Tasks Accomplished: 9) Collect Growth and Performance Data
Patrick Stewart and Sean Grealy, MVSG Staff, recorded oyster seed growth in the nurseries.
9) Collect Growth and Performance Data --
1999--Regularly (about every two weeks) throughout the growing season, samples of oysters and quahogs cultured in the nurseries were measured. The data was collected for several batches cultured at different densities in three of the four upweller nurseries. The data is presented in three pages of bar graphs titled Upweller Data Graphs which are attached.
On 6. August, 1999 Dr. Dale Leavitt and an assistant from the SouthEast Massachusetts Aquaculture Center traveled to the Island to measure current flow through one of the nurseries. Using a Marsh McBirney Paramagnetic Current Sensor an average flow rate through the tidal upweller was determined to be about 175 gallons per minute. The recorded flow rate appeared low, especially when one considers the exceptional growth rates recorded for the shellfish grown in the nurseries. Some of the growers timed the movement of pieces of seaweed flowing through the unit and from the observations estimated flow rates over six times the figure derived from the current sensor. More measurements over several tidal cycles are needed before a reliable figure for flow rate can be confidently reported .
2000 --Budget limitations prevented scheduled regular measurements of shellfish samples as were conducted in 1999. The growers, however, reported growth in 2000 to be similar to 1999.
A visual record of oyster growth in one group of seed oysters from Tom Berry’s upweller over the course of the summer was collected in a series of dated photos taken by Barbara Hanifan.