The TAC is calculated as:
$$\textrm{TAC} = (1-x)C_{\textrm{ave}}$$
where x lies between 0 and 1, and \(C_{\textrm{ave}}\) is average historical
catch over the previous yrsmth years.
The TAC is constant for all future projections.
References
Geromont, H. F., and D. S. Butterworth. 2015.
Generic Management Procedures for Data-Poor Fisheries: Forecasting with Few Data.
ICES Journal of Marine Science: Journal Du Conseil 72 (1). 251-61.