Reproductive cycle, spawning and early growth of soft shell clams (Mya arenaria) on Prince Edward Island

Reproductive evaluation of male and female soft shell clams ( Mya arenaria) was investigated using histologic examination of gonads from samples which were collected during spring, summer, and autumn months in the Malpeque Bay and Pinette River areas of Prince Edward Island (PEI) between 1997 and 1999. Clams were classified into 1 of 5 stages, inactive, active, mature, partially spent or completely spent. The data indicated that spawning commences mainly in the month of June and the duration of spawning varies between sites and years.

Triggers of spawning were examined including water temperature and month of year.

Several condition indices were tested to determine their accuracy in predicting spawning events. Steamed meat yield, a gravimetric index and a shell condition index were compared to results of histological analysis.

Larval monitoring was conducted using the plankton pump and plankton net methods to monitor the development of clam larvae in the water and to verify the date of clam spawning. (Abstract shortened by UMI.).