Thesis (MAppSc) -- AUT University, 2008. / Includes bibliographical references. Also held in print (xiv, 114 leaves : col. ill. ; 30 cm.) in the Archive at the City Campus (T 595.7 POH)

Thesis (Ph. D.)--Oregon State University, 1996. / Typescript (photocopy). Includes bibliographical references (leaves 121-141). Also available on the World Wide Web.

Thesis (M.S.)--Texas State University-San Marcos, 2007. / Vita. Includes bibliographical references (leaves 41-45).

The overall objective of this study was to provide a spatial pattern analysis offish distribution in the Great Lakes and to relate these patterns to shoreline features such as coastal wetlands, tributaries and substrate type. Very little is known regarding the distribution patterns of fish in the Great Lakes at the geographical scale of each lake basin. I first explored whether there were systematic patterns in distribution offish and coastal wetlands by looking at density maps of each and calculating nearest neighbor distances. I used three different classification schemes to sort the 139 fish taxa into functional categories to produce ecologically meaningful distribution maps. There were striking differences in the overall distribution pattern of nursery and spawning habitat in the five Great Lakes when data were compared for Jude and Pappas' classification taxocenes: open-water, intermediate and coastal. Overall, open-water species were the most abundant, and were also widely distributed throughout all five lakes. Coastal species were the least abundant and appeared to be restricted to the two lower lakes. The distribution pattern of coastal and intermediate taxa overlapped a great deal; both taxocenes made extensive use of the two lower lakes for spawning and nursery habitat during this synoptic survey, especially in western Lake Erie and eastern Lake Ontario. Fish distribution patterns sorted by thermal preference and by reproductive guild were compared with those sorted by taxocene. Results from a chi-square analysis indicated a high degree of overlap between thermal classes and taxocenes. There were also positive associations between many reproductive guilds and the three taxocenes, although these were not as strong as the previous comparison. I then examined spatial association between distributions of fish and coastal wetlands and other geomorphic features by testing the distribution offish along the shore of the Great Lakes and calculating the correlation between fish and coastal wetlands of Lake Ontario. A chi-square goodness-of-fit test indicated strong associations between the distribution offish and three shoreline classes: (wetland, sandy beach/dunes and bluff) and fish used coast~cl wetlands preferentially for spawning and nursery habitat at a basin-wide scale. Bivariate pattern analysis indicated that occurrences offish in L. Ontario were positively associated with both coastal wetlands and tributaries, although the relationship was considerably weaker for tributaries than for wetlands. Results from this study indicated that 1) Fish have an aggregated distribution pattern along the shores of Great Lakes and L. Ontario; 2) Coastal wetlands have an aggregated distribution pattern along the shores of Great Lakes and L. Ontario; 3) Spatial distribution offish and wetlands is positively associated; 4) The preferred utilization of coastal wetlands by majority of the Great Lakes fishes is consistent across geographic scales, from the site level to that of the entire Great Lakes basin. / Thesis / Master of Science (MSc)

