30 April 2001
Summary of Marine Mammal and Bird Observations
N.B. Palmer
 

A summary of the first week's marine mammal observations has been provided by Ari Friedlander. He reports the following observations made during the periods while the

ship was steaming and a survey was underway: Day 1-4 (24-27 April): Left PA, Chile through the Straits in reasonable weather (marginal swell, bss 3-4). Three groups of Commerson's dolphins were sighted, containing 5, 2, and 3 animals respectively) on the way east between Tierra Del Fuego and Patagonia. Soon after entering the Atlantic, one group of six hourglass dolphins was sighted. By the afternoon of 25 April, the weather in the Drake passage produced poor sighting conditions and only incidental mode was used. No other sightings occurred in this time.

Day 5: 28 April 2001: At Palmer Station several dozen fur and elephant seals were hauled out on rocky beaches. The ship then headed towards mooring #7 and then onto the first station for the transect grid. Weather was. Soon after leaving the station, one minke whale was sighted. Approximately 10 minutes later, a group of 3 humpback whales was seen. The animals were active at the surface with pectral fin waving, rolling, and fluking out. For the rest of the watch hours approximately 65 fur seals were sighted in the water.

Day 6: 29 April 2001: Patchy fog in the vicinity of stations 1 and 2 made sighting conditions moderate, as did BSS 5-6. The observation watch was maintained throughout the day until 1615 local time when light was too poor to survey. No sightings were made during watch hours, however, some mammal sightings were made at other times as noted in the report by Ribic and Chapman below.

Day 7: 30 April 2001: Blowing snow, high winds, and moderate seas made observations impossible in the morning and the observation watch was terminated by mid-day with no sightings.
 

Chris Ribic and Eric Chapman have summarized their bird observations.

29 April: Weather was our friend once again as snow flurries and 20 + knot winds subsided some as the sun rose this morning, allowing us to have 5.0 hours of surveying during transits between stations. It was great for us to be transiting between stations during so much of the daylight hours. Between stations 1 and 2, we surveyed between 12:49 and 17:04 GMT while BIOMAPER-II was deployed and operating. Between stations 2 and 3, we surveyed between 19:12 to 20:00 GMT when we no longer had enough light to detect birds within the our transect. Species list for the day: Southern Fulmar (Fulmarus glacialoides), Antarctic Petrel (Thalassoica antarctica), Blue Petrel (Halobaena caeruea), Cape Petrel (Daption capense), unidentified Storm Petrel.

Overall, densities were low today. Of birds that we observed, Cape Petrel, and Southern Fulmar were present in the greatest numbers. Antarctic Petrels were rare and a single unidentified Storm Petrel was observed off the transect. We also record marine mammal sightings and observed just two Southern Fur Seals (Arctocephalus gazella) today compared to the high numbers observed 28 April while leaving Anvers Island for the SO GLOBEC study area.

30 April: Despite snow and winds gusting to 40 + knots we managed to get 3 hours and 32 min of survey effort in today while transiting between CTD stations 4 through 7. Limited visibility within our 300 m and 600 m transects forced us to cut short our effort several times. Once again, we found bird densities to be low. Among the birds observed, Snow Petrels (Pagodroma nivea), Cape Petrels (Daption capense) and Southern Fulmars (Fulmarus glacialoides) were the most common. Species list for JD 120: Snow Petrel, Cape Petrel, Southern Fulmar, Antarctic Petrel (Thalassoica antarctica), Blue Petrel (Halobaena caeruea)

We also observed more Southern Fur Seals (Arctocephalus gazella) today, perhaps reflecting our proximity to land during today's transects. We also observed a single humpback whale (Megaptera novaengliae) within our 300m transect as we traveled parallel to Adelaide Island between stations 5 and 6. We notified the whale acoustics group who then dropped a sonabuoy at the location.

In spite of the difficulties with BIOMAPER-II, the work is proceeding on pace, and data from a variety of sources are now accumulating rapidly.

Cheers, Peter