II. _Overfishing._--The immediate and direct cause of the decline is _overfishing_. Increased demand causes a severe drain upon the shellfish beds, which soon leads to _over_fishing. It is not merely the hard working of the beds, but the continuous unmethodical and indiscriminate fishing which has caused the total extermination of once flourishing beds in certain localities. Under present methods a bed is worked until all its natural recuperatory power is exhausted, and then it is thrust aside as worthless, a barren area. Prof. Jacob Reighard, in "Methods of Plankton Investigation in their Relation to Practical Problems,"[3] aptly sums up the situation in his opening paragraph:-- In this country the fisherman as a rule continues to fish in any locality until fishing in that locality has become unprofitable. He then moves his operations to new waters until these in turn are exhausted. He is apt to look upon each new body of water as inexhaustible, and rarely has occasion to ask himself whether it is possible to determine in advance the amount of fish that he may annually take from the water without soon depleting it. In this way the shellfish beds have become exhausted through the indifference and lack of knowledge on the part of the fishing public. In colonial days the resources of the shellfisheries were apparently inexhaustible. The conviction that man could ever exhaust the resources of nature took firm hold of the Puritan mind, and even in the present generation many still cling to this illogical doctrine, although proof to the contrary can be seen on all sides. This idea has caused great harm to the shellfisheries, stimulating men to wreck certain localities by overfishing. III. _Pollution of Harbors and Estuaries and the Ill Effects upon Public Health through the Shellfisheries._--The unscientific disposal of sewage, sludge, garbage and factory waste may tend to rapidly fill up the harbor channels, as well as the areas where the currents are not so rapid.