Holothurian population resource assessment: Mombasa Marine National Park and nearby unprotected reefs.

A comparative survey of shallow water (< 2m) holothurian fauna was undertaken to determine patterns of distribution, abundance and diversity, and the possible role of management, habitat (reef flat and lagoon), topographic complexity and substrate cover, in six sites within protected and unprotected reefs near Mombasa. Visual surveys were done by use of belt transects (100m by 4m) and search sampling (1-h time counts), and 10m-line intercept transects for substrate cover and rugosity. A total of ten different species belonging to 2 orders (Aspidochirotida and Apodida) and 3 families (Holothuriidae, Stichopodidae and Synaptidae) were recorded, four most abundant being Holothuria leucospilota, H. atra, Synapta maculata and Stichopus chloronotus in descending order. Three least abundant species were H. hilla, H. impatiens and Stichopus herrmanni. The total holothurians fauna was typified by low densities and high diversity, although no significant differences occurred in diversity (Simpson's Index) between management and habitats. Protected reefs had higher densities on the reef flats and in lagoons than the unprotected reefs. Between-subjects effects analysis indicated that management was more powerful than habitat in controlling holothurian population densities. Rugosity was higher in the MPA than unprotected sites, and there was a positive significant correlation between rugosity and sea cucumber densities and abundance. The nine broad substrate categories indicated high variability between lagoons under different management regimes. Coral cover was higher in protected than unprotected areas, whereas algal turf, sand and seagrass were dominant in the unprotected sites. Hard coral had a positive significant correlation with sea cucumber density, whereas algal turf and sand, showed negative and positive significant correlations respectively. Sand also correlated negatively, but significantly with sea cucumber species diversity. Apart from S. maculata, all the other nine species recorded in the study area have commercial value, varying from medium to low. The overall average density of sea cucumbers of commercial value in the study area was 5.20/400 m2. The most abundant commercial species in the study area was the low value H. leucospilota. Commercial sea cucumber densities in protected and unprotected sites were 11.00/400m2 and 2.30/400m2, respectively. Resource assessment of holothurian populations can be useful for designing, developing and evaluating sea cucumber fishery management plans and strengthening conservation of the resource.

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Bibliographic Details
Main Authors: Orwa, P.O., Ntiba, M.J., Muthiga, N.A., Kawaka, J.A.
Other Authors: Hoorweg, Jan
Format: Book Section biblioteca
Language:English
Published: African Studies Centre 2009
Subjects:Protected resources, Echinoderm fisheries, Geographical distribution, Fishery management, Population structure,
Online Access:http://hdl.handle.net/1834/8321
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spelling dig-aquadocs-1834-83212021-05-19T06:15:37Z Holothurian population resource assessment: Mombasa Marine National Park and nearby unprotected reefs. Advances in Coastal Ecology: people, processes and ecosystems in Kenya. Orwa, P.O. Ntiba, M.J. Muthiga, N.A. Kawaka, J.A. Hoorweg, Jan Muthiga, N. Protected resources Echinoderm fisheries Geographical distribution Fishery management Population structure A comparative survey of shallow water (< 2m) holothurian fauna was undertaken to determine patterns of distribution, abundance and diversity, and the possible role of management, habitat (reef flat and lagoon), topographic complexity and substrate cover, in six sites within protected and unprotected reefs near Mombasa. Visual surveys were done by use of belt transects (100m by 4m) and search sampling (1-h time counts), and 10m-line intercept transects for substrate cover and rugosity. A total of ten different species belonging to 2 orders (Aspidochirotida and Apodida) and 3 families (Holothuriidae, Stichopodidae and Synaptidae) were recorded, four most abundant being Holothuria leucospilota, H. atra, Synapta maculata and Stichopus chloronotus in descending order. Three least abundant species were H. hilla, H. impatiens and Stichopus herrmanni. The total holothurians fauna was typified by low densities and high diversity, although no significant differences occurred in diversity (Simpson's Index) between management and habitats. Protected reefs had higher densities on the reef flats and in lagoons than the unprotected reefs. Between-subjects effects analysis indicated that management was more powerful than habitat in controlling holothurian population densities. Rugosity was higher in the MPA than unprotected sites, and there was a positive significant correlation between rugosity and sea cucumber densities and abundance. The nine broad substrate categories indicated high variability between lagoons under different management regimes. Coral cover was higher in protected than unprotected areas, whereas algal turf, sand and seagrass were dominant in the unprotected sites. Hard coral had a positive significant correlation with sea cucumber density, whereas algal turf and sand, showed negative and positive significant correlations respectively. Sand also correlated negatively, but significantly with sea cucumber species diversity. Apart from S. maculata, all the other nine species recorded in the study area have commercial value, varying from medium to low. The overall average density of sea cucumbers of commercial value in the study area was 5.20/400 m2. The most abundant commercial species in the study area was the low value H. leucospilota. Commercial sea cucumber densities in protected and unprotected sites were 11.00/400m2 and 2.30/400m2, respectively. Resource assessment of holothurian populations can be useful for designing, developing and evaluating sea cucumber fishery management plans and strengthening conservation of the resource. Published 2016-01-27T15:12:56Z 2016-01-27T15:12:56Z 2009 Book Section Not Known 978-90-5448-090-7 1876-018X http://hdl.handle.net/1834/8321 en African Studies Collection; 20 http://www.ascleiden.nl/publications/advances-coastal-ecology-people-processes-and-ecosystems-kenya pp.162-177 Kenya, Coast, Mombasa, Mombasa Marine Park African Studies Centre Leiden, Netherlands
institution UNESCO
collection DSpace
country Francia
countrycode FR
component Bibliográfico
access En linea
databasecode dig-aquadocs
tag biblioteca
region Europa del Oeste
libraryname Repositorio AQUADOCS
language English
topic Protected resources
Echinoderm fisheries
Geographical distribution
Fishery management
Population structure
Protected resources
Echinoderm fisheries
Geographical distribution
Fishery management
Population structure
spellingShingle Protected resources
Echinoderm fisheries
Geographical distribution
Fishery management
Population structure
Protected resources
Echinoderm fisheries
Geographical distribution
Fishery management
Population structure
Orwa, P.O.
