I can't give an actual value of huge in that case, but it's much of the west coast. Much of the State of California out in federal waters was put into a closure area. That's why they're not meant to be permanent, but temporary.
What motivated those closure areas, in addition to the dramatic decline in rockfish populations that spurred it, was the problem that they are multi-species fisheries. In the process of fishing one rockfish, you simultaneously collect another, and it's the other that is actually in concern based on the small population size. At depth, you can't discriminate which species you're taking, whether it's hook and line or net fishing. Unfortunately, the only way they could ensure the protection of the really endangered ones was to eliminate the take of all of those species within those areas.