Temporal and Spatial variability in Reef fish Density and Biomass within the Dar es Salaam Marine Reserve System, Tanzania

This study was conducted within the Dar es Salaam Marine Reserve System with the aim of investigating temporal and spatial variations in reef fish biomass and density. Benthic cover which is a key factor for fish distribution was also estimated. Sampling was conducted from August 2014 to April 2015. Underwater Visual Census (UVC) techniques were used for the assessment of reef fish density and biomass, and line intercept transect (LIT) was used for the estimation of benthic cover. Results showed that there was a significant seasonal and temporal variation in fish density and biomass at both Mbundya and Bongoyo Islands. Benthic cover of live coral was significantly higher at Mbudya than at Bongoyo. It was concluded that Mbudya Island has less seasonal variation than Bongoyo due to the existence of a larger fraction of live coral cover. These results have implications for the management of marine reserves with regard to destructive fishing practices, a key factor impacting the stability and biomass of reef fish populations

Assessment of reef fish and benthic cover of the North and South Dar es Salaam Marine Reserves system before the 2016 El Niño

The status of reef fish density, diversity, species richness, biomass and coral cover was evaluated by comparing the conditions in two Dar es Salaam Marine Reserves (DMRs); the North Dar es Salaam Marine Reserve (NDMR; gazetted in 1975), and the South Dar es Salaam Marine Reserves (SDMRs; gazetted in 2007), before the 2016 El Niño. A 10 m line-intercept transect was used to characterize benthic cover and a 50 m belt transect was used to assess reef fish population status. Sampling occurred between August 2014 and April 2015. The results showed that fish biomass in the (NDMRs) was 2.7 times higher than that in the (SDMRs) and live hard coral cover was 3 times higher. Higher reef fish density, biomass, diversity, species richness and live hard coral cover were revealed before 2016 El Niño in NDMRs as compared to the SDMRs. Differences in status are linked to differences in time of gazetting and level of effective management in the marine protected areas (MPAs), where NDMRs has a General Management Plan (GMP) while SDMRs does not, and the differences in management are likely to have contributed to the differences in fish biomass and coral cover

Adoption and consequences of new light-fishing technology (LEDs) on Lake Tanganyika, East Africa.

Maintaining sustainable fisheries requires understanding the influence of technological advances on catch efficiency, as technological creep can ultimately contribute to increased efficiency. Fisheries using light sources for attraction could be widely impacted by the shift to light emitting diode (LED) light systems. We studied the transition from kerosene lanterns to LED lamps in Lake Tanganyika, East Africa, examining factors that led to adoption as well as the impact of the new light sources on fish catch and composition. We used a combination of field experiments with catch assessments, fisher surveys, underwater light spectra measurements, and cost assessments to evaluate the impact of switching from kerosene to LED lamps. Overall, we found a very rapid rate of adoption of homemade outdoor LED light systems in Lake Tanganyika. Most of the batteries used to power these lamps were charged from the city power grid, rather than photovoltaic cells, although the potential exists for a reduction in greenhouse gas emissions. The LED light spectra was distinct from the kerosene light and penetrated much deeper into the water column. Regardless of light type, most of the fish caught within the two dominant species were below maturity. Although the LED lamps were associated with a slight increase in catch, environmental factors, particularly distance offshore, were generally more important in determining fish catch size and composition. The main advantages of the LED lamps were the lower operating costs and their robustness in bad weather. Thus, the primary effect of the use of battery-powered LED lighting systems to attract fish in Lake Tanganyika appears to reduce economic costs and increasing efficiency. However, overall the lake's fishery remains vulnerable to overfishing

The role of MPAs in reconciling fisheries management with conservation of biological diversity

A workshop of over 100 participants, balanced between fisheries management and biodiversity conservation backgrounds, reviewed and synthesised experiences regarding policy and institutional frameworks for use of MPAs in the contexts of fisheries management and conservation of biological diversity. The workshop concluded that although fisheries managers and biodiversity conservation agencies may give differing and sometimes opposing weights to the many objectives that could be set for MPAs, only 25% of fisheries objectives and 30% of biodiversity objectives were considered to be potential sources of conflict. MPAs that segregate activities in space could contribute to resolving all but one of the potential conflicts over objectives associated with desired ecological outcomes. Conflicts over social or economic objectives could be improved, made worse, or not be affected by MPAs, depending on how the MPAs were developed and managed. Seven features of planning processes and six features of the governance processes for MPAs were identified that could help find broadly supported solutions to the conflicts that did occur. Once established, the management of the MPA should be inclusive and participatory, as well as continuously learning and adaptive. Approaches to ensure management had those properties were identified, including twelve specific mechanisms that should be available to the MPA managers. On the basis of these conclusions about objectives, planning, and management, a general framework for the governance of MPAs for both fisheries and biodiversity conservation was developed. Its ten general characteristics and twelve steps necessary for progress were identified. We discuss the special challenges of establishing and managing MPAs for fisheries and biodiversity conservation on the high seas that deserve further attention include information-sharing, coordination and defining jurisdictions and stake-holding