The SALWRD website aims to assist anglers and fishery managers in Scotland determine the sea ages (number of “sea-winters”: 1SW or grilse; 2SW; 3SW or older) of captured salmon. This can now be achieved with high confidence (for over 95% of captured salmon) if the size of the fish and its date of capture are known, using a simple credit-card sized look-up table which may readily be carried whilst fishing.
The Single Fish Calculator illustrates how the size (length or weight) and date-of-capture of a Scottish salmon can be used to give the probabilities that it is respectively 1SW, 2SW, or 3SW-or-older. All salmon returning to rivers do so to spawn and very few Scottish spawners survive to spawn for a second time. So, the great majority of fish caught in Scotland will clearly be in one of the three sea-age classes given by the calculator, and not in the other two classes.
For further details, please look at the science underpinning these determinations, and at the explanatory leaflets and 'pocket information cards', which fishery managers and anyone fishing for salmon in Scotland might wish to carry with them and use to immediately determine the sea-ages of captured salmon.
SALWRD is a developing venture in information sharing. Fishery enthusiasts and officials with a particular interest in such topics may wish to register on the site, and thereby gain access to some of the pre-existing software used to develop this approach. This privilege would allow them to:
- provide, store and securely curate appreciable quantities of their own data.
- list the predicted sea-ages for their own fish records, as derived from other (regional Scottish) data-sets.
- fit sea-age vs length and capture date probability models to their own scale-aged data.
- generate custom tables of size ranges by sea-ages.