Interactions between bottlenose dolphins (Tursiops truncatus) and fishing gear have negative impacts on both dolphins and fisheries. Therefore, the damage and economic loss caused to the purse seine fishery were evaluated on a spatiotemporal scale, and the catch composition was addressed. Face-to-face interviews were conducted with the fishers, and observations aboard the boat were recorded between August 2018 and July 2019 in the M'diq region, northwestern Morocco. Throughout the study period, the frequency of fishing trips attacked by bottlenose dolphins was 44.75% (n=324), and the catch damage was 33%. In addition, depredated fishing operations were significantly lower in CPUE than unattacked ones. The total mending cost was 35,533.3$, with a difference between months and seasons. Bottlenose dolphins (Tursiops truncatus) attacked 32.2% of the fishing operations. However, this frequency of fishing operations depredated by depth was not significant. The current study proved that these interactions inflict substantial economic losses on the fishers of this region.