Everything I have ever read has said they go into deeper water as the season progresses. It's one reasons, among several, why the openers are often good at piers but quickly see a drop-off in lobster. Boaters being in deeper water continue to catch lobster later into the season. As to when they return, that's a good question but I am assuming it's in the spring March-April-May.
We were at Goleta until about 10 PM last Friday, and never pulled up anything but an empty net. I talked to a diver earlier in the season, who said he saw lots of shorts, and took a few keepers. I had hoped that a friend could at least catch some shorts, even though she could not keep them.