108 results for Hicks, Brendan J., ResearchCommons@Waikato

  • Fishing activity in the Waikato and Waipa rivers

    Hicks, Brendan J.; Allan, Dave G.; Kilgour, Jonathan T.; Watene-Rawiri, Erina M.; Stichbury, Glen; Walsh, Cameron (2013)

    Report
    University of Waikato

    The purpose of this research project is to collate information regarding the recent use of fisheries resources in the Waikato River and Waipa River catchment areas. In particular, the project sought to summarise the commercial, customary, and recreational fishing activity in the catchments of the Waikato and Waipa rivers in the spatial context of recently introduced co-governance areas. These fisheries include, but are not exclusive to, the broad range of aquatic life managed under the Fisheries Act 1996. Such information is required to support management which includes a co-management framework. The research describes the commercial, customary and recreational fisheries including species and quantities taken, fishing methods, and seasonal influences.

    View record details
  • Preliminary analysis of boat electrofishing in the Waikato River in the vicinity of the Huntly Power Station: Part 1 - fishing on 2 September 2013

    Hicks, Brendan J.; Tempero, Grant Wayne (2013)

    Report
    University of Waikato

    This report gives a basic summary of the first sampling of a three-part monitoring project for Genesis Power Ltd (Genesis) that the University of Waikato is undertaking in close collaboration with National Institute of Water and Environmental Research Institute Atmosphere Ltd (NIWA), Hamilton, Boat electrofishing results will eventually be combined with netting undertaken by NIWA in a final report to Genesis. The boat electrofishing survey took place on 2 September, the objective of which was to undertake the first of three surveys to estimate fish distributions and abundances over key seasons: 1. Early spring 2013 (end August/early September) to target peak trout abundances and cyprinid distributions during cooler months of the year. 2. Summer 2014 (Jan/February) to capture peak summer abundances for target indigenous and exotic species. 3. Winter 2014 (June/July) to target mullet and cyprinid distributions during cooler months of the year. At the surveyed reach is about 80 km from the sea, and at this point the Waikato River is a 7th order river with at a bed elevation of about 19.1 m above sea level. The catchment area upstream is 12,188 km², and the river has a mean flow of 352.3 m³ s⁻¹ and a mean annual low flow of 123.5 m³ s⁻¹ (Freshwater Fish Database Assistant version 6.1, I.G. Jowett).

    View record details
  • Aquatic ecology of Lake Rotokare, Taranaki, and options for restoration

    Hicks, Brendan J.; Bell, Dudley G.; Duggan, Ian C.; Wood, Susanna A.; Tempero, Grant Wayne (2013)

    Report
    University of Waikato

    Lake Rotokare is a 17.8-ha natural lake in eastern Taranaki, located 12 km east of Eltham in the 230-ha Rotokare Scenic Reserve. In 2008, the Rotokare Scenic Reserve Trust completed construction of an 8.2-km predator proof fence around the reserve. Frequent algal blooms in summer have led to long periods of lake closure to boating and contact recreation. As there are few lakes in the Taranaki region, these closures are a nuisance to the local community. The objectives of this study were to quantitatively survey the fish community of the lake and to evaluate the lake water quality for the Rotokare Scenic Reserve Trust for the purpose of advising on options for lake restoration. Water quality has not deteriorated since 1976-1980, and, if anything, has improved. Secchi disc depth in 2013 (1.95 m) was very similar to measurements in summer 1980 (mean 1.93 m on 30 January 1980). Mean dissolved reactive phosphorus (± 95% confidence interval) was greater in 1976 (190±50 mg/m³) than mean phosphate concentration in 2013 (93±31 mg/m³, p < 0.05, Kolmogorov-Smirnov two-sample test). The thermocline was deeper in 2013 at 6-7 m compared to 3-4 m in 1977. This indicates that a much greater volume of the lake was oxygenated in February 2013 than in February 1977. Also, the intensity of stratification was less in 2013, as the dissolved oxygen concentration below the thermocline was 21027% compared to just 3% in 1977. This suggests that an improvement in water quality has occurred, probably as a result of stock exclusion. To sample the fish community, boat electrofishing was used at the total of six sites. The total length fished was 1,656 m, which was 6,624 m² in area. Eighty minutes of boat electrofishing caught 234 fish (217 perch, 16 shortfin eels, and 1 longfin eel). Fishing at night showed a 16-fold increase in the catch rate of perch (125 fish/10 min of fishing) compared to fishing during the day (8 fish/10 min of fishing). Perch dominate the fish community in Lake Rotokare and the biomass and density of eels are low, which is unusual for Taranaki water bodies. The mean density of perch was 4.49 fish/100 m², and the mean density for eels was 0.29 fish/100 m². The lower eel density may be a result of impaired access for eels or may be the result of predation by perch on migrant juvenile eels. There have been changes in the zooplankton community since 1980. The North American invader Daphnia galeata was not found in 1980, and appears to have now replaced the cladoceran Bosmina meridionalis and copepod Boeckella sp. We also found a diverse rotifer community.

