THE RIVER DON TRUST- River in harmony River Don Hatchery Evaluation Prepared by Jamie Urquhart as part of the River Don Fishery Management Plan v.1 River Don Trust November 2012 1 P a g e
Contents 1. Introduction Page 3-5 2. Background Page 5-6 3. Discussion Page 7 a. Pros and Cons Page 7-8 b. Alternatives Page 9-12 4. Discussion & Conclusion Page 13-15 5. References Page 16 Appendix 1. Stocking Protocols Appendix 2. ASFB/RAFTS policy document 2 P a g e
1. Introduction The River Don Trust has been tasked with evaluating the hatchery programme as part of the River Don Fisheries Management Plan 2008. The document will follow the format of outlining and appraising the objectives of the stocking programme. It will also discuss; current best practice, scientific research, make arguments for and against the hatchery process and make recommendations for the future of the hatchery process on the River Don catchment. The document will use existing peer reviewed literature, Marine Scotland Science guidance documents and utilise data collected during the Fishery Management Plan process on the Don catchment. Stocking with hatchery reared broodstock has been part and parcel of many Scottish district salmon fisheries boards activities over recent decades and until recently has often thought to be the panacea for reverting stock declines. The augmentation of natural production is much more complicated than the addition of hatchery broodstock to the catchment, many factors affect the outcomes of a stocking programme and it should be considered where appropriate as one of a suite of choices to enhance or restore the fishery. Stocking can be separated into four main disciplines Restoration, Rehabilitation, Enhancement and Mitigation. Definitions from an Environment Agency Guidance document are as follows; Restoration stocking is defined as stocking which is carried out after the removal of the factor(s) that has been limiting or preventing natural production. Rehabilitation is defined as stocking which is supplementary to wild spawning where the catchment is though not to be at its carrying capacity the majority of stocking in Scotland falls under this category. Enhancement is defined as artificial production in excess of natural potential with the aim of increasing population size above natural carrying capacity to allow for increased harvest. Mitigation stocking is defined as stocking that is conducted to mitigate against lost production due to a scheme or activity that cannot be prevented or removed. Prior to any stocking activity being undertaken a rationale for the programme should be identified, costs, risks, and benefits should be considered and set against realistic goals and available resources. The following flow diagram Figure 1. is a useful illustration of the aforementioned approach. As identified in the ASFB/RAFTS policy document and the River Don Fishery Management Plan an assessment of the costs associated with the current stocking programme should be considered in order to fully evaluate the programme. Unfortunately the RDT was not able to attain the relevant financial information from the Board and therefore could not comment upon the financial aspects of in this evaluation. Consideration from the outset must be given to the potential carrying capacity of area to be stocked. If the site is already at carrying capacity then additional stocking asides from the introduction of smolts would have no benefit. 3 P a g e
The Atlantic Salmon Fishery Board (ASFB) and the Rivers and Fisheries Trusts for Scotland (RAFTS) have prepared a policy document (Appendix 2) on the regulation of Salmon and Sea Trout stocking programmes with a fishery district for the use by local DSFB s and Trusts. In this policy document the flow diagram from Figure 1 is referred to and the following statement is made Any stocking programme being considered by DSFBs of salmon and sea-trout SHOULD take into account appropriate advice from the local Fisheries Trust and/or the most recent literature. Such programmes SHOULD operate on a risk assessment basis to ensure that the biological and financial costs and benefits can be properly assessed. The ASFB/RAFTS also recommend that the following criteria must also be considered; Before consenting any stocking programme, DSFBs, with the assistance of their Fisheries Trusts (or where there is no Trust, consult the relevant literature and seek specialist advice). MUST: 4 P a g e - Establish a clearly justified need for the course of action is it for enhancement, mitigation or restoration. - Consider any issues associated with designated conservation sites