A influência da estrutura ambiental sobre os padrões de diversidade da ictiofauna de ecótonos são analisados para o reservatório do Broa, bacia do rio Tietê (22º10\'S; 47º54\'W). Paralelamente, são avaliadas as alterações na composição dessa comunidade entre 1985 e 2000. Constituída por 24 espécies (sete ordens e 12 famílias de peixes) e com um alto nível de diversidade (1,99 bits./ind.), a ictiofauna estudada não apresentou variação espacial ou temporal na abundância de suas espécies. Os padrões de baixa captura e freqüência das quatro espécies introduzidas, parecem não evidenciar risco potencial de impacto negativo aos estoques hospedeiros. Determinadas principalmente pelo fluxo d\'água e estado trófico, as variáveis ambientais evidenciaram as alterações estruturais a que ecótonos estudados vêm sendo submetidos. Apesar da ausência de variação significativa entre a estrutura da ictiofauna de zonas de transição e bancos de macrófitas, perante a sazonalidade, essas taxocenoses apresentaram distintos padrões de composição, estabilidade e variação estrutural. Bancos de macrófitas tornam a área alagada mais heterogênea, constituindo comunidades com maior riqueza e diversidade de espécies, sendo drasticamente afetadas pela sazonalidade. Entre as espécies constantes, 90% estiveram ordenadas junto aos bancos de macrófitas, onde variações na disponibilidade de recursos críticos (p.e. alimentação e abrigo) segregam nas sazonalmente, enquanto fluxo d\'água e estado trófico são os gradientes determinantes dos habitats de abundância predominante das espécies. / The influence of environmental aspects on diversity patterns for the ichthyofauna of ecotones were analyzed for the Broa reservoir, Tiete river basin (22º10\'S; 47º54\'W). Alterations in the ichthyofauna composition have also been analyzed considering the period from 1985 and 2000. This fauna constituted by 24 species (seven orders and 12 families) and a high diversity (1,99 bits/ind.), showed no spacial or temporal variations in species abundance. The pattern of low capture and frequency of four species introduced in inchangeable, not pointing out to the risk of a potential negative impact over the native species. Determined mainly by the inflow and trophic condition, the environmental variables show clearly the structural alterations that these ecotones studied have been undergoing. Although there was no significant seasonal variation between the ictiofauna structure of the transitional zones and macrophytes banks, these taxocenoses presented a distinct composition pattern, stability and structural variation. Macrophytes banks increase the environmental heterogeneity of wetland areas, resulting communities with high species diversity, being drastically affected by seasonality. Between the constant species 90% ordained along macrophytes banks, variations on the availability of critical resources (f.e. food and shelter) cause for the seasonal segregation of these species, inflow and trophic condition were the determinant gradients on the principal habitats occupied by the species.

A influência da estrutura ambiental sobre os padrões de diversidade da ictiofauna de ecótonos são analisados para o reservatório do Broa, bacia do rio Tietê (22º10\'S; 47º54\'W). Paralelamente, são avaliadas as alterações na composição dessa comunidade entre 1985 e 2000. Constituída por 24 espécies (sete ordens e 12 famílias de peixes) e com um alto nível de diversidade (1,99 bits./ind.), a ictiofauna estudada não apresentou variação espacial ou temporal na abundância de suas espécies. Os padrões de baixa captura e freqüência das quatro espécies introduzidas, parecem não evidenciar risco potencial de impacto negativo aos estoques hospedeiros. Determinadas principalmente pelo fluxo d\'água e estado trófico, as variáveis ambientais evidenciaram as alterações estruturais a que ecótonos estudados vêm sendo submetidos. Apesar da ausência de variação significativa entre a estrutura da ictiofauna de zonas de transição e bancos de macrófitas, perante a sazonalidade, essas taxocenoses apresentaram distintos padrões de composição, estabilidade e variação estrutural. Bancos de macrófitas tornam a área alagada mais heterogênea, constituindo comunidades com maior riqueza e diversidade de espécies, sendo drasticamente afetadas pela sazonalidade. Entre as espécies constantes, 90% estiveram ordenadas junto aos bancos de macrófitas, onde variações na disponibilidade de recursos críticos (p.e. alimentação e abrigo) segregam nas sazonalmente, enquanto fluxo d\'água e estado trófico são os gradientes determinantes dos habitats de abundância predominante das espécies. / The influence of environmental aspects on diversity patterns for the ichthyofauna of ecotones were analyzed for the Broa reservoir, Tiete river basin (22º10\'S; 47º54\'W). Alterations in the ichthyofauna composition have also been analyzed considering the period from 1985 and 2000. This fauna constituted by 24 species (seven orders and 12 families) and a high diversity (1,99 bits/ind.), showed no spacial or temporal variations in species abundance. The pattern of low capture and frequency of four species introduced in inchangeable, not pointing out to the risk of a potential negative impact over the native species. Determined mainly by the inflow and trophic condition, the environmental variables show clearly the structural alterations that these ecotones studied have been undergoing. Although there was no significant seasonal variation between the ictiofauna structure of the transitional zones and macrophytes banks, these taxocenoses presented a distinct composition pattern, stability and structural variation. Macrophytes banks increase the environmental heterogeneity of wetland areas, resulting communities with high species diversity, being drastically affected by seasonality. Between the constant species 90% ordained along macrophytes banks, variations on the availability of critical resources (f.e. food and shelter) cause for the seasonal segregation of these species, inflow and trophic condition were the determinant gradients on the principal habitats occupied by the species.

