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.

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24Maintaining sustainable fisheries requires understanding the influence of technological advances 25 on catch efficiency. Fisheries using light sources for attraction could be widely impacted by the 26 shift to light emitting diode (LED) light systems. We studied the transition from kerosene 27 lanterns to LED lamps in Lake Tanganyika, East Africa, examining factors that led to adoption 28 as well as the impact of the new light sources on fish catch and composition. We used a 29 combination of field experiments with catch assessments, fisher surveys, underwater light 30 spectra measurements, and cost assessments to evaluate the impact of switching from kerosene to 31 LED lamps. Overall, we found a very rapid rate of adoption of homemade outdoor LED light 32 systems in Lake Tanganyika. Most of the batteries used to power these lamps were charged from 33 the city power grid, rather than photovoltaic cells. The LED light spectra was distinct from the 34 kerosene light and penetrated much deeper into the water column. Regardless of light type, most 35 of the fish caught within the two dominant species were below maturity, indicating that current 36 fishery is not sustainable. Although the LED lamps were associated with a slight increase in 37 catch, environmental factors, particularly distance offshore, were generally more important in 38 determining fish catch size and composition. The main advantages of the LED lamps were the 39 lower operating costs and their robustness in bad weather. Overall, the use of battery-powered 40 LED lighting systems to attract fish in Lake Tanganyika appears to reduce economic costs but 41 not contribute new impacts on the fishery. 42 43 3 46 resource (2), but advances in technology periodically allow for new access and extraction, and 47 require reassessment of sustainable harvesting. Many changes related to the adoption of new 48 technologies in artisanal fisheries are not documented nor properly assessed, and thus cannot be 49 properly integrated into management strategies (3).50 51 An important natural resource, the pelagic fishery in Lake Tanganyika, East Africa, faces a 52 number of challenges. This critical fishery substantially contributes to poverty reduction (annual 53 earnings of USD 10 million or greater) and provides food security in all riparian countries 54 (Tanzania, Burundi, The Democratic Republic of Congo, and Zambia). Explicitly, the lake's 55 pelagic fish catches are vital source of food and livelihoods to millions of people living in the 56 lake basin (4, 5). Presently, fishing pressure is very high with declines in catch per unit effort in 57 some areas of the lake and the potential for local overfishing (5-7). There are also some 58 indications of destructive fishing methods due to increased presence of illegal fishing gears (8). 59 These issues of fisheries conservation and sustainability are widespread, as similar challenges 60 exist in the other East African Great lakes as well as other inland lakes and reservoirs(9, 10).61 62Understanding the impacts of cha...

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.