There are many fish measurement schemes developed by Kessler K. F., Varpahovsky N. A., J. L. B. Smith, et al.

The length of the fish to Smith - measured from the beginning of the snout to the end of the middle rays of the caudal fin.

James Leonard Brierley Smith (26 October 1897 - 7 January 1968) was a South African ichthyologist, chemist, and Rhodes University professor. He is credited with one of the greatest discoveries of the 20th century in the field of ichthyology - he was the first to identify a stuffed unknown caught fish as a celacanth, when it was believed that they had become extinct many millions of years ago.