Some considerations of diving of whales

鯨の潜水に関する考察

Ishikawa Yasutaro

広島大学水畜産学部紀要

Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University

In this article, two problems are mainly argued namely, (i) what mechanisms enable the whale to endure submergence so much longer than other animals, and (ii) how it can avoid getting caison disease when it makes the swift rising from the great depths.
(1). The duration and depth of submergence in whales are surveyed by making reference to the reliable informations.
(2). The balance of the oxygen store and its consumption is considered. As oxygen depots, the lung air, the blood and tissue fluids are enumerated, and as the oxygen consumption sources, basal metabolism, translational movement and vertical motion are taken into account. Thus, it is almost certain that the storage of oxygen cannot cancel the oxygen consumption during a long dive of the sperm whale or the bottle-nosed whale.
(3). The mechanisms which would reduce the oxygen consumption during apnoea are considered. The retia mirabilia are the most remarkable structures which may serve as the control mechanisms of oxygen distribution, preventing the brain and nervous system from the oxygen deficiency.
(4). The author discussed the problem as to whether the fat in the whale body is possible to act as the oxygen storage or to be concerned with gaseous exchange.
(5). It was argued whether the whale can get caison disease, when it makes a swift rising from the great depths. The present author was strongly inclined to conclude that any animal cannot get caison disease in its "mono-breath dive."

Zoology [ 480 ]

eng

広島大学水畜産学部

[ISSN] 0440-8756

[NCID] AN00213563