Dave,
Interesting point about relative weights vs. age. That's not commonly considered when looking at Wr's for a population. A common approach is just to look at average Wr's for each inch-group.
Your analogy gets the point across, but it is flawed in that fish have indeterminant growth, whereas we humans have determinant growth (at least when you talk about upward growth
)
But again, your point is important. Relative weights and growth are components you want to know about a bass population to successfully manage it. The way I do it is to age 1 to 3 bass per inch group and determine average length at age for a population. The results from aging 20 bass might be: (Age 1 - 8.4", Age 2 - 11. 3", Age 3 - 12.9", Age 4 - 13.5", Age 5 - 14.1") I then compare these growth rates to expected growth rates from the region I'm sampling. This would tell me if the fish are growing slower or faster than "expected".
Generally, fish that are growing slower than expected will have low relative weights, often as low as 70-80. It's pretty obvious from this that there is a correlation between slow growth and low relative weights.
If one wanted to look at relative weights classified by age group, all one would have to do is age all of the fish one is weighing and measuring. Since aging requires sacrificing the fish (at least in southern climes, fish scales don't work here AT ALL), most folks won't want to do this.
