Seagrass Ecosystems in the Western Indian Ocean

Gullström, Martin; Castro, Maricela de la Torre; Bandeira, Salomão; Björk, Mats; Dahlberg, Mattis; Kautsky, Nils; Rönnbäck, Patrik; Öhman, Marcus

doi:10.1639/0044-7447(2002)031[0588:seitwi]2.0.co;2

Cited by 32 publications

(17 citation statements)

References 99 publications

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“…So far nursery grounds were mainly reported in areas distant from the reef such as shallow waters, gravel regions and sea-grass (Beck et al 2001;Gullstrom et al 2002;Dorenbosch et al 2004;Mumby et al 2004). The finding of a deep nursery ground further stress the importance of deep coral reef research for understanding the ecological patterns and processes defining the reef community structure.…”

Section: Discussionmentioning

confidence: 99%

A deep nursery for juveniles of the zebra angelfish Genicanthus caudovittatus

et al. 2006

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Juveniles of many coral reef fish species are thought to either follow the same bathymetric distribution patterns as the adults, or to occupy shallower waters. However, our knowledge base suffers a dearth of data from the deep reefs (>40 m). In a recent survey of the deep reefs of the northern Gulf of Aqaba (<65 m), we examined the bathymetric distribution of 26 diurnal zooplanktivorous species. In sharp contrast to the general trend known from the literature and from this research, the abundance of juvenile zebra angelfish, Genicanthus caudovittatus, peaked at deeper waters (60-65 m) compared with the adults (30 m). This suggests that the deeper reefs may serve as nursery grounds for the zebra angelfish. Peak juvenile abundance coincided with relatively low predator abundances. This raises the question, which factors constrain the bathymetric distribution of the remaining species. Our findings stress the potential importance of deep coral reef research for understanding the ecological patterns and processes that govern reef community structure.

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Section: Discussionmentioning

confidence: 99%

A deep nursery for juveniles of the zebra angelfish Genicanthus caudovittatus

et al. 2006

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“…Thirteen different seagrass species can be found in the Western Indian Ocean (Gullström et al 2002), and eight species in northern Zanzibar, of which the most common are Thalassia hempriichii and Thalassodendron ciliatum (formerly Cymodocea ciliate). Close to the beach there is a mixture of seagrass species: Halodule sp.(Forsk.)…”

Section: Study Sitesmentioning

confidence: 99%

Changes in an East African social-ecological seagrass system: invertebrate harvesting affecting species composition and local livelihood

Nordlund

Erlandsson

Torre‐Castro

et al. 2010

Aquat. Living Resour.

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-Seagrass meadows support high biodiversity and are important for invertebrate harvesting activities in developing countries. The aim of this study was to estimate the social and ecological effects of invertebrate harvesting, i.e. how this exploitation may affect/has affected seagrass variables (biomass, shoot density and canopy height), macrofaunal community structure, the use and importance of these resources for the livelihood of local people over time. A multi-disciplinary approach was used, including interviews with harvesters, observations of the number/activities of invertebrate harvesters, and a biological field study in Zanzibar, Tanzania. The study showed that women/children harvest invertebrates, and they prefer large seagrass patches, high to medium shoot density, and high seagrass cover. All interviewees said they had noticed a decline in seagrass distribution over the last decade, >20% considered it a large decline. Interviewees also reported decreased numbers of animals, but no change in the number of animal species over the last decade. The main reasons for the decline of seagrass and animals according to interviewees, are an increase in the number of harvesters, and a change in attitude, i.e. people being less careful about the intertidal zone and seagrasses. Invertebrate harvesting was found important for food security and provision of cash income. The current average catch weight was ca. 2 kg/collection day/person, and 3 kg and 5 kg, 5-10 and 30 years ago respectively according to interviewees. At present, the harvesting women earn ca 60-70% and ca 40% of what they would have if catches were the same sizes as they were 5-10 and 30 years ago respectively, according to our calculations. The field sampling within seagrass beds showed that an inaccessible/remote site had significantly higher invertebrate abundance and species richness/diversity than an exploited site (ANOVA). Multivariate statistics further revealed weak but significant differences for animal abundance and biomass between these sites. By combining findings from both interviews and field sampling this study shows that invertebrate harvesters can influence macrofaunal community structure in seagrass meadows, which in turn results in negative impacts on local harvesters' economy and livelihood.

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“…Most studies have focused on the importance of coral reefs and mangroves, while seagrasses have generally been neglected. However, recent studies have addressed the need to focus on seagrass research in relation to biodiversity and ecosystem services (Duarte 2000) importance for the local populations (Gullstrom et al 2002), food webs dynamics (Valentine et al 2002), seascape interactions (Moberg and Rönnbäck 2003) and ecological resilience (Gunderson 2001) beside fertilizers and traditional medicine (Torre-Castro and Rönnbäck 2004). The use of the roots of Enhalus acoroides as a remedy against stings of different kinds of rays and scorpion is very popular.…”

Section: Introductionmentioning

confidence: 99%

Antibacterial activity of three South Indian seagrasses, Cymodocea serrulata, Halophila ovalis and Zostera capensis

Kumar

Sarada

Gideon

et al. 2008

World J Microbiol Biotechnol

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The antibacterial properties of the three seagrasses namely Cymodocea serrulata, Halophila ovalis and Zostera capensis were tested against the human pathogens Staphylococcus aureus, Bacillus cereus, B. subtilis, Escherichia coli, Salmonella paratyphi, Salmonella typhimurium and Micrococcus luteus, using six different solvents namely, petroleum ether, chloroform, ethyl acetate, acetone, methanol and water. Ethyl acetate and methanol extracts showed maximum activity against most of the pathogens when compared to other solvents. Experiments are underway to isolate active compound(s) implicated in controlling the growth of the pathogens in vitro.

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Seagrass Ecosystems in the Western Indian Ocean

Cited by 32 publications

References 99 publications

A deep nursery for juveniles of the zebra angelfish Genicanthus caudovittatus

A deep nursery for juveniles of the zebra angelfish Genicanthus caudovittatus

Changes in an East African social-ecological seagrass system: invertebrate harvesting affecting species composition and local livelihood

Antibacterial activity of three South Indian seagrasses, Cymodocea serrulata, Halophila ovalis and Zostera capensis

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