- Title
- Zoning the Southwestern Indian Ocean to mitigate impacts from ocean-based hydrocarbon exploration and production on sea turtles
- Creator
- Pretorius, Dirk
- Subject
- Ocean zoning
- Subject
- Marine ecology -- Indian Ocean Sea turtles -- Indian Ocean Marine animals -- Ecology
- Date Issued
- 2019
- Date
- 2019
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10948/43303
- Identifier
- vital:36787
- Description
- The conflict between sea turtles and the numerous socio-economic developments in the Southwestern Indian Ocean (SWIO) are set to intensify as countries are looking to develop their ocean-based economies. The Hydrocarbon Exploration and Production (HEP) industry is of particular importance, since many of the SWIO governments view it as catalyst for development. This has raised concerns about potentially significant environmental impacts from the HEP industry, to sea turtles and their habitats, based on international examples where sea turtles have been severely negatively impacted upon, like the Deepwater Horizon spill in the Gulf of Mexico. Given that the four sea turtles species in the SWIO are listed on the IUCN Red List of threatened species, the aim of this study was to derive priority areas for sea turtles in the face of HEP, that could be used in an ocean zoning strategy for sustainable economic development of HEP in the SWIO region. To achieve this, the study spatially represented the main life-history stages of sea turtles, i.e. the breeding, migrating and foraging areas of Caretta caretta (loggerhead turtles), Dermochelys coriacea (leatherback turtles), Chelonia mydas (green turtles) and Eretmochelys imbricata (hawksbill turtles), within a telemetry derived distribution for each species. This spatial representation was used to quantify the extent of Marine Protected Areas (MPAs) conserving sea turtles in the SWIO, which revealed that sea turtle breeding areas were well represented in MPAs, including C. caretta (~40 %), C. mydas (~53 %), E. imbricata (~59 %) and D. coriacea (~22 %), the latter being least protected by MPAs during breeding, possibly due to a far greater extent of their internesting areas than the other three species. MPA coverage of breeding areas could be positively correlated to the increasing population trends of C. caretta and C. mydas in the SWIO, and therefore the assumption was made that increasing population trends of sea turtles are in part related to MPA protection of their breeding areas. In addition, the potential impacts on sea turtles from existing and proposed HEP developments were assessed and mapped by using a novel, species-specific rating index. The results revealed the extensive nature of potential water pollution impacts on sea turtles, constituting 16 of the top 28 most significant impacts from HEP on sea turtles. Other significant impacts on sea turtles associated with the HEP industry, included habitat destruction, light pollution and noise pollution. Importantly, this study found that ~70 % of all potential HEP impacts (irrespective of significance) on adult nesting sea turtles could be avoided if seasonal sea turtle movement during critical life stages are included as species-specific HEP mitigation measures. The data and maps on the main life-history stages of sea turtles, and the potential cumulative impacts from the HEP industry, were used in a Systematic Conservation Planning process, to derive a concept ocean zoning. As final outcome of this study, the concept ocean zoning highlighted areas where increased protection to sea turtles, and management of the conflict between sea turtles and the HEP industry, will be required if the HEP industry is to develop in a sustainable manner in the SWIO.
- Format
- 148 leaves
- Format
- Publisher
- Nelson Mandela University
- Publisher
- Faculty of Science
- Language
- English
- Rights
- Nelson Mandela University
- Hits: 1044
- Visitors: 1086
- Downloads: 63
Collections
NMU School of Environmental Sciences
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | Dirk Pretorius.pdf | 16 MB | Adobe Acrobat PDF | View Details Download |