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Managing sea cucumber fisheries and aquaculture: Studies of social-ecological systems in the Western Indian Ocean
Stockholm University, Faculty of Science, Department of Systems Ecology. (Marine Ecotoxicology)
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Collecting sea cucumbers to supply the high value Chinese dried seafood market is a livelihood activity available to many people in the Western Indian Ocean (WIO), making it an important part of local economies. These fisheries are generally not successfully managed and tropical sea cucumber fisheries show continuing signs of decline. This thesis takes a social-ecological systems approach to guide better management of sea cucumber fisheries and aquaculture in the WIO. Papers 1 and 2 analyse the fishery situation in Zanzibar and find that in the absence of effective management institutions and income alternatives among fishers, leading to dependence, there are unsustainable expanding processes. Paper 3 compares the unmanaged fishery in Zanzibar to the highly controlled situation in Mayotte. In Mayotte, a protection effect is evident and the commercial value of stocks is significantly higher than in Zanzibar. The analysis of the situation in Mayotte demonstrates the importance of matching the fishery – management temporal scales through prepared and adaptive management to avoid processes that reinforce unsustainable expansion. Paper 4 analyses sea cucumber community spatial distribution patterns at a coastal seascape-scale in Mayotte establishing baseline patterns of habitat utilization and abundance, which can be used as reference in management. Paper 5 reviews the potential for sea cucumber aquaculture in the WIO. The review illustrates that this activity, which is currently gaining momentum, does so based on inflated promises and with significant social-ecological risks. Emphasis for improvements is, in this thesis, placed on the importance of prepared and adaptive institutions to govern and control expanding processes of the fishery. These institutional features may be achieved by increasing the level of knowledge and participation in governance and by integration of sea cucumber resources management into higher-level policy initiatives.

Place, publisher, year, edition, pages
Stockholm: Department of Systems Ecology, Stockholm University , 2012. , 43 p.
Keyword [en]
Sea cucumbers, Bêche-de-mer, Trepang, Echinoderms, Fisheries, Aquaculture, Governance, Trade, Seafood, Tropical seascape, Zanzibar, Mayotte, Western Indian Ocean
National Category
Ecology
Research subject
Marine Ecotoxicology
Identifiers
URN: urn:nbn:se:su:diva-75515ISBN: 978-91-7447-515-9 (print)OAI: oai:DiVA.org:su-75515DiVA: diva2:523937
Public defence
2012-06-01, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 12, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.

Available from: 2012-05-10 Created: 2012-04-20 Last updated: 2012-10-08Bibliographically approved
List of papers
1. Resource degradation of the sea cucumber fishery in Zanzibar, Tanzania: a need for management reform
Open this publication in new window or tab >>Resource degradation of the sea cucumber fishery in Zanzibar, Tanzania: a need for management reform
2010 (English)In: Aquatic Living Resources, ISSN 0990-7440, E-ISSN 1765-2952, Vol. 23, 387-398 p.Article in journal (Refereed) Published
Abstract [en]

This study assessed the Zanzibar sea cucumber fishery using a multidisciplinary approach. Data was collected by (i) interviewing various groups of actors in the fishery and reviewing management documentation and legislation, (ii) by monitoring catches and (iii) through a visual census of coastal sea cucumber populations in areas open and closed to fishing. The fishery showed clear signs of being unsustainable with high fishing effort, and weak formal and informal management institutions. The fishery operation was characterised by an intricate cross-scale structure with both fishers and sea cucumber products being transported across national borders. The visual census of commercial sea cucumber stocks at three sites open to fishing around Zanzibar showed low densities across the range of sea cucumber value groups including low value species. Furthermore, the diversity of commercial sea cucumber species was lower in fished reefs than on a protected reef. The poor status of the sea cucumber populations was confirmed by the perception of an overfished resource by the interviewed actors active in the fishery. This was also depicted by the paucity of high value species, and high representation of low value and newly commercialised species in fishers catch. We conclude that the current state of Zanzibar’s sea cucumber populations is compromising the fisheries self-replenishment and existence and that the fishery is in urgent need of a complete management reform. 

