Determination of the Sea Age of Atlantic Salmon in Scottish Catches from Length Composition Data

The importance of obtaining reliable estimates of the sea age composition of reported salmon catches are discussed. The use of length frequency distributions to determine the sea age of salmon in samples taken from the North Esk commercial catch are described. The results obtained using this technique are compared to those obtained from scale reading on a 4 weekly basis over a 16-year period. The use of length frequencies is shown to provide a reliable estimate of the sea age composition of catch samples. The adoption of this technique in catch sampling programmes is labour saving and facilitates rapid sampling.