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: A supercapacitor based enhancement technique for stand-alone surge protection circuits

authors: Fernando, Jayathu

subjects: supercapacitors

abstract: With the International Technology Roadmap for Semiconductors predicting below-25nm feature-size VLSIs, powered by DC power supplies of less than 1V, protection against transients has become mandatory for modern electronic systems. Surge protection circuits are usually designed using non-linear devices such as metal oxide varistors and semiconductor devices and these devices are rated for short-term energy absorption, based on transient waveforms defined by standards such as IEEE C62.41. Despite their very low voltage DC ratings, supercapacitors are characterized by large time constants and significant continuous energy absorption ratings. This paper presents details of a patent-pending technique where multi-winding magnetic core with a supercapacitor based energy absorber stage can be combined with the commonly used non-linear devices, for enhanced protection. Comparison of the supercapacitor-enhanced circuit together with a commercial surge protection circuit is provided.

text: A supercapacitor based enhancement technique for stand-alone surge protection circuits With the International Technology Roadmap for Semiconductors predicting below-25nm feature-size VLSIs, powered by DC power supplies of less than 1V, protection against transients has become mandatory for modern electronic systems. Surge protection circuits are usually designed using non-linear devices such as metal oxide varistors and semiconductor devices and these devices are rated for short-term energy absorption, based on transient waveforms defined by standards such as IEEE C62.41. Despite their very low voltage DC ratings, supercapacitors are characterized by large time constants and significant continuous energy absorption ratings. This paper presents details of a patent-pending technique where multi-winding magnetic core with a supercapacitor based energy absorber stage can be combined with the commonly used non-linear devices, for enhanced protection. Comparison of the supercapacitor-enhanced circuit together with a commercial surge protection circuit is provided.

year: 2013

title: An evaluation of Te Rau Puawai workforce 100: Academic mentor's perspectives

authors: Nikora, Linda Waimarie

subjects: Maori students

abstract: To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
As an integral component of the Te Rau Puawai programme and as a specialised
source of support, academic mentors were identified as an important group to receive
comment from. This report documents the evaluative exchange that occurred by way
of email questionnaire, that we had with 18 out of 46 academic mentors of Te Rau
Puawai bursars in the College of Humanities and Social Sciences responded to our
questionnaire.

text: An evaluation of Te Rau Puawai workforce 100: Academic mentor's perspectives To evaluate the Te Rau Puawai programme, the Ministry of Health commissioned the
Maori and Psychology Research Unit of the University of Waikato in July 2001. The
overall aim of the evaluation was to provide the Ministry with a clearer understanding
of the programme including: the perceived critical success factors, the barriers if any
regarding Te Rau Puawai, the impact of the programme, the extent to which the
programme may be transferable, gaps in the programme, and suggested
improvements.
As an integral component of the Te Rau Puawai programme and as a specialised
source of support, academic mentors were identified as an important group to receive
comment from. This report documents the evaluative exchange that occurred by way
of email questionnaire, that we had with 18 out of 46 academic mentors of Te Rau
Puawai bursars in the College of Humanities and Social Sciences responded to our
questionnaire.

year: 2002-05-01