GROWTH AND MORTALITY OF NORTHERN QUAHOG, (LINNAEUS, 1758) MERCENARIA-MERCENARIA IN PRINCE-EDWARD-ISLAND

Quahogs (Mercenaria mercenaria) from three locations in Prince Edward Island, Canada, were studied to determine growth and mortality levels in the northern limit of their natural geographical distribution. There were no significant differences among growth curves of these sites, although quahogs from Pownal Bay require an average of 13 years to reach legal commercial size (50 mm) compared to approximately 9 years in West River and Hillsbourough River. A reciprocal transfer experiment showed that the differences in growth rates observed between quahogs from Pownal Bay and West River were site specific. Among environmental parameters evaluated from these two sites, chlorophyll a correlated well with growth. High mortality levels at the West River site are attributed to the presence of a nemertean worm, Cerebratulus lacteus.