“Little Marian Crawford, trowel in hand, searches for clams at Holmes Harbor. In the background with the shovel is Davin Fladager McCullough.Jim Larsen, staff photoThe first day of summer coincided with extremely low tides Thursday, driving Whidbey Islanders out onto the beaches in droves.Clinton resident Gina Crawford, for example, decided it was a fine time to take kids in her care to Freeland Park on Holmes Harbor. First they stopped at Sebo’s to buy the required licenses and read up on shellfish regulations, then they hit the beach, shovels and trowels in hand.The youngsters didn’t get right down to clam digging, however. Crawford served as the unofficial species expert as one kid after another brought her tiny crabs, shellfish and worms to identify.Eventually, Crawford hoped, the kids would do some serious clam digging, enough for three limits, more clams than anyone will eat. But even without clams, the venture onto the beach was worthwhile.My favorite thing to do in the summer is to take the kids adventuring, she said.Shellfish licenses are available at all fishing tackle dealers and cost $7.67 for adults ages 16 to 69. Those 70 and older pay $5.48. There will also be a dealer’s fee. Kids under 15 do not need a license.The minimum size limit for the most popular species of clams, such as littlenecks, butters and manilas, is 1 1/2 inches. The daily limit is 40 clams or 10 pounds in the shell, whichever comes first, all species combined. “