title: Waitangi Soda Springs alum dosing – bioavailability of aluminium 2015

authors: Ling, Nicholas

abstract: Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2010 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected in November 2015 to determine the bioavailability and bioaccumulation of aluminium to satisfy annual resource consent conditions 11.7 and 11.8 of resource consent 65966. Comparative analyses were undertaken on goldfish collected from Lake Rotorua and compared to values obtained from goldfish and kōura collected from Lakes Rotoehu, Rotorua and Rotoiti in 2013. Lake Rotoehu kōura and goldfish showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium as a result of alum discharge from the Waitangi Soda Springs but little evidence for significant bioaccumulation in tissues.

text: Waitangi Soda Springs alum dosing – bioavailability of aluminium 2015 Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2010 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected in November 2015 to determine the bioavailability and bioaccumulation of aluminium to satisfy annual resource consent conditions 11.7 and 11.8 of resource consent 65966. Comparative analyses were undertaken on goldfish collected from Lake Rotorua and compared to values obtained from goldfish and kōura collected from Lakes Rotoehu, Rotorua and Rotoiti in 2013. Lake Rotoehu kōura and goldfish showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium as a result of alum discharge from the Waitangi Soda Springs but little evidence for significant bioaccumulation in tissues.

year: 2016

title: Smelt (Retropinna retropinna) population dynamics and predation by rainbow trout (Salmo gairdneri) in Lake Taupo

authors: Stephens, R.T. Theo

abstract: This study examines smelt (Retropinna retropinna) population biology in Lake Taupo, New Zealand, and describes the development of a model which simulated their population dynamics and interactions with rainbow trout (Salmo gairdneri), their principal predator. The model was used to predict the effects of variation in habitat features on smelt population processes and on their consumption by trout. Implications for fisheries management are discussed.
The smelt population was comprised of three year classes. The juvenile 0+ year class occupied only the pelagic zone and fed exclusively on plankton whilst the adult 1+ year class also occupied the littoral zone and insects present there were included in their diet. A few smelt either failed to spawn at two years old or survived spawning. These grew rapidly, fed on larval bullies (Gobiomophus cotidianus) and spawned in late winter. Juvenile smelt reached 28-34mm FL after one year, 40-55mm FL after two years and 60-110mm FL when nearly 3 years old. Growth occurred all year but was most rapid between May and November.
Spawning commenced in October when adults first became abundant in the littoral zone and continued until April. Females often recovered and spawned a second time, 6 - 8 weeks after the first spawning. Males were sexually active for an extended period. Eggs were scattered over sandy areas along beaches in water less than 3.0m deep and in the lower reaches of tributary streams where water currents were sufficient to prevent formation of algal mats and deposition of silt or detritus. Egg mortalities were correlated with water temperature but not with their density, which reached 5000m⁻² off Waihaha Beach and 40,000⁻² in the Waihora and Whanganui streams. Habitat perturbations caused by extreme weather conditions were thought to cause the most serious egg mortalities. Starvation was probably the principal source of larval mortality as there was little predation on 0+ smelt. Larger (730mm) 1+ smelt were the most important item in the diet of rainbow trout, comprising over 80% by volume of items eaten. Trout tended to select the larger smelt available and the intensity of selection was correlated with measures of smelt abundance. Trout generally gathered in places where 1+ smelt densities were high.
Smelt population dynamics were simulated using length and density dependent models for movements between habitat zones, feeding, growth or starvation, breeding and predatory mortality. The form of simulated length frequency distributions largely determined the rates of these processes and was itself modified by the operation of each process. Modal groups occurred at lengths where food intake was equivalent to metabolic maintenance requirements and this was controlled by the interaction of diet breadth, the size structure and quantity of the food resource and the number of fishes sharing the same food particle size range. Growth of modal groups was controlled both by the duration of the spawning season and by seasonality in food resource quantity and size structure. Pelagic productivity and the ratio of littoral to pelagic habitat area were the most influential habitat features controlling smelt densities while densities of medium sized (30-55mm) smelt and water clarity were the most important factors controlling simulated quantities of smelt eaten by individual trout. Trout predation exerted little influence on simulated smelt population dynamics and consequently, the quantity eaten by individual trout was little affected by trout density. This result and comparison with trout stocking rates used in Canada suggest that a 1 - 2 order of magnitude increase in numbers of trout released annually into the larger Rotorua lakes would not significantly reduce their growth rates.

