Ok, Bert was laughing cause it was the logo for Hot Tuna, a Aussie classic surf supplier.
They opened the business in the 1960's and were pretty well know in the hard core surf crowd in Australia, but it was never as well know internationally as names like Quicksilver and Rip Curl. Business apparently was booming for Hot Tuna in the '80s when Bert was out surfing.
We popped into a surf shop to see if they had a bumper sticker (cause I thought the fish was so cute,
haha). The guy at the counter looked up at Bert, "Old school, huh?"
Nothing like reminding somebody they aren't in their teens anymore!
Here are a couple of pics from the 'old school'
surfie.

Wind surfing....

Skimboarding when he was younger...
Most resent pictures of 'old school surfie' .... (above at Waitpinga, South Australia coming in from what I the newbie surfie would classify as terrifying waves:)

And here out in California (Oceanside I think)....