2019-03-072019-03-071994NAGA 17 (2): 27-30https://hdl.handle.net/20.500.12348/2870This essay presents evidence that check marks on the hard parts of tropical fishes can be used for aging these, in spite of the small seasonal temperature and other environmental oscillations prevailing in the tropics. The ideas presented in this article were over 50 years ahead of their time.application/pdfCC BY 4.0Journal Article