Mitchell Bay, SJI to Prevost Harbor, Stuart Island.
After stopping at Roche Harbor for lunch and switching captains, we began sailing towards Stuart Island. At 14:00 we deployed the CRT hydrophone. The cable for the hydrophone was very sensitive causing interference and picked up a lot of flow noise. At 14:30, the hydrophone array was deployed.
There was still some flow noise interference, but it was much better than the CRT. As we reeled in the hydrophone array at 14:50, a group of Dall’s porpoises swam alongside the Gato Verde. There were 5-6 which included a hybrid with a Harbor porpoise. They were seen at latitude 48 deg. 43.08 min. N and longitude 123 deg.14.90 min. W.
students watching Dall's porpoise ride bow wake
While the Dal’s porpoises were riding around our boat, a male elephant seal poked his head above the water for a minute.
Just two days after having our first encounter with the transient killer whales, another marine mammal drew our attention. We were practicing deploying the linear array of hydrophones and comparing the differences between it and a single hydrophone in the afternoon of Wednesday April 22nd. As Peter was reeling in the array, a group of 5-6 Dall’s porpoises began swimming in the wake created by the bow of the Gato Verde. They swam with us for a good ten minutes, easily surpassing the boat just to fall back underneath again. Everyone ran to the bow of the boat and sat on the trampoline (net) between the two hulls of the boat. There were a few times that the porpoises surfaced under the trampoline seemingly to get everyone to scream in startlement.
Having fun swimming with our boat.
There was one porpoise that was determined to be a hybrid between the Dall’s porpoise and the Harbor porpoise. The animal was gray and white instead of the custom black and white of the Dall’s porpoise. The hybridization between the two species of porpoises always seems to occur with a male Harbor porpoise and a female Dall’s porpoise. The offspring is always seen with the Dall’s porpoises because the mother raises the young.
These animals are being massively hunted in the Pacific Ocean by Japan. When the International Whaling Committee banned commercial whaling, fisherman began focusing their attention on the Dall’s porpoise. More information about this animal can be learned at http://dallsporpoise.org/, and what you can do to help their plight.