Use of biological reference points for the conservation of Atlantic salmon, Salmo salar , in the River Lune, North West England

• Published in: Fisheries Management and Ecology
• Main Authors: APRAHAMIAN, M. W., WYATT, R. J., SHIELDS, B. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2006
• Subjects: Ecology; Aquatic Science; Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1111/j.1365-2400.2006.00468.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2400.2006.00468.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2400.2006.00468.x

Abstract The development and use of biological reference points (BRPs) for salmon, Salmo salar L., conservation on the River Lune, England were examined. The Lune supports recreational and net fisheries with annual catches averaging 1332 and 2146 salmon, respectively. Using models transported from other river systems, BRPs were developed that were exclusive to the Lune; specifically the number of eggs deposited and carrying capacity estimates for age 0+ and 1+ parr. The conservation limit was estimated at 11.9 million eggs, and to ensure that the conservation limit was exceeded 80% of the time, the management target was set at 14.4 million eggs (equivalent to ∼5000 adults). Between 1989 and 1998 the management target was exceeded in only 2 years. Comparison of juvenile salmon densities in 1991 and 1997 with estimates of carrying capacity indicated that 0+ and 1+ parr densities were at around 60% of carrying capacity and may relate to the number of eggs deposited in 1990 and 1996 being approximately 70% of the target value. From, and including, the 2000 fishing season, regulations to ensure that the conservation limit is met 4 years out of 5 were introduced. These consisted of a reduction from 26 to 12 haaf nets, from 10 to seven drift nets and a four‐fish bag limit for the rod fishery. In the period between 2000 and 2004 there was a marked increase in the estimated number of salmon spawning and the management target value of ∼5000 spawning adults was exceeded in all years. There was also an increase in the juvenile salmon population. The estimated level of exploitation in the net and rod fisheries reduced from 29.9% to 13.8% and from 26.4% to 14.8% respectively, after the introduction of the regulations.