pnw/pubs/journals/pnw_1998_bryant001.pdf |
| Summary: | Abstract.-Karst topography is a unique and distinct landscape and its geology may have important implications for salmon productivity in streams. The relationship between salmonid communities and water chemistry and the influence of habitat was examined in a set of streams on north Prince of Wales Island, southeast Alaska. Streams in karst landscapes showed higher alkalinities (1,500-2,300 µeq/L) than streams not influenced by karst landscapes (750-770 µeq/L). A significant, positive relationship was observed between alkalinity and density of coho salmon parr Oncorhynchus kitsutch. Backwater pools supported higher densities of coho salmon than did other habitat units. Both coho salmon fry and parr tended to be larger in most karst-influenced streams than in nonkarst streams. Although past timber harvest practices in the riparian areas of several of the streams appeared to influence stream habitat and water temperature, streams flowing through karst landscapes had a distinct water chemistry. Furthermore, these streams appeared to support more fish than nonkarst streams. Karst topography is a unique geological feature formed by the differential dissolution of limestone (Harding and Ford 1993). The landscape typically has an irregular surface topography with sinkholes, caves, underground streams, and upwelling water (Ford and Williams 1989). Karst topography occurs in several distinct areas of southeast Alaska (Soja 1990; Busch 1994) and is best represented on the northern end of Prince of Wales Island and islands along its west coast (Baichtel 1993). Dissolution of limestone increases the alkalinity of streams as they flow through karst terrain, and higher alkalinity has been associated with increased growth rates for brown trout Salmo trutta |
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