Ntiba, M.J.
Muthiga, N.A.
Kawaka, J.A.
Holothurian population resource assessment: Mombasa Marine National Park and nearby unprotected reefs.
description A comparative survey of shallow water (< 2m) holothurian fauna was undertaken to determine patterns of distribution, abundance and diversity, and the possible role of management, habitat (reef flat and lagoon), topographic complexity and substrate cover, in six sites within protected and unprotected reefs near Mombasa. Visual surveys were done by use of belt transects (100m by 4m) and search sampling (1-h time counts), and 10m-line intercept transects for substrate cover and rugosity. A total of ten different species belonging to 2 orders (Aspidochirotida and Apodida) and 3 families (Holothuriidae, Stichopodidae and Synaptidae) were recorded, four most abundant being Holothuria leucospilota, H. atra, Synapta maculata and Stichopus chloronotus in descending order. Three least abundant species were H. hilla, H. impatiens and Stichopus herrmanni. The total holothurians fauna was typified by low densities and high diversity, although no significant differences occurred in diversity (Simpson's Index) between management and habitats. Protected reefs had higher densities on the reef flats and in lagoons than the unprotected reefs. Between-subjects effects analysis indicated that management was more powerful than habitat in controlling holothurian population densities. Rugosity was higher in the MPA than unprotected sites, and there was a positive significant correlation between rugosity and sea cucumber densities and abundance. The nine broad substrate categories indicated high variability between lagoons under different management regimes. Coral cover was higher in protected than unprotected areas, whereas algal turf, sand and seagrass were dominant in the unprotected sites. Hard coral had a positive significant correlation with sea cucumber density, whereas algal turf and sand, showed negative and positive significant correlations respectively. Sand also correlated negatively, but significantly with sea cucumber species diversity. Apart from S. maculata, all the other nine species recorded in the study area have commercial value, varying from medium to low. The overall average density of sea cucumbers of commercial value in the study area was 5.20/400 m2. The most abundant commercial species in the study area was the low value H. leucospilota. Commercial sea cucumber densities in protected and unprotected sites were 11.00/400m2 and 2.30/400m2, respectively. Resource assessment of holothurian populations can be useful for designing, developing and evaluating sea cucumber fishery management plans and strengthening conservation of the resource.
author2 Hoorweg, Jan
author_facet Hoorweg, Jan
Orwa, P.O.
Ntiba, M.J.
Muthiga, N.A.
Kawaka, J.A.
format Book Section
topic_facet Protected resources
Echinoderm fisheries
Geographical distribution
Fishery management
Population structure
author Orwa, P.O.
Ntiba, M.J.
Muthiga, N.A.
Kawaka, J.A.
author_sort Orwa, P.O.
title Holothurian population resource assessment: Mombasa Marine National Park and nearby unprotected reefs.
title_short Holothurian population resource assessment: Mombasa Marine National Park and nearby unprotected reefs.
title_full Holothurian population resource assessment: Mombasa Marine National Park and nearby unprotected reefs.
title_fullStr Holothurian population resource assessment: Mombasa Marine National Park and nearby unprotected reefs.
title_full_unstemmed Holothurian population resource assessment: Mombasa Marine National Park and nearby unprotected reefs.
title_sort holothurian population resource assessment: mombasa marine national park and nearby unprotected reefs.
publisher African Studies Centre
publishDate 2009
url http://hdl.handle.net/1834/8321
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