title: Grass carp and incidental invaders from aquaculture: a study of impacts on zooplankton communities and invader origins

authors: Branford, Suzanne Nicola

subjects: Biological Invasions

abstract: The movement of fish from aquaculture facilities has led to invasions of non-native species globally, including of ‘hitch-hiking’ species, resulting in impacts on the composition of communities in recipient ecosystems. This thesis employs both community scale analysis and sensitive molecular techniques to assess the effects of grass carp translocations on zooplankton communities and to determine the origins of an incidental non-native invader. 

In the first component, I tested the effects of grass carp translocations from aquaculture facilities on ponds in the Auckland region, New Zealand. Zooplankton community composition was quantified in 34 ponds that had been subject to grass carp release and 31 which had no grass carp introductions. A significant difference in zooplankton community composition was observed between ponds that had received grass carp translocations and those that had not. Differences in zooplankton community composition between ponds with and without carp releases were attributable to: 1) the establishment of zooplankton originating from aquaculture ponds, including non-native species; and 2) the effects of grass carp activity, through habitat modification. Effective measures to curb the proliferation of non-native taxa within aquaculture facilities, and to mitigate the unintentional movement of non-native taxa with translocations from these facilities, are required to reduce future introductions.

In the second component of this thesis I used a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene to more precisely identify the origins of invasions of freshwater calanoid copepod Skistodiaptomus pallidus (Herrick 1879). This was applied to populations sampled from within New Zealand, which have been linked to the release of fish from aquaculture facilities, and to populations found in Germany, which have possible links to a shipping vector. The S. pallidus COI sequences placed both the New Zealand and German specimens with those from the most easterly regions of the USA (e.g., New York, Virginia and Georgia). However, several haplotypes were found to be divergent between the New Zealand and German populations, indicating the exact sources of the introductions were likely different for each country. German sequences had greater haplotype diversity than those from New Zealand, supporting the suggestions of a shipping related vector of introduction to Germany. Both German and New Zealand populations contained haplotypes that were closely related to North American sequence records. However, further sampling of the native range will be required to determine the exact origin of the non-indigenous S. pallidus populations. With this additional information it may also be possible to determine more precisely the vectors of introduction. 

Collectively, the two research chapters provide a broader understanding of invasion processes and the effects of grass carp translocations on the zooplankton communities within recipient ponds in New Zealand. My research has immediate application in the re-evaluation of fish translocation management practises and impacts.

text: Grass carp and incidental invaders from aquaculture: a study of impacts on zooplankton communities and invader origins The movement of fish from aquaculture facilities has led to invasions of non-native species globally, including of ‘hitch-hiking’ species, resulting in impacts on the composition of communities in recipient ecosystems. This thesis employs both community scale analysis and sensitive molecular techniques to assess the effects of grass carp translocations on zooplankton communities and to determine the origins of an incidental non-native invader. 

In the first component, I tested the effects of grass carp translocations from aquaculture facilities on ponds in the Auckland region, New Zealand. Zooplankton community composition was quantified in 34 ponds that had been subject to grass carp release and 31 which had no grass carp introductions. A significant difference in zooplankton community composition was observed between ponds that had received grass carp translocations and those that had not. Differences in zooplankton community composition between ponds with and without carp releases were attributable to: 1) the establishment of zooplankton originating from aquaculture ponds, including non-native species; and 2) the effects of grass carp activity, through habitat modification. Effective measures to curb the proliferation of non-native taxa within aquaculture facilities, and to mitigate the unintentional movement of non-native taxa with translocations from these facilities, are required to reduce future introductions.

