LMG03-02 Weekly Cruise Report

23 February 2003



The RV Laurence M. Gould (LMG) left Palmer Station Monday (2/17) and headed northwest towards the shelf break to start recovering the SIO and WHOI moorings deployed in the study area last year on LMG02-01A. Despite rough weather during the first few days, we were able to safely recover the four outer SIO moorings (S2A, S4A, S5A, and S6A) and one inner SIO mooring (S7A) by early Friday morning, when we headed towards the mouth of Marguerite Bay to the WHOI C3 mooring. The C3 mooring was retrieved late Friday afternoon in excellent condition.  When we arrived at the C2 mooring early Saturday, we found a very large iceberg just upwind of the mooring, so we quickly retrieved C2 before the iceberg could drift over the site.  We then moved to the C1 mooring, and even though we could talk to the acoustic release and could “see” the mooring in the ship's sonar, the release would not fire.  We left the C1 mooring in place and moved to the last SIO mooring (S9) near Adelaide Island.  S9 was safely recovered that evening, and we returned to C1 Sunday morning to work on C1. After the release still would not fire, we make one drag and cut the C1 mooring line just below the 325-m instrument. After getting the upper part of C1 with most of the instrumentation safely on deck, we spent the afternoon making a second drag for the remaining near-bottom VACM and release. After this drag was completed, the release responded that it was still in place and vertical, indicating that we had missed the mooring. This seemed a good time to stop mooring operations and regroup before attempting to drag again for C1.  The ship headed into more sheltered water just off Adelaide in order to safely move the Zodiacs down to the main deck with the main crane.  After this is completed, we will head south for the ice edge at the northeastern tip of Alexander Island to start more intensive marine mammal work. We plan to spend the next two days working off Alexander Island before returning back near C1.


During the daylight transits between moorings, the IWC observers have been busy, doing surveys and recording whale and other animal sightings along the track.  On Wednesday, as we finished recovering S2A off the shelf break, several groups of sei whales were spotted as they moved towards the ship.  Two sonobuoys were launched and with the ship declutched to minimize ship noise, we spent two hours recording these whales.  These are the first high-quality recordings of sei whales made in combination with visual identification of the whales when they surfaced.  Numerous humpback and minke whales have also been seen.


In summary, all of the SIO and WHOI moored instrumentation was recovered this week with just two exceptions, the bottom part of C1 and the northernmost S1A mooring.  This is in contrast with last year, when only two of the three WHOI B-line moorings set across the mouth of Marguerite Bay were recovered, and both B2 and B3 had significant iceberg damage. The three C moorings appear undamaged.  The C3 mooring was set at the B2 site, so we will have a two-year record at that site.


There is still considerable work to do in addition to marine mammal work before we head back to Palmer Station. We have three remaining WHOI isobaric floats to deploy, plus try again to recover the bottom part of C1.  If there is time, we may visit one or both of the AWS stations.


Bob Beardsley

Chief Scientist