Effectiveness of interventions to shift drivers of roving banditry and reduce illegal fishing by Vietnamese blue boats

Abstract

Illegal fishing via roving banditry, or fishing illegally in other countries’ territorial waters, continues to threaten the security, sustainability, and biodiversity of global marine resources. Yet, little is known about the behavioral drivers of banditry, and whether interventions can shift these. We address this critical knowledge gap by quantitatively surveying 82 fishers in two known port havens (Da Nang and Sa Ky, central Vietnam) for roving banditry by Vietnamese “blue boats,” before and after interventions aimed at reducing illegal fishing. We present three key findings: (1) displacement from the South China Sea and degraded local resources were primary behavioral drivers, (2) interventions increased perceptions of risk and shame if apprehended, and (3) the source of bail money (i.e., family vs. business) was highly predictive of whether fishers saw punishment as an adequate deterrent to illegal fishing. Lastly, we discuss the implications of these findings for regional policy and management strategies.