title: Boat electrofishing survey of the lower Waikanae River, Ratanui Lagoon, and Lake Waitawa

authors: Hicks, Brendan J.

subjects: New Zealand

abstract: We conducted the first electrofishing boat survey of the lower Waikanae River, Ratanui Lagoon, and Lake Waitawa on 11-12 July 2006. We caught five introduced and five native fish species in 4.74 km of fished length from a total of nine sites. Assuming that the bow-mounted anodes caught fish within a 1-m radius, the width fished was 4 m, and the total area fished was 16,200 m² or 1.62 ha.
We landed a total of 125 fish comprising five introduced and five native fish species at the nine fished sites (Table 3). Shortfin eels were the most numerous species but are mostly not included in this total. We did not bring eels on board because of the handling time this involved, except for two sites 263 and 264 where densities were 1.19 fish 100 m⁻², which is moderate density of eels compared to previous boat electrofishing one-pass estimates, perch, tench, and rudd were found at most sites in Lake Waitawa. Goldfish had a much more restricted distribution, and were caught at only one site. Four adult brown trout were caught in the lower Waikanae River. Because of their large size, adult brown trout and tench comprised a significant part of the fish biomass where they occurred.
No koi carp were caught, probably because of a combination of low density and low water temperature. Water temperature at the time of fish (10.2-10.5 °C in Lake Waitawa) may have influenced the susceptibility to koi carp to electrofishing. Common carp are known to seek winter refuge in deep water at temperatures below 11°C. Electrofishing is limited to the upper 3 m of the water column and would be ineffective if koi carp, Cyprinus carpio) are also less active during periods of low water. Inactivity reduces the probability of encountering fish and lowers catch rates. The optimal period for sampling koi carp begins as the water warms in spring, when koi carp move into the littoral shallows to spawn and are therefore highly visible. Common carp in Australia begin to spawn when water temperatures reach 15°C and koi carp have been observed spawning in New Zealand in Lake Waikare as early as 11 September in a water temperature 15.3°C. However, it is encouraging that no small koi carp were caught because this is evidence that breeding is not occurring in Lake Waitawa or Ratanui Lagoon, where koi carp are known to occur (Ian Cooksley, DOC, pers. comm.).
Previous fishing with the electrofishing boat in the North Island, in similar conductivities and habitats and with similar machine settings, has caught a full size range of eels, smelt, bullies, grey mullet, rudd, brown bullhead catfish, perch, tench, goldfish, and koi carp. Thus we believe that these results reflect an accurate picture of fish abundance in the Waikanae area but we acknowledge that fishing in spring or summer in higher water temperatures is likely to increase the likelihood of catching koi carp.
This fish data have been entered into NIWA’s New Zealand Freshwater Fish Database as card numbers 15190 to 15198.

text: Boat electrofishing survey of the lower Waikanae River, Ratanui Lagoon, and Lake Waitawa We conducted the first electrofishing boat survey of the lower Waikanae River, Ratanui Lagoon, and Lake Waitawa on 11-12 July 2006. We caught five introduced and five native fish species in 4.74 km of fished length from a total of nine sites. Assuming that the bow-mounted anodes caught fish within a 1-m radius, the width fished was 4 m, and the total area fished was 16,200 m² or 1.62 ha.
We landed a total of 125 fish comprising five introduced and five native fish species at the nine fished sites (Table 3). Shortfin eels were the most numerous species but are mostly not included in this total. We did not bring eels on board because of the handling time this involved, except for two sites 263 and 264 where densities were 1.19 fish 100 m⁻², which is moderate density of eels compared to previous boat electrofishing one-pass estimates, perch, tench, and rudd were found at most sites in Lake Waitawa. Goldfish had a much more restricted distribution, and were caught at only one site. Four adult brown trout were caught in the lower Waikanae River. Because of their large size, adult brown trout and tench comprised a significant part of the fish biomass where they occurred.
No koi carp were caught, probably because of a combination of low density and low water temperature. Water temperature at the time of fish (10.2-10.5 °C in Lake Waitawa) may have influenced the susceptibility to koi carp to electrofishing. Common carp are known to seek winter refuge in deep water at temperatures below 11°C. Electrofishing is limited to the upper 3 m of the water column and would be ineffective if koi carp, Cyprinus carpio) are also less active during periods of low water. Inactivity reduces the probability of encountering fish and lowers catch rates. The optimal period for sampling koi carp begins as the water warms in spring, when koi carp move into the littoral shallows to spawn and are therefore highly visible. Common carp in Australia begin to spawn when water temperatures reach 15°C and koi carp have been observed spawning in New Zealand in Lake Waikare as early as 11 September in a water temperature 15.3°C. However, it is encouraging that no small koi carp were caught because this is evidence that breeding is not occurring in Lake Waitawa or Ratanui Lagoon, where koi carp are known to occur (Ian Cooksley, DOC, pers. comm.).
Previous fishing with the electrofishing boat in the North Island, in similar conductivities and habitats and with similar machine settings, has caught a full size range of eels, smelt, bullies, grey mullet, rudd, brown bullhead catfish, perch, tench, goldfish, and koi carp. Thus we believe that these results reflect an accurate picture of fish abundance in the Waikanae area but we acknowledge that fishing in spring or summer in higher water temperatures is likely to increase the likelihood of catching koi carp.
This fish data have been entered into NIWA’s New Zealand Freshwater Fish Database as card numbers 15190 to 15198.

