[Bug]: growth discrepancy when season duration is < 1.0 (months < 12) and growth type is Gompertz-Richards

[Rick-Methot-NOAA]

Describe the bug

A user reported unexplained growth differences when season duration is < 1.0, for example by setting a 1 season model with only 3 months that season.

Also note that when AFIX2 is not 999 , the calculated Linf from Lmax can be affected, but that is not cause of the issue above. For this, suggest investigate creation and use of AFIX_delta

To Reproduce

Take an annual model and change N months in the season. Examine the vector of length-at-age. So far, I find the expected pattern:

Expected behavior

I expected differences to be explainable by the differing number of seasons to reach the same effective age. Still doing that test.

Screenshots

No response

Which OS are you seeing the problem on?

No response

Which version of SS3 are you seeing the problem on?

No response

Additional Context

No response

[Rick-Methot-NOAA]

Quang suggested:
I think this line is what is causing the over-reduction in K: https://github.com/nmfs-ost/ss3-source-code/blob/main/SS_biofxn.tpl#L598

In my model, the K parameter is reduced by 0.25 twice with VBK_seas and seasdur.
Shouldn't it be: VBK_temp2 = exp(VBK_temp * VBK_seas) - 1 ?

But Rick found that change to create wrong result for a seasons in year model.