i carry a glock .40 cal off duty. my authority as a peace officer is basically only while on duty. therefore, my ability to carry a weapon is only for my personal protection. but, any citizen who can legally carry a weapon can use it in the defense of his/her own saftey. the key is to only use it to prevent great bodily injury or death. doesn't matter if it's a person, seal, or otherwise. but, the situation must be of immidiate danger, not the threat of. a seal swimming and barking around your boat doesn't count. but, a seal jumping up in a small boat does. the seal could cause the boat to capsize and a pissed off seal in a confined space is what i would concider immidiate danger. basically, if a seal breaches my boat, he is going to be full of holes. if this type of situation should happen to you, it would be best to dock the boat a.s.a.p and alert the cops. credability would be in your favor. how else would you get a 450 lb seal in your boat!?!