| 1. |
- Alonso Aller, Elisa, et al.
(författare)
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Fishing weakens a positive link between herbivore abundance and plant growth in tropical seagrass beds
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Herbivory is a key process influencing the structure and function of both terrestrial and aquatic systems. In seagrass ecosystems, moderate levels of herbivory may stimulate plant growth, compensating for the loss of eaten tissue. However, the relationship between herbivory and seagrass growth can be influenced by an array of factors, such as seasonality, herbivore abundance, and presence of epiphytes, many of which can be directly or indirectly affected by human activities like fishing. Here, we used data from a multi-season field survey in fished and protected seagrass beds to assess how fishing and seasonality affect the link between herbivores, herbivory, and plant growth in seagrasses. Path analyses revealed an interactive effect of seasonality and protection. In protected seagrass beds, seasonally high herbivore abundance positively affected herbivory rates, which in turn enhanced seagrass growth. This link was however not apparent in seagrass beds subjected to fishing activities. At the same time, seasonality effects seemed stronger in fished areas, suggesting that in addition to weakening a positive herbivory-plant growth interaction, fishing increases temporal instability of ecosystems. Our results highlight the need for evaluating not only the direct effects of fisheries exploitation on fish populations, but also the potential indirect effects on ecosystems, to improve fisheries management.
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| 2. |
- Alonso Aller, Elisa, et al.
(författare)
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Marine protected areas increase temporal stability of community structure, but not density or diversity, of tropical seagrass fish communities
- 2017
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:8
-
Tidskriftsartikel (refereegranskat)abstract
- Marine protected areas (MPAs) have been shown to increase long-term temporal stability of fish communities and enhance ecosystem resilience to anthropogenic disturbance. Yet, the potential ability of MPAs to buffer effects of environmental variability at shorter time scales remains widely unknown. In the tropics, the yearly monsoon cycle is a major natural force affecting marine organisms in tropical regions, and its timing and severity are predicted to change over the coming century, with potentially severe effects on marine organisms, ecosystems and ecosystem services. Here, we assessed the ability of MPAs to buffer effects of monsoon seasonality on seagrass-associated fish communities, using a field survey in two MPAs (no-take zones) and two unprotected (open-access) sites around Zanzibar (Tanzania). We assessed the temporal stability of fish density and community structure within and outside MPAs during three monsoon seasons in 2014-2015, and investigated several possible mechanisms that could regulate temporal stability. Our results show that MPAs did not affect fish density and diversity, but that juvenile fish densities were temporally more stable within MPAs. Second, fish community structure was more stable within MPAs for juvenile and adult fish, but not for subadult fish or the total fish community. Third, the observed effects may be due to a combination of direct and indirect (seagrass-mediated) effects of seasonality and, potentially, fluctuating fishing pressure outside MPAs. In summary, these MPAs may not have the ability to enhance fish density and diversity and to buffer effects of monsoon seasonality on the whole fish community. However, they may increase the temporal stability of certain groups, such as juvenile fish. Consequently, our results question whether MPAs play a general role in the maintenance of biodiversity and ecosystem functioning under changing environmental conditions in tropical seagrass fish communities.
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| 3. |
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| 4. |
- Jones, Benjamin L. H., et al.
(författare)
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Dependence on seagrass fisheries governed by household income and adaptive capacity
- 2022
-
Ingår i: Ocean and Coastal Management. - : Elsevier BV. - 0964-5691 .- 1873-524X. ; 225
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Tidskriftsartikel (refereegranskat)abstract
- Seagrass meadows, like other tropical coastal ecosystems, are highly productive and sustain millions of people worldwide. However, the factors that govern the use of seagrass as a fishing habitat over other habitats are largely unknown, especially at the household scale. Using socioeconomic factors from 147 villages across four countries within the Indo-Pacific, we examined the drivers of household dependence on seagrass. We revealed that seagrass was the most common habitat used for fishing across villages in all the countries studied, being preferred over other habitats for reliability. Using structural equation modelling, we exposed how household income and adaptive capacity appears to govern dependence on seagrass. Poorer households were less likely to own motorboats and dependent on seagrass as they were unable to fish elsewhere, whereas wealthier households were more likely to invest in certain fishing gears that incentivised them to use seagrass habitats due to high rewards and low effort requirements. Our findings accentuate the complexity of seagrass social-ecological systems and the need for empirical household scale data for effective management. Safeguarding seagrass is vital to ensure that vulnerable households have equitable and equal access to the resource, addressing ocean recovery and ensuring sustainable coastal communities.
