I've just come back from a trip to spain where taking
anything on scuba be it a crab, and octobus or a scallop is completely illegal, if caught the the penalty is the forfeiture of your kit and if you are diving from a boat you forfeit that too. The only way to dive for dinner is free diving.
Frankly I am happy to take a few scallops or the odd lobster/crab for the pot but I try to do it responsably, if there are plenty around then fine, if it's the only one I've seen all dive I'll leave it, and if the only way to stop dredging is to make an area a complete "no take" zone then I will happily oblige, I've seen the damage a dredger causes and it isn't pretty. I'd rather have plenty to see.

__________________
Give a hungry man a fish and he will eat for a day
Teach a hungry man to fish and he will buy a bad hat
Talk to a hungry man about fishing and you are a consultant.
Safe diving
Pete