title: Boat electrofishing survey of the lower Waikato River and its tributaries

authors: Hicks, Brendan J.

subjects: New Zealand

abstract: We conducted the first electrofishing boat survey of the lower Waikato River and its tributaries between 8 and 15 February 2005. We caught 2,915 fish comprising seven introduced and six native fish species in 5.63 km of fished length from a total of 27 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 22,520 m² or 2.252 ha.
Common smelt were the most numerous species caught (mean density 9.3 fish 100 m⁻²), followed by koi carp (mean density 1.7 fish 100 m⁻²) and goldfish (mean density 1.4 fish 100 m⁻²). Relatively few longfin eels, trout, bullies, and torrentfish were caught. In addition, three koi carp-goldfish hybrids were caught.

Koi carp comprised 285 kg, or 69% (range 0-97% per site) of the 410 kg of fish caught. The majority of koi carp were caught in Zones 2-4, where they occurred in all habitats except mid-channel sand bars. Koi carp biomasses up to 124 g m⁻² were associated with willow fringed and macrophyte beds. Biomass is more accurate reflection of the potential ecological impact of koi carp than their density. 

Adult trout were found only in the confluence habitats of Zone 1; all were brown trout except for one rainbow trout caught at LW007. Grey mullet comprised the greatest biomass of any native fish species, and shortfin eels, through widespread, did not comprise a high biomass. Only one torrentfish was found; this small juvenile (36 mm TL) was caught on a mid-channel bar at Mercer (site LW035).

Koi carp size increased with distance downstream, suggesting that the upper zones were more important for rearing than the lower river. The mean biomass for koi carp for all sites was 16 g m⁻², but previous results suggest that 21-73% of the total population estimate is caught on the first removal, depending on water visibility. As we fished over 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. Of ecological concern for the Waikato region is the dominance of the fish biomass by introduced koi carp, which have a deleterious impace on aquatic habitats.

The fish data have been entered into NIWA’s New Zealand Freshwater Fish Database as card numbers 25,836 to 25,862.

text: Boat electrofishing survey of the lower Waikato River and its tributaries We conducted the first electrofishing boat survey of the lower Waikato River and its tributaries between 8 and 15 February 2005. We caught 2,915 fish comprising seven introduced and six native fish species in 5.63 km of fished length from a total of 27 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 22,520 m² or 2.252 ha.
Common smelt were the most numerous species caught (mean density 9.3 fish 100 m⁻²), followed by koi carp (mean density 1.7 fish 100 m⁻²) and goldfish (mean density 1.4 fish 100 m⁻²). Relatively few longfin eels, trout, bullies, and torrentfish were caught. In addition, three koi carp-goldfish hybrids were caught.

Koi carp comprised 285 kg, or 69% (range 0-97% per site) of the 410 kg of fish caught. The majority of koi carp were caught in Zones 2-4, where they occurred in all habitats except mid-channel sand bars. Koi carp biomasses up to 124 g m⁻² were associated with willow fringed and macrophyte beds. Biomass is more accurate reflection of the potential ecological impact of koi carp than their density. 

Adult trout were found only in the confluence habitats of Zone 1; all were brown trout except for one rainbow trout caught at LW007. Grey mullet comprised the greatest biomass of any native fish species, and shortfin eels, through widespread, did not comprise a high biomass. Only one torrentfish was found; this small juvenile (36 mm TL) was caught on a mid-channel bar at Mercer (site LW035).

Koi carp size increased with distance downstream, suggesting that the upper zones were more important for rearing than the lower river. The mean biomass for koi carp for all sites was 16 g m⁻², but previous results suggest that 21-73% of the total population estimate is caught on the first removal, depending on water visibility. As we fished over 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. Of ecological concern for the Waikato region is the dominance of the fish biomass by introduced koi carp, which have a deleterious impace on aquatic habitats.

The fish data have been entered into NIWA’s New Zealand Freshwater Fish Database as card numbers 25,836 to 25,862.

year: 2005

title: Testing broadcast seeding methods to restore urban forests in the presence of seed predators

authors: Overdyck, Elizabeth

subjects: avian seed dispersal

abstract: Forest restoration in urban areas often occurs in isolation from remnant forest, limiting the chances for recolonization by native species. Plants with bird-dispersed seeds can be particularly vulnerable to dispersal limitation and regeneration can be further impeded by non-native seed predators. We used a factorial experiment to investigate broadcast seeding as a method to reintroduce trees with large seeds and fleshy fruits into early successional forests. We assessed rates of seed and fruit loss, germination and seedling establishment in three seed treatments: (1) caging to exclude introduced mammalian seed predators; (2) removal of fleshy fruit pericarp; and (3) placing seeds in nutritionally enriched clay balls. Across all species (Beilschmiedia tawa, Elaeocarpus dentatus, and Litsea calicaris) seeds and fruits accessible to mammalian predators suffered significantly greater loss (58%) than those protected by cages (4%). However, seed and fruit loss in the presence of predators was reduced to only 35% across all species by the treatment combining the removal of fruit flesh and clay ball application to seeds. Establishment of B. tawa seedlings after 1 year was significantly enhanced by the clay ball treatment (12% of seeds sown vs. 6% without clay balls). Very low establishment rates were recorded for E. dentatus and L. calicaris. Broadcast seeding was found to be a viable method of improving regeneration of large-seeded late successional trees and may be a cost-effective alternative to planting saplings. Seedling establishment can be improved with fruit flesh removal and clay ball treatments, especially in the presence of mammalian seed predators.

