The proposed rule will revise the Harbor Porpoise Take Reduction Plan - Mid-Atlantic to require a change in a gear characteristic in the gillnet fisheries regulated by the Plan.  The current Plan requires the use of twine no smaller than 0.9mm in diameter in large mesh gillnet gear in the Mid-Atlantic during certain times of the year. This proposed rule would modify the twine size requirement to align with a recent Joint Action by the New England and Mid-Atlantic Fishery Management Councils intended to reduce bycatch of sturgeon listed as endangered or threatened under the Endangered Species Act.  Measures included in the Framework Adjustments to the Monkfish and Spiny Dogfish Management Plans require a twine size of 0.81mm as part of a suite of gear modifications known as low profile gillnets. NMFS published a proposed rule to approve and implement through regulations the measures in the Framework Adjustments intended to reduce the bycatch of Atlantic Sturgeon (89 FR 65576, August 12, 2024). The twine diameter used in the low profile gillnets is described as a critical component of the nets’ success. NMFS is exercising its discretion and authority under the Marine Mammal Protection Act (16 U.S.C. 1387, Sec. 118 (f)) to make this change in the Plan to correspond with the Councils’ action.  Harbor porpoise mortality and serious injury in gillnets fished in the Mid-Atlantic management area is approaching insignificant levels. Reducing the allowed twine diameter is not expected to measurably affect that trend. This proposed rule is intended to allow fishers to continue fish while remaining in compliance with the Plan after the expected effective date for enactment of the low profile gillnet portion of the Councils’ action, which is January 1, 2026.