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Table 2: fish density approximation

Species Technique Date/Location Fish no./area fished Density(fish/m2)
Koaro Electric fishing
(1 pass)
27/05/04, Gorge lower 1 km 5/130 0.039
Koaro Electric fishing
(1 pass)
10/06/03, Above dam 31/240 0.13
LF eel Electric fishing
(1 Pass)
27/05/04, Gorge lower 1 km 5/130 0.039
LF eel Electric fishing
(1 Pass)
10/06/03, Above dam 11/240 0.045
Shortjaw K Spotlighting 27/05/04 Below gorge outlet 4/1600 0.0025
Shortjaw K Spotlighting 2001 – GB/NthWest Nelson
SJK survey (D.O.C.)
Mean density of 34 sjk stms 0.0048

Invertebrate densities, expressed in number of animals per square metre, showed a similar
density pattern to koaro density differences (Appendix 2). The average number of animals per
square metre in samples taken above the gorge on 09/07/04 equals 1774 animals. This
compares to an average of 381 animals per square metre in the top of the gorge, downstream
of the dam, from samples taken on the same date. Earlier samples taken on 27/05/04, in the
lower end of the gorge (sites 1 & 2), have an average density of 353 animals per square metre.


While not the specific focus of this assessment, a blue duck was noted in the main-stem
Parapara River around 300 metres below the Glen Gyle confluence. One suspected blue duck
feather was also located around 1 km above the gorge outlet.

Discussion

At time of survey, the Parapara River had a moderate flow having just dropped from a recent
winter rainfall event. The Glen Gyle Stream had been subject to a very high intensity
localised rainfall event in January 2004, and severe erosion had occurred within this tributary.
As a result, very little instream fish cover or invertebrate food production existed within this
tributary, as gravel/cobble interstices had all been in-filled. There was only one pool within
the lower 200 metres which had retained fish cover, in the form of an undercut bank, and it
was within this pool that two shortjaw kokopu were captured in a fyke net. Very few
invertebrates were observed, although kick net sample results show the presence of some
species (Appendix 2). The stream should slowly recover from this natural event after a period
of years and pools/fish cover should slowly reform, along with increased invertebrate recolonisation.

The native fish assemblage within the Parapara River Gorge and the intermediate gradient
section of the river immediately below the gorge outlet, was a typical representation of


Fish & Game New Zealand
Nelson Marlborough Region Sports Fish and Game Bird Management ...p19

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