Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Buoyancy and Balance

Image of a Coelacanth fish by Bruce A.S. Henderson from MD Fraser, BAS Henderson, PB Carstens, AD Fraser, SB Henderson; MD Dukes, MN Bruton. Live coelacanth discovered off the KwaZulu-Natal South Coast, South Africa. South African Journal of Science. 116, 2020. doi:10.17159/sajs.2020/7806 via Wikimedia Commons

Existing species of coelacanths (pictured above) are descendants of a group of fish that existed about 410 million years ago, during the early Devonian period. They can be found in the Western Indian Ocean off the coast of Indonesia. These fish are really interesting because they have very low metabolic rates. In fact, their metabolism is among the lowest of any other existing vertebrate. Even sloths are jealous of their slow lifestyle. These lobe finned fish live at depths ranging from 100-400 meters. They move so slowly that researchers have been interested in studying how they even stay afloat and balance in the water.   

Dr. Henrik Lauridsen presented research conducted with colleagues from Aarhus University and the University of Copenhagen at last month’s Experimental Biology conference in Philadelphia that examined this very question. They found that the fish have a high amount of fat in their tissues to help them stay afloat, so they need very little energy to move their fins.

Given their remarkably low energetic needs, it is perhaps not surprising to learn that these fish live very long lives – up to a century in fact according to a study published in Current Biology. These fish live such slow lives that they reach sexual maturity around age 55 and gestation takes about 5 years! Wow!


H Lauridsen, JMH Pedersen, S Ringgaard, PR Moller. Bouyancy and hydrostatic balance in the West Indian coelacanth Latimeria chalumnae. 2022 Experimental Biology Conference Abstracts.

K Mahe, B Ernande, M Herbin. New scale analyses reveal centenarian African coelacanths. Current Biology. 31(16): 3621-3628, 2021.

Categories: Aging, Exercise, Extreme Animals, Nature's Solutions, Ocean Life, Physiology on the Road

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