首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Land use,associated eel production,and abundance of fish and crayfish in streams in Waikato,New Zealand
Authors:Brendan J Hicks  Helen M C McCaughan
Institution:Department of Biological Sciences , University of Waikato , Private Bag 3105, Hamilton, New Zealand
Abstract:Abstract

The density and biomass of fish and crayfish, and the production of eels, was compared among streams in native forest, exotic forest, and pasture. Populations were estimated by multiple‐pass electroshocking at 11 sites in hill‐country streams in the Waikato region, North Island. Three sites were in native forest, four in exotic forest, and four in pasture. Length of stream sampled at each site was 46–94 m (41–246 m2 in area), and catchment areas up stream of the sites ranged from 0.44 to 2.01 km2.

A total of 487 fish were caught. The species were longfinned and shortfinned eels, banded kokopu, Cran's and redfinned bullies, and common smelt. Eels were the most abundant fish in all three land‐use types, and shortfinned eels were more abundant at pastoral sites (mean density 1.11 fish m?2) than longfinned eels (mean density 0.129 fish m?2). Banded kokopu were present only at forested sites. Mean fish densities were greater at pastoral sites (1.55 fish m?2) than under either native forest (0.130 fish m?2) or exotic forest (0.229 fish m?2). Mean fish biomass was also greater at pastoral sites (89.7 g m?2) than under native forest (12.8 g m?2) or exotic forest (19.3 g m?2). Longfinned eels made a greater contribution to the fish biomass at all sites than did shortfinned eels. Densities of crayfish were high (0.46–5.40 crayfish m?2), but were not significantly different between land‐use types. Crayfish biomass ranged from 1.79 to 11.2 g m?2. Total eel production was greater at pastoral sites (mean 17.9 g m?2 year1) than at forest sites (mean 2.39 gm?2 year?1).
Keywords:eels  bullies  common smelt  density  biomass  land use  native forest  exotic forest  pasture  streams  production
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号