For crab its fine lobster you may want to consider a parlour as lobster can find their way out over time, a week is ok though. Just put plenty of bait in the pot if your leaving them for a week.
Its a spider crab I have occasionally use them as bait for lobster when I have been short of fish bait. Some of the old past fisherman used to only use spider crab for lobster as it also kept the pots empty of crab but you must make sure they are over the legal size limit. you can also use cooked crab remains