Identifying Spatial Distribution of Fishing Effort of Artisanal Fishers in Coastal Kenya

Sammanfattning: Coastal ecosystems such as coral reefs are under threat from multiple stressors, which include overfishing, pollution, and climate change. These ecosystems provide services to society for example fisheries provide income and a source of food. The disruption of marine ecosystems has diminished the services available. Marine Spatial Planning is a strategy used to couple social, cultural, economic, and political aspects that overlay biophysical attributes of ecosystems, to help resolve potential stakeholder conflicts. Marine protected areas (MPAs) are used to prevent overexploitation and reduce degradation of the marine ecosystems and their services. However with inadequate information MPA placement can be wide of the mark, reducing the resilience and sustainability of the system. Designating MPAs is especially important for artisanal fishers who fish as a source of livelihood. This study develops a method to identify spatial distribution of fishing effort of artisanal fishers, by comparing métiers (gear and vessel combination) at five locations off the coast of Kenya. K-means clustering algorithm was used to segment GPS fishing tracks into different behaviours e.g. travelling and fishing, by using speed and turning angle (change in heading). Once clusters that indicate travelling were identified a heat map was created with the proportion of time spent in each cell. Subsequently Spearman’s rank correlation coefficient was undertaken between unfiltered (all GPS points) and filtered (estimated fishing locations) data, and between métiers. The results of intra-métier analyses indicated there was a difference, but all showed a positive correlation (0.47 to 0.93). Filtered inter-métier analyses produced negative correlations suggesting that all métiers are spatially segregated. This information is useful for many platforms and scales, and will provide a pathway to couple social and ecological systems together to ensure a resilient and sustainable future.