Crowninshield and Gerry islands with your dog: tide-timed walks in Marblehead

The regulations for the two islands match line for line. Dogs must be leashed at all times, and everyone, pets included, should be checked for ticks. Watercraft may land and nothing more, hunting is not permitted, alcohol is prohibited, and trash is carry in, carry out. The Trustees also warn that poison ivy persists in places despite work to remove it, and they advise treading carefully and wearing closed-toed shoes, which is one more reason to keep a dog on the path.

Neither island is on The Trustees' list of reservations that allow off-leash dog walking, and the organization's dog guidelines ask walkers to keep dogs from chasing or harassing wildlife and from disturbing vegetation. On islands this small, ringed with tide pools, a dog on a short leash does far less damage than one ranging at the end of a long line. Bag the waste and carry it back across, since the islands run on a carry in, carry out policy.

Gerry Island sits at the end of a natural gravel land bridge that is exposed at low tide, a rocky tombolo next door to Crowninshield, and it can be seen from Fort Sewall and from Gas House Beach. The Trustees say it can typically be reached only within about 90 minutes of low tide, and that a boat, kayak or paddleboard is needed at high tide. Allow at least half an hour on the island, and wear footwear that grips an uneven, slippery rocky shore.

The listed address is Gas House Lane, and that matters for a dog in summer. Gas House Beach is a town swimming beach, and Marblehead's bylaw section 13-11 closes town beaches to dogs from May 1 to October 1. The Trustees' page does not say whether the walk to the bar crosses that sand, so between those dates ask Marblehead Animal Control at (781) 631-1212 before you lead a dog across. Because of the terrain and the slope up from the bar, the island is not wheelchair accessible.

A low-tide walk leaves salt in the coat, seaweed in the feathering and a smell that rides home with you. A bath and brush at Dogtown, 210 Eastern Ave in Gloucester, means a warm wash, blow-dry and brush-out, priced by size from $55 for a dog up to 25 pounds to $85 for one over 90 pounds, and $95 for an extra-large long coat. An antiseptic or fungal shampoo is an $8 add-on if your vet has suggested one.

Grooming needs no evaluation, so the first bath can be booked online or in the Dogtown app. Marblehead is not a Pup Van town, since the van's $10 fare covers Gloucester, Rockport, Essex and Manchester-by-the-Sea, so plan to drive up through Salem and Beverly to Route 128, about 40 minutes outside rush hour by our estimate. When the low tide falls on a Saturday morning, book the bath ahead so it is waiting for you.