Ocean-scale footprint of a highly mobile fishing fleet: social-ecological drivers of fleet behaviour and evidence of illegal fishing

Managing the footprint of highly mobile fishing fleets is increasingly important due to continuing declines of fish populations. However, social-ecological drivers for fisher behaviour remain poorly understood for many fleets globally.

Using the Sri Lankan fleet as a case study, we explored the role of social, environmental and policy drivers of effort distribution and illegal fishing. We used semi-structured interviews and participatory mapping with 95 fishers, combined with explanatory modelling (Generalised Linear Models, GLM) and multivariate statistics, including Principal Component Analysis (PCA).

Our findings highlight broad footprint (~3,800,000 km2) of this fleet, with fishing effort expended in high seas (53.9%), domestic (40.9%) and, illegally, in foreign waters (5.2%). 26% of fishers directly admitted to fishing illegally in foreign waters during interviews, whereas 62% of fishers indicated doing so during participatory mapping.

GLMs explained underlying decisions o...