It shows, based on actual captures, what a speckled trout of a given length should weigh. Now, obviously, it's an inexact science. Just like in humans, length and weight don't always correspond.

The cutbow trout (Oncorhynchus mykiss x clarkii) is a fertile hybrid of rainbow and cutthroat trout. Little published length-weight data is available for this hybrid, and a standard weight curve ...