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Ecology of the migration and distribution of the anchovy Engraulis capensis off Namibia
This thesis investigates the patterns of distribution and migration of the adult and recruit shoals of anchovy Engraulis capensis off Namibia and the environmental factors most important to such distributions and migrations. It also examines anchovy feeding patterns. The distributions of anchovy sho...
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| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2016
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| Summary: | This thesis investigates the patterns of distribution and migration of the adult and recruit shoals of anchovy Engraulis capensis off Namibia and the environmental factors most important to such distributions and migrations. It also examines anchovy feeding patterns. The distributions of anchovy shoals in summer months were recorded during extensive, acoustic surveys along the whole Namibian coastline from November 1978 to March 1982. A purse-seine fishing vessel was used to identify the shoals detected. Winter surveys of selected parts of the coastal waters recorded shoal distribution and sampled the fish and environmental factors associated with the densest shoal groups. Shoal groups were followed for periods in excess of 24 hours and sampled at 4-hour intervals. Winter distribution, length and age composition were also obtained from the commercial fishery statistics. Stomach contents extracted from samples of anchovy shoals were compared to water samples from their environment. Data on diet obtained from the fishery catch statistics are analysed to indicate feeding trends. |
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