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| 5. |
- Jones, Benjamin L., et al.
(författare)
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Seagrass Structural Traits Drive Fish Assemblages in Small-Scale Fisheries
- 2021
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Seagrasses - a group of foundation species in coastal ecosystems - provide key habitat for diverse and abundant faunal assemblages and support numerous ecosystem functions and services. However, whether the habitat role of seagrasses is influenced by seagrass diversity, by dominant species or both, remains unclear. To that end, we sought to investigate the specific seagrass characteristics (e.g., species diversity, seagrass traits) that influence tropical fish assemblages, and place this in the context of small-scale fishery use. We surveyed seagrass variables at 55 plots, nested within 12 sites around Zanzibar (Tanzania) in the Western Indian Ocean, and used Baited Remote Underwater Video (BRUV) systems to assess fish assemblages across plots. Using linear mixed models, we reveal that seagrass structural complexity and depth were the best predictors of fish abundance, with higher abundance occurring in deeper meadows or meadows with high canopy, leaf length and number of leaves per shoot. Moreover, an interaction between seagrass cover and land-use was the best predictor of fish species richness, where sites closer to human impacts were less affected by cover than sites with lower human impact. Overall, models with seagrass species richness or functional diversity as predictors poorly explained fish assemblages. Fish taxa that were important for small-scale fishery sectors (e.g., emperors, snappers, rabbitfish, and parrotfish) were primarily driven by seagrass structural complexity. Our results provide a unique analysis of the relationship between seagrass habitat and its associated fish assemblages in that we show that seagrass species diversity had little effect on seagrass fish assemblages, which instead appear driven by specific seagrass traits and seagrass cover. If conserving high value species that support adjacent fisheries is the priority for protecting seagrass meadows, then seagrass areas should be chosen with high cover and structural complexity that are in deeper waters. Any conservation measures also need to balance the needs of fishers that use the resources supported by seagrasses.
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| 6. |
- Wallner-Hahn, Sieglind, et al.
(författare)
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Destructive gear use in a tropical fishery : Institutional factors influencing the willingness-and capacity to change
- 2016
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Ingår i: Marine Policy. - : Elsevier BV. - 0308-597X .- 1872-9460. ; 72, s. 199-210
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to empirically assess institutional aspects shaping fishers' behavior leading to unsustainable resource use, by using the example of destructive drag-net fishing in Zanzibar, Tanzania. A broad institutional approach was used to specifically assess institutional factors influencing the fishers' reasons for the current use of destructive drag-nets as well as their willingness- and economic capacity to change to less destructive gears. Different regulative, normative, cultural-cognitive and economic factors (tradition, group-belonging, social acceptance, common practice, identity of drag-net users and weak economic capacity) were identified as critical elements influencing the current use of destructive gears, as well as obstructing changes to other gears. Hence, the importance of addressing all of these factors, matching to the different contexts, rather than focusing on fast-moving regulative measures, is emphasized to increase chances of management success. More promising approaches would be resource allocations to more sustainable fishing gears, well-managed gear exchange programs, as well as alterations of slow-moving normative and cultural factors, e.g. awareness raising on the advantages of more sustainable fishing gears, their traditional and cultural values, information on the actual income they generate, as well as education and an exchange of traditional knowledge on how to use them.
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| 7. |
- Alonso Aller, Elisa, et al.
(författare)
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Single and joint effects of regional- and local-scale variables on tropical seagrass fish assemblages
- 2014
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 161:10, s. 2395-2405
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Tidskriftsartikel (refereegranskat)abstract
- Seagrass beds are highly important for tropical ecosystems by supporting abundant and diverse fish assemblages that form the basis for artisanal fisheries. Although a number of local- and regional-scale variables are known to influence the abundance, diversity and assemblage structure of seagrass-associated fish assemblages, few studies have evaluated the relative and joint (interacting) influences of variables, especially those acting at different scales. Here, we examined the relative importance of local- and regional-scale factors structuring seagrass-associated fish assemblages, using a field survey in six seagrass (Thalassodendron ciliatum) areas around Unguja Island (Zanzibar, Tanzania). Fish density and assemblage structure were mostly affected by two regional-scale variables; distance to coral reefs, which positively affected fish density, and level of human development, which negatively affected fish density. On the local scale, seagrass biomass had a positive (but weaker) influence on fish density. However, the positive effect of seagrass biomass decreased with increasing level of human development. In summary, our results highlight the importance of assessing how multiple local and regional variables, alone and together, influence fish communities, in order to improve management of seagrass ecosystems and their services.
