Monday, July 14, 2003
I got up before sunrise (but not so early - it was 7:30) and went for a run in the beautiful morning light with clouds scattering the sky into oranges and yellows. Some fur seals were swimming, extending their pectoral flippers in the air. A man on the beach photographed them. The sun finally appeared at about 7:55. I terrified the cows as I ran through their pasture so that I had to stop and walk and talk soothingly to them.
After breakfast, Tim, Jenny, and Anita prepped us with basic information on the dolphins and on our research. Here are some of the things we learned.
In New Zealand, duskies inhabit the waters over the edge of a canyon over 1500 meters (4875 feet). In this location, there's a subtropical convergence zone where currents come together creating an upwelling of nutrient-rich water, which leads to excellent feeding. Here, the dolphins feed at night on lanternfish and squid, which come closer to the surface after dark. In the daytime, the dolphins rest, socialize, and mate in waters closer to shore. They are found in large groups of hundreds to thousands of animals.
We learned that aboard the Punua Aihe, we will be measuring environmental parameters as well. We'll use an anemometer to clock wind speed a compass for wind direction and, a refractometer to measure salinity, a thermometer for water temperature, and lower a secchi disk into the water to measure turbidity, or water clarity.
The tour boats also have allowed researchers to collect data aboard the tours themselves, learning that 90% of the dolphins viewed are in large pods, the boat is stationary 60 percent of the time during swims and the engine off 48 percent of the time. The average trip includes three "drops" of swimmers into the water and the average length of each drop is eight minutes.
Mating and young
Large groups of dolphins usually comprise smaller groups of individuals. In the summer, there may be hundreds of animals in a groups, while in the winter there may be thousands.
Seasonal migration and residency
The dolphins we saw in Kaikoura in the winter traveled from the south to spend the winters there, while those seen in Kaikoura in the summer move north in the winter to the Marlborough Sounds, on the north end of the South Island. The interesting thing is that the dolphins in the sounds, such as Admiralty Bay and Queen Charlotte Sound, act more like those seen by Bernd Wursig and other researcher in Golfo San Jose in Argentina. The continent does not seem to matter as much as the local environment. The Texas A&M researchers have learned that there about 250 dolphins in Admiralty Bay in the winter, many of them adult males. They travel in group sizes that average five or six animals and they feed during the daytime on schooling fish such as mullet and pilchard.
Next we were briefed on safety information and life aboard the research boat, the 5.5-meter (18-foot) inflatable Punua Aihe (Dolphin Calf). We learned how to use the radio in an emergency (Channel 16 - the international distress channel) and conversationally (Channel 80). The Earthwatch team has a good relationship with the dolphin tour operators. We went over some common sense things that might be the first forgotten in an emergency - remember to tell your potential rescuers where you are first, and also don't forget if you use a flare to aim it away from the boat!