Thesis (Ph. D.)--University of Oklahoma, 1999. / Includes bibliographical references.

This thesis uses a range of different size spectra to compare contrasting benthic habitats in the aquatic realm. Temporal and spatial variation in benthic size spectra were investigated across a full salinity gradient (i.e. from freshwater, through estuarine to marine) in the River Yealm, south Devon, in order to gauge the influence of large differences in taxonomy and evolutionary history. Abundance and biomass size spectra showed a similar pattern among sites in all seasons but winter, suggesting that the size structure of benthic communities may be similar in sites with very different community compositions. A subsequent study comparing size spectra across salinity by employing artificial substrata suggested that substratum type also had little effect on the size structure of these benthic communities. A technique was developed for obtaining microbial size distributions for benthic communities and showed that microbial size structures were also similar between the marine and freshwater sites within the Yealm system. A final study demonstrated that the shape of size spectra was clearly affected by metal contamination. Size spectra across a salinity gradient -(i.e. from freshwater to lower estuary) in the highly contaminated Fal system were very different to those in the uncontaminated Yealm, due mostly to the low macrofaunal abundance in the former. This thesis is the first to assess patterns in benthic size spectra across a full salinity range in the same system. It is hoped that it will provide a base line for further studies in this exciting research area in macroecology and that biomass spectra might also prove useful as metrics for biomonitoring.

<p> Over the past decade public decision makers have become increasingly concerned with the potential impacts of their decisions upon values associated with fish resources. These impacts can often involve large-scale alternation of natural habitats. Recreation is an important use of the fisheries resource. Anglers in Ontario spent more than 43 million days engaged in sport fishing expending more than 650 million dollars within the Province in 1980 (Government of Ontario, 1980). This paper deals largely with conceptual methods of measuring the economic benefits of recreational fishing. It is intended to serve several purposes: to present a review of the economic evaluations of recreational fishing and to expand certain conceptual concepts of the subject. High priority steps that should be taken to develop appropriate fishing values which can be used in policy decisions are also presented.</p> / Thesis / Candidate in Philosophy

Intertidal wetland habitats in southeastern Australia have changed significantly during the past sixty years. Mangrove habitats have expanded both seawards and landwards, the latter being at the expense of saltmarsh habitats. This relatively common phenomenon is generally suggested to be an outcome of sea-level rise. Several factors potentially responsible for this change are examined, including changes in mean sealevel during the past 50 to 100 years, changes in climate, population growth, catchment landuse, and estuary type. A protocol for mapping estuarine habitats was developed and implemented, incorporating the application of geographic information systems. Spatial and temporal coastal wetland habitat changes at nine sites along the New South Wales coast are illustrated. These habitat dynamics were shown to not correlate between sites. The results demonstrate that sea-level rise in this region cannot solely account for the extent of change during the past sixty years. With the exception of one site (Careel Bay), there have been no correlations between contemporary mean sea-level rise and mangrove incursion of the saltmarsh habitats at the study sites, or with rainfall patterns, at the scale of observation in this study, which was largely decadal. The only correlations determined during this study have been between population growth and coastal wetland habitat dynamics in some sites. In spite of saltmarsh habitat loss being a regional phenomenon, local factors appear to have a profound bearing on the rates of change. Neither contemporary mean sea-level rise, rainfall patterns, estuary type, catchment landuse, catchment natural cover nor population pressure can account solely for the patterns in the spatial and temporal dynamics of the coastal wetlands of New South Wales. It seems apparent that regional factors create preconditions favourable for mangrove incursion, but that localised conditions have been responsible for the extent of these incursions from site to site. That is, despite higher sea-level and greater rainfall, the extent of change has been determined by the unique characteristics of each site. The results have important implications for current estuary management practices in the state of New South Wales. The lack of spatial and temporal trends in coastal wetland habitat dynamics point to the need for management to be conducted on a localised, rather than regional scale. Additionally, anthropogenic influences must be carefully managed, since the extent of mangrove habitat expansion into saltmarsh areas is unlikely to be a natural occurrence.