The Cultured Abalone farm in Goleta, California, also is farming halibut, Hippoglosuss hippoglosus. The experimental project is not on a commercial scale as this point but does occasionally sell a limited amount to local restaurants. Dough is the resident marine biologist that is heading up the project. They keep a brood stock of mature halibut. Dough is experimenting with feed and can vary the final product by how the fish is fed the last 2-3 weeks prior to harvest. He uses sardines to produce a fish with a higher fat content.
European companies are already on a commercial scale. Scotland is producing 200 metric tons and Norwegian concerns are producing 500 metric tons. There are challenges in making is sustainable. One odd fact is that male halibut outnumber female 3:1. The issue is that male halibut have a growth plateau that makes them less economical to bring to market size. Here is a link that has more details.
The halibut were delivered live, in a plastic bag with sea water and an oxygen flush. I place them in the fridge overnight and they were dead the next day. The fish had a lot of slime on the skin which seemed unusual. Preparation was easy. I prepared the fish by dredging in flour and sautéing in butter with a lemon-wine deglazing and more butter. The flesh was firm, not dry and a pleasant, mild taste. The two fish were enough to serve four guests.
Juvenile Halibut, 1-2"
Market Ready Halibut, 3 years
Halibut Fillet Sautéed