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| 8. |
- de la Torre-Castro, Maricela, et al.
(författare)
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Gender analysis for better coastal management - Increasing our understanding of social-ecological seascapes
- 2017
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Ingår i: Marine Policy. - : Elsevier BV. - 0308-597X .- 1872-9460. ; 83, s. 62-74
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Tidskriftsartikel (refereegranskat)abstract
- Although highly recognized as needed, studies linking gender and coastal/marine management are scarce. This research illustrates the importance of gender analysis in natural resource management by linking gender and coastal management i.e. Marine Spatial Planning. The research was conducted in various Zanzibar seascapes (Unguja Island, Tanzania). Using a typology comprising gender structure, symbolism and identity; the results show a clear gendered division of labor, highly associated with a gender symbolism in which traditional roles of women as responsible for reproduction activities played a major role. Men used the whole seascape for their activities, while women remained in coastal forests and shallow areas collecting wood, invertebrates and farming seaweed. These activities allowed women to combine productive and reproductive work. Ecosystem importance for subsistence decreased with distance from land for both genders, while the importance for income increased with distance for men. Both genders acknowledged seagrasses as very important for income. Income closely followed the universal pattern of men earning more. Identities were defined by traditional ideas like women are housewives, while men identities were strongly associated with fisheries with reinforced masculinity. Livelihood diversity was higher for women also showing a tendency of slow change into other roles. Management was found to be strongly androcentric, revealing a deep gender inequality. The research exemplifies how a gender analysis can be conducted for management enhancement. It also invites replication around the world. If management is found to be androcentric in coastal locations elsewhere, a serious gender inequality can be at hand at global level.
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| 9. |
- de la Torre-Castro, Maricela, et al.
(författare)
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Seagrass importance for a small-scale fishery in the tropics : The need for seascape management
- 2014
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X .- 1879-3363. ; 83:2, s. 398-407
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Tidskriftsartikel (refereegranskat)abstract
- Small-scale fisheries (SSF) in tropical seascapes (mosaics of interconnected mangroves, seagrasses and corals) are crucial for food and income. However, management is directed mostly to corals and mangroves. This research analyzes the importance of seagrasses compared to adjacent ecosystems in Chwaka Bay, Zanzibar, Tanzania. Using fish landings; the study investigated: location of fishing effort, fish production (biomass and species), and monetary benefits (aggregated value and per capita income). Seagrasses were the most visited grounds providing highest community benefits. Per capita benefits were equivalent to those from corals and mangroves. All three habitats provided income just above extreme poverty levels; however catches from seagrass appeared more stable. Seagrass are key ecosystems supporting SSF and protection and management are urgently needed. Adoption of a seascape approach considering all ecosystems underpinning SSF and the social aspects of fishing and a shift in emphasis from pure conservation to sustainable resource management would be desirable.
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| 10. |
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| 11. |
- de la Torre-Castro, Maricela, 1965-, et al.
(författare)
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Women and adaptive capacity to climate change in East African seascapes - Zanzibar as an example
- 2022
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- As the climate crisis persists, there is a crucial need to increase knowledge on adaptive capacity and the underlying factors building it. This is particularly important for disadvantaged groups, such as coastal women in East Africa. Women's livelihoods in these seascapes are and will be more severely affected by climate change and the capacity of East African states to deal with these challenges is limited in terms of financial and human capital. In this research, we investigated the underlying factors building the adaptive capacity of coastal women in Zanzibar (Unguja Island), Tanzania. Coastal women (N=117) were interviewed in villages around the island to gather information about potential factors supporting adaptive capacity. This was analysed applying Cinner et al (2018) five domains typology for adaptive capacity, i.e. assets, flexibility, organizations, learning and agency. The results show that women had relatively low adaptive capacity, extended poverty and very high dependence on seaweed farming of red algae, a livelihood providing low income and already being seriously affected by climate variability and change. Women's observations of key variables related to environmental changes corresponded to most scientific findings. It was, however, unclear how that knowledge is useful and enhances adaptive capacity. Adaptive capacity was generally low but individual differences were found in which ten women had a high income. The results show that the factors underlying adaptive capacity are complex and interact with each other, being positive, negative and unclear. Many of the identified factors deserve future research. This study adds to the pool of knowledge by addressing women (not only men); coastal ecosystems (as land and freshwater systems are more studied) and the individual level (since most studies focus on national and community levels). The study illustrates that institutional renewal, bridging and cooperation is possible in Zanzibar bringing good news to the region.
