You Guys must be insane I saw those guys on the discovery channel Weapons and Warfare unlike Sasquatch the Seals are real and dont like people shooting at them with sling shots and BB guns.
Seriously there isn't a heck of alot you can do other than hollering and throwing things which will make a lot of noise and any thing you throw becomes litter so why not just go about your bussiness and see what happens. The way we are polluting the sound you probably wont be seeing harbor seals and sea lions as often down the road ,so enjoy it while you can it is just part of the marine enviroment that we are enjoying when we go out there.