New Zealand Journal of Marine and Freshwater Research abstracts
Land use, associated eel production, and abundance of fish
and crayfish in streams in Waikato, New Zealand
BRENDAN J. HICKS
HELEN M. C. McCAUGHAN
Department of Biological Sciences
University of Waikato
Private Bag 3105
Hamilton, New Zealand
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
year-1) than at forest sites (mean 2.39 g m-2
year-1).
Keywords eels; bullies; common smelt; density; biomass; land
use; native forest; exotic forest; pasture; streams; production
New Zealand Journal of Marine and Freshwater Research, 1997, Vol. 31:
635-650
0028-8330/97/3105-0635 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (1191K); (scanned from paper original: notes about this process)
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