Presentation on theme: "The Costs and Benefits of Stocking: Managing Expectations and Making the Best Use of Resources 28 th November 2013."— Presentation transcript:
The Costs and Benefits of Stocking: Managing Expectations and Making the Best Use of Resources 28 th November 2013
The Spey Experience: A Summary The Spey has operated two hatcheries between 2004-2010 and produced up to 2.2 million fry and eyed ova per year. We are now operating one hatchery producing 230,000. From the genetic analysis of rod-caught fishery and broodstock samples, the indications are that our hatcheries may have contributed up to 150 fish to a rod catch of 8,000 – 10,000. Hatcheries can be an effective fishery management tool – in certain circumstances. BUT, they are not the only tool in the box and when operated for enhancement purposes, they appear to have little impact! We need to raise awareness of this. The Spey is continuing to stock, but for mitigation rather than enhancement, and has been able ro re-allocate resources to habitat improvement.
The Spey Fishery Board’s Hatcheries The SFB has operated two hatcheries – our own at Sandbank in Glenlivet, the other at Tulchan which is owned and was operated by the Estate, at their expense, but under the supervision of the Board. 230,000 Salmon fry currently being produced – previously up to 2.2 million. Capacity reduced as areas opened-up by e.g. CASS Life. Full-time Hatchery Manager and formerly a Part-time Assistant (60%). A 24hrs a day, 7 days a week, 365 days a year commitment. Cost up to £120,000 per annum to operate – for one hatchery. Broodstock Capture Licence (and Appropriate Assessment for SACs).
Aim and Influence of the SFB’s Stocking Policy Aim: –The aim of the Stock Enhancement Policy is to boost the natural smolt output from the Spey catchment, and hence adult returns. In turn, extra fish may be caught in the rod fishery (842). (2004 Annual Report). This followed an apparent increase in marine mortality and impact upon the number of fish returning to the catchment. Hatchery Influence: –Previously we had said that we were confident our Hatcheries were not causing any harm. –Only recently have we been able to determine whether they were actually doing any good, rather than simply not doing any harm.
FASMOP: Objectives for the River Spey Three Principle Aims for the Project: –To assign fish caught in Mixed Stock Fisheries to their river of origin. –To determine whether our stock consists of sub- populations, so as to better-inform our management of the fishery. –To identify whether fish caught in the rod fishery had originated from our hatcheries using the genetics of maternity/paternity.
FASMOP: The Technology Initially used a suite of 17 Microsatellites, 14 of which had been used in a similar project in Ireland. Highly effective in identifying maternity/paternity – hatchery contribution to the rod fishery. Insufficient resolution to give a clear picture of sub-population structuring. Co-operation with CIGENE in Norway led to analysis using Single Nucleotide Polymorphisms (SNPs or “SNiPs”). Three-fold increase in differentiating samples. Assignment of fish to river of origin with up to 85% confidence. This enables the identification of fish caught in a Mixed Stock Fishery that are destined for the Spey.
River Spey Genetic Samples YearRod-catch Broodstock (male) Broodstock (female) 2004-241284 2005-240189 2006-234261 2007163252234 2008301156164 2009257108118 2010113*150172 2011217-- 2012204-- Total125313811422 Over 4,000 samples in total.
Initial Results of Genetic Parentage Analysis YearRod- catch sampled Assigned both parents (hatchery) Confirmed by breeding records Broodstock sampled ‘offspring’ Assigned both parents (hatchery) Confirmed by breeding records 20071630N/A4750N/A 20083011 (0.3%) YES3221 (0.3%) YES 20092571 (0.4%) YES2207 (3.2%) YES 2010830N/A3280N/A TOTA L 804213458 Probability of 2 individuals having same genetic profile ~ 3.5 x10 -32 On the basis of this research, our hatcheries were contributing ~ 0.5% of the rod catch. Average catch 2006 to 2010 was ~ 10,000 Salmon and Grilse. Hatcheries (on the basis of this research) contributing ~ 50 fish.
Hatcheries’ Contribution to Rod Fishery The initial analysis had not been complete. 2010 rod-caught samples had not been available at the time. Two-sea-winter fish emanating from our stocking during 2005 were therefore absent. This research has since been undertaken, and enhanced with analysis of the 2011 & 2012 rod- caught samples and 2006 & 2007 broodstock samples.
Results of Genetic Parentage Analysis Hatcheries contribution to rod catch relatively consistent and low – up to 1.8% (~150 fish to the rods). Broodstock would have produced some fish if left to spawn naturally. Sample of rod caught fish was large - averaging 2.5% of catch. Year Sample size Assigned one parent (hatchery) Assigned both parents (hatchery) % of sample attributed to hatchery Rod-catch 2008299210.3% 2009257210.4% 2010 (rod) Spey Dam 80000% 33000% 2011217141.8% 2012204031.5%
Management Implications for Stocking on the Spey After the initial findings, the popular perception was that the Spey Board would immediately close its hatcheries. Our hatcheries had cost the Board alone up to £120,000 per year. If only from an economic perspective, closure was perceived to be the logical next step.
Management Implications for Stocking on the Spey Fishery management is not only based upon sound science; politics and common sense also play important parts. Scientific opinion towards stocking has hardened in recent years. But many anglers and ghillies continue to look upon hatcheries as the panacea of fishery management.
Stocking as a Fishery Management Tool A hatchery is but one tool in the fishery manager’s box. BUT it shouldn’t be the first one we reach for! We as Fishery Managers need to improve our communication and raise awareness of when to use a hatchery – and when NOT to. We have to take people with us in any decision we take on our stocking policy. FASMOP has contributed to our decision to reduce our stocking. There are other factors to consider too.
Fishery Management on the Spey: The Way Forwards Stocking is continuing for the next five years - but for mitigation, rather than enhancement purposes. Now producing ~ 230,000 fed fry in one hatchery, rather than two. This has enabled a reallocation of resources. Bailiffs are now able to spend more time improving fishery habitat as their commitment to the Hatchery has been reduced.
Fishery Management on the Spey: Habitat Improvements
The Spey Experience: In Conclusion The Spey has operated two hatcheries between 2004-2010 and produced up to 2.2 million fry and eyed ova per year. We are now operating one hatchery and producing 230,000. From the genetic analysis of rod-caught fishery and broodstock samples, the indications are that our hatcheries may have contributed up to 150 fish to a rod catch of 8,000 – 10,000. Hatcheries can be an effective fishery management tool – in certain circumstances. BUT, they are not the only tool in the box and when operated for enhancement purposes, they appear to have little impact! We need to raise awareness of this. The Spey is continuing to stock, but for mitigation rather than enhancement, and has been able to re-allocate resources to habitat improvement.
Manage Fisheries: Why Bother? Circa £15 million to the local economy. 367 full-time equivalent jobs. High Conservation Value (SAC). Challenge to maintain economic value of fisheries while achieving long-term conservation obligations