Use of Market Data to Assess Bushmeat Hunting Sustainability in Equatorial Guinea

Abstract: Finding an adequate measure of hunting sustainability for tropical forests has proved difficult. Many researchers have used urban bushmeat market surveys as indicators of hunting volumes and composition, but no analysis has been done of the reliability of market data in reflecting village offtake. We used data from urban markets and the villages that supply these markets to examine changes in the volume and composition of traded bushmeat between the village and the market (trade filters) in Equatorial Guinea. We collected data with market surveys and hunter offtake diaries. The trade filters varied depending on village remoteness and the monopoly power of traders. In a village with limited market access, species that maximized trader profits were most likely to be traded. In a village with greater market access, species for which hunters gained the greatest income per carcass were more likely to be traded. The probability of particular species being sold to market also depended on the capture method and season. Larger, more vulnerable species were more likely to be supplied from less‐accessible catchments, whereas there was no effect of forest cover or human population density on probability of being sold. This suggests that the composition of bushmeat offtake in an area may be driven more by urban demand than the geographic characteristics of that area. In one market, traders may have reached the limit of their geographical exploitation range, and hunting pressure within that range may be increasing. Our results demonstrate that it is possible to model the trade filters that bias market data, which opens the way to developing more robust market‐based sustainability indices for the bushmeat trade.     

Trace metal pollution in aquatic sediments and some fish species from the Kwilu-Ngongo River,Democratic Republic of Congo (Bas-Congo)

In this study, the concentrations of some metals in sediments and consumable fish from the Kwilu Ngongo River, province of Bas-Congo, Democratic Republic of Congo, are investigated. The digested muscle tissue, whole fish, and river sediment samples were subjected to trace element analysis by inductively coupled plasma mass spectroscopy and by using an automatic mercury analyzer. The highest values of trace metals in fish muscle tissue were found for Cr, Cu, Pb and Hg, with maximum values of 8.6 (Cr), 15.7 (Cu), 6.0 (Pb) and 3.3 (Hg) mg kg^?1. These values are higher than maximum tolerable limits recommended by the European Commission Regulation for Food. The highest metal concentrations in sediments were 81 (Cr), 86 (Cu), 21 (Sb), 41 (Pb), and 0.8 (Hg) mg kg^?1. Sediment toxicity tests using benthic crustaceans (ostracods) revealed mortality rates of up to 30% after six days of exposure to the sediments near the sugarcane industry outlet pipe discharge. The contamination of the sediments and fishes by the elements and the bio-accumulation of mercury in fish most likely arise from the adjacent agricultural fields where intensive sugarcane cultivation since 1925 has probably contaminated the soils through the long-term use of fertilizers and pesticides.     

Threats of illegal,unregulated, and unreported fishing to biodiversity and food security in the Republic of the Congo

Illegal, unregulated, and unreported (IUU) fishing poses a major threat to effective management of marine resources, affecting biodiversity and communities dependent on these coastal resources. Spatiotemporal patterns of industrial fisheries in developing countries are often poorly understood, and global efforts to describe spatial patterns of fishing vessel activity are currently based on automatic identification system (AIS) data. However, AIS is often not a legal requirement on fishing vessels, likely resulting in underestimates of the scale and distribution of legal and illegal fishing activity, which could have significant ramifications for targeted enforcement efforts and the management of fisheries resources. To help address this knowledge gap, we analyzed 3 years of vessel monitoring system (VMS) data in partnership with the national fisheries department in the Republic of the Congo to describe the behavior of national and distant-water industrial fleets operating in these waters. We found that the spatial footprint of the industrial fisheries fleet encompassed over one-quarter of the Exclusive Economic Zone. On average, 73% of fishing activity took place on the continental shelf (waters shallower than 200 m). Our findings highlight that VMS is not acting as a deterrent or being effectively used as a proactive management tool. As much as 33% (13% on average) of fishing effort occurred in prohibited areas set aside to protect biodiversity, including artisanal fisheries resources, and the distant-water fleet responsible for as much as 84% of this illegal activity. Given the growth in industrial and distant-water fleets across the region, as well as low levels of management and enforcement, these findings highlight that there is an urgent need for the global community to help strengthen regional and national capacity to analyze national scale data sets if efforts to combat IUU fishing are to be effective.