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| 12. |
- Drury O'Neill, Elizabeth, 1988-, et al.
(författare)
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Who benefits from seafood trade? A comparison of social and market structures in small-scale fisheries
- 2018
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Ingår i: Ecology and Society. - 1708-3087. ; 23:3
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Tidskriftsartikel (refereegranskat)abstract
- We examine the benefits flowing from a coastal seascape through seafood trade to various social groups in two distinct small-scale fishery case studies. A knowledge gap currently exists in relation to how benefits from a fishery, and the associated trade, are ultimately distributed, specifically, how market structures and relations, and the combined dynamics of the local fishing society, can mediate these flows. Previous research into improved fisheries governance for food and livelihood security has failed to integrate the structure of the market place as well as the multidimensional nature of actor relations that influence extractive behavior. Using a value chain framework, we take a relational approach to study these gaps. Surveys were conducted in two fisheries (Zanzibar and the Philippines) as part of a comparative analysis including market-types, assistance networks, and income inequality. Chain structures, gender roles, and levels of contractualization within the two cases differed vastly, appearing to give rise to different types of income inequalities and barriers to participation. In the Philippines economic exchanges revolve more around provision of financial capital, although in both systems social standing and obligations play a role in determining market structures. In Zanzibar trading agents engaging customers in predetermined sale arrangements earn relatively more than their counterpart freelancers, however at the production level no income differences are seen between those with or without arrangements. Both cases stand to be further integrated into the international seafood market, which raises questions over how certain actors will benefit, based on their current participation and access. Results emphasize the need for more evidence in regards to benefits flows and how aspects such as gender and transaction forms impact them. This is necessary for governance decisions around fisheries, poverty alleviation, and increased global market integration.
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| 13. |
- Fröcklin, Sara, et al.
(författare)
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Fish Traders as Key Actors in Fisheries : Gender and Adaptive Management
- 2013
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 42:8, s. 951-962
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Tidskriftsartikel (refereegranskat)abstract
- This paper fills an important gap towards adaptive management of small-scale fisheries by analyzing the gender dimension of fish trade in Zanzibar, Tanzania. We hypothesize that gender-based differences are present in the fish value chain and to test the hypothesis interviews were performed to analyze: (i) markets, customers, and mobility, (ii) material and economic resources, (iii) traded fish species, (iv) contacts and organizations, and (v) perceptions and experiences. Additionally, management documents were analyzed to examine the degree to which gender is considered. Results show that women traders had less access to social and economic resources, profitable markets, and high-value fish, which resulted in lower income. These gender inequalities are linked, among others, to women’s reproductive roles such as childcare and household responsibilities. Formal fisheries management was found to be gender insensitive, showing how a crucial feedback element of adaptive management is missing in Zanzibar’s management system, i.e., knowledge about key actors, their needs and challenges.
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| 14. |
- Fröcklin, Sara, et al.
(författare)
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Seaweed mariculture as a development project in Zanzibar, East Africa : A price too high to pay?
- 2012
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 356, s. 30-39
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Tidskriftsartikel (refereegranskat)abstract
- Seaweed mariculture has been promoted as a development project in tropical countries and Zanzibar, Tanzania, is commonly presented as a successful story. However, the results of the present research provide a nuanced picture of the activity identifying serious health problems among farmers. Semi-structured interviews were conducted with female seaweed farmers (n=140) and non-seaweed farmers (n=140) in Zanzibar to evaluate health and working conditions. In-depth interviews with additional 28 female seaweed farmers were performed to deepen the understanding of the working conditions and related problems. The research was undertaken at seven different locations to cover areas where seaweed is extensively executed during August to September 2009 and May to June 2010. Seaweed farmers considered their health significantly poorer than non-seaweed farmers with fatigue, musculoskeletal pain, hunger, respiratory problems, eye related problems, injuries from hazardous animals and sharp shells in the water and allergies as the most serious issues (p<0.05). Income was further reported below the extreme poverty line. Since seaweed farming affects thousands of households in the tropics these results should encourage changes towards better working conditions and sustainability.
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| 15. |
- Fröcklin, Sara, et al.
