title: Monogenean Parasites of Non-Native Freshwater Fish in New Zealand: Ecology and New Distributional Records

authors: Renner, Ethan

abstract: Monogeneans are common aquatic ectoparasites within the phylum Platyhelminthes. Freshwater monogeneans have been little studied in New Zealand, with only three taxa having been recognised in the country until recently, including only two to species level. Twenty-one non-native freshwater fish species have established populations in New Zealand, yet only one of these has been reported with monogenean infestations. Based on the diversity of monogenean species known from these fish species globally, it is likely that many monogenean species will have established populations in New Zealand that remain unreported. The prevalence and intensity of parasite infection and infestation are known to vary with season and in relation to host factors such as size and sex, but little is known of their ecology in New Zealand freshwater fish species.

I report for the first time the presence of eleven monogenean species infesting non-native freshwater fish in New Zealand. Two of these species belong to the family Ancyrocephalidae, a family new to New Zealand. A seasonal study of two species infesting Gambusia affinis (Baird & Girard, 1853) in two interconnected ponds in Hamilton, Salsuginus seculus (Mizelle & Arcadi, 1945) and Gyrodactylus gambusiae Rogers and Wellborn, 1965, represents the first ecological study of monogeneans undertaken in New Zealand, a country with a mild climate and narrow annual temperature range relative to better studied northern temperate populations. The prevalence of S. seculus changed significantly over the course of a year, reaching a peak during the summer. However, no significant correlation with temperature was found for either the prevalence or mean intensity of S. seculus. Prevalence was instead correlated with the concentration of chlorophyll a and pH. However, it is likely these correlations were simply due to chlorophyll a concentrations similarly increasing over summer affecting the pH, rather than either variable being causative. As G. affinis is known to experience large increases and decreases in population density annually, with individuals coming into physical contact during breeding, this was likely the cause of the increase in monogenean prevalence. A greater number of hosts would provide more habitat for monogeneans and their increased density would facilitate transmission of the parasites. The sex of fish was found to be a significant predictor of prevalence and intensity of monogeneans S. seculus, but this was on the basis of size. Longer and heavier fish had higher prevalence and mean intensity of S. seculus, and as female G. affinis are typically larger than males, this led to the difference in infestation between the sexes. Larger individuals represent larger habitat patches and for this may be the reason that prevalence and intensity of monogeneans was higher on these individuals. A similar test was conducted on Carassius auratus (L.), where two size classes were observed, representing juveniles and adults. The juvenile fish had significantly higher prevalence and intensities of Dactylogyrus spp., indicating a parasite vulnerability in juveniles. This thesis contributes to the knowledge of the species diversity and ecology of freshwater monogeneans in New Zealand.

text: Monogenean Parasites of Non-Native Freshwater Fish in New Zealand: Ecology and New Distributional Records Monogeneans are common aquatic ectoparasites within the phylum Platyhelminthes. Freshwater monogeneans have been little studied in New Zealand, with only three taxa having been recognised in the country until recently, including only two to species level. Twenty-one non-native freshwater fish species have established populations in New Zealand, yet only one of these has been reported with monogenean infestations. Based on the diversity of monogenean species known from these fish species globally, it is likely that many monogenean species will have established populations in New Zealand that remain unreported. The prevalence and intensity of parasite infection and infestation are known to vary with season and in relation to host factors such as size and sex, but little is known of their ecology in New Zealand freshwater fish species.

I report for the first time the presence of eleven monogenean species infesting non-native freshwater fish in New Zealand. Two of these species belong to the family Ancyrocephalidae, a family new to New Zealand. A seasonal study of two species infesting Gambusia affinis (Baird & Girard, 1853) in two interconnected ponds in Hamilton, Salsuginus seculus (Mizelle & Arcadi, 1945) and Gyrodactylus gambusiae Rogers and Wellborn, 1965, represents the first ecological study of monogeneans undertaken in New Zealand, a country with a mild climate and narrow annual temperature range relative to better studied northern temperate populations. The prevalence of S. seculus changed significantly over the course of a year, reaching a peak during the summer. However, no significant correlation with temperature was found for either the prevalence or mean intensity of S. seculus. Prevalence was instead correlated with the concentration of chlorophyll a and pH. However, it is likely these correlations were simply due to chlorophyll a concentrations similarly increasing over summer affecting the pH, rather than either variable being causative. As G. affinis is known to experience large increases and decreases in population density annually, with individuals coming into physical contact during breeding, this was likely the cause of the increase in monogenean prevalence. A greater number of hosts would provide more habitat for monogeneans and their increased density would facilitate transmission of the parasites. The sex of fish was found to be a significant predictor of prevalence and intensity of monogeneans S. seculus, but this was on the basis of size. Longer and heavier fish had higher prevalence and mean intensity of S. seculus, and as female G. affinis are typically larger than males, this led to the difference in infestation between the sexes. Larger individuals represent larger habitat patches and for this may be the reason that prevalence and intensity of monogeneans was higher on these individuals. A similar test was conducted on Carassius auratus (L.), where two size classes were observed, representing juveniles and adults. The juvenile fish had significantly higher prevalence and intensities of Dactylogyrus spp., indicating a parasite vulnerability in juveniles. This thesis contributes to the knowledge of the species diversity and ecology of freshwater monogeneans in New Zealand.

