The Distribution of Senescence 



R. esculenta 14 + , 16+, R. temporaria 9+ (Sebesta 1935), Lepto- 

 dactylus pentadactylus 15 years 9 months (Gonant and Hudson, 

 1949). 



2-2-5 FISH 



Seriously acceptable records of longevity in the larger fish are 

 very few. The longest accepted by Flower are Silurus glanis, 

 60+ years, Anguilla anguilla, 55, A. chrisypa, 50 (Flower 1935). 

 Some of the more celebrated legends of fish longevity (up to 

 170, 200, 300, or 400 years in carp, and 250 years in pike) are 

 revived by Backmann (1938) and by Wurmbach (1951). 'Wenn 

 auch diese Angaben hier und da iibertreiben sein sollten', re- 

 marks Wurmbach, 'so kann doch gar kein Zweifel daran herr- 

 schen, dass der Karpfen wirklich ausserordentlich alt wird, und 

 das Alter des Menschen weitaus iibertrifft' — this is quite pos- 

 sibly true. Many exaggerated estimates have been based upon 

 size, as extrapolations of the normal mean growth rate for the 

 species — upon this basis, a 720 kg. sturgeon should be about 

 200 years old, and occasional examples weighing 1200 to 1600 

 kg. would be of fantastic antiquity. In no case, however, are 

 any of these estimates supported by otolith or comparable 

 studies, and the extrapolation is almost certainly unjustified. It 

 is a matter of considerable biological importance to get proper 

 age determination upon exceptionally large specimens of this 

 kind. 



The life-span of small fish is certainly limited in captivity 

 (Aphya pellucida, 1 year; Lebistes, 1-2; Xiphophorus, 2-3; Mol- 

 liensia latipinna, 3-4; Betta pugnax, 1J-2 — Wurmbach, 1951). A 

 few species of Gobius and Latrunculus must be regarded as 

 annuals, even in captivity (Bourliere, 1946, Meyers 1952). In 

 this field there is little new information since the seventeenth 

 century. 'The life of fishes is more doubtful than that of land 

 beasts, since, living below the waters, they are less observed. 

 Dolphins are said to live about thirty years; this is obtained by 

 experiment upon some of them, the tail being marked by cut- 

 ting; they grow for ten years. In Caesar's fishponds were certain 

 Muraenae found to have lived to the sixtieth year. Indeed, they 

 were grown with long use so familiar, that Crassus the orator 

 mourned for the death of one. The pike, of freshwater fish, is 



53 



