title: Fish exclosures versus intensive fishing to restore charophytes in a shallow New Zealand lake

authors: Dugdale, Tony M.

subjects: submerged vegetation

abstract: 1. Disturbance by alien, herbivorous and benthivorous fish species has previously been found to limit the colonization of native charophytes in Lake Rotoroa, Hamilton. This paper compares two methods to reduce the impact of fish on charophyte establishment in this water body. 
2. A 1 ha compartment of the lake was partitioned off and intensively fished by conventional netting methods. A total of 5115 fish, total weight 451 kg, was removed from the compartment over 17 months. Allowing for growth and reproduction within the sampling period, intensive netting reduced the original fish biomass by 86% from about 200 to 28 kg ha-1. 
3. Catfish (Ameiurus nebulosus Le Sueur) comprised 74% of the fish numbers and 57% of the fish biomass. Perch (Perca fluviatilis L.), shortfinned eel (Anguilla australis Richardson), rudd (Scardinius erythrophthalmus L.), tench (Tinca tinca L.), and goldfish (Carassius auratus L.) were present, in order of reducing abundance. These species are alien to New Zealand, with the exception of shortfinned eel. 
4. Charophytes were transplanted inside and outside of the fished 1 ha compartment and their subsequent survival and establishment was monitored. Despite the extensive fish removal from the 1 ha compartment, repeat transplants inside it did not establish in the long term. 
5. Outside of the 1 ha compartment, charophytes were also transplanted into nine 6.25-m2 fish exclosures with netting sides to establish founder colonies of charophytes. Within these small exclosures, charophytes established (75% cover) within 1 yr; when five of the exclosures were removed, these unprotected plants survived and expanded over the next year. 
6. This study shows that small exclosures can be used to establish founder colonies of charophytes in the presence of herbivorous and benthivorous fish, and that intensive fish removal is likely to be a less successful and more costly method to restore charophytes in lakes.

text: Fish exclosures versus intensive fishing to restore charophytes in a shallow New Zealand lake 1. Disturbance by alien, herbivorous and benthivorous fish species has previously been found to limit the colonization of native charophytes in Lake Rotoroa, Hamilton. This paper compares two methods to reduce the impact of fish on charophyte establishment in this water body. 
2. A 1 ha compartment of the lake was partitioned off and intensively fished by conventional netting methods. A total of 5115 fish, total weight 451 kg, was removed from the compartment over 17 months. Allowing for growth and reproduction within the sampling period, intensive netting reduced the original fish biomass by 86% from about 200 to 28 kg ha-1. 
3. Catfish (Ameiurus nebulosus Le Sueur) comprised 74% of the fish numbers and 57% of the fish biomass. Perch (Perca fluviatilis L.), shortfinned eel (Anguilla australis Richardson), rudd (Scardinius erythrophthalmus L.), tench (Tinca tinca L.), and goldfish (Carassius auratus L.) were present, in order of reducing abundance. These species are alien to New Zealand, with the exception of shortfinned eel. 
4. Charophytes were transplanted inside and outside of the fished 1 ha compartment and their subsequent survival and establishment was monitored. Despite the extensive fish removal from the 1 ha compartment, repeat transplants inside it did not establish in the long term. 
5. Outside of the 1 ha compartment, charophytes were also transplanted into nine 6.25-m2 fish exclosures with netting sides to establish founder colonies of charophytes. Within these small exclosures, charophytes established (75% cover) within 1 yr; when five of the exclosures were removed, these unprotected plants survived and expanded over the next year. 
6. This study shows that small exclosures can be used to establish founder colonies of charophytes in the presence of herbivorous and benthivorous fish, and that intensive fish removal is likely to be a less successful and more costly method to restore charophytes in lakes.

year: 2006

title: The hydrodynamics of the southern basin of Tauranga Harbour

authors: Tay, H.W.

subjects: hydrodynamic model

abstract: The circulation of the southern basin of Tauranga Harbour was simulated using a 3-D hydrodynamic model ELCOM. A 9-day field campaign in 1999 provided data on current velocity, temperature and salinity profiles at three stations within the main basin. The tidal wave changed most in amplitude and speed in the constricted entrances to channels, for example the M2 tide attenuated by 10% over 500 m at the main entrance, and only an additional 17% over the 15 km to the top of the southern basin. The modelled temperature was sensitive to wind mixing, particularly in tidal flat regions. Residence times ranged from 3 to 8 days, with higher residence times occurring in sub-estuaries with constricted mouths. The typical annual storm events were predicted to reduce the residence times by 24%–39% depending on season. Model scenarios of storm discharge events in the Wairoa River varying from 41.69 m3/s to 175.9 m3/s show that these events can cause salinity gradients across the harbour of up to 4 PSU.

