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   Bill Lang

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   OEMM Web Team

Position on 07/03/2005, 02:59 UTC; 29 04.959N; 088 06.591W

The Gulf greeted us with rather strong winds and our way out of the Gulfport Channel and the route south was very choppy and wet. We deployed the hydrophone array around 04:00 local time and began our regular acoustic monitoring. We had planned to head south almost into the middle of our survey area and then turn west. However, just before we were planning to make the turn, at around 05:00 in the morning, we heard faint clicks. The next listening station 15 minutes later confirmed that we had encountered a group of sperm whales. We switched from surveying to tracking and by 06:30 local time we had seen the first blows. Even though the wind had calmed down somewhat, the sea was still very rough and made spotting and getting to whales difficult. The first few attempts ended in the whale fluking before we were close, or in us loosing sight of the blows between all the white caps.

Fortunately, the weather improved slowly during the day, and by 12:00 we had a good idea of how many animals we were dealing with and their approximate distribution. This was a group of individuals that were widely distributed, did not exhibit coordinated behavior, and we estimated that there were four animals in the area.  They were clicking regularly and fluking up (see Photo 1). During this time, they moved in roughly north-easterly direction. Interestingly, this heading coincides well with the direction of the continental slope.

As usual, though, just when you think you know what to expect (in this case: the animals remain separated and do not coordinate their behavior), the whales topple all of that: At 14:30 local time, they stopped their regular clicking and dives and started grouping. First, we had two animals join together, than a third, while a fourth individual remained in the distance. By 15:40, the fourth animal had joined the trio (see Photos 2 and 3). They were either logging at the surface blowing very slowly, or they shallow-dove and disappeared from the surface for up to half an hour. None of them clicked or fluked anymore. Finally, a fifth animal appeared around 17:30. As previously, we first saw the blows at a distance, and kept track of them. We never saw the animal fluke (although we may have missed that in the distance) and this fifth whale did not click either.

The animals stopped vocalizing and started to click again sometime during our dinner break. We are currently tracking them and are planning to stay with this groups throughout the night to determine if they continue with their north-easterly movement.

Photo 1: Even though working on sperm whales involves long periods of patient tracking, when a whale is at the surface, things have to happen quickly. Here, Christoph is taking the fluke ID photo (in front),while Sam measures the distance to the fluke (at back with laser range finder) from the bow of the Summer Breeze.

Photo 2: View across the Summer Breeze, with the four logging sperm whales just recognizable right behind the stern of our research vessel.

Photo 3: Two of the socializing sperm whales, with  platform A (Ram-Powell) in the background.

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Last Updated: 08/08/2008, 01:52:02 PM