Keyword
Bêche-de-mer Fisheries Overfishing Holothurians Echinoderms Trepang Western Indian Ocean
National Category
Ecology
Identifiers
urn:nbn:se:su:diva-75513 (URN)10.1051/alr/2011002 (DOI)
Available from: 2012-04-20 Created: 2012-04-20 Last updated: 2017-12-07Bibliographically approved
2. Mobility, Expansion and Management of a Multi-Species Scuba Diving Fishery in East Africa
Open this publication in new window or tab >>Mobility, Expansion and Management of a Multi-Species Scuba Diving Fishery in East Africa
2012 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 4, e35504- p.Article in journal (Refereed) Published
Abstract [en]

Background: Scuba diving fishing, predominantly targeting sea cucumbers, has been documented to occur in an uncontrolled manner in the Western Indian Ocean and in other tropical regions. Although this type of fishing generally indicates a destructive activity, little attention has been directed towards this category of fishery, a major knowledge gap and barrier to management. 

Methodology and Principal Findings: With the aim to capture geographic scales, fishing processes and social aspects the scuba diving fishery that operate out of Zanzibar was studied using interviews, discussions, participant observations and catch monitoring. The diving fishery was resilient to resource declines and had expanded to new species, new depths and new fishing grounds, sometimes operating approximately 250 km away from Zanzibar at depths down to 50 meters, as a result of depleted easy-access stock. The diving operations were embedded in a regional and global trade network, and its actors operated in a roving manner on multiple spatial levels, taking advantage of unfair patron-client relationships and of the insufficient management in Zanzibar. Conclusions and

Significance: This study illustrates that roving dynamics in fisheries, which have been predominantly addressed on a global scale, also take place at a considerably smaller spatial scale. Importantly, while proposed management of the sea cucumber fishery is often generic to a simplified fishery situation, this study illustrates a multifaceted fishery with diverse management requirements. The documented spatial scales and processes in the scuba diving fishery emphasize the need for increased regional governance partnerships to implement management that fit the spatial scales and processes of the operation. 

National Category
Ecology
Research subject
Marine Ecotoxicology
Identifiers
urn:nbn:se:su:diva-75520 (URN)10.1371/journal.pone.0035504 (DOI)000305347400055 ()
Note

Author count: 3;

Available from: 2012-04-20 Created: 2012-04-20 Last updated: 2017-12-07Bibliographically approved
3. Breaking degradation of sea cucumber resources: a social-ecological analysis of the fisheries in Zanzibar and Mayotte Islands in the Western Indian Ocean
Open this publication in new window or tab >>Breaking degradation of sea cucumber resources: a social-ecological analysis of the fisheries in Zanzibar and Mayotte Islands in the Western Indian Ocean
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Despite increasing research and management attention to tropical sea cucumber fisheries no apparent successes have been documented. To broaden the perspective of recent advances in management tools this study analyses the social-ecological processes in two contrasting sea cucumber fisheries situations, Zanzibar (Tanzania) and Mayotte (France) in the Western Indian Ocean. Zanzibar has an on-going fishery while the fishery in Mayotte operated approximately 10 years before it was closed in 2004. The study compares how different management strategies in Mayotte and Zanzibar were taken to address increasing fishing effort and a declining sea cucumber population. The comparison provide an opportunity learning and reflection. A visual census of stocks shows that the commercial value is nearly 30 times higher in Mayotte than Zanzibar owing to different fishery and management practices. In Mayotte less than 100 people were engaged in the fishery when it was active and the fishery was a comparatively small enterprise. In contrast, over 1000 people collect sea cucumbers as part of an expansive trade network that has developed in Zanzibar. In addition, in this site fishers are dependent on the resource for livelihood and expanding fishery processes have therefore occurred as a response to declines in catch abundance and value. These responses have taken place in the context of insufficient management and reinforce an unsustainable fishery situation difficult to break – referred to as a social-ecological trap. In contrast, management in Mayotte was receptive and adaptive to changes. The closure of the fishery illustrates the importance and positive outcome of matching the fishery – management temporal scales to avoid reinforcing fishery processes and to maintain ecosystem integrity. The multiple fisheries targeting sea cucumbers documented in this study captures how different management approaches and management plans are required, building on an understanding of the social-ecological context of the fishery. In addition, the comparison illustrates the importance of management systems with adequate resources (e.g. human and economic) and functioning information flows for positive management outcomes.  