year: 2023

title: Keeping Track of the semantic Web: Personalized Event Notification

authors: Hinze, Annika

subjects: computer science

abstract: The semantic web will not be a static collection of formats, data and meta-data but highly dynamic in each aspect. This paper proposes a personalized event notification system for semantic web documents (ENS-SW). The system can intelligently detect and filter changes in semantic web documents by exploiting the semantic structure of those documents. In our prototype, we combine the functionalities of user profiles and distributed authoring systems. Typically, both approaches would lack the ability to handle semantic web documents. 
This paper introduces the design and implementation of our event notification system for semantic web documents that handles the XML representation of RDF. We analyzed our prototype regarding accuracy and efficiency in change detection. Our system supports sophisticated change detection including partial deletion, awareness for document restructuring, and approximate filter matches.

text: Keeping Track of the semantic Web: Personalized Event Notification The semantic web will not be a static collection of formats, data and meta-data but highly dynamic in each aspect. This paper proposes a personalized event notification system for semantic web documents (ENS-SW). The system can intelligently detect and filter changes in semantic web documents by exploiting the semantic structure of those documents. In our prototype, we combine the functionalities of user profiles and distributed authoring systems. Typically, both approaches would lack the ability to handle semantic web documents. 
This paper introduces the design and implementation of our event notification system for semantic web documents that handles the XML representation of RDF. We analyzed our prototype regarding accuracy and efficiency in change detection. Our system supports sophisticated change detection including partial deletion, awareness for document restructuring, and approximate filter matches.

year: 2006

title: The Application of Critical Discourse Theory: A Criterion-Referenced Analysis of Reports Relating to Language Revitalisation in Australia and New Zealand

authors: Lewis, Roger Brian

subjects: te reo Māori

abstract: The discipline of language policy and planning (LPP) is often proposed as a viable tool for language revitalisation. However, the conventional paradigm upon which LPP is based is inadequate for such an inherently political, contentious and problematic area of social policy, and does not address the hegemonic and counter-hegemonic discourse that is at the very core of language revitalisation efforts. It is therefore argued here that LPP needs to be explicitly underpinned by critical discourse theory (CDT) if it is to be of genuine use to those involved in language revitalisation efforts, particularly to grass roots language activists. Following an introductory chapter which provides a background to the research and a rationale for it (Chapter 1), there is a critical review of selected literature on LPP and CDT, a review which ends by proposing a list of criteria which, it is argued, can be used to determine the extent to which discourse that is intended to be counter-hegemonic adheres to the principles of effective counter-hegemonic discourse as outlined in the literature on CDT (Chapter 2). In the following three chapters (Chapters 3, 4 & 5), these criteria are applied to the analysis of three recent reports that have a direct bearing on indigenous language revitalisation in Australia (Our Land Our Languages) and New Zealand (Ko Aotearoa Tēnei and Te Reo Mauriora). The first of these reports is found to adhere very closely to the criteria; the second less so; the third almost not at all. The different ways in which each of these reports has been received would tend to support the hypothesis that, other things being equal, the more closely a text of this type conforms to the criteria - that is, the more closely it is aligned to the fundamental principles of effective counter-hegemonic discourse as outlined in CDT - the more likely it is to be positively received and, therefore, to represent an effective challenge to the existing hegemony. The overall conclusion is that CDT can not only assist language activists by providing a basis for determining how successful counter-hegemonic discourse is likely to be in achieving its aims but has the potential to provide LPP with a secure theoretical foundation (Chapter 6).

text: The Application of Critical Discourse Theory: A Criterion-Referenced Analysis of Reports Relating to Language Revitalisation in Australia and New Zealand The discipline of language policy and planning (LPP) is often proposed as a viable tool for language revitalisation. However, the conventional paradigm upon which LPP is based is inadequate for such an inherently political, contentious and problematic area of social policy, and does not address the hegemonic and counter-hegemonic discourse that is at the very core of language revitalisation efforts. It is therefore argued here that LPP needs to be explicitly underpinned by critical discourse theory (CDT) if it is to be of genuine use to those involved in language revitalisation efforts, particularly to grass roots language activists. Following an introductory chapter which provides a background to the research and a rationale for it (Chapter 1), there is a critical review of selected literature on LPP and CDT, a review which ends by proposing a list of criteria which, it is argued, can be used to determine the extent to which discourse that is intended to be counter-hegemonic adheres to the principles of effective counter-hegemonic discourse as outlined in the literature on CDT (Chapter 2). In the following three chapters (Chapters 3, 4 & 5), these criteria are applied to the analysis of three recent reports that have a direct bearing on indigenous language revitalisation in Australia (Our Land Our Languages) and New Zealand (Ko Aotearoa Tēnei and Te Reo Mauriora). The first of these reports is found to adhere very closely to the criteria; the second less so; the third almost not at all. The different ways in which each of these reports has been received would tend to support the hypothesis that, other things being equal, the more closely a text of this type conforms to the criteria - that is, the more closely it is aligned to the fundamental principles of effective counter-hegemonic discourse as outlined in CDT - the more likely it is to be positively received and, therefore, to represent an effective challenge to the existing hegemony. The overall conclusion is that CDT can not only assist language activists by providing a basis for determining how successful counter-hegemonic discourse is likely to be in achieving its aims but has the potential to provide LPP with a secure theoretical foundation (Chapter 6).

year: 2014