Title: Economic valuation of illegal fishing: an empirical study of beach seine ban enforcement in Lake Victoria Kenya

Beach seining was banned in Kenya in 2001 largely due to growth overfishing. To date compliance with this regulation remains a challenge to managers and policy makers. This paper applies Gary Becker’s model of rational criminality to examine violation of this ban in Lake Victoria Kenya using enforcement records between 2001 and 2012 with a view to identify its drivers.

Using 275 cases in Siaya, Kisumu and Homa bay counties, expected net benefit to fishing in violation of this ban was positive to both seine owners and crews (Ksh 1,079.40 and 746.75 respectively). This largely resulted from low probability of detecting (pd=0.1390) and arresting perpetuators (pa_c = 0.1136, for crew and pa_o=0.2300 for seine owner). Probability of a violator being proved guilty and penalised was 0.9897 and 0.9891 respectively while average penalty was Ksh 6,769.10 with most violators paying Ksh 10,000. Court penalty to owner of seine and crew was not significantly different although expected cost was. Increasing fines could deter violation but would likely not stop it altogether even if the prescribed upper limit was applied. Seine owners were most sensitive to pd, pa, revenue and cost of inputs. Improving probabilities of detecting seine owners with subsequent forfeiture of gear is most critical in enforcing this regulation. Although a hint to positive normative influence to compliance was observed, continued perpetuation of violation by few risk compromising legitimate and social concerns of those complying. Seeking these concerns alongside mechanisms that promote marginal deterrence is prescribed.