Coefficient and efficiency estimates
Fuel and crew expenses had significant positive impacts on the amount of landed shrimp. This likely indicates that boats on longer trips that cover more area and have more crew tend to land more shrimp per trip. In contrast, miscellaneous repairs and vessel depreciation had significant negative coefficients, indicating that higher vessel repair expenses lead to a higher likelihood of being prone to trouble at sea, which affects productivity. The negative impact of vessel depreciation expense
indicates that a high-value boat does not necessarily imply more landed shrimp. Ice had a positive coefficient, while grocery expense had a negative sign; both however, are statistically insignificant. The monthly dummies indicate that relative to December, trips made in June, July and September have significantly higher landings per trip. On the other hand, October and May are relatively lean months compared with December. The monthly differences in landings per trip indicate differences in stock abundance per month. Figure 1 provides the frequency distribution of technical efficiency per trip. The overall average efficiency of the fleet studied here is 0.46 implying that boats are only 46% of their full technical potential