Current State of Seagrasses in Zanzibar: Impacts of Coastal Economic Activities and Marine Protected Areas on Seagrass Cover

Seagrass meadows are located abundantly in Zanzibar, Tanzania and provide essential ecosystem services, such as sediment nutrient enrichment and blue carbon sequestration. However, seagrasses have been less researched or protected than other marine ecosystems. Although environmental variables affect seagrass health, evidence suggests that anthropogenic impacts are their greatest threats. The rapid expansion of seaweed farming and tourism and widespread use of harmful small-scale fishing practices in Zanzibar have contributed to the degradation and removal of seagrass meadows, disrupted coastal marine food chains, and reduced local biodiversity that seagrasses support. Public or private marine protected areas (MPAs) protect most of Zanzibar’s coastal marine ecosystems, yet evidence is unclear whether MPAs effectively conserve marine ecosystems. Using geographic information systems (GIS) to estimate the change in percent of seagrass cover from 2006 to 2019, we conducted Spearman’s rank correlation analyses to identify whether seagrass degradation was correlated with seaweed farming, fishing, or tourism and whether MPA management plans were protective. Tourism was negatively correlated with seagrass cover, r(9) = -0.74, p = 0.044, suggesting that tourism is an important driver of seagrass declines in Zanzibar. No other variables were significantly correlated with seagrass cover decline. To improve the management of seagrass meadows, plans must identify seagrasses as critical ecosystems, expand seagrass restoration projects, and address harmful practices in the tourism industry and other human impacts

Recent rise in exploitation of Tanzanian octopuses: a policy and management challenge

The artisanal octopus fishery is important for the coastal communities in Tanzania. In this work the octopi landing data from the United Nations Food and Agriculture Organization (FAO), Ministry of Livestock and Fishery Development (MLFD) and trade statistics from Comtrade of the United Nations were analysed. The FAO dataset show that from 1980 to 2017 annual octopus landings stayed below 2000 tons until 2018 when the catch increased to 2864 tons, and doubled to 5,687 tons in 2019. FAO datasets show large catches in 1995, 2003 and 2019, with 2019 recording the largest catch. For both Comtrade and MLFD export statistics, approximately 5,818 and 2,254 tons of octopus were exported globally from 2018 to 2020 with an equivalent value of approximately 13 and 19 million US$ respectively. Portugal was the largest importer of Tanzanian octopi, followed by Turkey, Italy, Spain, Netherlands, Israel, France and Panama. The current management interventions relating to octopi are presented, including the challenges needed to be addressed for sustainability of the octopi fishery. Voluntary octopi closures indicated some signs of success, but an in-depth assessment of the associated effects is required. The study recommends a need for verification mechanisms to ensure consistency of FAO and MLFD statistics, stock assessments, in-situ research on recruitment patterns of octopi, as well as innovation and research in designing sustainable fishing gear to support development of policies for sustainability

Comparison of Seaweed Growth, Fish Abundance and Diversity in Deep Water Floating Raft with Tubular Nets and Shallow Water Off-bottom lines Seaweed Farms

This study compared the growth performance of Eucheuma denticulatum, fish abundance anddiversity between deep water (using tubular nets) versus shallow water (off-bottom) seaweedfarming methods. For each farming method, three plots were set and fish abundance, diversity andseaweed growth rates were measured at intervals of 15 days. Belt transects measuring 10 m x 4 meach, were established on seaweed farms for fish observations. Fish were identified to the lowestpossible taxonomic level by underwater census. The results showed that the growth rate of E.denticulatum in deep water farms was slightly higher at an average daily growth rate (DGR) of3.42 ± 0.18% day−1 compared with 3.01 ± 0.27% day−1 for shallow water farms but with nosignificant differences (p = 0.079) likely due to higher herbivory in the deep water farms. Fishabundance and diversity were higher in deep water farms but insignificant (t (34) = 0.69, p = 0.49and t (34) = 0.424, p = 0.67, respectively). Habitat complexity and seaweed growth rate were almostsimilar for both farming methods hence attracting comparable numbers of fish. Further studies arerecommended on fish community structures, differences between the two farming methods andeffects of herbivory. Keywords: E. denticulatum; seaweed farming methods; growth; fish diversity and abundanc

Abundance, spatial distribution and threats to Indo-Pacific bottlenose dolphins (Tursiops aduncus) in an Important Marine Mammal Area in Tanzania

Funding: Thanks to the US Marine Mammal Commission (MMC) and the People’s Trust for Endangered Species who funded his work via the Wildlife Conservation Society (WCS).Abundance estimates of cetaceans in the western Indian Ocean are rare, but important, as many cetacean populations are under threat, especially those in coastal habitats. This study aimed to generate first estimates of abundance for Indo-Pacific bottlenose dolphins (Tursiops aduncus), assessed as Near Threatened on the IUCN Red List, in an area identified by the Marine Mammal Protected Area Task Force as an ‘Important Marine Mammal Area’. Two study sites were surveyed along the east and west coastlines of the Pemba Channel, Tanzania. In west Pemba, between 2014 and 2016 four boat-based visual surveys conducted a total of 2467 km of survey effort sighting a total of 16 groups of T. aduncus. Abundance was estimated using mark-recapture models of photo-identified individuals as 83 animals (CV 7.8%, 95% CI 72-97) in the 1084km2 study area. In the Tanga study area in 2016 two boat-based visual surveys covered 1254 km of effort during which 15 groups of T. aduncus were sighted, resulting in a photo-ID based mark-recapture abundance estimate of 196 (CV 8.9%, 95% CI 165-233) individuals in the 1562 km2 study site. Group encounter rate for this species in Tanga was double that recorded in the Pemba study site. A total of 23% of identified dolphins bore the scars of interactions with fishing gear.Publisher PDFPeer reviewe

Improvement of Tuberculosis Laboratory Capacity on Pemba Island, Zanzibar: A Health Cooperation Project.

