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The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem
Bibliography : pages 178-202.
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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Department of Biological Sciences
2016
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| _version_ | 1867613253851414528 |
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| access_status_str | Open Access |
| author | van der Lingen, Carl David |
| author2 | Hutchings, Laurence |
| author_browse | Hutchings, Laurence van der Lingen, Carl David |
| author_facet | Hutchings, Laurence van der Lingen, Carl David |
| author_sort | van der Lingen, Carl David |
| collection | Thesis |
| description | Bibliography : pages 178-202. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/17510 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:12.104Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Department of Biological Sciences |
| publisherStr | Department of Biological Sciences |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/17510 The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem van der Lingen, Carl David Hutchings, Laurence Field, John G Zoology Bibliography : pages 178-202. Combined laboratory and field studies were employed to examine the feeding ecology of sardine Sardinops sagax in order to evaluate conflicting hypotheses regarding the trophic position of clupeoids in upwelling ecosystems, and to compare the trophodynamics of sardine with those of the co-occurring anchovy Engraulis capensis. Carbon and nitrogen budget models constructed using data from these studies were used to quantify the effect of particular food environments upon sardine growth. Sardinops sagax is primarily a filter-feeder, with food particles <1230μm total length eliciting a filtering response while larger particles elicit particulate-feeding at low concentrations and filter-feeding at high concentrations. This species is able to retain cells as small as 13μm, feeds at near-maximum efficiency when filterfeeding, and displays size-selectivity during particulate-feeding. Significant linear relationships between respiration rate and swimming speed obtained for sardine demonstrate that filter-feeding is the most energetically cheap feeding mode. Although omnivorous, sardine absorbs carbon and nitrogen more efficiently from zooplankton than from phytoplankton. Gastric evacuation follows an exponential pattern in sardine, and is influenced by food type; phytoplankton is evacuated faster than zooplankton. Feeding periodicity in sardine is size dependent; small fish show a feeding peak at, or around, sunset whereas larger fish appear to feed continuously. Estimates of daily ration range between 0.99 to 7.58% wet body mass.d-¹, depending on fish size and food type. Sardine stomach contents are numerically dominated by small particles, principally dinoflagellate phytoplankton, but the majority of the sardine's dietary carbon is derived from zooplankton, principally small calanoid and cyclopoid copepods. The budget models indicate that sardine is capable of positive growth under most of the trophic conditions it is likely to encounter in the southern Benguela upwelling system. The classical hypothesis that the high abundance of clupeoids in upwelling ecosystems results from their phytophagy is rejected; like anchovy, sardine are primarily zoophagous. However, these two species are trophodynamically distinct and show resource partitioning on the basis of prey size; sardine consume small zooplankton whilst anchovy consume large zooplankton. This difference is likely to contribute to regime shifts observed between these two species. 2016-03-04T16:52:15Z 2016-03-04T16:52:15Z 1999 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/17510 eng application/pdf Department of Biological Sciences Faculty of Science University of Cape Town |
| spellingShingle | Zoology van der Lingen, Carl David The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem |
| thesis_degree_str | Doctoral |
| title | The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem |
| title_full | The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem |
| title_fullStr | The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem |
| title_full_unstemmed | The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem |
| title_short | The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem |
| title_sort | feeding ecology of and carbon and nitrogen budgets for sardine sardinops sagax in the southern benguela upwelling ecosystem |
| topic | Zoology |
| url | http://hdl.handle.net/11427/17510 |
| work_keys_str_mv | AT vanderlingencarldavid thefeedingecologyofandcarbonandnitrogenbudgetsforsardinesardinopssagaxinthesouthernbenguelaupwellingecosystem AT vanderlingencarldavid feedingecologyofandcarbonandnitrogenbudgetsforsardinesardinopssagaxinthesouthernbenguelaupwellingecosystem |