Virginia Institute of Marine Science
Proceedings of the National Shellfisheries Association
In using traps to remove drills from oyster ground, assuming that trapping is an effective method of reducing the activities of these pests, it is important to keep costs at a minimum. One way of reducing the cost of trapping is to increase the time interval between lifts, but if the efficiency of traps varies with time, the nature of this relationship should be considered in choosing the optimum fishing interval.
The influence of time on the catch must also be known to determine the significance of the catch per trap in drill trapping experiments. Dr. Andrews, in the first paper of this series, used the catch per 100 traps per day as an index of availability. Are these indices comparable when the period between lifts of the traps varies, as it sometimes did on account of bad weather or for other reasons?
McHugh, J. L., Trapping Oyster Drills In Virginia II. The time factor in relation to the catch per trap (1955). Proceedings of the National Shellfisheries Association, 46, 155-168.