Re: Gender distribution of Humpback whales

From: Erich Hoyt (
Date: Tue Jan 11 2000 - 16:55:31 EST

Dear Claire,

A good question!

I have read more about the North Atlantic humpbacks (from the excellent
YONAH study) than about the North Pacific humpbacks. In the North Atlantic,
the sex ratio on the feeding grounds is equal. On the breeding grounds,
however, there are considerably more males than females that have been
biopsied. The researchers are not sure why, but it may be that the females
are going to some unknown location, or that the researchers are doing their
work primarily in an area where more males than females are found. In some
studies off Australia, similarly, more males were found on migration than
females (again using biopsies), but this may well also reflect the same
biases as above.

In Hawaii, I would suggest getting in touch with Deborah Glockner-Ferrari as
I know she was an early pioneer in sexing the whales around Maui. Dan
McSweeney, who runs a whale watch operation, will also probably have some
thoughts on this from his long background in research. Jim Darling, who is
based in Tofino, British Columbia, and who has worked extensively in Hawaii
(and shows up every year at the Whales Alive meetings), would also be able
to give a good answer -- the best that is known about the North Pacific

Hope this helps at least as a good starting point.

Best wishes,

Erich Hoyt

>Subject: Gender distribution of Humpback whales
>Date: Tue, Jan 11, 2000, 6:40 AM

> Aloha from Hawaii--
> I'm a boat captain and whale watch narrator/naturalist working on boats off
> the Kohala Coast of the Big Island of Hawaii. I was recently asked a
> question on one of the whale watch charters that I was unable to answer.
> Perhaps you could help. What is the proportion of male to female whales in
> the general humpback population? Do we know the proportion of males to
> females in the North Pacific Humpback stock? Is anyone trying to track
> gender distribution?
> Any clues you could give me would be much appreciated.
> Thanks,
> Captain Claire

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