(författare)
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Small-scale innovations in coastal communities : shell-handicraft as a way to empower women and decrease poverty
- 2018
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Ingår i: Ecology and Society. - 1708-3087. ; 23:2
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed the potential of small-scale innovations, such as shell-handicraft, as a way to foster transformation toward sustainability, decrease poverty, and increase women's empowerment in Zanzibar, Tanzania. The shell-handicraft project was founded by USAID in 2006 and was introduced as an alternative livelihood to low-paid seaweed farming and invertebrate harvesting activities. The main objective, however, was to not only alleviate poverty and empower women, but also to improve management of coastal resources, and allegedly by doing so, break poverty traps. To analyze the potential benefits of this enterprise, and more specifically whether or not women involved in this project have been empowered, a framework was used that comprises three inter-related dimensions; agency, access to resources, and outcome. Agency includes the process of decision making, negotiation, etc., in which choices are made and put into effect. Access to resources (financial, physical, human, and social) is the medium through which agency is exercised, and outcome can be defined as the result of agency. Simply put, resources and agency make up people's potential for living the lives they want. Semistructured interviews were administered to a group of women (n = 36) involved in shell-handicraft and a group of women not involved in shell-handicraft (n = 36) in five villages located in central/south Zanzibar. The results show that over time, the women engaged in shell-handicraft have improved their access to a range of resources, mainly physical (house, cell phone, freezer, and electricity), human (knowledge in marketing, leadership, and entrepreneurship), and social (organization). This further resulted in reported improved self-confidence and decision-making authority within the household. Regarding financial resources, both savings and income improved for the targeted group, but more research is advised. Positively, the environmental impacts of the activity are seemingly low. Old shells are collected for handicraft and a number of no-take zones, as part of the project, have been established to preserve marine resources, which allowed for women's participation in coastal management. The project has also empowered women and challenged stereotypes, aspects critical for progressive and inclusive management. Although all in all, the women interviewed were satisfied and had increased their standard of living, the discussion problematizes this innovation by addressing scaling up possibilities, market constraints, and the kick-off process having external top-down elements. Even though the recipients of the benefits from the project have been few, this case has valuable elements to learn from and can provide inspiration to drive coastal systems into more sustainable paths.
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| 16. |
- Fröcklin, Sara, et al.
(författare)
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Towards Improved Management of Tropical Invertebrate Fisheries : Including Time Series and Gender
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:3, s. e91161-
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Tidskriftsartikel (refereegranskat)abstract
- Invertebrate harvesting is an important livelihood in tropical settings providing income and food for numerous populations throughout the world. However, the lack of research, policy and management directed towards this livelihood hinders the analysis of time trends to evaluate invertebrate resources status. Another missing aspect is the consideration of gender analysis, i.e., the different roles and interests of men and women engaged in this activity. Based on interviews, catch assessments and inventories this multi-disciplinary study from Chwaka Bay (Zanzibar, Tanzania) shows how unregulated harvesting of invertebrates may result in sharp declines in animal abundance over a relatively short period of time (2005 to 2010), threatening the sustainability of the fishery. Specifically, the results show that catches in general, and prime target species of gastropods and bivalves in particular, had been significantly reduced in number and size. Interviews revealed gender disparities; female harvesters experienced less access to good fishing/ collecting grounds and species of high value, which subsequently resulted in lower individual income. This is tightly linked to women's reproductive roles, which not only leads to limited mobility but also lessen their chances to accumulate livelihood assets (natural, physical, financial, social and human capital) thus impacting livelihood strategies. To protect invertebrate resources from overexploitation, and assure a constant flow of income and food for future generations, this case study illustrates the need for formal monitoring to assess changes in invertebrate resources, and possible ecological consequences, over time. Managers and policy-makers must also address gender to evaluate the contribution of all resource users, their capacity to cope with changing conditions, as well as specific interests.
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| 17. |
- Gustavsson, Madeleine, et al.
