Thursday, March 3, 2011

There and Back Again

The green sea turtle (Chelonia mydas) or honu, is a familiar sight on our beaches and from our boat the Honu Kai as we traverse Kane'ohe Bay with our groups.

For many of us this is a fairly new phenomena - when I moved here a couple of decades ago turtles were here, but you really had to go out of your way to find them. Federal and state protections and education have made a difference.

I remember that it used to be very common to be doing a presentation to Elementary kids about turtles, and to have at least one kid announce, "my dad eats turtles." I have to say that this does still happen at times, but much less so than before.

As the turtle populations rebound, I now hear occasional rumblings about taking turtles again. There is a feeling that more turtles mean more shark attacks, although this does not seem to be the case. It is one of those attractive ideas that people will say "just feels right" - so it must be true. . . even if there is no evidence. Shark attack rates continue to be quite flat in number - probably tied more to more people (not turtles) in the water than anything else. It certainly seems possible that a shark could mistake a surfer for a turtle, but we still only have a few more shark attacks each year than Nebraska. So I am not worrying much - the lolo who nearly broadsided me in my car the other day is much higher on my list of worries.

This is similar to the idea that the shark feeding operation off of the North Shore would cause sharks to follow the boats back into shore. Folks are still sure this is true - despite a nice study that showed that it was just not true. Not at all, not even a little bit. However, it makes sense to people (based on what they fear), not what is real. But I digress.

The other argument I hear is that there are so many turtles now, it would not hurt to eat some of them. We have to keep in mind though that these are very slow growing animals, maturing at about 25 years of age. And that they are very obvious animals - many have even been named. It just seems like a lot, because they are large and visible. I don't mind eating ta'ape (the introduced snapper), there are schools of hundreds of them around. Don't see many "schools" of hundreds of turtles yet though.

But back to the main point of this post. On our DNA map matching activity, we place one green sea turtle by Oahu and one by French Frigate Shoals up in the Northwestern Hawaiian Islands. And the question asked is if the two belong to the same population.
The answer is yes, because about 90% of our turtle population swim back to French Frigate Shoals every so often (once they mature) to mate or lay eggs. This was finally confirmed last fall by a nice tracking study done by the Balazs Lab. Follow this link to a fascinating study of the travels of Hiwahiwa (L-2) and her 1000 mile trek to French Frigate Shoals and back. Thanks to one of our volunteers for sending this article on to be posted.



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