April 12-13: Strong Start to Pioneer 21 Leg 2

Leg 2 of the Pioneer 21 spring expedition kicked off with smooth transit from Woods Hole and calm seas that allowed for CTD work along the LTER line. The science and engineering teams used the transit time to finalize documentation and prep for the operational push ahead.

At the Central (CN) site, operations began with an ROV dive to inspect the CNSW-1 mooring. The MFN and buoy were recovered—biofouled but mechanically intact—and a damaged Prawler was also brought aboard. The recovery was streamlined using the ROV to hook both riser and anchor in a single lift.

The new CN mooring, prepped at WHOI, was deployed without issue. CTD and anchor surveys followed, while the crew shifted focus to the Western site.

WESW-2 was deployed ahead of the recovery dive, which proved challenging due to 0.70-knot currents. The ROV eventually located the MFN (surrounded by fish), and the recovery was completed before nightfall.

Science resumed the next morning with CTD surveys and Bongo net tows led by visiting researchers from UNC and ECU, investigating larval fish distribution. On deck, the team cleaned biofouled gear and began building the SOPM-2 buoy.

A postponed meteorological survey at CNSM is set for tonight, with profiler mooring operations at the Southern site planned for tomorrow—weather looks favorable.