the 2017 Cooke Aquaculture net-pen collapse ... released some 260,000 nonnative Atlantic salmon into the sea
“It’s about the disease vectors and how that can escape into wild populations”
(Longer article on such fish farming)
Related, Reuters from February:
In an experiment a decade in the making, biologists are releasing hatchery salmon onto flooded Northern California rice fields, seeking to replenish endangered fish species while simultaneously benefiting the farmers' business model
Now, for the cost and inconvenience of flooding their fields, rice farmers are earning goodwill and betting that a healthy salmon population will avoid new regulations to protect wildlife and keep adequate water flowing.
In recent years, biologists discovered that as rice straw decomposes in flooded fields it creates a broth rich in fish food. They call it "zoop soup."
"The zooplankton are so big and they're so juicy, it's like filet mignon"