Understanding the factors influencing the abundance and distribution of tropical floodplain fishes is an important component of fisheries management plans to support future sustainable resource use. This thesis uses a multi-scale approach to understand the habitat factors controlling the distribution and abundance of arapaima (Arapaima spp.) in river floodplains of the lower Amazon River, near the municipality of Santarém, Para State, Brazil. In chapter 1, a study of eight environmental variables in 13 dry season floodplain lakes demonstrates that lake depth, relative depth, conductivity, and transparency were significantly related to the probability of arapaima presence at individual locations within lakes. Further, the study revealed that smaller arapaima were more likely to be found near macrophyte coverage than in open water locations. In chapter 2, a landscape scale approach was used to examine the interactions between management systems, landscape habitat coverage, and spatial arrangement on arapaima population sizes in 73 floodplain lakes. Results showed that all three influences were important in explaining variability in arapaima abundances. Management and habitat variables contributed equally in controlling arapaima abundances. Both had strong patterns of spatial arrangement and overlapped significantly, suggesting that analysis of either management systems or landscape habitats without the other would lead to overestimations of the strength of their influence. Findings from both chapters support the notion that future sustainable use of arapaima populations requires a dualistic approach combining habitat conservation with fisheries management techniques enacted at a local scale. / Master of Science / Understanding where fishes choose to live within aquatic habitats, and why they do so, is important for their long-term protection habitat destruction and overfishing. This thesis looks at fish habitats at both small and large scales to understand the variables affecting populations of the megafish arapaima (<i>Arapaima spp.</i>) in lakes of the lower Amazon River, near the municipality of Santarém, Pará State, Brazil. In chapter 1, a study of eight environmental variables in 13 lakes shows that for each lake, deeper, muddier (less clear), and more electricallyconductive waters were more likely placed to find arapaima. Further, the study revealed that young arapaima were more likely to be found near aquatic plants than in open water areas near the middle of the lake. In chapter 2, a larger-scale approach was used to examine the interactions between humans, habitats, and spatial groupings for arapaima population sizes in 73 lakes. Results showed that all three factors were important in explaining how many arapaima were found in each lake. Human and habitat variables were equally important variables affecting arapaima. Both were strongly related to spatial groupings and overlapped significantly, suggesting that analysis of either human systems or habitats without the other would lead researchers to overestimate how important they are for arapaima. Findings from both chapters support the notion that future sustainable use of arapaima populations requires an approach combining habitat conservation with fisheries management techniques enacted at a local scale.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/73479 |
| Date | 17 November 2016 |
| Creators | Richard, Jordan Conner |
| Contributors | Fisheries and Wildlife Sciences, Castello, Leandro, Angermeier, Paul L., Orth, Donald J. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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