Softshell Clams (Mya arenaria) - may be taken only from approved areas as classified by NHDES. Open to residents only, 6 years of age or older, license required ($30, free to ages 68+). Clam license must be displayed while clamming. Ten liquid quarts unshucked clams per day may be taken one half hour before sunrise to sunset on Saturdays only, from the day after Labor Day to May 31. The September opening of some areas may be delayed until mid/late autumn. Hampton/Seabrook Harbor flats will not open until November. Note that temporary harvest closures may occur due to heavy rainfall, high bacteria levels, red tide, or other factors. Call 1-800-43-CLAMS for updated information. Handheld tools with handles not exceeding 18 inches may be used. No shucked clams are allowed on or while leaving the waters of the state. Clam license number must be permanently marked on the outside of the clam container. New Hampshire clams may not be sold. The major softshell clam beds are located in Hampton/Seabrook Harbor, though softshell clams are present in less abundance in Little Harbor, Great Bay, Little Bay, and other locations.
Oysters (Crassostrea virginica) - may be taken only from approved areas as classified by NHDES. Open to residents only; license required ($30, free to ages 68+); season closed July and August; open September 1 to June 30, although the September opening of some areas may be delayed until mid/late autumn. Note that temporary harvest closures may occur due to heavy rainfall, high bacteria levels, red tide, or other factors. One-half bushel of unshucked oysters may be taken daily by hand or hand tongs only, between sunrise and sunset. No shucked oysters may be possessed while on or leaving any waters under the jurisdiction of the state. Illegal to take through the ice. New Hampshire oysters may not be sold. Oyster license number must be permanently marked on the outside of the container. Harvester shall have license on person. The major oyster beds are found in Great Bay.
Blue Mussels (Mytilus edulis) - may be taken only from approved areas. No license required; no limit. May be taken by residents only and for personal use only. Note that temporary closures of harvest areas may occur due to heavy rainfall, high bacteria levels, red tide, or other factors. In the Hampton/Seabrook estuary, blue mussels may be taken 1/2 hour before sunrise to sunset on Saturday only, from November 1 to May 31.
Surf Clams (Spisula solidissima), Mahogany Quahogs (Arctica islandica), and Razor Clams (Ensis directus) - may be taken only from approved areas as classified by NHDES. Surf clams and mahogany quahogs may be found along the Atlantic Coast, while razor clams primarily occur in the Great Bay Estuary. Open to residents only, no recreational license required. Recreational harvest by hand or hand held tools. Recreational harvest of surf clams and quahogs is limited to approved waters within 500 feet of the low tide line. Note that temporary closures of harvest areas may occur due to heavy rainfall, high bacteria levels, red tide, or other factors. Commercial harvest of surf clams or quahogs requires a commercial license ($300) Commercial digging may be by dredge with blade or knife not larger than 48 inches. Daily limit is 500 bushels of unshucked clams.
Source: NHF&G 2010 Saltwater Fishing Digest