In the second component of this thesis I used a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene to more precisely identify the origins of invasions of freshwater calanoid copepod Skistodiaptomus pallidus (Herrick 1879). This was applied to populations sampled from within New Zealand, which have been linked to the release of fish from aquaculture facilities, and to populations found in Germany, which have possible links to a shipping vector. The S. pallidus COI sequences placed both the New Zealand and German specimens with those from the most easterly regions of the USA (e.g., New York, Virginia and Georgia). However, several haplotypes were found to be divergent between the New Zealand and German populations, indicating the exact sources of the introductions were likely different for each country. German sequences had greater haplotype diversity than those from New Zealand, supporting the suggestions of a shipping related vector of introduction to Germany. Both German and New Zealand populations contained haplotypes that were closely related to North American sequence records. However, further sampling of the native range will be required to determine the exact origin of the non-indigenous S. pallidus populations. With this additional information it may also be possible to determine more precisely the vectors of introduction. 

Collectively, the two research chapters provide a broader understanding of invasion processes and the effects of grass carp translocations on the zooplankton communities within recipient ponds in New Zealand. My research has immediate application in the re-evaluation of fish translocation management practises and impacts.

year: 2016

title: Ōhiwa Harbour Delft3D sediment transport modelling to support the National Policy Statement on Freshwater (NPS-FM)

authors: Bryan, Karin R.

abstract: A suspended sediment transport model was set up for Ōhiwa Harbour, which was validated against in situ observations collected between 19/4/21 and 17/5/21. Four sediment grain size fractions were modelled; two cohesive (silt) sediment grain size fractions, and two non-cohesive (sand) sediment grain size fractions. Characteristics of these grain size fractions were selected based on a sensitivity analysis and the match of modelled suspended sediment to the magnitude and temporal patterns recorded at the observation stations. Suspended non-cohesive grain size fractions reflect local current strengths at the sites measured, whereas cohesive grain size fractions are advected longer distances by the ebbing or flooding currents.

Sediment loading was input at the freshwater discharge points using loading scenarios provided by the Bay of Plenty Regional Council. Sediment loading was converted to a concentration and discharge, and input into the model as a cohesive sediment grain size fraction. Model scenarios were run for 1 year in blocks of 3 months, using the environmental conditions (discharge, wind, tides) from 2014 as a base-case scenario. Loading scenarios consisted of contemporary, natural, RCP45 and RCP85 conditions. A 7-day model “warm up” period prior to each of the 3-month blocks was discarded.

text: Ōhiwa Harbour Delft3D sediment transport modelling to support the National Policy Statement on Freshwater (NPS-FM) A suspended sediment transport model was set up for Ōhiwa Harbour, which was validated against in situ observations collected between 19/4/21 and 17/5/21. Four sediment grain size fractions were modelled; two cohesive (silt) sediment grain size fractions, and two non-cohesive (sand) sediment grain size fractions. Characteristics of these grain size fractions were selected based on a sensitivity analysis and the match of modelled suspended sediment to the magnitude and temporal patterns recorded at the observation stations. Suspended non-cohesive grain size fractions reflect local current strengths at the sites measured, whereas cohesive grain size fractions are advected longer distances by the ebbing or flooding currents.

Sediment loading was input at the freshwater discharge points using loading scenarios provided by the Bay of Plenty Regional Council. Sediment loading was converted to a concentration and discharge, and input into the model as a cohesive sediment grain size fraction. Model scenarios were run for 1 year in blocks of 3 months, using the environmental conditions (discharge, wind, tides) from 2014 as a base-case scenario. Loading scenarios consisted of contemporary, natural, RCP45 and RCP85 conditions. A 7-day model “warm up” period prior to each of the 3-month blocks was discarded.

year: 2023

title: A case study of using the He Pikinga Waiora Implementation Framework: Challenges and successes in implementing a twelve-week lifestyle intervention to reduce weight in Māori men at risk of diabetes, cardiovascular disease and obesity

authors: Oetzel, John G.

