A good way to see the Delaware Bay and the Lewes Canal harbor is to take a tour, by land or by sea. You can pick up a self-guided tour brochure from the visitor center in the Fisher-Martin House, on Kings Highway. It covers more than 40 sites and gives brief descriptions of each one. For sightseeing cruises from Lewes, call Fisherman's Wharf Cruises, 217 Anglers Rd. (tel. 302/645-8862), which operates narrated excursions around the historic harbor of Lewes and the Delaware breakwater areas. Trips include a 2-hour dolphin-watching cruise; a 4-hour whale- and dolphin-watching cruise; a 2-hour sunset cruise; and a 2-hour buffet dinner cruise. Prices range from $15 to $30. Most tours are offered June through September; call for details and departure times.