title: Effects of environmental and behavioural factors on fish swimming performance and passage success

authors: Burbach Crawford, Rachel

abstract: Instream structures like culverts, dams, and other anthropogenic barriers fragment river networks worldwide, posing a significant threat to the connectivity and migration of freshwater fish communities. Designing effective fish passage solutions requires a comprehensive understanding of the swimming abilities, behaviours, and environmental tolerances of diverse fish species. This thesis aims to address this need by investigating the factors influencing the swimming performance and passage success of multiple migratory fish species in New Zealand, with implications for improving fish passage design and connectivity restoration efforts.
Two methods for assessing swimming performance, critical swimming speed (Ucrit) and sprint swimming speed (Usprint), were compared across two fish species. Results revealed no significant statistical difference between swimming speeds estimated using Ucrit versus Usprint protocols for the pelagic Galaxias maculatus and the benthic-associated Galaxias fasciatus. This suggests that shorter time-stepped swimming speeds tests can be used to measure swimming abilities of benthic-associated species, allowing comparisons across a broader range of fish for passage design.
Inter- and intraspecies variation in swimming speeds across nine migratory New Zealand fish species was quantified. Galaxias brevipinnis, Galaxias argenteus, and Galaxias postvectis exhibited the strongest swimming abilities. Galaxias maculatus was among the weakest swimmers. Body length was positively correlated with maximum speed, indicating that barriers select against weaker swimming species and smaller individuals within species. Maximum allowable culvert velocities should be significantly lower than previous standards to accommodate most individuals across species.
The impact of varying acute water temperatures on critical swimming speeds of four migratory species was investigated. At higher temperatures (26°C), three species (Galaxias maculatus, Galaxias brevipinnis, Gobiomorphus cotidianus) exhibited significant reductions in swimming performance compared to lower temperatures (8°C, 15°C). In contrast, Galaxias fasciatus showed no water temperature-related changes. These findings underscore the importance of designing fish passages to accommodate acute temperature fluctuations, to ensure successful migration under changing environmental conditions.
Potential benefits of collective navigation were explored using the small-bodied Galaxias maculatus. Experiments with an artificial velocity barrier revealed that fish swimming in groups had faster entry and passage rates, as well as lower metabolic rates indicating reduced energy expenditure, compared to solitary individuals. These findings highlight the importance of designing fish passes to facilitate movement of gregarious species by accommodating group dynamics.
The effect of repeated exposure on passage performance through an experimental raceway with high water velocities was examined. Over five consecutive days, passage success increased significantly, suggesting a role for cognition and spatial memory in improving passage performance. However, approach and entry rates did not improve, indicating other factors like attraction flows or fish physiology may be important for locating and entering structures. 
This thesis provides insights into the factors influencing swimming performance and passage success for migratory New Zealand species. By studying variation across species in water temperature effects, group behaviour, and cognitive abilities, this research provides a comprehensive understanding to guide the development of more inclusive and effective fish passage solutions. The findings highlight the importance of accounting for many sources of variation when designing instream structures to facilitate unimpeded fish migration.

text: Effects of environmental and behavioural factors on fish swimming performance and passage success Instream structures like culverts, dams, and other anthropogenic barriers fragment river networks worldwide, posing a significant threat to the connectivity and migration of freshwater fish communities. Designing effective fish passage solutions requires a comprehensive understanding of the swimming abilities, behaviours, and environmental tolerances of diverse fish species. This thesis aims to address this need by investigating the factors influencing the swimming performance and passage success of multiple migratory fish species in New Zealand, with implications for improving fish passage design and connectivity restoration efforts.
Two methods for assessing swimming performance, critical swimming speed (Ucrit) and sprint swimming speed (Usprint), were compared across two fish species. Results revealed no significant statistical difference between swimming speeds estimated using Ucrit versus Usprint protocols for the pelagic Galaxias maculatus and the benthic-associated Galaxias fasciatus. This suggests that shorter time-stepped swimming speeds tests can be used to measure swimming abilities of benthic-associated species, allowing comparisons across a broader range of fish for passage design.
Inter- and intraspecies variation in swimming speeds across nine migratory New Zealand fish species was quantified. Galaxias brevipinnis, Galaxias argenteus, and Galaxias postvectis exhibited the strongest swimming abilities. Galaxias maculatus was among the weakest swimmers. Body length was positively correlated with maximum speed, indicating that barriers select against weaker swimming species and smaller individuals within species. Maximum allowable culvert velocities should be significantly lower than previous standards to accommodate most individuals across species.
The impact of varying acute water temperatures on critical swimming speeds of four migratory species was investigated. At higher temperatures (26°C), three species (Galaxias maculatus, Galaxias brevipinnis, Gobiomorphus cotidianus) exhibited significant reductions in swimming performance compared to lower temperatures (8°C, 15°C). In contrast, Galaxias fasciatus showed no water temperature-related changes. These findings underscore the importance of designing fish passages to accommodate acute temperature fluctuations, to ensure successful migration under changing environmental conditions.
Potential benefits of collective navigation were explored using the small-bodied Galaxias maculatus. Experiments with an artificial velocity barrier revealed that fish swimming in groups had faster entry and passage rates, as well as lower metabolic rates indicating reduced energy expenditure, compared to solitary individuals. These findings highlight the importance of designing fish passes to facilitate movement of gregarious species by accommodating group dynamics.
The effect of repeated exposure on passage performance through an experimental raceway with high water velocities was examined. Over five consecutive days, passage success increased significantly, suggesting a role for cognition and spatial memory in improving passage performance. However, approach and entry rates did not improve, indicating other factors like attraction flows or fish physiology may be important for locating and entering structures. 
This thesis provides insights into the factors influencing swimming performance and passage success for migratory New Zealand species. By studying variation across species in water temperature effects, group behaviour, and cognitive abilities, this research provides a comprehensive understanding to guide the development of more inclusive and effective fish passage solutions. The findings highlight the importance of accounting for many sources of variation when designing instream structures to facilitate unimpeded fish migration.