    View record details
  • Boat electrofishing survey of the lower Waikanae River, Ratanui Lagoon, and Lake Waitawa

    Hicks, Brendan J.; Daniel, Adam Joshua; Bell, Dudley G. (2006)


    University of Waikato

    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.

    View record details
  • Remote sensing of water quality in the Rotorua lakes

    Allan, Mathew Grant; Hicks, Brendan J.; Brabyn, Lars (2007)

    Report
    University of Waikato

    The aim of this study was to determine empirical models between Landsat imagery and lake water quality variables (chlorophy11(ch1) a and Secchi depth) to enable water quality variables to be synoptically quantified. These models were then applied to past satellite images to determine temporal patterns in the spatial variation of water quality. Monitoring of lakes to determine temporal patterns in the spatial variation of water quality. Monitoring of lakes using traditional methods is expensive and lakes the ability to effectively monitor the spatial variability of water quality within and between lakes. Remote sensing can provide truly synoptic assessments of water quality, in particular the spatial distribution of phytoplankton. Recent studies monitoring lake water quality using Landsat series platforms have been successful in predicting water quality with a high accuracy. Analysis was carried out on two Landsat 7 Enhanced Thematic Mapper (ETM+) satellite images of the Rotorua lakes and Lake Taupo, for which most in situ observations were taken within two days of image capture. Regression equations were developed between the Band 1/Band 3 rations (B1/B3) from Landsat images from summer (25 Jan 2002) and spring (24 Oct 2002) and water quality variables measured in the lakes by Environment Bay of Plenty. For summer, the regression of in situ ch1 a concentration in µg/1 from ground data against the Band 1/Band 3 ratio (B1/B3) was Ln ch1 a = 14.141 – 5.0568 (B!/B3) (r² = 0.91, N=16, P<0.001). Ch1 a water quality maps were than produced using these models which were also applied to other images without in situ observations near the time of image capture.

    View record details
  • Boat electrofishing survey of five Waitakere City ponds

    Hicks, Brendan J.; Brijs, Jeroen; Bell, Dudley G.; Powrie, Warrick (2007)

    Report
    University of Waikato

    We conducted a fish survey of five ponds (Lake Panorama, Paremuka Pond 1 & 2, Danica Esplanade and Longbush Pond) in the Waitakere District by single-pass boat electrofishing on 18 and 19 of July 2007. We caught 337 fish comprising four introduced and two native fish species in 2.89 km of fished distance from all 5 ponds. Assuming that each of the two bow-mounted anodes caught fish within a 1 m radius, the width fished was 4 m, and the total area fished was 11,537 m² or 1.154 ha. The water temperature for the 5 different ponds ranged between 10.8°C and 14.9°C. In Lake Panorama, shortfinned eel (Anguilla australis) were the most numerous species caught (130 fish ha⁻¹ ), followed by perch (Perca fluviatilis) (100 fish ha⁻¹) and tench (Tinca tinca) (40 fish ha⁻¹). In Paremuka Pond 1, koi carp (Cyprinus carpio) were the most numerous species caught (120 fish ha⁻¹), followed by shortfinned eels (50 fish ha⁻¹). In Paremuka Pond 2, koi carp were again the most numerous species caught (340 fish ha⁻¹), followed by tench (250 fish ha⁻¹) and shortfinned eels (70 fish ha⁻¹). In Danica Esplanade and Longbush Pond, shortfinned eels were the most numerous species caught (140 and 550 fish ha⁻¹respectively), followed by mosquitofish (Gambusia affinis). There was more macrophyte cover around the edges of Danica Esplanade compared to Longbush Pond and this decreased the catch rate as a large number of eels in Danica Esplanade were sighted but were unable to be captured. Koi carp were only caught in the Paremuka ponds. The majority of koi carp were caught on the edges of the lake in macrophytes and rushes. Koi carp biomasses were highest in Paremuka Pond 2 at 261 kg ha⁻¹ compared to 106 kg ha⁻¹ in Paremuka Pond 1. Biomass is a more accurate reflection of the potential ecological impact of koi carp than their density. Previous results suggest that 21-73% of the total population is caught on the first removal, depending on water visibility. As we fished the area at each site only once, the estimates in this survey represent a minimum abundance, and true population sizes are likely to be 1.4-4.8 times greater. The density of eels in both the Paremuka ponds is also likely to be higher as a large proportion of eels were able to escape into the macrophytes before they could be captured in the nets. Mosquitofish were also observed to be living in both the Paremuka ponds. Of ecological concern for the Paremuka ponds is the dominance of the fish biomass by introduced koi carp, which have a deleterious impact on aquatic habitats. Another concern for these ponds is the presence of small koi carp (<200 mm), which suggests that natural spawning is most likely occurring, although recent releases of carp into the ponds in another possibility. The fate of the introduced fish varied depending on what species they were. Perch and tench were released back into the ponds after captures as they are classified as sports fish. Koi carp and mosquitofish are classified as unwanted organisms and were humanely destroyed with an anaesthetic overdose (benzocaine), and retained for further analysis.