year: 2006

title: Greenpeace, political purposes – “There and back again”; Reflections on New Zealand charity law

authors: Chevalier-Watts, Juliet

subjects: charity

abstract: The political purpose doctrine, a key part of the charity law landscape for many common law jurisdictions, has been subject to much judicial and academic criticism over the years. Its continued influence on the charity sector in relation to whether or not charities can operate effectively, or indeed, whether they may lose their registered status, gives rise still to such criticisms. It is against this backdrop that this article critically assesses the doctrine in light of newly-emerging decisions from the New Zealand courts that have fundamentally changed the charity law landscape from a national perspective, and considers some of the issues associated withthis newly-evolved doctrine. Thus, what can besaidisthatNewZealandcharity law jurisprudence is evolving and this article provides some useful insights in to contemporary charity law issues predominantly through the New Zealand lens as but one legal approach, and also compares some of these issues against two international perspectives.

text: Greenpeace, political purposes – “There and back again”; Reflections on New Zealand charity law The political purpose doctrine, a key part of the charity law landscape for many common law jurisdictions, has been subject to much judicial and academic criticism over the years. Its continued influence on the charity sector in relation to whether or not charities can operate effectively, or indeed, whether they may lose their registered status, gives rise still to such criticisms. It is against this backdrop that this article critically assesses the doctrine in light of newly-emerging decisions from the New Zealand courts that have fundamentally changed the charity law landscape from a national perspective, and considers some of the issues associated withthis newly-evolved doctrine. Thus, what can besaidisthatNewZealandcharity law jurisprudence is evolving and this article provides some useful insights in to contemporary charity law issues predominantly through the New Zealand lens as but one legal approach, and also compares some of these issues against two international perspectives.

year: 2022-12-21

title: Comparative fish abundance in the shallow Waikato lakes Whangape and Hakanoa

authors: Hicks, Brendan J.