year: 2024

title: A genus in the bacterial phylum Aquificota appears to be endemic to Aotearoa-New Zealand.

authors: Power, Jean F.

subjects: New Zealand

abstract: Allopatric speciation has been difficult to examine among microorganisms, with prior reports of endemism restricted to sub-genus level taxa. Previous microbial community analysis via 16S rRNA gene sequencing of 925 geothermal springs from the Taupō Volcanic Zone (TVZ), Aotearoa-New Zealand, revealed widespread distribution and abundance of a single bacterial genus across 686 of these ecosystems (pH 1.2-9.6 and 17.4-99.8 °C). Here, we present evidence to suggest that this genus, Venenivibrio (phylum Aquificota), is endemic to Aotearoa-New Zealand. A specific environmental niche that increases habitat isolation was identified, with maximal read abundance of Venenivibrio occurring at pH 4-6, 50-70 °C, and low oxidation-reduction potentials. This was further highlighted by genomic and culture-based analyses of the only characterised species for the genus, Venenivibrio stagnispumantis CP.B2T, which confirmed a chemolithoautotrophic metabolism dependent on hydrogen oxidation. While similarity between Venenivibrio populations illustrated that dispersal is not limited across the TVZ, extensive amplicon, metagenomic, and phylogenomic analyses of global microbial communities from DNA sequence databases indicates Venenivibrio is geographically restricted to the Aotearoa-New Zealand archipelago. We conclude that geographic isolation, complemented by physicochemical constraints, has resulted in the establishment of an endemic bacterial genus.

text: A genus in the bacterial phylum Aquificota appears to be endemic to Aotearoa-New Zealand. Allopatric speciation has been difficult to examine among microorganisms, with prior reports of endemism restricted to sub-genus level taxa. Previous microbial community analysis via 16S rRNA gene sequencing of 925 geothermal springs from the Taupō Volcanic Zone (TVZ), Aotearoa-New Zealand, revealed widespread distribution and abundance of a single bacterial genus across 686 of these ecosystems (pH 1.2-9.6 and 17.4-99.8 °C). Here, we present evidence to suggest that this genus, Venenivibrio (phylum Aquificota), is endemic to Aotearoa-New Zealand. A specific environmental niche that increases habitat isolation was identified, with maximal read abundance of Venenivibrio occurring at pH 4-6, 50-70 °C, and low oxidation-reduction potentials. This was further highlighted by genomic and culture-based analyses of the only characterised species for the genus, Venenivibrio stagnispumantis CP.B2T, which confirmed a chemolithoautotrophic metabolism dependent on hydrogen oxidation. While similarity between Venenivibrio populations illustrated that dispersal is not limited across the TVZ, extensive amplicon, metagenomic, and phylogenomic analyses of global microbial communities from DNA sequence databases indicates Venenivibrio is geographically restricted to the Aotearoa-New Zealand archipelago. We conclude that geographic isolation, complemented by physicochemical constraints, has resulted in the establishment of an endemic bacterial genus.

year: 2024-01-02

title: Key informant views on biobanking and genomic research with Māori

authors: Hudson, Maui

abstract: The aim of the Te Mata Ira project was to explore Māori views on biobanking and genomic research, and to identify ways to address Māori concerns over the collection and use of human tissue. Key informant interviews and workshops were conducted with Māori to identify Māori views in relation to biobanking and genomic research; and, informed by these views, interviews and workshops were conducted with Māori and non-Māori key informants (Indigenous Advisory Panel (IAP) members and science communities) to explore key issues in relation to Māori participation in biobanking and genomic research. Māori key informants identified the following as key deliberations: (1) the tension for Māori between previous well-publicised negative experiences with genomic research and the potential value for whanau and communities as technologies develop, (2) protection of Māori rights and interest, (3) focus on Māori health priorities, (4) control of samples and data, (5) expectations of consultation and consent and (6) a desire for greater feedback and communication. Māori and non-Māori key informants highlighted the need to enhance levels of Māori participation in the governance of genomic research and biobanking initiatives, and acknowledged that only by increasing the level of transparency and accountability in relation to these activities will Māori communities feel that their whakapapa, rights and interests are being appropriately protected.

text: Key informant views on biobanking and genomic research with Māori The aim of the Te Mata Ira project was to explore Māori views on biobanking and genomic research, and to identify ways to address Māori concerns over the collection and use of human tissue. Key informant interviews and workshops were conducted with Māori to identify Māori views in relation to biobanking and genomic research; and, informed by these views, interviews and workshops were conducted with Māori and non-Māori key informants (Indigenous Advisory Panel (IAP) members and science communities) to explore key issues in relation to Māori participation in biobanking and genomic research. Māori key informants identified the following as key deliberations: (1) the tension for Māori between previous well-publicised negative experiences with genomic research and the potential value for whanau and communities as technologies develop, (2) protection of Māori rights and interest, (3) focus on Māori health priorities, (4) control of samples and data, (5) expectations of consultation and consent and (6) a desire for greater feedback and communication. Māori and non-Māori key informants highlighted the need to enhance levels of Māori participation in the governance of genomic research and biobanking initiatives, and acknowledged that only by increasing the level of transparency and accountability in relation to these activities will Māori communities feel that their whakapapa, rights and interests are being appropriately protected.

year: 2016