(författare)
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Procedural and distributive justice in a community-based managed Marine Park Area in Zanzibar, Tanzania
- 2014
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Ingår i: Marine Policy. - : Elsevier BV. - 0308-597X .- 1872-9460. ; 46, s. 91-100
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Tidskriftsartikel (refereegranskat)abstract
- Local participation in governance and management is assumed to lead to something good. But it is rarely explicitly stated who are participating and in what. The study investigates this in the context of a Marine Protected Area (MPA) in Zanzibar, Tanzania, and in particular the Memba Island - Chwaka Bay Marine Conservation Area (MIMCA). This is done by applying Pretty's typology of participation in addressing procedural justice, which is according to Paavola linked to distributive justice, i.e. the just distribution of costs and benefits. How does participation in MIMCA facilitate procedural and distributive justice? To answer this question a number of fishermen, women seaweed farmers, local leaders, and representatives of the private sector were interviewed (n=136) in five villages. Interviews were also made with government officials at relevant departments. The results show that Village Fishermen Committees were participating in the implementation of MIMCA but not in its planning phase. Participation was mainly in the form of manipulative and passive participation. Other local actors did not participate at all. Instead, the government assumed that justice was achieved by distributing equipment, alternative income generating projects, and relying on tourism for local development. However, the distributed equipment and tourism development have created conflict and injustice within and between villages, because of the insufficient resources which did not target those in need. Tourism created problems such as inequality between livelihoods, environmental destruction and local power asymmetries between hotel management and local people. The MIMCA top-down intervention has not increased participation or justice, nor has it achieved sustainable resource use and conflict resolution. It is suggested that interactive participation by all local actors is needed to create just trade-offs. justice needs to be explicitly addressed for integrated conservation and development projects to achieve sustainability.
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| 18. |
- Hedberg, Nils, et al.
(författare)
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Habitat preference for seaweed farming - A case study from Zanzibar, Tanzania
- 2018
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Ingår i: Ocean and Coastal Management. - : Elsevier BV. - 0964-5691 .- 1873-524X. ; 154, s. 186-195
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Tidskriftsartikel (refereegranskat)abstract
- Global marine seaweed aquaculture is growing rapidly. In Zanzibar, Tanzania, seaweed farming, primarily conducted by women, is the main coastal aquaculture activity. Many types of aquaculture are linked to a specific ecosystem (e.g. shrimp-mangrove), and understanding if such a coupling exists for seaweed farming important for further development. A prerequisite to understand if farming affects coastal habitats is the need to know where, and on which habitat, the farms are located. In this study, we investigated the habitat preferences of seaweed farmers by interviews, field observations and satellite imagery analysis. We found that the majority of the farms were distributed in a narrow corridor (380-600 m from shore) along the coast where water depth (x) over bar = 2 m) and tidal regime (+/- 2 m) allow for a suitable environment for both the algae and the farmers. Within this corridor, thus defined by depth, the water is deep enough for the algae not to be overexposed to sunlight but also sufficiently shallow for the women to access and work on the farms at low tide. The farmers accordingly expressed depth as the major limiting factor when choosing the site for their farms, and the preferred habitat type was seagrass beds. Most farms (92%) were partly located on seagrass meadows, but also other habitats, such as sand. The total area of the studied seaweed farms was 65.6 ha, with 39% of this being seagrass meadow, which is significantly more than the seagrass cover in the farming corridor. The farms also covered 43% sand; however, the interviews indicate that a substantial part of the sandy areas was, in fact, also recently covered by seagrasses. Our findings are relevant for improved management, conservation, and marine spatial planning, as we show where and on which habitats seaweed farms are preferably located. This information can be used to further investigate the ecological impact on the habitats and their associated fauna and in order to provide more effective management actions. Furthermore, this is much-needed baseline information for investigating the increased production of seaweed, i.e. if the habitat has any effect on the algae growth.
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| 19. |
- Hedberg, Per, et al.
(författare)
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Fish larvae distribution among different habitats in coastal East Africa
- 2019
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 94:1, s. 29-39
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Tidskriftsartikel (refereegranskat)abstract
- Fish larvae abundances, diversity and trophic position across shallow seagrass, coral reef and open water habitats were examined to characterize their distribution in coastal East Africa. Larvae were identified to family and analysed for abundance differences between sites and habitats, trophic level using stable-isotope analysis and parental spawning mode. Abundances differed greatly between sites with the highest numbers of larvae occurring in the open-water and seagrass habitats. Larval fish diversity was high across habitats with 51 families identified with small differences between sites and among habitats. Notably, larvae of abundant large herbivorous fishes present in reef and seagrass habitats were almost completely absent at all sampling locations. In the seagrass, demersal spawned larvae were more abundant compared with the reef and open-water habitats. Stable-isotope analysis revealed that fish larvae have a varied diet, occupying trophic level two to three and utilizing planktonic prey. This study offers new insights into distributional aspects of fish larvae along the East African coast where such information is sparse.
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| 20. |
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| 21. |
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| 22. |
- Nyström, Stina, et al.
