The forecast last night was for winds around 12 knots this morning, but it dawned very calm. The whales we stopped working with at 9 last night were near a main concentration of beaked whales seen last year. To get the best odds of being with whales this morning, we conducted an acoustic survey of much of last year's concentration from midnight to 0700 when there starts being enough light for the visual team to work. Unfortunately, there were so many dolphins that it was difficult to search for the subtle clicks of beaked whales among the cacaphony of sound that dolphins make in the Med when they are feeding at night. In fact, one of the sounds is called nacchere in Italian. This is the word for castanets. When striped dolphins are around at night, there is often a constant background of these sounds.
Because it was so hard to detect beaked whales acoustically last night, we positioned the ship where we last were with whales at 9 the night before. The dolphins were still active acoustically, but the observation conditions were excellent for the visual observers. As the morning went on, the sounds of the dolphins became quieter, making it possible to search for beaked whale clicks acoustically as well.
Just before 11 AM the visual observers sighted beaked whales, and as before, several groups were sighted relatively quickly in the same general area. As before on this cruise, there seem to be clusters of groups of animals. The observers first settled on a group of 4 adult whales, 2 males (which can easily be identified by the white coloration of the front of their bodies), and 2 females.
The tag boat was deployed just before 1140. The best opportunity to tag this group came when the tag boat was within about 100 m of a surfacing, the perfect distance, but as the tag boat moved over, a group of dolphins swam over to the beaked whales and swam around them. Apparently, they were bothering the whales, as one of the beaked whale breached right among them. After the dolphin incident, the behavior of the whales changed. They changed their direction of travel and this prevented the tag boat from completing its approach.
At 1343, the visual observers switched to follow a group with two females and one male that was with a dorsal fin that was curled over to the side. This marking made it easier to make sure we were on the same group. In addition, this group seemed to keep surfacing in pretty much the same area, making it easier to position the tag boat.
After the observers switched to the group of three, the white male surfaced and blew normally, and then swam for about ten minutes just several meters below the sea surface. It was quite easy from the ship to observe the white shape of the male continuously, and the visual observers directed the tag boat close enough that they were able to follow him underwater even from their lower vantage point. They tailed long behind him until he and the females surfaced. Even though they were quite close, the beaked whales were travelling, and at this speed it was hard for the small tag boat to close on them for tagging.
In the end we were able to follow the same group of 3 beaked whales from surfacing to surfacing over a period of 5 hours. This leads to what probably are the craziest tracks that the Alliance has ever made. It is a tribute to the bridge officers that they are able to position such a large ship so well for following whales. The ability to make these kinds of observations is remarkable for a species that is so cryptic that new species of these large mammals are regularly discovered each decade. The coordination with the tag boat was excellent, and they had several good opportunities for tagging, but in the end we just were not able to close to a few meters distance for tagging. This is the reality with tagging beaked whales. There are a series of steps, each of which takes time, skill, and the appropriate equipment. It just takes a reasonable number of attempts even in the best of conditions to succeed in getting all steps done in time.
This was the last day of tagging effort before a partial change of crew tomorrow. We had to stop an hour before sunset and recover the tag boat. The entire team had a barbecue out in the middle of the study area as the sun went down before we head into port.
Everyone who is leaving wishes the second phase of the cruise fair seas and best of luck with tagging.