Derelict fishing nets remain a persistent and widely dispersed form of marine pollution, particularly along remote northern Australian coastlines where detection and recovery are logistically constrained. This presentation examines how Beyond Visual Line of Sight (BVLOS) uncrewed aerial vehicle (UAV) operations extend low-altitude coastal survey capability for detecting stranded nets, with emphasis on mission planning and communication reliability. Surveys were conducted using a battery-powered fixed-wing UAV in the Anindilyakwa Indigenous Protected Area, operating at 60 m AGL to achieve centimetre-scale resolution sufficient to detect small, fragmented, or partially obscured nets. Propagation-aware mission design, incorporating line-of-sight and first Fresnel zone clearance, was used to maintain stable command-and-control (C2) links under low-altitude conditions. Results from 20 BVLOS missions covering 210 km of coastline are presented alongside statistical modelling of C2 link performance, showing that communication reliability is primarily constrained by distance, with terrain effects largely mitigated through pre-flight planning. Comparison with simulated Visual Line of Sight (VLOS) scenarios demonstrates substantial gains in survey coverage and detection availability under BVLOS deployment. Together, these findings indicate that BVLOS operations provide a necessary framework for large-area, high-resolution coastal monitoring when supported by propagation-informed mission design.