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Journals 2003/2004

Elizabeth Gibbs
Thompson Middle School, Newport, Rhode Island

"Impact of human activities on dusky dolphin behavior and population biology"
Field Station, Kaikora, New Zealand
July 13 - 25, 2003

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Friday, July 11, 2003

I arrived in New Zealand yesterday after a 12-hour flight from Los Angeles to Auckland. It was 9:30 p.m. Tuesday, July 8 when we left L.A. and 5 a.m. Thursday, July 10 when we reached New Zealand. What happened to Wednesday?! New Zealand time is 16 hours ahead of Eastern Daylight Savings Time. So when it's noon Monday in Rhode Island, it's 4 a.m. Tuesday in New Zealand. What's even weirder is that when I leave Auckland it will be 4 p.m. August 10, but when the flight lands, about 12 hours later, in L.A., it will be only 9 a.m. August 10! You "lose a day" on the way there, but "gain a day" on the way back.

Another thing that is a little hard to get used to is that in July, it's winter here! We could see snow-covered mountains from the plane when landing in Christchurch. There is rarely snow on the coast in the winter and the temperature so far has been in the 40s-not too cold. But the sun doesn't rise until about 8 a.m. and it sets about 5 p.m. Even at noon, it looks like it's about 3 p.m. The sun is very low. At home, at noon in the summer we don't cast a shadow. Here, at noon, a person's shadow is already longer than their height.

Another thing that's different is the night sky. I like to go look at stars in the evening at home-I look for the Big Dipper and the North Star, Orion, Andromeda, Perseus, the Pleiades (Seven Sisters), Taurus the Bull, Gemini, Sagittarius. But when I first looked at the night sky in New Zealand, what could I recognize? The moon! That was it! Now I know the Southern Cross, but that's all so far. I hope to know many more by the end of my trip.

Even the moon is strange here, and the sun too. In Rhode Island (and the rest of the northern hemisphere), they appear to "travel" from left to right (east to west), passing through the south. So at noon, the sun is in the southern sky. But in the southern hemisphere, the sun appears in the northern sky at noon. While it still "travels" from the eastern to the western sky, there it moves from right to left. And the quarter moon, which was illuminated on the right and dark on the left in L.A., is the opposite here!

Prior to the trip and on the plane, I've been reading some articles about dusky dolphins to prepare for my field experience. Here are some interesting things I've learned so far:

  • Dusky dolphins live only in the southern hemisphere, but they are found off the coasts of South America, southern Africa, and New Zealand.
  • Duskies are fairly small, about 1.8 meters (just under 6 feet), which means that an adult may be about as long as I am tall.
  • Off the New Zealand coast, dolphins travel in pods. The pods may be made up of smaller "subgroups" that contain five to 15 individuals each. These subgroups will often dive together for food. The pod moves tightly together when searching for their favorite food-fish and squid.
  • The dolphins may dive to 100 meters (325 feet) or more to catch food. The dive normally takes about 3 to 5 minutes.
  • Dusky dolphins are known for their acrobatic leaps and spins. The reason for this behavior is not fully known, but makes a lot of noise and appears to be to signal other dolphins.
  • Orcas prey on dusky dolphins.
  • Dusky dolphins in Argentina work together in cooperative groups to hunt, but in New Zealand they don't seem to do this as much.
  • In Kaikoura, tourists can swim with dolphins from boats.
  • Off the coast of Kaikoura, dusky dolphins rest in shallower water during the daytime and feed over deeper water at night.
  • Dolphins are descended from land animals (wow!). They have very small vestigial bones where their ancestors once had legs.
  • It is believed that dolphins have no sense of smell and little or no taste.
  • The fastest dolphin (I'm not sure what species) can swim 28 to 32 kilometers per hour (17.5 to 20 miles per hour).

Here are a few that questions I have

  • Are there reasons besides signalling that dolphins leap?
  • Do dolphins sleep? If so, how?
  • When do duskies mate and give birth?
  • Does the abundance and type of prey differ seasonally?
  • What's the difference between a dolphin and a porpoise?
  • Do duskies rely heavily on echolocation to catch their food?

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