April 16-17: Final Mooring Operations & Wrapping Up at Sea

The Pioneer 21 Leg 2 expedition continued with steady progress over the past two days, successfully completing the final major mooring operations and supporting regional oceanographic research.

Operations began with a shift to the East Array Profiler Mooring (EAPM) site, where the team conducted a smooth and efficient mooring turnover. Under sunny skies and calm seas, EAPM-2 was deployed according to plan, followed by a CTD verification cast and the recovery of EAPM-1. While the deck crew cleaned and prepared recovered equipment, the science team completed anchor surveys and began assembling the NEPM-2 buoy.

Throughout the evening, the ship transited between surface mooring sites, collecting EK80 acoustic data in excellent conditions. Early the next morning, the team resumed operations at the NEPM site.

Work at NEPM began before sunrise with the deployment of the new NEPM-2 mooring. Following a deeper post-deployment CTD cast, the team successfully recovered NEPM-1, noting that the buoy and riser remained in good mechanical condition. Minor equipment adjustments were completed during the recovery process, and the crew continued the established routine of cleaning, inspecting, and preparing gear.

Anchor recovery proceeded smoothly, and by afternoon, the deck was cleared and reorganized. The team also supported visiting scientists from the University of North Carolina and East Carolina University, who conducted CTD casts and Bongo net tows to study fish egg and larval distributions across the Mid-Atlantic Bight.

With the final profiler mooring deployments completed, the team will next conduct an ROV dive on the SEPM-1 anchor to assess its condition. Following the dive and anchor recovery, the Pioneer 21 cruise objectives will be fully accomplished. Departure from the Mid-Atlantic Bight array is scheduled for tomorrow afternoon, with arrival at Woods Hole planned in time for the Sunday morning tide.

(c): Nikki Arm, WHOI