NOTES Gauldie and Czochanska' Hyperostosic bones from Chrysophrys suratus 



205 



Figure 3 



The ratio of hyperostosis/vertebra width in Chrysojihrys auratus is 

 plotted against forlv length. 



but the correlation between hyperostosic bone size and 

 fish size was low. The relative size of snapper hyper- 

 ostosic bones did not appear to be related with any 

 more significance to age than to size. 



The fat content of the snapper hyperostosic bones 

 was not significantly different from that of the verte- 

 brae. Nor was the composition of fat in the snapper 

 hyperostosic bones significantly different from either 

 the vertebrae of snapper or fats found in marine fishes 

 generally. The difference in fat content between snap- 

 per hyperostosic bones and vertebrae is low (Worth- 

 ington and Loveil 1973) compared with the potential 

 range of differences in fat content known in fishes. 



Snapper hyperostoses are vacuolated, but no more 

 so than other bones in fish. The contribution of fat in 

 hyperostosis to buoyancy is difficult to assess. The 

 amount of lipid as a percent dry weight varies between 

 individuals, but in some individuals is of the same order 

 as the lipid content of the bones of fish species in which 

 bone lipid may have a role in neutral buoyancy (Lee 

 et al. 1975). However, the low correlation with both 

 size and age suggests that if hyperostoses are related 

 to buoyancy correction, then that relationship is tem- 

 pered by factors other than size. 



The use of hyperostoses to discriminate species both 

 in Recent genera, such as Chrysophrys (Yasuda and 

 Mizuguchi 1969) and fossil species (Fierstine 1968) 

 points to another possible e.xplanation. Hyperostoses 

 occur with great regularity in certain bones in those 



species which display hyperostoses. We interpret such 

 regularity as indicating that hyperostoses are under 

 genetic control and are therefore good species char- 

 acters, as are other genetically determined characters. 

 But the expression of hyperostoses results from an in- 

 determinate kind of ontogenetic process in which there 

 is only a loose correlation between size of the hyper- 

 ostoses and size or age. Thus the hyperostoses involve 

 the local proliferation of cells (Breder 1952) but in a 

 way that could be seen as physiologically between a 

 normal bony growth and a bony tumor, almost a kind 

 of controlled tumor which contains both fat cells and 

 bony trabeculae. Snapper hyperostoses are readily ob- 

 tainable and may provide a useful model to study the 

 ultrastructural interactions between proliferating bone 

 and fat cells. 



Acknowledgments 



The snapper used in this study came from a tagging 

 study conducted by Arthur Hoare of the Fisheries 

 Management Division, MAF, New Zealand. Annual 

 check-ring ages were provided by Larry Paul of the 

 Fisheries Research Division. Expert technical help was 

 provided by Kevin Mulligan. 



Citations 



Breder. CM. 



1952 The problem of directives to cellular proliferation as illus- 

 trated liy ontogenetic processes in certain fishes. Growth 16: 

 189-198. 



Fierstine, H.L. 



1968 Swollen dorsal fin elements in living and fossil Caranx 

 (Teleostei: Carangidae). Contrib. Sci. Los Ang. 137:1-10. 



Hofstetter, H.H., N. Sen, and R.T. Holman 



1965 Equivalent chain lengths of fatty acids. J. Am. Oil Chem. 

 Soc. 42:537-.587. 



Hughes, J.T., Z. Czochanska. L. Pickston, and E.L. Hove 



1980 The fatty acid content of some New Zealand fish. N.Z. 

 J. Sci. 23:4.3-51. 

 Jamieson, G.R. 



1969 Ec^uivalent chain lengths of fatty acids. In Gunstone, 

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Konnerth, A. 



1966 Tilly bones. Oceanus 12:6-9. 

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 Love, R.M. 



1980 The chemical biology of fishes. Acad. Press. NY, 579 p. 

 Olsen, S.J. 



1971 Swollen bones in the AUantic cutlass fish Trirhmnis lep- 

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