I'm guessing those are "shore crabs". Here are the regulations for those with a valid tidal license:
http://www.pac.dfo-mpo.gc.ca/fm-gp/r...quille-eng.htm
Crab, Shore
Area 1 to 27 Limit: 75 Apr 1 - Mar 31
Area 28 and 29 Limit: 0 Closed
Here's the map showing you where Areas 1-29 are.
http://www.pac.dfo-mpo.gc.ca/fm-gp/r...-carte-eng.asp
So if you have a license, you can retain up to 75 shore crabs from Areas 1 to 27 which are outside the Lower Mainland. The Lower Mainland span Areas 28 and 29 and you can keep 0 from there.
Now for "Other Crabs" like hermit crabs, you can keep 4.
Crab, Other
Areas 1 to 29 Limit: 4 Apr 1 - Mar 31
You can even keep 6 starfish per day with a license (useful for those who want cheap food for their Harlequin shrimps).