[CINC] excellent photos of a minke whale breaching

[whalebear at cs.com]

These are outstanding photos of a Balaenoptera acutorostrata.  The falcate dorsal fin is well-shown, as is the white band on the pectoral fins.  One gets a sense of how much more anterior (forward) the placement of the dorsal fin is relative to the larger baleen whales.  One also gets a good sense of how streamlined these balaenopterids are; this was rarely depicted properly in drawings until the advent of modern underwater photography.  Excellent views delineate how streamlined the rostrum is; one of them also shows the volcano-like ring of musculature that surrounds the blowholes (Remember that breathing in Cetaceans occurs by contracting this volcano of musculature and opening the blowhole.  It is at a high level of voluntary control; even light levels of anesthesia will render Cetaceans unable to breathe.).  The blood on the ventral surface is not copious, and there are multiple possible explanations.  Most Odontocetes examined at necropsy are fairly heavily scarred, with the primary causes being trauma (often from conspecifics--members of the same species), infectious diseases, or parasites (even rapidly-swimming Odontocetes can be parasitized).  It is often underappreciated how frequently Mysticetes are scarred also, with the same etiologies.  Considering that the bleeding does not appear heavy and that the population of B acutorostrata is fairly robust, I would not be particularly alarmed.

Cheers,

Chuck Rennie
Los Angeles County Museum of Natural History

-----Original Message-----
From: Mr Zalophus <mr.zalophus at gmail.com>
To: channel_islands_ naturalist_corps <channel_islands_naturalist_corps at rain.org>
Sent: Fri, Jul 12, 2013 6:09 pm
Subject: [CINC] excellent photos of a minke whale breaching


Scientists were alarmed to note blood on the ventral surface of a minke whale that breached repeatedly.
You can see the fantastic breaching photos (and blood) at

http://quoddylinkmarine.blogspot.ca/2013/07/what-great-day.html


Bob Perry
Condor Express


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