abstract: The Waikato-Tainui College for Research and Development contracted the University of Waikato to conduct boat electrofishing estimates of the fish abundance in lakes Whangape and Hakanoa; both are shallow, riverine lakes in the lower Waikato River floodplain and are about 2,000 years old. Lake Whangape (latitude 37.46853°S, longitude 175.05120°W) is a large (1,450 ha), shallow (maximum depth 2.7 m) lake to the west of the Waikato River; Lake Hakanoa (latitude 37.55258°S, longitude 175.16859°W) is a 52-ha lake in suburban Huntly with a maximum depth of 2.5 m.
We fished 10 sites for 10 mins in both lakes Whangape and Lake Hakanoa; sites fished were 253-609 m long (1,012-2,436 m² in area) in Lake Whangape and 125-276 m long (500-1,104 m² in area) in Lake Hakanoa.
No submerged aquatic macrophytes were seen in either lake. Fishing was conducted close to the water's edge in Lake Hakanoa, but the shallow margins in Lake Whangape restricted fishing at most sites to 30-70 m from the shoreline. The shoreline was much more accessible in Lake Hakanoa, and was dominated by raupo (Typha orientalis) with willows (Salix spp.) in places. Submerged tree trunks and logs in Lake Hakanoa made navigation difficult in parts of the lake margins.
We caught a total of 118 fish in Lake Whangape, where shortfin eels (Anguilla australis) were the most abundant fish, and 594 fish in Lake Hakanoa, where gambusia (Gambusia affinis) the most abundant species. In Lake Whangape, shortfin eels comprised the greatest total biomass (12.4 kg), with koi carp (Cyprinus carpio) almost equally abundant (11.4 kg). In Lake Hakanoa, koi carp were most abundant (74.4 kg), followed by shortfin eels (22.1 kg).
Fish were unevenly spread among sites in Lake Whangape and koi carp were relatively sparsely among sites. In Lake Hakanoa, in contrast, fish were more evenly spread among sites, but with higher concentrations of catfish (Ameiurus nebulosus) and goldfish (Carassius auratus) at a few sites. Biomass of fish caught in each of the ten 10-min fishing shots reflected the numerical distributions, with some wide variations between sites. Fish densities were generally lower in Lake Whangape than in Lake Hakanoa; however, common smelt (Retropinna retropinna) and grey mullet (Mugil cephalus) occurred in Whangape but not in Hakanoa. Areal fish biomass was dominated by shortfin eels and koi carp in Lake Whangape, but koi carp dominated the fish biomass in Lake Hakanoa, despite the smaller number of carp than eels. This was because of the large mean weight of koi carp (about 1,000 g) compared to the smaller shortfin eels (mean weight about 200 g in both lakes).

text: Comparative fish abundance in the shallow Waikato lakes Whangape and Hakanoa The Waikato-Tainui College for Research and Development contracted the University of Waikato to conduct boat electrofishing estimates of the fish abundance in lakes Whangape and Hakanoa; both are shallow, riverine lakes in the lower Waikato River floodplain and are about 2,000 years old. Lake Whangape (latitude 37.46853°S, longitude 175.05120°W) is a large (1,450 ha), shallow (maximum depth 2.7 m) lake to the west of the Waikato River; Lake Hakanoa (latitude 37.55258°S, longitude 175.16859°W) is a 52-ha lake in suburban Huntly with a maximum depth of 2.5 m.
We fished 10 sites for 10 mins in both lakes Whangape and Lake Hakanoa; sites fished were 253-609 m long (1,012-2,436 m² in area) in Lake Whangape and 125-276 m long (500-1,104 m² in area) in Lake Hakanoa.
No submerged aquatic macrophytes were seen in either lake. Fishing was conducted close to the water's edge in Lake Hakanoa, but the shallow margins in Lake Whangape restricted fishing at most sites to 30-70 m from the shoreline. The shoreline was much more accessible in Lake Hakanoa, and was dominated by raupo (Typha orientalis) with willows (Salix spp.) in places. Submerged tree trunks and logs in Lake Hakanoa made navigation difficult in parts of the lake margins.
We caught a total of 118 fish in Lake Whangape, where shortfin eels (Anguilla australis) were the most abundant fish, and 594 fish in Lake Hakanoa, where gambusia (Gambusia affinis) the most abundant species. In Lake Whangape, shortfin eels comprised the greatest total biomass (12.4 kg), with koi carp (Cyprinus carpio) almost equally abundant (11.4 kg). In Lake Hakanoa, koi carp were most abundant (74.4 kg), followed by shortfin eels (22.1 kg).
Fish were unevenly spread among sites in Lake Whangape and koi carp were relatively sparsely among sites. In Lake Hakanoa, in contrast, fish were more evenly spread among sites, but with higher concentrations of catfish (Ameiurus nebulosus) and goldfish (Carassius auratus) at a few sites. Biomass of fish caught in each of the ten 10-min fishing shots reflected the numerical distributions, with some wide variations between sites. Fish densities were generally lower in Lake Whangape than in Lake Hakanoa; however, common smelt (Retropinna retropinna) and grey mullet (Mugil cephalus) occurred in Whangape but not in Hakanoa. Areal fish biomass was dominated by shortfin eels and koi carp in Lake Whangape, but koi carp dominated the fish biomass in Lake Hakanoa, despite the smaller number of carp than eels. This was because of the large mean weight of koi carp (about 1,000 g) compared to the smaller shortfin eels (mean weight about 200 g in both lakes).

year: 2016