An inquest has begun into the deaths of four fishermen whose boat was recovered off Perth.
The 5.5-metre Yeah Buoy was reported missing after the group failed to return to Woodman Point from a trip to Rottnest Island on October 3, 2018.
The bodies of Jacob Tuan Pham, 24, and Justin O'Neill, 31, were found west of Garden Island in the days following.
Divers discovered human remains a month later belonging to Jacob's father, 50-year-old Uock Pham.
Uock Pham's brother, Tuan Pham, 43, has never been found.
The search for the older men was called off about a week after they went missing but a fisherman spotted debris about 13km off the coast between Carnac Island and Rottnest Island, prompting police to start looking again in late October.
Coroner Michael Jenkin is holding an inquest at the request of Tuan Pham's partner, seeking to confirm his death and establish how it occurred.
Counsel assisting the coroner Sergeant Lyle Housiaux said in his opening address on Friday witnesses would be called from WA Police and the marine safety branch of the Department of Transport.