(författare)
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Social structure of Indo-Pacific bottlenose dolphins (Tursiops aduncus) off the south coast of Zanzibar
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The social structure of Indo-Pacific bottlenose dolphins (Tursiops aduncus) resident in Menai Bay, Zanzibar, east Africa, was investigated using group characteristics and association records collected 1999-2002. On average, groups were large compared to those reported from other bottlenose dolphin studies. Groups were also significantly larger when the dolphins exhibited socializing behavior or when calves were present, indicating that large groups could be attributed to social benefits related to reproduction and caring for calves. To investigate relationships between identified individuals, an association analysis was performed using half-weight association indices (HWIs), calculated for 67 well-marked individuals sighted 9 or more times. While the overall distribution of HWIs was skewed towards lower values, relationships were stronger and more long-term than would be expected if dolphins were associating at random. A temporal analysis, performed to model the stability of associations, suggested that these relationships may last for as long as 7 years. Multidimensional scaling and cluster analysis revealed two female clusters and a male pair that had high HWIs across all years of sampling. These preferred relationships may be formed to obtain reproductive benefits as well as safety against predators and other threats. For example, the dolphins in Menai Bay are subject to anthropogenic threats from fishing and tourism activities in the area. Unless kept at a sustainable level, such threats could ultimately disrupt the long-term relationships observed in the present study and adversely influence the health of the population.
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| 23. |
- Pike, Felicity, et al.
(författare)
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Adaptive capacity within tropical marine protected areas – Differences between men- and women-headed households
- 2022
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Ingår i: Global Environmental Change. - : Elsevier BV. - 0959-3780 .- 1872-9495. ; 76
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Tidskriftsartikel (refereegranskat)abstract
- Households within tropical coastal communities face a multitude of stressors related to environmental, social and economic change. To minimise negative impacts on households, a priority is to understand and if possible build adaptive capacity to enable adjustment to both extant, and anticipated stressors. Adaptive capacity may not be equally distributed across households due to social differences and inequalities, including gender. In this study we sought to understand whether the factors underlying adaptive capacity differ between men- and women-headed households across three marine protected areas (MPAs) in Zanzibar, Tanzania. Adaptive capacity was significantly higher in men-headed households compared to women-headed households between different MPAs as a whole, however significant differences were not found for men and women-headed households within the MPAs. The factors underlying adaptive capacity were investigated through boosted regression trees, a relatively novel approach within the field, and found to be similar between men and women counterparts. These factors were agency, material conditions, low ecosystem dependence, education, occupational multiplicity and needs satisfaction (i.e. a poverty indicator) which was singularly important in women-headed households. While the factors themselves were similar in men and women–headed households, gendered differences were found regarding differing levels in the identified factors. Accordingly, the processes that underly the differences found should be addressed within initiatives seeking to understand and build adaptive capacity.
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| 24. |
- Pike, Felicity, 1993-, et al.
(författare)
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Dynamic livelihoods, gender and poverty in marine protected areas : Case study from Zanzibar, Tanzania
- 2024
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Ingår i: Ambio. - 0044-7447 .- 1654-7209.
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Tidskriftsartikel (refereegranskat)abstract
- Livelihood initiatives are common within marine protected areas (MPAs) aiming for poverty alleviation or higher income opportunities. However, results can be mixed in reality, as well as change over time. Furthermore, who benefits is a key consideration, as results can vary based on inequalities, including gender. Here, the monetary outcomes of different livelihood strategies were investigated across three MPA regions in Zanzibar, Tanzania. Using a quantitative approach, the results show that livelihoods have shifted in a six-year period, with livelihood strategies differing in poverty incidence and income. Livelihood initiatives, namely seaweed farming and tourism, did not provide significantly higher monetary returns compared to long-standing livelihoods, such as fisheries. Seaweed farming showed income stability but a high poverty incidence predominantly within women-headed households. During the study period, men primarily remained in fisheries, whilst women shifted to small-scale businesses and fisheries, largely exiting seaweed farming. This underscores a need for adaptive, gender sensitive management within fast changing coastal contexts.
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| 25. |
- Pike, Felicity, 1993-, et al.
