LAND-USE, ASSOCIATED EEL PRODUCTION, AND ABUNDANCE OF FISH AND CRAYFISH IN STREAMS IN WAIKATO, NEW-ZEALAND

The density and biomass of fish and crayfish, and the production of ee ls, was compared among streams in native forest, exotic forest, and pa sture. Populations were estimated by multiple-pass electroshocking at II 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 m(2 ) in area), and catchment areas up stream of the sites ranged from 0.4 4 to 2.01 km(2). A total of 487 fish were caught. The species were lon gfinned and shortfinned eels, banded kokopu, Cran's and redfinned bull ies, and common smelt. Eels were the most abundant fish in all three l and-use types, and shortfinned eels were more abundant at pastoral sit es (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. M ean fish densities were greater at pastoral sites (1.55 fish m(-2)) th an under either native forest (0.130 fish m(-2)) or exotic forest (0.2 29 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 fis h biomass at all sites than did shortfinned eels. Densities of crayfis h were high (0.46-5.40 crayfish m(-2)), but were not significantly dif ferent 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) year(-1)) than at forest sites (mean 2.39 g m(-2) year(-1)) .