An assessment of the grilse error associated with reported salmon, Salmo salar L., catches from two rod‐and‐line fisheries on the River Spey, Scotland, UK

• Published in: Fisheries Management and Ecology
• Main Authors: MACLEAN, J.C., SMITH, G.W., LAUGHTON, R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1996
• Subjects: Salmo salar
• Online Access: http://dx.doi.org/10.1111/j.1365-2400.1996.tb00136.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2400.1996.tb00136.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2400.1996.tb00136.x

Abstract Catch returns are often analysed as a means of inferring the status of salmon stocks. One aspect of such analyses is the problem of grilse error (the misreporting of one‐sea‐winter salmon as multi‐sea‐winter salmon), which may have important consequences for the management of salmon stocks. Reported catches from two estates on the River Spey between 1982 and 1992 were compared with the sea ages of the fish determined from scale reading. Weight was an important factor in determining the reported sea age of salmon in catch returns; the relationship between weight and sea age in the reported catch remained relatively constant throughout the angling season. Analysis of the scale sample data, however, indicated that the relationship between weight and actual sea age changed through the angling season, grilse accounting for increasing proportions of all weight classes up to 10 lbs (4.5 kg) as the season progressed. Grilse error was an identifiable problem at both estates, resulting in grilse catches being underreported by over 20%.