Low-income countries with high Tuberculosis burden have few reference laboratories able to perform TB culture. In 2006, the Zanzibar National TB Control Programme planned to decentralize TB diagnostics. The Italian Cooperation Agency with the scientific support of the "L. Spallanzani" National Institute for Infectious Diseases sustained the project through the implementation of a TB reference laboratory in a low-income country with a high prevalence of TB. The implementation steps were: 1) TB laboratory design according to the WHO standards; 2) laboratory equipment and reagent supplies for microscopy, cultures, and identification; 3) on-the-job training of the local staff; 4) web- and telemedicine-based supervision. From April 2007 to December 2010, 921 sputum samples were received from 40 peripheral laboratories: 120 TB cases were diagnosed. Of all the smear-positive cases, 74.2% were culture-positive. During the year 2010, the smear positive to culture positive rate increased up to 100%. In March 20, 2010 the Ministry of Health and Social Welfare of Zanzibar officially recognized the Public Health Laboratory- Ivo de Carneri as the National TB Reference Laboratory for the Zanzibar Archipelago. An advanced TB laboratory can represent a low cost solution to strengthen the TB diagnosis, to provide capacity building and mid-term sustainability

Supporting Spatial Management of Data-Poor, Small-Scale Fisheries With a Bayesian Approach

Marine conservation areas are an important tool for the sustainable management of multispecies, small-scale fisheries. Effective spatial management requires a proper understanding of the spatial distribution of target species and the identification of its environmental drivers. Small-scale fisheries, however, often face scarcity and low-quality of data. In these situations, approaches for the prioritization of conservation areas need to deal with scattered, biased, and short-term information and ideally should quantify data- and model-specific uncertainties for a better understanding of the risks related to management interventions. We used a Bayesian hierarchical species distribution modeling approach on annual landing data of the heavily exploited, small-scale, and data-poor fishery of Chwaka Bay (Zanzibar) in the Western Indian Ocean to understand the distribution of the key target species and identify potential areas for conservation. Few commonalities were found in the set of important habitat and environmental drivers among species, but temperature, depth, and seagrass cover affected the spatial distribution of three of the six analyzed species. A comparison of our results with information from ecological studies suggests that our approach predicts the distribution of the analyzed species reasonably well. Furthermore, the two main common areas of high relative abundance identified in our study have been previously suggested by the local fisher as important areas for spatial conservation. By using short-term, catch per unit of effort data in a Bayesian hierarchical framework, we quantify the associated uncertainties while accounting for spatial dependencies. More importantly, the use of accessible and interpretable tools, such as the here created spatial maps, can frame a better understanding of spatio-temporal management for local fishers. Our approach, thus, supports the operability of spatial management in small-scale fisheries suffering from a general lack of long-term fisheries information and fisheries independent data.En prens

Social, economic and trade characteristics of the elasmobranch fishery on Unguja Island, Zanzibar, East Africa

Understanding the socio-economic drivers underpinning fishers' decisions to target elasmobranchs is considered vital in determining sustainable management objectives for these species, yet limited empirical data is collected. This study presents an overview of elasmobranch catch, trade and socio-economic characteristics of Zanzibar's small-scale, artisanal fishery. The value of applying this information to future elasmobranch fisheries policy is demonstrated. In August 2015, interviews were conducted with fishers (n = 39) and merchants (n = 16) at two landing sites, Kizimkazi-Dimbani and Mkokotoni, along with the main market site in Stone Town. Additionally, elasmobranch catches were recorded across the same locations between June and August 2015. Elasmobranchs were listed as target species by 49% of fishers interviewed. Whilst most fishers (n = 30) stated that 76–100% of their household income came from fishing, there was variation in how elasmobranch catch and trade contributed. One-third of fishers (n = 36) that caught and sold elasmobranchs reported that 41–60% of their income came from elasmobranch catch. However, for some fishers (n = 8) elasmobranch catch represented 0–20% of their income, whilst for others (n = 4) it represented 81–100%. Differences in fisheries income and elasmobranch price could be attributed to several interacting factors including season, weather, fishing effort, fishing gear, target catch and consumer demand. Further, elasmobranch price was influenced by size and species. The study revealed information on catch, trade, markets and socio-economy that is important for future research, conservation and management of elasmobranchs and fisheries in Zanzibar. The methods utilised have potential for broader application to understudied, artisanal elasmobranch fisheries in the western Indian Ocean