Longevity of Fishes in Captivity 225 



organs of haemopoiesis. Fishes with these abnormahties may 

 Hve for an exceptionally long time, even when the kidneys are 

 extensively damaged, since the osmoregulation function of 

 this organ can be taken over in part by the gills. Finally, arterio- 

 or atherosclerosis has not been found in fishes. 



Summary 



Fishes are susceptible to a variety of parasitic and metabolic 

 diseases, many of which are counterparts of those that occur 

 in mammals. These diseases, together with changes in the 

 physical, chemical and biological characteristics of the environ- 

 ment, are responsible for mortality. 



Athero- or arteriosclerosis has not been found in fishes but 

 pathological changes indicative of ageing do occur in other 

 organs. These are cirrhosis and fatty changes in the liver and 

 kidneys, haemochromatosis, hypochromic anaemia, degenera- 

 tion of mucus-producing glands of the skin, hyperostosis of the 

 haemal arch bones and other vertebral abnormalities. 



Some lifespans of fishes in the New York Aquarium and in 

 other institutions are listed. The long-lived fishes kept in 

 captivity have certain general characteristics, and the signifi- 

 cance of some of these is discussed. 



REFERENCES 



Berg, L. S. (1947). Classification of Fishes, both Recent and Fossil. 



Ann Arbor : J. W^. Edwards. 

 BouRLiERE, F. (1946). Annee bioL 22, 249. 

 Breder, C. M., Jr. (1934). Zoologica, N.Y., 18, 57. 

 Breder, C. M., Jr. (1936a). Bull N.Y. zool. Soc, 39, 116. 

 Breder, C. M., Jr. (19366). Bull. N.Y. zool. Soc, 39, 149. 

 Breder, C. M., Jr. (1952). Growth, 16, 189. 

 Brown, M. E. (1957). In Physiology of Fishes, 1, 861. New York: 



Academic Press. 

 Comfort, A. (1956). The Biology of Senescence. New York: Rinehart. 

 Flower, S. S. (1925). Proc. zool. Soc, Lond., 247. 

 Flower, S. S. (1935). Proc zool. Soc, Lond., 265. 

 Hafter, E. (1952). J. Morph., 90, 55. 

 HiNTON, S. (1959). Personal Communication. 



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