Understanding how fish escape does not require technical expertise. Fish bought by farmers are kept in pens or holding facilities and some way or another get away. Wave surges can break away from their anchors and in 1989 a major winter storm resulted in an algae bloom which killed so many fish it weighed down the pen and actually sank. Some fishermen also view aquaculture as competition and actually feel they may become obsolete. Luckily both the fish farmers and environmentalists can work together to reduce the numbers of fish escapes.
Releases result in a loss of profit for farmers and environmental concerns for scientists.
Improving anchoring devices to prevent damaged pens from washing away can solve losses from storms. More research and development into farm location, and insurance company demands forcing farm owners to meet certain requirements before startup of a farm. That is a good point but let me explain something first. The fish that escape have been held in captivity and are not truly wild fish. Many if not all of them are genetically altered compared to wild salmon.