Keyword
Bêche-de-mer, Trepang, Fisheries, Management, Transformation, Adaptive management, Fisheries governance
National Category
Ecology
Identifiers
urn:nbn:se:su:diva-75523 (URN)
Available from: 2012-04-20 Created: 2012-04-20 Last updated: 2012-05-04Bibliographically approved
4. Sea cucumber (Aspidochirotida) community, distribution and habitat utilization on the reefs of Mayotte, Western Indian Ocean
Open this publication in new window or tab >>Sea cucumber (Aspidochirotida) community, distribution and habitat utilization on the reefs of Mayotte, Western Indian Ocean
2012 (English)In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 452, 159-170 p.Article in journal (Refereed) Published
Abstract [en]

The tropical sea cucumber (Aspidochirotida) fishery for the lucrative Asian dried-seafood trade is a multi-species fishery with little ecological knowledge. To improve ecological understanding of the targeted species, the reefs of Mayotte, Western Indian Ocean, were surveyed to document the distribution, species assemblage and habitat utilization of commercial sea cucumbers. This is one of the few reef areas in the region protected from fishing, thus providing an important and unique opportunity to investigate sea cucumber ecology. Twenty-two species were observed. The medium-value Bohadschia atra and the high-value Holothuria nobilis were the most abundant species. Species distribution varied but the density was generally similar across areas and habitats. Multivariate analysis (ANOSIM) indicated that the community was similar between surveyed areas and reef habitats. Diversity was lower in one of the surveyed areas and in the ocean-facing barrier reef habitat. Habitat complexity was not a significant driver of diversity or abundance. A principal component analysis showed that the 6 most common species (B. atra, Holothuria atra, H. fuscopunctata, H. nobilis and Thelenota ananas) were associated with different substrate types. Clustering these species according to substrate variables indicated both habitat utilization overlap and segregation among species, valuable information for spatial planning of fisheries management and conservation. Although unique species were observed in some areas, the present study shows that, at a large spatial scale, the unfished reefs in Mayotte consist of similar commercial sea cucumber communities, an important baseline finding.

Keyword
Coral reefs, Bêche-de-mer, Trepang, Habitat, Ecosystem-based management, Fisheries management, Tropical seascape
National Category
Ecology
Identifiers
urn:nbn:se:su:diva-75522 (URN)10.3354/meps09665 (DOI)000303213900012 ()
Available from: 2012-04-20 Created: 2012-04-20 Last updated: 2017-12-07Bibliographically approved
5. Sea Cucumber Aquaculture in the Western Indian Ocean:  Challenges for Sustainable Livelihood and Stock Improvement
Open this publication in new window or tab >>Sea Cucumber Aquaculture in the Western Indian Ocean:  Challenges for Sustainable Livelihood and Stock Improvement
2012 (English)In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 41, no 2, 109-121 p.Article in journal (Refereed) Published
Abstract [en]

The decline in sea cucumber fisheries that serve the Asian dried seafood market has prompted an increase in global sea cucumber aquaculture. The tropical sandfish (Holothuria scabra) has in this context been reared and produced with mixed success. In the Western Indian Ocean, villagers often participate in the export fishery for sea cucumbers as a source of income. However, with a growing concern of depleted stocks introduction of hatcheries to farm sandfish as a community livelihood and to replenish wild stocks is being promoted. This review identifies and discusses a number of aspects that constitute constraints or implications with regard to development of sandfish farming in the region. The conclusion is that for sandfish farming to live up to its expectations the possible impacts need to be further studied, and that improved evaluation of ongoing projects is required. In the interim a precautionary approach towards new enterprise activities is suggested. 

Keyword
Sandfish, Holothuria scabra, Farming, Re-stocking, Environmental impacts, Governance
National Category
Ecology
Identifiers
urn:nbn:se:su:diva-75521 (URN)10.1007/s13280-011-0195-8 (DOI)000303464700001 ()
Available from: 2012-04-20 Created: 2012-04-20 Last updated: 2017-12-07Bibliographically approved

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Output format
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