    View record details
  • Boat electrofishing survey of common smelt and common bullies in the Ohau Channel

    Brijs, Jeroen; Hicks, Brendan J.; Bell, Dudley G. (2008)

    Report
    University of Waikato

    We conducted a boat electrofishing survey of the Ohau Channel, which flows from Lake Rotorua to Lake Rotoiti, on 13 December 2007. The purpose of the survey was to investigate the longitudinal pattern in densities of common smelt (Retropinna retropinna) and common bullies (Gobiomorphus cotidianus) along the Ohau Channel. We caught 1,267 fish comprising three native fish species and two introduced fish species in 1.58 km of fished distance at a total of 10 sites. Native species caught were the common smelt, common bully and longfinned eel (Anguilla dieffenbachii) and introduced species were rainbow trout (Oncorhynchus mykiss) and goldfish (Carassius auratus). Assuming that the bow-mounted anodes effectively fished a 4 m swath then the total area fished was 6,328 m2 (0.632 ha). Common smelt densities varied among the 10 different sites in the Ohau Channel ranging from 0 to 10.6 fish 100 m-2. Smelt density was higher at the upstream end of the channel near the weir at the Lake Rotorua outlet, decreasing with increasing distance from the weir. Smelt were found in the littoral zones but were not caught in mid-channel habitats. In the upstream reaches of the Ohau Channel, directly below the weir, a high number of juveniles (4.4 fish 100 m-2) were captured compared to the amount of juveniles captured at the other sites (0 – 1.2 fish 100 m-2). Common bully densities varied among the 10 different sites in the Ohau Channel ranging from 0.2 to 58.3 fish 100 m-2. No longitudinal pattern in the distribution of common bullies was evident along the channel. The highest densities were found halfway along the Ohau Channel where there was an abundance of dense macrophyte beds. Common bully densities were found to be much higher in the edge habitats with macrophyte beds compared to the mid-channel habitats and the willow edge habitat where there were relatively low densities. Size frequency data shows that there is generally a higher proportion of small bullies than larger ones suggesting that recruitment is occurring. Both adult and juvenile rainbow trout were observed in the Ohau Channel. Most of these individuals were found in the upstream section of the channel below the weir and ranged from a 75 mm juvenile to a fully grown adult about 500 mm long. Large longfinned eels were also captured and were only found in the downstream section of the Ohau Channel in willow-dominated edges. In the bottom third section of the channel, near the possible artificial embayment, goldfish were present.

    View record details
  • The use of boat electrofishing for koi carp (Cyprinus carpio) control in the Kauri Point catchment.

