Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa
South Africa lacks a commercial oyster hatchery. To inform the sourcing of seed for future hatchery establishments, we compared half-sib Pacific oyster Crassostrea gigas cohorts from hatcheries in Namibia and Chile. We measured oyster growth, mortality, condition and feeding organ morphology in Algo...
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ftjafricanj:oai:ojs.ajol.info:article/115120 2023-05-15T15:58:10+02:00 Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa Nel, A Pitcher, G Richoux, NB Jackson, S 2015-04-01 application/pdf http://www.ajol.info/index.php/ajms/article/view/115120 eng eng NISC http://www.ajol.info/index.php/ajms/article/view/115120/104718 http://www.ajol.info/index.php/ajms/article/view/115120 Copyright for articles published in this journal is retained by the publisher. African Journal of Marine Science; Vol 36, No 4 (2014) 1814-232X info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article 2015 ftjafricanj 2015-04-04T23:50:15Z South Africa lacks a commercial oyster hatchery. To inform the sourcing of seed for future hatchery establishments, we compared half-sib Pacific oyster Crassostrea gigas cohorts from hatcheries in Namibia and Chile. We measured oyster growth, mortality, condition and feeding organ morphology in Algoa Bay (AB, Eastern Cape) and Saldanha Bay (SB, Western Cape), South Africa, from July 2011 to June 2012. Within SB, 14.3% of mean daily sea temperatures exceeded this species’ thermal optimum of 19 °C, compared to 50.5% in AB. Food abundance (mean daily chlorophyll a concentration) in SB (7.8 mg m–3) was double that in AB (3.9 mg m–3) where, presumably to increase particle clearance rates in a relatively phytoplankton-poor environment, oysters had larger gill:palp surface area ratios. Plankton fatty acid profiles (indicators of food quality) differed between locations. In AB, instantaneous growth rates differed between cohorts, and trends varied seasonally. Within both locations, condition index was usually higher in Chilean oysters, whereas shell density was higher in Namibian oysters. In AB only, Chilean seed suffered substantially higher summer mortalities than Namibian seed, suggesting that the latter are more suited to temperatures in AB. AB should also be assessed for culture of the indigenous oyster species that occur there.Keywords: bivalves, fatty acid composition, long-line culture, mortality, phenotypic plasticity, phytoplanktonAfrican Journal of Marine Science 2014, 36(4): 481–491 Article in Journal/Newspaper Crassostrea gigas Pacific oyster AJOL - African Journals Online Pacific |
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Open Polar |
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AJOL - African Journals Online |
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ftjafricanj |
language |
English |
description |
South Africa lacks a commercial oyster hatchery. To inform the sourcing of seed for future hatchery establishments, we compared half-sib Pacific oyster Crassostrea gigas cohorts from hatcheries in Namibia and Chile. We measured oyster growth, mortality, condition and feeding organ morphology in Algoa Bay (AB, Eastern Cape) and Saldanha Bay (SB, Western Cape), South Africa, from July 2011 to June 2012. Within SB, 14.3% of mean daily sea temperatures exceeded this species’ thermal optimum of 19 °C, compared to 50.5% in AB. Food abundance (mean daily chlorophyll a concentration) in SB (7.8 mg m–3) was double that in AB (3.9 mg m–3) where, presumably to increase particle clearance rates in a relatively phytoplankton-poor environment, oysters had larger gill:palp surface area ratios. Plankton fatty acid profiles (indicators of food quality) differed between locations. In AB, instantaneous growth rates differed between cohorts, and trends varied seasonally. Within both locations, condition index was usually higher in Chilean oysters, whereas shell density was higher in Namibian oysters. In AB only, Chilean seed suffered substantially higher summer mortalities than Namibian seed, suggesting that the latter are more suited to temperatures in AB. AB should also be assessed for culture of the indigenous oyster species that occur there.Keywords: bivalves, fatty acid composition, long-line culture, mortality, phenotypic plasticity, phytoplanktonAfrican Journal of Marine Science 2014, 36(4): 481–491 |
format |
Article in Journal/Newspaper |
author |
Nel, A Pitcher, G Richoux, NB Jackson, S |
spellingShingle |
Nel, A Pitcher, G Richoux, NB Jackson, S Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa |
author_facet |
Nel, A Pitcher, G Richoux, NB Jackson, S |
author_sort |
Nel, A |
title |
Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa |
title_short |
Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa |
title_full |
Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa |
title_fullStr |
Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa |
title_full_unstemmed |
Culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the Pacific oyster Crassostrea gigas in South Africa |
title_sort |
culture environment and hatchery of origin influence growth, condition and feeding organ morphology in the pacific oyster crassostrea gigas in south africa |
publisher |
NISC |
publishDate |
2015 |
url |
http://www.ajol.info/index.php/ajms/article/view/115120 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Crassostrea gigas Pacific oyster |
genre_facet |
Crassostrea gigas Pacific oyster |
op_source |
African Journal of Marine Science; Vol 36, No 4 (2014) 1814-232X |
op_relation |
http://www.ajol.info/index.php/ajms/article/view/115120/104718 http://www.ajol.info/index.php/ajms/article/view/115120 |
op_rights |
Copyright for articles published in this journal is retained by the publisher. |
_version_ |
1766393901337280512 |