Spring and summer salmon are treated separately because they have different levels of vulnerability and conservation needs. Spring salmon, also referred to as 2 Sea Winter (2SW) or Multi Sea Winter (MSW) salmon, are often larger, older fish that contribute strongly to spawning. Summer salmon, also referred to as 1 Sea Winter (1SW) salmon, tend to be smaller and return later.
The Technical Expert Group on Salmon (TEGOS) provides scientific advice for 144 salmon rivers on an annual basis. Separate catch advice is given for 1SW and 2SW stock components in 16 rivers of these rivers, where a significant MSW spring salmon stock component has been identified.
The status of a given fishery provided for in the Regulations (Open, Catch & Release, or Closed), may vary for the 1SW or 2SW stock components of those 16 rivers, depending on whether a surplus is available or not for either stock component.
For rivers which have commercial salmon draft net fisheries, the total identified harvestable surplus for each river, including both the 1SW and MSW components wherever applicable, is included. The total combined harvestable surplus (Total Allowable Catch - TAC) identified for the river is divided between the commercial and angling sectors (as advised by the local Fisheries District Committee) to arrive at the final quota allocation for each sector.
A declining trend is evident in the spring salmon stock component. These salmon are of high conservation and genetic value as they carry significantly more eggs than summer salmon, due to their much larger size. Managing these stocks separately is therefore important for sustaining future salmon stocks and due regard for this subset of salmon is factored into the advice provided for, and measures reflected in, the annual Regulations.