    Hicks, Brendan J.; Brijs, Jeroen; Heaphy, John; Bell, Dudley G. (2008)

    Report
    University of Waikato

    The koi carp is an ornamental strain of the common carp (Cyprinus carpio) which is believed to be one of the most ecologically detrimental of all freshwater invasive fish species. They are widespread in the Auckland and Waikato region and appear to be spreading both north and south of these areas. The presence of koi carp in 3 ornamental ponds at Kauri Point, Katikati which is located in the western Bay of Plenty region was confirmed in late 2006. Because koi carp is designated an unwanted organism under the Biosecurity Act it was decided by the Department of Conservation (DOC) that an attempt to eradicate them from this locality would occur. One possible option for eradication of koi carp in this catchment was the use of and electric fishing boat from the University of Waikato. This boat operates by putting a pulsed DC current into the water column where it attracts and then incapacitates fish, allowing operators to remove them from the water with hand nets. The Centre for Biodiversity and Ecology Research (CBER) at the University of Waikato was contracted to attempt to eradicate koi carp from the three ponds at Kauri Point by boat-electrofishing. The objectives were (1) to survey the fish abundance, (2) to remove as mand koi as possible in an attempt for eradication and (3) to estimate the proportion of koi carp removed from the system by boat-electrofishing. On 21 and 22 April 2008, a total of 327 fish comprising of 307 koi carp (137.5 kg of biomass), 1 goldfish(Carassius auratus) and 19 koi-goldfish hybrids were captured and removed from the 3 ponds located within the Kauri Point catchment by a combination of electric fishing (307 fish) and gill netting (20 fish). The majority of these fish (299 koi, 1 goldfish, 19 koi-goldfish hybrids) were removed from the largest pond (pond A). Boat-electrofishing caught a wide size range of koi (70 mm to 510 mm) and at least four distinct size classes of koi were apparent. The high proportion of juvenile (<200 mm) caught along with reasonable numbers of mature males and females in pond A strongly suggests that breeding is occurring within the Kauri Point aquatic ecosystem. Results from analysing scales of a small sub sample of koi (n=34) also shows that there was a wide range of ages of pond A (ages 1 to 8 years old). Pond A had a relatively high density of 4.6 koi carp 100 m⁻² compared to pond B and C which had low densities of 0.5 and 0.2 koi carp 100 m⁻² respectively. No juvenile carp were observed to be present in ponds B and C. Population and total biomass estimates for koi carp in pond A prior to removal of fish were calculated to be 358±66 koi carp and 145.14 ±44.27 kg (mean ±95% C. I) respectively. 299 koi carp or 122.30 kg of biomass (71-84% of the estimated population) were removed from pond A over two days of electric fishing, leaving a possible 125 koi carp or 67.11 kg of biomass remaining in the pond. Boat-electrofishing proved to be a successful too for removing a large proportion of the estimated biomass of koi carp in the Kauri Point ponds. Eradication of koi carp by boat-electrofishing from this system was not possible due to poor water visibility (difficult to spot narcotised carp), limited time allocated and successful koi carp breeding occurring in the ponds. Viable options of koi carp eradication in the Kauri Point catchment would involve the partial draining and poisoning of the three ponds and the associated tributaries where koi carp are found.

    View record details
  • Top down or bottom up? Feasibility of water clarity restoration in the lower Karori Reservoir by fish removal

    Hicks, Brendan J.; Hamilton, David P.; Ling, Nicholas; Wood, Susanna A. (2007)

    Report
    University of Waikato

    As part of an overall ecosystem assessment of lower Karori Reservoir Sabctuary, Wellington, a number of variables are being monitored routinely, including temperature, nutrients, and phytoplankton and zooplankton populations. Ammonium (NH₄) tends to be the dominant species of inorganic nitrogen most of the time except in late winter when nitrate (NO₃) becomes dominant. Total nitrogen concentrations place Karori Sancturay in a mesotrophic to eutrophic category.

    View record details
  • Boat electrofishing survey of Lake Rotokaeo, Hamiton

    Hicks, Brendan J.; Brijs, Jeroen; Bell, Dudley G. (2009)

