Comparative survival of color morphs of the bay scallop Argopecten irradians irradians

Restoration of the bay scallop Argopecten irradians irradians in the Peconic Bays of Long Island, New York began in 2006 after the decimation of the population by brown tide algal blooms between 1985 and 1995. The uncommon “skunk” color morph (one or more white rays on a dark shell background) was planted to help track the contribution of restoration efforts to population rebuilding. Preliminary studies on survivability suggested that skunks may have a lower survival rate than “normal” color morphs (dark shell without white rays). To examine this hypothesis, four types of analyses were done: tensile strength of shells and growth rates of different color morphs were determined, relative proportions of the color morphs within natural populations were quantified at different life stages (post-set, large juvenile, adult) and rates of predation by mud crabs Dyspanopeus sayi, on different color morphs were compared. Results show that the “normal” color morph has a much higher tensile strength than all other color morphs tested as well as a slower growth rate. Predation experiments gave no significance for differences in predation although there are suggestions that “skunks” may be more likely to be preyed upon than the “normal” color morph. It was also seen that the proportion of skunks within the population increased as they grew from spat to adults which was unexpected. In conclusion, the “skunk” color morph is significantly weaker than the normal color morph and there are indications it may be subject to higher predation rates and thus higher mortality.