|
Position at 29.49
88 40
We left Gulfport
today at 13:00 and are now heading back to the area were we observed
the group of five whales four days ago. We should reach that area
sometime around midnight. Regular acoustic monitoring will start
once we are deep (> 200 meters) water.
The days ashore
were used to take care of some important things. Not the least of
these were Jonathan’s ears, which received appropriate medical
attention as soon as we arrived in Gulfport on June 20. He felt much
better yesterday when he was heading to the airport to fly back to
Scotland. On the 22nd, Raul arrived so we are a full team
of seven again.
Several boat
repairs were completed, and we began work on a structure to mount a
directional hydrophone to a frame, which in turn is attached to the
boat. Besides the hydrophone array being towed behind the vessel
and that allows us to listen while underway, we also use a hand-held
directional hydrophone for tracking sperm whales at close range.
Until now, this directional hydrophone, which is attached to a long
pole, was deployed from the back deck. This is no problem when the
boat is perfectly still and there are no currents. Clearly, this is
only rarely the case, so usually, the person using this hydrophone
has to use some force to keep it from drifting, all the while trying
to interpret the sounds being picked up by the hydrophone. The
directional hydrophone mounted to the fixed frame will eliminate
that problem, and should also allow us to use the hydrophone during
moderate boat speeds. First trials this evening were promising,
although the drop-shaped housing for the hydrophone seems to be
turning away from the boat when in the water. We will work on that
issue during the coming days.
|