Sunday, August 9, 2009

Working to tag beaked whales

Last night we set a track line for today designed to get a combination of the best weather suggested by our forecasts and the best beaked whale habitat. This morning there were low waves and whitecaps -- marginal for sighting and tracking beaked whales, but possible. We were hearing pilot and beaked whales near sunrise. We were not able to sight the beaked whales we heard, but we did sight pilot whales by 9:30. We decided to continue to try for beaked whales as they are our top priority for tagging.

The weather did not cooperate with us through most of the day, and the wind came up in the middle of the day. However, at 6 PM, the wind had changed direction and the seas lay down quickly.

The visual observers sighted beaked whales and we directed the ship to head towards the whales. Within half an hour the acoustics team picked up beaked whale clicks, probably from a different group, as the sighted whales were still making shallow dives. Right in this area, we sighted several different groups of beaked whales in a relatively short time, and hauled in the hydrophone arrays to get better mobility of the ship.

We selected a group of 3 beaked whales with no calves and with a male with a well marked dorsal fin to be the focal group we would try to tag. We prepared the tagging boat to be ready to deploy and maneuvered the ship towards the whales, which surfaced just a few hundred meters from the ship. We then slowed down the ship and were able to deploy the tag boat close to the whales, which were doing shallow dives.

For the next two hours until sunset, the weather and visibility conditions remained excellent, and the visual team used a plot of the times and locations of this group's surfacings to direct the tag boat to get as near as possible to where they thought the whales would surface. The plot comes from the GIS system that integrates all of the different kinds of data logged during the project, a real advance over earlier ways to store and display data from this kind of cruise. The key is to direct the tag boat to get within a few hundred meters of where the whales surface after a dive, so that the tag boat has time to maneuver to the whales with enough time to get close enough on a slow, quiet approach, to tag them. The tag boat did get within 20 m, but unfortunately, we ran out of daylight before we were able to tag them. The entire sequence from sighting, to acoustic detections, to maneuvering the ship and then the tag boat were as good as it gets!

It was great for the morale of the team to see how well our training has paid off. We just need more time with animals and good weather!