Subject: Humpback whale paper/Birth (fwd)

Mike Williamson (
Tue, 16 Nov 1999 08:41:06 -0500 (EST)

---------- Forwarded message ----------
Date: Mon, 15 Nov 1999 15:23:25 -0500
From: Phil Clapham <>
Reply-To: Marine Mammals Research and Conservation Discussion
Subject: Humpback whale paper

The following paper was recently published:

Clapham, P.J., Wetmore, S.E., Smith, T.D. and Mead, J.G.  1999.  Length
at birth and at independence in humpback whales.  J. Cetacean res.
Manage. 1: 141-146.

This paper reviews published and unpublished data on length at birth and
at independence in the humpback whale (Megaptera novaeangliae).  The
available data indicate that humpback whale calves are 3.96 to 4.57 m
(13 to 15 ft) in length at birth, and approximately 8 to 10 m (26.25 to
30.48 ft) at independence.  Timing is important in such assessments:
because of the strong seasonal breeding cycle of this species, for young
calves (i.e. those observed or taken in winter on the breeding range),
there is no question that length data alone are sufficient to determine
their status.  In cases where actual length data are unavailable or
unreliable, apparent length relative to that of an accompanying adult
(i.e. the possible mother) may be used to define a calf, but only for
young animals (< 3 months of age) during winter.  Simulations based upon
available length frequencies are used to calculate probabilities
associated with such a ratio; the results indicate that any animal whose
length appears to be less than 63% of that of an accompanying whale is
probably a calf.

Reprints should be available in the near future (requests to me,

Phil Clapham


Phillip J. Clapham, Ph.D.
Large Whale Biology Program
Northeast Fisheries Science Center
166 Water Street
Woods Hole, MA 02543

tel (508) 495-2316
fax (508) 495-2066