Northern quahogs Mercenaria mercenaria are bivalve molluscs found in the intertidal to subtidal zones of shallow, protected coastal embayments from the southern Gulf of St. Lawrence to the Gulf of Mexico. The northern quahog is an important species for both the commercial and recreational fisheries as well as for aquaculture purposes in Prince Edward Island. The management strategy of the quahog resource is largely based on the minimum legal size of 50 mm (Landry et al. 1999). At the same time, there is a growing concern regarding the sustainability of the clam industry and hence, an evolving interest in stock enhancement. Effective brood-stock management, however, requires basic information about the animal's reproductive biology (DFO 1996).

Canadian populations of Mercenaria deserve recognition as stocks distinct from the larger population of the U.S. Atlantic coast. Although the hard clam occupies a virtually continuous range from Florida to Massachusetts, its distribution north of Cape Cod becomes disjunct.

The northern quahaug fishery complements the oyster fishery. For example, there is a concurrent oyster and quahaug spring relay fishery in PEI. The main commercial beds are located in the Miramichi and Cocagne areas in NB, Hillsborough Bay area in PEI and Pugwash/Wallace area in NS (Landry et al. 1999).

The quahaug fishery is composed of three major components: i) open water commercial, ii) closed areas (bacterially contaminated) and conditionally approved commercial* and iii) recreational. All three adhere to a minimum legal size regulation which is 50mm in NB and 38mm elsewhere. The recreational component has been controlled by a daily bag limit since 1994 (300 NB and PEI, 100 NS, total mix of all clam species). Harvesting activity in areas closed due to bacterial contamination has increased the relay fishery mainly in PEI and NS (DFO 1996).