Populations of Mercenaria mercenaria texana (Gmelin) in Texas bays and their commercial potential

Moderate to low, contagious populations of Texas quahog clams (Mercenaria mercenaria texana) occupy high-salinity portions of Texas bays intertidally to over 3-m depths (rarely over 4 clams multiplied by m super (-2), usually much less). Small clams, less than 3 yr old, predominate directly adjacent to major passes, indicating more favorable conditions for recruitment and early survival. With increasing distance from the passes, population size-frequency composition shifts toward larger and older clams (upper Christmas Bay contains mostly clams 4 yr and older). Growth rates are comparable to those of the northern-quahog clam M. mercenaria (Linne) in Florida (30-40 mm high in the first year). Within Texas, growth appears somewhat more rapid in the southern bays (Corpus Christi) than in the northern bays (Galveston). Natural populations will not support a clam fishery in Texas, but hatchery development and a bay seeding program may support such a fishery.