Water, carbon, and nitrogen contents were analysed in both juvenile and adult specimens of Diaphus theta, Stenobrachius leucopsarus, and S. nannochir, which are the dominant myctophid species in the subarctic and transition waters of the North Pacific. The relationship between body length and dry weight, carbon content, and nitrogen content of these three species were expressed as double logarithmic equations. The differences in chemical content among the different size-classes of each species may be associated with reproductive biology.