text: Testing broadcast seeding methods to restore urban forests in the presence of seed predators Forest restoration in urban areas often occurs in isolation from remnant forest, limiting the chances for recolonization by native species. Plants with bird-dispersed seeds can be particularly vulnerable to dispersal limitation and regeneration can be further impeded by non-native seed predators. We used a factorial experiment to investigate broadcast seeding as a method to reintroduce trees with large seeds and fleshy fruits into early successional forests. We assessed rates of seed and fruit loss, germination and seedling establishment in three seed treatments: (1) caging to exclude introduced mammalian seed predators; (2) removal of fleshy fruit pericarp; and (3) placing seeds in nutritionally enriched clay balls. Across all species (Beilschmiedia tawa, Elaeocarpus dentatus, and Litsea calicaris) seeds and fruits accessible to mammalian predators suffered significantly greater loss (58%) than those protected by cages (4%). However, seed and fruit loss in the presence of predators was reduced to only 35% across all species by the treatment combining the removal of fruit flesh and clay ball application to seeds. Establishment of B. tawa seedlings after 1 year was significantly enhanced by the clay ball treatment (12% of seeds sown vs. 6% without clay balls). Very low establishment rates were recorded for E. dentatus and L. calicaris. Broadcast seeding was found to be a viable method of improving regeneration of large-seeded late successional trees and may be a cost-effective alternative to planting saplings. Seedling establishment can be improved with fruit flesh removal and clay ball treatments, especially in the presence of mammalian seed predators.

year: 2013

title: Ngā ia nōnoke taketake

authors: Manuirirangi, Hōri

subjects: whātōtō nōnoke mamau

abstract: Tā tēnei tuhinga, he titiro ki ngā kōrero onamata mō ngā mahi nōnoke a te Māori. I mua, whāia ai te nōnoke e ētehi hapori Māori hei koringa tinana, hei tū hākinakina, hei tākaro hoki. Ko te nōnoke, te whātōtō, te taitai me te mamau, he rite katoa. Nō te kuhutanga mai o ngā tini whakaawenga a tauiwi, ka nui hoki te Māori i tahuri ki hākinakina kē. Nāwhai ā ka mimiti te whāia o te nōnoke. Kei tēnei tuhinga, ka āta wetekina ngā kupu me ngā kōrero o te reo nōnoke o mua, arā ngā tohutohu a ngā pāhake e whakaahua ana i ngā tūmomo neke, i ngā whiu me ngā puringa mahia ai e te kaiwhātōtō. Ka arohaehaetia tēnei mea te karakia, te waiata me te pepeha kia kuhuna ai te hinengaro o te kaiwhātōtō e mārama rawa ai te ia o ōna whakaaro, tōna waiaro me tōna whanonga. Waihoki ko ngā pūrākau o mua, kua whakaemia ētehi tauira kia tīroua ngā karere i whaona ki roto. Ko te tino whāinga, ko te whera i ngā rangahau nei kia āta mōhio ki ngā koronga me ngā horopaki whāia ai e te Māori o mua ngā mahi nōnoke.

text: Ngā ia nōnoke taketake Tā tēnei tuhinga, he titiro ki ngā kōrero onamata mō ngā mahi nōnoke a te Māori. I mua, whāia ai te nōnoke e ētehi hapori Māori hei koringa tinana, hei tū hākinakina, hei tākaro hoki. Ko te nōnoke, te whātōtō, te taitai me te mamau, he rite katoa. Nō te kuhutanga mai o ngā tini whakaawenga a tauiwi, ka nui hoki te Māori i tahuri ki hākinakina kē. Nāwhai ā ka mimiti te whāia o te nōnoke. Kei tēnei tuhinga, ka āta wetekina ngā kupu me ngā kōrero o te reo nōnoke o mua, arā ngā tohutohu a ngā pāhake e whakaahua ana i ngā tūmomo neke, i ngā whiu me ngā puringa mahia ai e te kaiwhātōtō. Ka arohaehaetia tēnei mea te karakia, te waiata me te pepeha kia kuhuna ai te hinengaro o te kaiwhātōtō e mārama rawa ai te ia o ōna whakaaro, tōna waiaro me tōna whanonga. Waihoki ko ngā pūrākau o mua, kua whakaemia ētehi tauira kia tīroua ngā karere i whaona ki roto. Ko te tino whāinga, ko te whera i ngā rangahau nei kia āta mōhio ki ngā koronga me ngā horopaki whāia ai e te Māori o mua ngā mahi nōnoke.

year: 2017