    Report
    University of Waikato

    Lake Rotokaeo (Forest Lake) is a small (3.7 ha) lake set in suburban surroundings in the north-west of Hamilton city located at 37° 46.387’S and 175° 15.059’E. The lake is very shallow, with ~80% of its area <1.8 m water depth, depending on season. The bed is composed of soft sediments, and margins vary from grassed parkland to restored native wetlands and forest vegetation. On 12 December 2008, we conducted eleven 10-min fishing shots comprising nine shoreline shots and two mid-lake shots. The shallowness of the lake precluded fishing along the western shored of the lake. All introduced fish species were removed and humanely killed, whilst all native fish species were counted, measured for length and returned to the lake. Water temperature recorded at the start of fishing was 21.3°C, and electrical conductivity was 110 µS cm⁻¹ ambient and 118 µS cm⁻¹ specific. The water had a distinct brownish hue, indicating tannin staining, but there was no obvious suspended sediment. The black disc measurement (horizontal water clarity) was 0.55 m. Aquatic plants present in the lake included filamentous algae, water lily (Nymphaea sp.), and parrot’s feather (Myriophyllum aquaticum). Carex species and raupo (Typha orientalis) comprised the riparian and marginal vegetation.

    View record details
  • Boat electrofishing survey of common smelt and common bullies in the Ohau Channel in December 2008

    Brijs, Jeroen; Hicks, Brendan J.; Bell, Dudley G. (2009)

    Report
    University of Waikato

    We conducted a boat electrofishing survey of the Ohau Channel, which flows from Lake Rotorua to Lake Rotoiti, on 11 December 2008. The purpose of this was to repeat a survey that took place on 13 December 2007 concerning the longitudinal pattern in densities of common smelt (Retropinna retropinna) and common bully (Gobiomorphus cotidianus). We caught 776 fish comprising three native species and three introduced species in 2.03km of fished distance at a total of 10 sites. Native species caught were common smelt, common bully and longfin eel (Anguilla dieffenbachii) and introduced species were rainbow trout (Oncorhynchus mykiss), goldfish (Carassius auratus) and mosquitofish (Gambusia affinis). The total area fished was 8,133 m² (0.813 ha) giving an estimated density of 9.5 fish 100 m⁻².

    View record details
  • Boat electrofishing survey of the upper Turitea Reservoir, Palmerston North.

    Hicks, Brendan J.; Brijs, Jeroen; Bell, Dudley G.; Ling, Nicholas; Blair, Jennifer Marie; Powrie, Warrick (2009)

    Report
    University of Waikato

    The upper Turitea Reservoir is a 12-ha reservoir that supplies water to the city of Palmerston North (Figure 1). It was constructed in 1957 and is located in the foothills of the Tararua Ranges at 40.43208°S, 175,67669°E. The 2,300 hectare catchment area is comprised mainly of native forest with a small section of pine forest bordering the northern end of the reservoir. The reservoir is contained by a 39-m high concrete gravity arch dam.

    View record details
  • Pest fish survey of Hokowhitu (Centennial) Lagoon, Palmerston North

    Brijs, Jeroen; Hicks, Brendan J.; Ling, Nicholas; Bell, Dudley G. (2009)

    Report
    University of Waikato

    The koi carp is an ornamental strain of the common carp which is believed to be one of the most ecologically detrimental of all freshwater invasive fish species. Numerous “koi carp” sightings have been made by the public in the Holowhitu Lagoon, Palmerston North. Because koi carp is designated an unwanted organism under the Biosecurity Act, the Department of Conservation commissioned a survey be undertaken to determine whether koi carp were present in the lagoon. Due to the abundance of aquatic birds and the public nature of the lagoon, nets were unable to be set and thus the use of an electric fishing boat from the University of Waikato was required. This method provided a non-lethal, quantifiable, method of collecting freshwater fish species in a non-wadeable freshwater habitat. The boat operated by supplying a pulsed DC current into the water column where it attracts and then incapacitates fish, allowing operators to remove them from the water with hand nets.

    View record details
  • Abundance of mysid shrimp (Tenagomysis chiltoni) in shallow lakes in the Waikato region and implications for fish diet

    Brijs, Jeroen; Hicks, Brendan J.; Powrie, Warrick (2009)