text: The hydrodynamics of the southern basin of Tauranga Harbour The circulation of the southern basin of Tauranga Harbour was simulated using a 3-D hydrodynamic model ELCOM. A 9-day field campaign in 1999 provided data on current velocity, temperature and salinity profiles at three stations within the main basin. The tidal wave changed most in amplitude and speed in the constricted entrances to channels, for example the M2 tide attenuated by 10% over 500 m at the main entrance, and only an additional 17% over the 15 km to the top of the southern basin. The modelled temperature was sensitive to wind mixing, particularly in tidal flat regions. Residence times ranged from 3 to 8 days, with higher residence times occurring in sub-estuaries with constricted mouths. The typical annual storm events were predicted to reduce the residence times by 24%–39% depending on season. Model scenarios of storm discharge events in the Wairoa River varying from 41.69 m3/s to 175.9 m3/s show that these events can cause salinity gradients across the harbour of up to 4 PSU.

year: 2013

title: Te mōhiotangaora: Within the knowing healing begins

authors: Witehira, Tracey Moana

abstract: This thesis investigates the intersection of the colonized self and the Māori self, examining how these dual identities coexist within the same physical, mental, and spiritual space. Grounded in Māori ontology and wellness (Durie, 1998), the study uses an interdisciplinary approach that combines academic analysis, creative writing, pūrākau  (Lee, 2009), journal reflections, and artistic practice to explore two distinct ways of knowing that operate within this duality.
In this academic study, the colonized self is defined as a Māori woman shaped and constrained by the effects of colonization (Gemmell, 2013: Mikaere, 2003). Conversely, the Māori self represents the awakened Wahine Māori who has embraced mātauranga  Māori. She actively learns, embodies, practices, and lives Māori values and traditions as part of her everyday life. However, the Wahine Māori is not entirely free from the ongoing impacts of colonization, given the long history of conflict between Māori and European peoples in Aotearoa.  The colonization of New Zealand, marked by the signing of the Treaty of Waitangi in 1840, resulted in the systematic loss of cultural markers central to Māori identity (Jackson, 1998, 1995; Walker, 1990). Furthermore, government policies have contributed to the marginalization of Māori culture in areas such as family, education, religion, and loss of language (Pihama, 2001; Smith, 1999).
Through this creative practice research, the practice of raranga whatu is explored using both traditional and contemporary techniques, contributing to the development of mātauranga Māori art forms (Campbell, 2019; Smith, 2019). This study examines how the process of weaving supports one woman’s journey of reclaiming and empowering her Indigenous identity. Whatu raranga serves as a transformative practice, embodying the duality of the self within a uniquely Māori space of being. Within a Kaupapa Māori framework, the process of restoring cultural connections has supported the reawakening of Mana Wahine identity and the reclamation of Māori spaces, as recognized and embodied by kairaranga  (Campbell, 2019; Pere, 1991; H. Smith, 2019; Yates-Smith, 1980).

text: Te mōhiotangaora: Within the knowing healing begins This thesis investigates the intersection of the colonized self and the Māori self, examining how these dual identities coexist within the same physical, mental, and spiritual space. Grounded in Māori ontology and wellness (Durie, 1998), the study uses an interdisciplinary approach that combines academic analysis, creative writing, pūrākau  (Lee, 2009), journal reflections, and artistic practice to explore two distinct ways of knowing that operate within this duality.
In this academic study, the colonized self is defined as a Māori woman shaped and constrained by the effects of colonization (Gemmell, 2013: Mikaere, 2003). Conversely, the Māori self represents the awakened Wahine Māori who has embraced mātauranga  Māori. She actively learns, embodies, practices, and lives Māori values and traditions as part of her everyday life. However, the Wahine Māori is not entirely free from the ongoing impacts of colonization, given the long history of conflict between Māori and European peoples in Aotearoa.  The colonization of New Zealand, marked by the signing of the Treaty of Waitangi in 1840, resulted in the systematic loss of cultural markers central to Māori identity (Jackson, 1998, 1995; Walker, 1990). Furthermore, government policies have contributed to the marginalization of Māori culture in areas such as family, education, religion, and loss of language (Pihama, 2001; Smith, 1999).
Through this creative practice research, the practice of raranga whatu is explored using both traditional and contemporary techniques, contributing to the development of mātauranga Māori art forms (Campbell, 2019; Smith, 2019). This study examines how the process of weaving supports one woman’s journey of reclaiming and empowering her Indigenous identity. Whatu raranga serves as a transformative practice, embodying the duality of the self within a uniquely Māori space of being. Within a Kaupapa Māori framework, the process of restoring cultural connections has supported the reawakening of Mana Wahine identity and the reclamation of Māori spaces, as recognized and embodied by kairaranga  (Campbell, 2019; Pere, 1991; H. Smith, 2019; Yates-Smith, 1980).

year: 2025-01