(författare)
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Intertidal gleaning fisheries : Recognising local-scale contributions and management scenarios
- 2024
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Ingår i: Marine Policy. - : Elsevier. - 0308-597X .- 1872-9460. ; 162
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Tidskriftsartikel (refereegranskat)abstract
- Intertidal gleaning is a widespread means through which women participate in the fishery harvest sector. However, the fishery is often under recognised in management and policy-making. Accordingly, there is a need to further our understanding of the fishery, and how local factors may help or hinder effective management. This study focuses on Zanzibar, Tanzania, using focus group discussions (FGDs) and interviews to investigate local-scale contributions from gleaning in seagrass dominated areas – which are particularly frequented gleaning grounds locally, and more widely in the Indo-Pacific region. The study also gathered insight into how gleaners perceived different management scenarios used elsewhere within the small-scale fishery sector. Despite being typically viewed as a sustenance means, gleaning was found to be primarily an economic activity, mainly through catching the bivalve, Anadara antiquata, and commercial gastropod species (Chicoreus ramosus and Pleuroploca spp). FGD respondents held positive pre-conceived ideas about rotating no-take zone scenarios as a management strategy, as well as indicating preferences for community-based measures. In order for no-take zones to have a higher chance of success, further investigation is needed to understand the life histories of commonly gleaned species in order to inform rotation periods, as well as developing means of cross-community cooperation due to the shared, open access nature of intertidal zones. These results demonstrate the economic importance of gleaning for coastal women in Zanzibar, who have invaluable insights, built on lived experience and local knowledge, which could enable and benefit a more inclusive management system.
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| 26. |
- Yahya, Saleh A. S., et al.
(författare)
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Coral bleaching and habitat effects on colonisation of reef fish assemblages : an experimental study
- 2011
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Ingår i: Estuarine, Coastal and Shelf Science. - : Elsevier BV. - 0272-7714 .- 1096-0015. ; 94:1, s. 16-23
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Tidskriftsartikel (refereegranskat)abstract
- Degradation and mortality of corals is increasing worldwide and is expected to have significant effects on coral reef fish; hence studies on these effects are essential. In the present study, a field experiment was set up within Mafia Island Marine Park in Tanzania (East Africa) to examine the effects of bleaching and habitat structure on colonisation of coral reef fish assemblages. Live and bleached staghorn coral Acropora formosa was transplanted onto plots in a site dominated by sand and rubble, and the experimental design comprised of three treatments: live coral, bleached coral and eroded coral rubble. There was an immediate increase (within 24 h) in fish abundance and diversity in the two treatments with standing corals. Overall, live and bleached coral plots showed similar effects, but differed from the eroded coral plots which had a much lower abundance and diversity of fish. In general, fish species diversity changed with time over the study period while fish abundance did not. Multivariate analyses showed that while there were differences in fish assemblage structure between standing corals and the eroded coral treatment, there was neither a difference between live and bleached coral treatments nor any temporal effects on fish assemblage structure. Our findings suggest that physical structure and complexity of habitat have stronger effects on colonisation of reef fish assemblages than changes in coral health (such as bleaching) which do not affect coral structure. This may have important implications for appropriate coral reef management.
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| 27. |
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| 28. |
- Yahya, Saleh A.S. 1972-
(författare)
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Habitat structure, degradation and management effects on coral reef fish communities
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Coral reefs are among the most diverse and productive ecosystems on earth, and are critical to the survival of tropical marine ecosystems and sustenance of local human populations. However, coral reefs are quite vulnerable to disturbances, both natural and anthropogenic. This thesis looks at how coral reef communities have responded to climactic disturbances, particularly the 1997-98 El Niño Southern Oscillation (ENSO) and subsequent coral bleaching and mortality that affected much of the Indian Ocean, including the coastal waters of Tanzania, where the study was conducted. In particular, it investigates the effects of coral bleaching, habitat degradation and reef spatial arrangement on reef fish assemblages. Habitat structural complexity and spatial arrangement of reefs had an effect on reef fish communities. Fish communities showed patterns in distribution among habitats and between patch and continuous reefs. Fishes preferred live to bleached/dead or eroded coral, but trophic groups reacted differently to patch and continuous reefs. There were slight changes in fish abundance and significant changes in fish diversity on experimental, bleached branching Acropora coral plots over a period of one year. While fish abundance on one site increased shortly after a bleaching event, 6 years later fish abundance had decreased significantly. Conversely, coral reef communities in northern Tanzania had changed little over an 8-year period, with minor changes associated with the 1997-98 ENSO and the presence or absence of fisheries management. The coral reefs in the region were found to show high variability in community structure and responses of associated fish and invertebrate communities. The findings of this thesis indicate the importance of habitat structure and spatial arrangement of reefs, the detrimental effects of coral bleaching, and the possibility that some reefs and some (generalist) reef fish taxa may exhibit resilience to climate change.
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