I've seen them several times in the canal. Once to the right of the Cape side east end to the right of the jetty in 3 feet of water. Amazing how shallow they will swim. I think they eat crill and plankton.
They eat jellyfish, and since we get alarge amount every year (think about the "fire in the water" which is caused by plankton inside small jellyfish) and it's no wonder they are seen every year.