Codders, yes really is no tresspassing.
As Jky says, they are bait tanks. Beneath the floating deck, are holding pens for ,small mackeral/sardines/anchovies/squid.
The sportfishing boats pull alongside and use large dip nets to fill the bait tanks on the boats. they are open 24 hrs a day.
Small boats can pull up also, but now the price has gone up due to the depletion of bait fish stocks. So a scoop (big enough to fill a small 10 gall live bait tank ) is about $30.00.
So they want to keep people off these barges as it interferes with their business . as well as its a great place to fish as it attracts a lot of fish(especially barraccuda ). Of course, when the Sealions are in; you may as well forget it. They will bite a fish right of your hook.They are very skilled at biting through the fish and just leaving the head on your line
Its always a love hate situation with these animals. They are great to watch and have around;just not when your'e fishing.
PS and yes always approach from upwind.