How smart can a seal really be?

[Willy]

Has this happened to any of you?

My buddy took our hoops out to Mission Bay last week, just after the big storms we had.
He said the bugging along the jetty was skunk, and they had a terrible time with the seals. More than the usual terrible time the Mission Bay seals, they were dragging the hoops around, of course stealing the bait baskets, and here's the kicker:

My friend began a pull...it felt heavy...he got excited, until he found the bait basket gone, and the hoop filled with rocks!

Could the seals have filled the hoop with rocks, or used them to break the bait basket open?
I hoop a lot (not in the bay so much) and have never had this happen.
Anyone?

By the way there were no divers in the water, as it was still post storm zero viz...

Willy