text: Smelt (Retropinna retropinna) population dynamics and predation by rainbow trout (Salmo gairdneri) in Lake Taupo This study examines smelt (Retropinna retropinna) population biology in Lake Taupo, New Zealand, and describes the development of a model which simulated their population dynamics and interactions with rainbow trout (Salmo gairdneri), their principal predator. The model was used to predict the effects of variation in habitat features on smelt population processes and on their consumption by trout. Implications for fisheries management are discussed.
The smelt population was comprised of three year classes. The juvenile 0+ year class occupied only the pelagic zone and fed exclusively on plankton whilst the adult 1+ year class also occupied the littoral zone and insects present there were included in their diet. A few smelt either failed to spawn at two years old or survived spawning. These grew rapidly, fed on larval bullies (Gobiomophus cotidianus) and spawned in late winter. Juvenile smelt reached 28-34mm FL after one year, 40-55mm FL after two years and 60-110mm FL when nearly 3 years old. Growth occurred all year but was most rapid between May and November.
Spawning commenced in October when adults first became abundant in the littoral zone and continued until April. Females often recovered and spawned a second time, 6 - 8 weeks after the first spawning. Males were sexually active for an extended period. Eggs were scattered over sandy areas along beaches in water less than 3.0m deep and in the lower reaches of tributary streams where water currents were sufficient to prevent formation of algal mats and deposition of silt or detritus. Egg mortalities were correlated with water temperature but not with their density, which reached 5000m⁻² off Waihaha Beach and 40,000⁻² in the Waihora and Whanganui streams. Habitat perturbations caused by extreme weather conditions were thought to cause the most serious egg mortalities. Starvation was probably the principal source of larval mortality as there was little predation on 0+ smelt. Larger (730mm) 1+ smelt were the most important item in the diet of rainbow trout, comprising over 80% by volume of items eaten. Trout tended to select the larger smelt available and the intensity of selection was correlated with measures of smelt abundance. Trout generally gathered in places where 1+ smelt densities were high.
Smelt population dynamics were simulated using length and density dependent models for movements between habitat zones, feeding, growth or starvation, breeding and predatory mortality. The form of simulated length frequency distributions largely determined the rates of these processes and was itself modified by the operation of each process. Modal groups occurred at lengths where food intake was equivalent to metabolic maintenance requirements and this was controlled by the interaction of diet breadth, the size structure and quantity of the food resource and the number of fishes sharing the same food particle size range. Growth of modal groups was controlled both by the duration of the spawning season and by seasonality in food resource quantity and size structure. Pelagic productivity and the ratio of littoral to pelagic habitat area were the most influential habitat features controlling smelt densities while densities of medium sized (30-55mm) smelt and water clarity were the most important factors controlling simulated quantities of smelt eaten by individual trout. Trout predation exerted little influence on simulated smelt population dynamics and consequently, the quantity eaten by individual trout was little affected by trout density. This result and comparison with trout stocking rates used in Canada suggest that a 1 - 2 order of magnitude increase in numbers of trout released annually into the larger Rotorua lakes would not significantly reduce their growth rates.

year: 1984

title: Ascending the Poutama: Culturally responsive diabetes care for Māori communities

authors: Crosswell, Rebekah Jane

subjects: culturally responsive

abstract: Introduction
Type 2 diabetes (T2D) significantly impacts Māori populations in Aotearoa New Zealand (NZ) who experience health disparities including suboptimal disease management.

Aim
To explore culturally responsive approaches to supporting Māori living with T2D from the perspective of healthcare providers.

Methods
Nine semi-structured interviews were conducted with clinicians from various disciplines (general practitioner, podiatrist, exercise physiologist, three kaiāwhina, dietitian, two pharmacists); five clinicians identify as Māori, four as non-Māori. Kaupapa Māori inductive thematic analysis was used.

Results
Four key themes emerged: empowering patient-centred communication, whānau involvement, interprofessional collaboration, and culturally appropriate analogies.

Discussion
The findings underscore the need for holistic, culturally responsive T2D care that prioritises culturally appropriate communication to improve patient engagement, health outcomes and address Māori health disparities.

text: Ascending the Poutama: Culturally responsive diabetes care for Māori communities Introduction
Type 2 diabetes (T2D) significantly impacts Māori populations in Aotearoa New Zealand (NZ) who experience health disparities including suboptimal disease management.

Aim
To explore culturally responsive approaches to supporting Māori living with T2D from the perspective of healthcare providers.

Methods
Nine semi-structured interviews were conducted with clinicians from various disciplines (general practitioner, podiatrist, exercise physiologist, three kaiāwhina, dietitian, two pharmacists); five clinicians identify as Māori, four as non-Māori. Kaupapa Māori inductive thematic analysis was used.

Results
Four key themes emerged: empowering patient-centred communication, whānau involvement, interprofessional collaboration, and culturally appropriate analogies.

Discussion
The findings underscore the need for holistic, culturally responsive T2D care that prioritises culturally appropriate communication to improve patient engagement, health outcomes and address Māori health disparities.

year: 2025