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Friday, October 26, 2012

Bow riding

Ready for Pelagic Week #2?  During the next week I'll be highlighting sightings from a boat trip to Bodega Canyon and Cordell Bank on 26 October 2012.  Here's a chance to meet your offshore neighbors!

Northern Right Whale Dolphins (Lissodelphis borealis) are challenging to photograph.  They streak through the water and leap into the air at unpredictable moments.  Today a few decided to ride the bow waves of the boat.

Remember that right whale dolphins lack dorsal fins, so their backs are extremely smooth.

If you look closely at these pictures, you can see the small, curved pectoral fins held out to the side.  These fins are used for steering (the flukes, not visible in these photographs, are used for propulsion).

Here's a view of an animal under water.

A couple of new facts I learned about right whale dolphins (thanks to the Mammalian Species account by Jefferson and Newcomer and the Field Guide to Marine Mammals of the Pacific Coast by Allen, Mortenson, and Webb) :
  • Females give birth every 2 to 3 years
  • In the North Pacific, calves are born during summer 
  • Calves are not black like adults, but instead have brown/gray/cream coloration; they become black by the end of their first year
  • When born, the calves are estimated to be ~80-100 cm in length

For more information about Northern Right Whale Dolphins (Lissodelphis borealis), review the post from early September.

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