The catch form return time series runs from 1997 to the most recently published season.

The annual return of forms across all Scotland is provided as the number of forms issued, together with the numbers of forms returned reporting catch or effort (identified as "Data" returns) and the numbers of Nil returns. The annual return rate of forms is indicated as the sum of "Data" and "Nil" returns expressed as a percentage of the total number of forms issued.

Information on salmon rod effort reporting is included from the 2023 season onwards. The return rate of rod effort is provided as the number of rod forms returned with effort information expressed as a percentage of the number of rod forms returned. The total number of rod-caught salmon covered by reported salmon rod effort is expressed as a percentage of the total number of rod-caught salmon.