Subject: Abstract - humpback whales (fwd)

Mike Williamson (
Sat, 14 Jun 1997 22:33:22 -0400 (EDT)

---------- Forwarded message ----------
Date: Fri, 13 Jun 1997 21:18:58 -0400
From: Phil Clapham <CLAPHAMP@NMNH.SI.EDU>
Reply-To: Marine Mammals Research and Conservation Discussion
Subject: Abstract - humpback whales

Mikhalev, Y.A.  1997.  Humpback whales Megaptera novaeangliae in the
Arabian Sea.  Marine Ecology Progress Series 149: 13-21.

ABSTRACT: The population identity of humpback whales in the Arabian
Sea has long been a matter of dispute.  New information is presented
from this region, based upon whaling and observations conducted by the
Soviet Union, primarily in November 1966.  In that month, a total of 238
humpbacks were killed off the coasts of Oman, Pakistan and
northwestern India; four others were killed in previous years.  Biological
examination of these whales showed that they differed significantly from
Antarctic humpbacks in terms of size, coloration, body scars and
pathology.  In addition, analysis of the length distribution of 38 foetuses
indicates that the reproductive cycle of the Arabian Sea whales was
unequivocally that of a northern hemisphere population.  Mean lengths
were 12.8 m for males (range: 9.5 to 14.9 m, n = 126) and 13.3 m for
females (range: 9.5 to 15.2 m, n = 112).    All whales 12.5 m or more in
length were sexually mature.  Among 97 females examined, 12 (12.4%)
were immature.  Of the 85 mature females, 39 (45.9%) were pregnant, 3
(3.5%) were lactating, and 43 (50.6%) were resting.  A more plausible
pregnancy rate, adjusted for underrepresentation of lactating females,
was estimated at 39%.  A majority of stomachs examined contained
food, including euphausiids and fish.  Overall, the data presented here
argue strongly that Arabian Sea humpbacks constitute a discrete
population which remains in tropical waters year-round, a situation
which is unique for this species.

This paper is based upon illegal Soviet whaling catch data.  Reprints
should be available shortly; please send requests to me, not the author.

Phil Clapham
Smithsonian Institution