(a) General rule.--When the United States Fish and Wildlife Service or its successor certifies, on the basis of scientific evidence, that the catch of shad in the Delaware River and Bay and their tributaries has declined 100,000 fish or more under the previous year's catch in such waters and that there is evidence of prospective depletion, or when the commission, after investigation and on the basis of scientific evidence, finds that the fishery is threatened by depletion or that the fishing rate is too high to permit the continuance of a constant annual yield or that present exploitation threatens the future maximum yield of that fishery, it shall provide for the withdrawal in the following season of some or all of the licenses previously issued. In this connection, it may enter into administrative agreements with the pertinent administrative officials of the other states mentioned in section 7308 (relating to issuance of additional licenses) for the purpose of arranging a joint reduction of units of gear.

(b) Notice of intention.--When units of gear are to be reduced, the commission shall give public notice, in the manner set forth in section 7308, of intention to do so and of the number and character of units of gear to be withdrawn and from which areas.

(c) Method of withdrawal.--In effecting a reduction of fishing effort under the provisions of this section the commission shall withdraw shad licenses to be affected in the inverse order in which the shad licenses were issued except that if reduction of fishing intensity is sought with respect to a particular area or a particular operation license, withdrawals shall be in the inverse order in which the licenses were issued for that area or operation. In all instances where this procedure cannot be followed, resort shall be had to lots.