    Report
    University of Waikato

    Tenagomysis chiltoni, a species of mysid shrimp, is widely distributed amongst the riverine lakes of the lower Waikato basin. They appear to thrive in turbid waters, with the greatest abundances found in lakes such as Waahi and Waikare, which have low Secchi transparencies and sparse aquatic macrophyte communities representing remnants of formerly dense beds (Kirk, 1983; Chapman el al., 1991). Maximum mysid abundances of 2,868 and 857 individuals m⁻² in Lake Waahi and Waikare respectively were recorded by Chapman et al. (1991) in March-April 1987. Anecdotal evidence suggests that mysid abundance in Lake Waikare is markedly reduced since the late 1980s (Gary Watson, Te Kauwhata, pers. comm.) with the arrival and proliferation of koi carp (Cyprinus carpio) presumed to be the cause. Koi carp arrived in Lake Waikare after 1987 and by 2007 it was estimated that over 80% of the fish biomass present in Lake Waikare was comprised of koi carp (Hicks, 2007). Sable isotope studies on carp (Matsuzaki et al., 2007) have shown that mysid shrimp can form a significant component of their diet. This suggests that mysid shrimp may be predated on by koi carp in the Waikato which has implications on mysid shrimp abundance as well as the abundance of native fish species which rely on mysid shrimp as a food source (Champman et al., 1991). The objective of this study was to measure mysid abundance in three shallow, turbid lakes in the lower Waikato basin (Lake Waikare, Whangape and Waahi) to compare with previous abundance estimates made in the late 1980s. A second objective was to determine whether mysid shrimp form a significant component of the diet of koi carp in the study sites by examining their stable isotope signatures.

    View record details
  • Ecological values of Hamilton urban streams (North Island, New Zealand): constraints and opportunities for restoration

    Collier, Kevin J.; Aldridge, Brenda Michelle Te Aroha; Hicks, Brendan J.; Kelly, Johlene; Macdonald, Amy; Smith, Brian J.; Tonkin, Jonathan D. (2009)

    Journal article
    University of Waikato

    Urban streams globally are characterised by degraded habitat conditions and low aquatic biodiversity, but are increasingly becoming the focus of restoration activities. We investigated habitat quality, ecological function, and fish and macroinvertebrate community composition of gully streams in Hamilton City, New Zealand, and compared these with a selection of periurban sites surrounded by rural land. A similar complement of fish species was found at urban and periurban sites, including two threatened species, with only one introduced fish widespread (Gambusia affinis). Stream macroinvertebrate community metrics indicated low ecological condition at most urban and periurban sites, but highlighted the presence of one high value urban site with a fauna dominated by sensitive taxa. Light-trapping around seepages in city gullies revealed the presence of several caddisfly species normally associated with native forest, suggesting that seepage habitats can provide important refugia for some aquatic insects in urban environments. Qualitative measures of stream habitat were not significantly different between urban and periurban sites, but urban streams had significantly lower hydraulic function and higher biogeochemical function than periurban streams. These functional differences are thought to reflect, respectively, (1) the combined effects of channel modification and stormwater hydrology, and (2) the influence of riparian vegetation providing shade and enhancing habitat in streams. Significant relationships between some macroinvertebrate community metrics and riparian vegetation buffering and bank protection suggest that riparian enhancement may have beneficial ecological outcomes in some urban streams. Other actions that may contribute to urban stream restoration goals include an integrated catchment approach to resolving fish passage issues, active reintroduction of wood to streams to enhance cover and habitat heterogeneity, and seeding of depauperate streams with native migratory fish to help initiate natural recolonisation.

    View record details
  • Acetylene reduction associated with Zostera novazelandica Setch. and Spartina alterniflora Loisel., in Whangateau Harbour, North Island, New Zealand

    Hicks, Brendan J.; Silvester, Warwick B.

    Journal article
    University of Waikato

    Nitrogen fixation (acetylene reduction) was investigated in Zostera novazelandica Setch. and Spartina alterniflora Loisel., in the North Island of New Zealand. Moderate rates of acetylene reduction were found in sediments in which plants were growing (means ± 95% confidence limit: 15.2 ± 2.8 |jmol C2H4 nrr2 h~l for Zostera and 24.7 ± 4.6 |amol C2H4 m~2 h"1 for Spartina). Activity was closely correlated with the dry weight of root; (r2 = 0.65, N = 15 for Zostera, and r2 = 0.85, A' =10 for Spartina). Sediment close to the plant beds, but without plants, exhibited only low rates of acetylene reduction (2.9 ± 2.2 and 4.5 ± l.OjLtmol C2H4 m~2 h"1, respectively). Sediments associated with Z. novazelandica and S. alterniflora in New Zealand exhibit moderate rates of nitrogenase activity compared to rates found in other countries. N fixation may contribute significantly to the nutrition of these plants in New Zealand estuaries.

