Condition of the quahog,Mercenaria mercenaria, from polluted and unpolluted waters

Abstract

The meat volume-shell length regressions and the relationship of the meat volume to shell length in the formula, K=meat volume/shell lengthⁿ, were used to compare the condition of quahogs,Mercenaria mercenaria, from polluted and unpolluted waters in Point Judith Pond, Rhode Island. Quahogs were collected in November, 1961 from adjacent waters on each side of the pollution line set by the state and from the cleaner waters near the mouth of the estuary.

Interpretations based on the comparison of condition (K) did not agree with those based on the comparison of the meat volume-shell length relationships. Sampling variation, inherent in the estimation of n, probably resulted in unrepresentative K values. Conclusions as to the relative condition of quahogs were based on the comparison of the meat volume-shell length relationships by covariance. These analyses suggest that, if environmental conditions, including indirect effects of pollution, are beneficial to quahogs, the gain in meat volume is not impressive. The adjusted mean meat volume of quahogs sampled from cleaner waters of the estuary was only 1.19 cm³, less than that of quahogs from the area adjacent to but outside the portion of the estuary classed as polluted. There was little difference between quahogs from the harvested area below the pollution line and those from adjacent locations up-estuary.