What sounds like the beginning of a Dr. Seuss book is actually a good way to describe the big fish swimming off San Diego's coast this week.A 10News viewer -- who is also a pilot -- submitted a picture of what appears to be a large shark about 10 miles off the coast of Carlsbad. He took it while flying in his plane, and he estimated the shark to be between 12 and 15 feet long.Dr. Nigella Hillgarth at the Birch Aquarium at Scripps looked at the pilot's picture and said, "The first reaction is definitely a shark and it's probably quite a large one."Hillgarth said she couldn't tell what kind of shark it was or the actual size."We have a lot of big sharks in this area; You'd be surprised," Hillgarth told 10News.That includes much smaller leopard sharks. On Friday, hundreds were spotted by Sky10 just feet from the beach at La Jolla Shores."It is an eerie experience until you get used to it," said Los Angeles resident Jack Foster, who was visiting the beach."It's one of the great wildlife sights around here. We get up to 800," said Hillgarth.Leopard sharks regularly come to La Jolla Shores every August to breed and are not considered dangerous to humans.