Protection of marine environment and reduction of GHG emissions are currently imperative criterion for ship design. For ships in service, including fishing vessels powered by internal combustion engines, options of retrofitting are sought to reduce their hydrodynamic resistance and fuel consumption. One such possibility is the addition of a simple-shape bulbous bow, which can be installed at low cost to upgrade a fishing vessel. We present an analysis of the effect that the bulbous bow has on fishing vessel resistance across the whole range of speeds at which the entire work cycle of the vessel is carried out. The resistance was calculated using a calculation of fluid dynamics (CFD) method for the actual size of the vessel. We show that it is possible to develop such a bulbous bow for which the resistance of fishing vessel with a bulbous bow is going to be lower than that of an unmodified shape. For the modified shape of the fishing vessel, fuel consumption, amount and composition of exhaust gases were calculated and the obtained results were compared with the parameters of the vessel without modification. The tests carried out and the obtained calculation results indicate that a significant reduction of fuel consumption and GHG emissions may be obtained for the existing old fishing vessels at low anticipated modernization costs.