    View record details
  • Acetylene reduction associated with zostera novazelandica Setch. and Spartina alterniflora Loisel., in Whangateau harbour, North Island, New Zealand

    Hicks, Brendan J.; Silvester, Warwick B. (1990)

    Journal article
    University of Waikato

    Nitrogen fixation (acetylene reduction) was investigated in Zostera novazelandica Setch. and Spartina alterniflora Loisel., in the North Island of New Zealand. Moderate rates of acetylene reduction were found in sediments in which plants were growing (means ± 95% confidence limit: 15.2 ± 2.8 |jmol C2H4 nrr2 h~l for Zostera and 24.7 ± 4.6 |amol C2H4 m~2 h"1 for Spartina). Activity was closely correlated with the dry weight of root; (r2 = 0.65, N = 15 for Zostera, and r2 = 0.85, A' =10 for Spartina). Sediment close to the plant beds, but without plants, exhibited only low rates of acetylene reduction (2.9 ± 2.2 and 4.5 ± l.OjLtmol C2H4 m~2 h"1, respectively). Sediments associated with Z. novazelandica and S. alterniflora in New Zealand exhibit moderate rates of nitrogenase activity compared to rates found in other countries. N fixation may contribute significantly to the nutrition of these plants in New Zealand estuaries.

    View record details
  • Estimating the abundance of banded kokopu (galaxias fasciatus gray) in small streams by nocturnal counts under spotlight illumination

    Hicks, Brendan J. (2002)

    Journal article
    University of Waikato

    The abundance of banded kokopu (Galaxias fasciatus Gray) in small streams has usually been determined by the labour intensive and invasive method of electric fishing. Recently, nocturnal counts under spotlight illumination have been used to determine presence or absence and relative abundance of banded kokopu, but the proportion of the population seen was unknown. We compared 20 spotlight counts of banded kokopu in approximately 20 m reaches in streams in the North Island, New Zealand, to population estimates determined by removal electric fishing in the same reaches. Spotlight counts were related to population estimates over a range of densities, and on average, spotlight counts were 64% of the population estimates. Though we tried to separate age-0 fish from older fish visually in the spotlight counts, the size frequency distribution of the fish caught by electric fishing showed that the visual separation was not reliable. In addition, visual counts were generally inefficient for age-0 fish (40-70 mm total length), as only about 40% were observed. Banded kokopu were also recorded in streams using time-lapse video recordings with a camera sensitive to low light levels. Diel activity showed two major peaks, one in the early morning from 0400 h to 0900 h, and the other in the afternoon and evening from 1300 h to 1900 h. Fish were less disturbed by the observer.s approach after dark than during the day, so we suggest that from dusk to about 2200 h is the best time for visual counts of banded kokopu by spotlight in summer months.

    View record details
  • Boat electrofishing survey of Lake Ngaroto

    Hicks, Brendan J.; Brijs, Jeroen (2009-10)

    Report
    University of Waikato

    Lake Ngaroto, a 130-ha hypertrophic lake located near Te Awamutu, has previously been found to contain a diverse fish fauna of both native and introduced fish. Native fish in the lake are common bullies (Gobiomorphus cotidianus), shortfin eels (Anguilla australis), longfin eels (Anguilla dieffenbachii) and common smelt (Retropinna retropinna). Introduced species include goldfish (Carassius auratus), brown bullhead catfish (Ameiurus nebulosus), rudd (Scardinius erythrophthalmus), gambusia (Gambusia affinis) and koi carp (Cyprinus carpio), with some koi carp/goldfish hybrids. As part of the ongoing research of the invasive fish research programme, run by the Centre for Biodiversity and Ecology Research (CBER), current baseline values for species abundance and indigenous biodiversity need to be established for at least 5 Waikato lakes over 5 ha in size, with Lake Ngaroto selected as a candidate.

    View record details
  • Assessing movement of rainbow trout and common smelt between Lake Rotoiti and Lake Rotorua using otolith chemical signatures: A summary of work so far

    Blair, Jennifer Marie; Hicks, Brendan J. (2009-07)

    Report
    University of Waikato

    This study used otolith microchemistry to investigate movement of common smelt and rainbow trout between Lake Rotorua and Lake Rotoiti. Rainbow trout were collected from Lake Rotoiti, Lake Rotorua and the Ohau Channel, and smelt were collected from several locations in Lake Rotoiti and Lake Rotorua.

    View record details