subjects: Science & Technology

abstract: BACKGROUND: Māori men have stark health inequities around non-communicable diseases. This study describes the case of a partnership attempting to develop and implement a culturally centred intervention through a collaborative partnership to potentially address the inequities. In particular, the partnership followed a participatory, co-design approach using the He Pikinga Waiora (HPW) Implementation Framework; the study presents lessons learnt in addressing health inequities following this framework. METHODS: The partnership involved a university research team and a Māori community health provider. They engaged with other stakeholders and several cohorts of Māori men through a co-design process to adapt a 12-week lifestyle intervention. The co-design process was documented through meeting notes and interviews with partners. Two cohorts participated in separate single group pre-intervention/post-intervention designs with multi-method data collection. Key outcome measures included weight loss, self-reported health, physical activity, and nutrition. Post-intervention data collection included qualitative data. RESULTS: The co-design process resulted in a strong and engaged partnership between the university team and the provider. There were significant challenges in implementing the intervention including having two additional partner organisations dropping out of the partnership just after the initial implementation phase. However, a flexible and adaptable partnership resulted in developing two distinct lifestyle interventions run with 32 Māori men (in two different cohorts of 8 and 24). All but one in the first cohort completed the programme. The first cohort had a modest although statistically insignificant improvement in weight loss (d = 1.04) and body mass index (BMI; d = 1.08). The second cohort had a significant reduction in weight loss (d = 1.16) and BMI (d = 1.15). They also had a significant increase in health-related quality of life (d = 1.7) and self-rated health (d = 2.0). CONCLUSION: The HPW Framework appears to be well suited to advance implementation science for Indigenous communities in general and Māori in particular. The framework has promise as a policy and planning tool to evaluate and design interventions for chronic disease prevention in Indigenous communities. Despite this promise, there are structural challenges in developing and implementing interventions to address health inequities. TRIAL REGISTRATION: Retrospectively registered, Australia New Zealand Clinical Trials Registry, ACTRN12619001783112.

text: A case study of using the He Pikinga Waiora Implementation Framework: Challenges and successes in implementing a twelve-week lifestyle intervention to reduce weight in Māori men at risk of diabetes, cardiovascular disease and obesity BACKGROUND: Māori men have stark health inequities around non-communicable diseases. This study describes the case of a partnership attempting to develop and implement a culturally centred intervention through a collaborative partnership to potentially address the inequities. In particular, the partnership followed a participatory, co-design approach using the He Pikinga Waiora (HPW) Implementation Framework; the study presents lessons learnt in addressing health inequities following this framework. METHODS: The partnership involved a university research team and a Māori community health provider. They engaged with other stakeholders and several cohorts of Māori men through a co-design process to adapt a 12-week lifestyle intervention. The co-design process was documented through meeting notes and interviews with partners. Two cohorts participated in separate single group pre-intervention/post-intervention designs with multi-method data collection. Key outcome measures included weight loss, self-reported health, physical activity, and nutrition. Post-intervention data collection included qualitative data. RESULTS: The co-design process resulted in a strong and engaged partnership between the university team and the provider. There were significant challenges in implementing the intervention including having two additional partner organisations dropping out of the partnership just after the initial implementation phase. However, a flexible and adaptable partnership resulted in developing two distinct lifestyle interventions run with 32 Māori men (in two different cohorts of 8 and 24). All but one in the first cohort completed the programme. The first cohort had a modest although statistically insignificant improvement in weight loss (d = 1.04) and body mass index (BMI; d = 1.08). The second cohort had a significant reduction in weight loss (d = 1.16) and BMI (d = 1.15). They also had a significant increase in health-related quality of life (d = 1.7) and self-rated health (d = 2.0). CONCLUSION: The HPW Framework appears to be well suited to advance implementation science for Indigenous communities in general and Māori in particular. The framework has promise as a policy and planning tool to evaluate and design interventions for chronic disease prevention in Indigenous communities. Despite this promise, there are structural challenges in developing and implementing interventions to address health inequities. TRIAL REGISTRATION: Retrospectively registered, Australia New Zealand Clinical Trials Registry, ACTRN12619001783112.

year: 2020