- Assess what the likely results and benefits will be from the stocking programme. - Assess what risks may be involved with a programme. - How the programme will be monitored to assess its efficacy This hatchery evaluation therefore begins to satisfy the requirements of the ASFB s policy document alongside that of the River Don Fishery Management Plan. This policy document is currently being review by a subcommittee of RAFTS and ASFB members, the River Don Trust is also part of this sub-committee. 2. Background The River Don District Salmon Fishery Board has operated a hatchery at the site of the Mill of Newe by Strathdon since the late 1960 s. The site makes use of an inaccessible tributary the Newe burn an old meal mill building at the place of Newe. The Newe Burn is the source of the water for the hatchery incubation and holding tanks and also acts to retain broodstock due to the modification of the burn adjacent to the mill to facilitate the holding of collected broodstock prior to stripping. The hatchery was initially introduced to help overcome the depletion of stocks as a result of point source pollution problems in the lower don, particularly associated with industrial effluent from paper and textile mills in Aberdeen. However the scale of the hatchery process has reduced somewhat in previous years from numbers over 1million salmon eggs at the height of its capacity to recently more modest figures as illustrated in Table 1. Table 1. Hatchery broodstock numbers over the past five seasons. 5 P a g e 423,000 75,000 Year Salmon Eyed Ova Salmon Trout Trout Fry Total combined Fry Eyed Ova Salmon Trout 2008-09 153,500 269,500 0 21,000 ST 54,000 BT 2009-10 0 408,000 0 6,000 ST 408,000 6,000 2010-11 311,000 0 0 36,000 ST 311,000 36,000 2011-12 160,000 0 0 0 160,000 0 2012-11 70,000** 70,000*** 0 0 0 140,000 0 * ST = Sea Trout, BT =Brown Trout **Denotes Upper catchment maximum number of eggs anticipated from a 10x10 cross. ***Denotes Middle catchment maximum number of eggs anticipated from in stream broodstock collection and 10x10cross. Broodstock heading for the upper catchment are intercepted at a single point, on the mainstem of the River Don the weir at Newe (NJ 370 120). Fish are collected using an existing lade sluice and catching bowl as a trap. Fish entering the bowl following the attraction velocities from the opened sluice are then trapped by closing the gate behind after a period an hour with the sluice open to enable fish to enter. The fish are then captured using large dip nets and then transferred the short distance to the hatchery. The fish are held in the impoundment in the
Newe Burn and checked on a regular basis. When the hens are ripe they are stripped and the fertilised eggs laid down in the incubation tanks in the hatchery. The stripped fish are held in recovery tanks for a period of 24 hours or until fit to return to the river below their point of capture. Following 2006 the progeny have been stocked out as eyed ova into artificial redds (salmon) or transplanted as unfed fry (trout) early the following year into areas throughout the upper catchment which appeared to be underused from the previous year s redd counts and electric fishing surveys. The River Don District Salmon Fishery Board and the River Don Trust have now been collectively working on managing fish stocks within the catchment for three years. During the year 2010-11 the River Don Trust (RDT) recommended that the Don District Salmon Fishery Board (DDSFB) adopt some new policies for broodstock management, these include recommended protocols for broodstock capture and crossing, and also a recommendation for planting out the progeny at identified locations see Appendix 1. The RDT have recommended that a minimum of a 10x10 cross undertaken following guidance from MSS. This is the crossing of 10 pairs of fish, the purpose of this exercise is to reduce any inbreeding depression which can reduce the fitness of the offspring. This minimum crossing will often result in a varied number of eggs but the figure of 70,000 has been given as a maximum for the Don stock. The new protocol adapted the existing approaches to bring the broodstock crossing in line with current best practice and amended the process for targeted broodstock planting locations. Marine Scotland Science (MSS) have recently reviewed hatchery practices and produced several reports and guidance documents which were utilised to prepare the protocol. The DDSFB had previously sought advice on the construction of artificial redds from MSS, further recommendations were made to the densities of egg planting by the RDT. From the RDT s and the Don DSFB s analysis it was perceived that existing approaches did not optimise the volume of broodstock progeny planted out. The RDT and DDSFB s electro fishing and habitat surveys enabled the RDT to make recommendations in the form of RDT Stocking Briefing Notes prepared each season in order to determine the locations and volume of eggs required to stock areas which were inaccessible to migratory fish or where these fish were found to be absent or at low densities from the survey results. This enabled more appropriate stocking practices which had illustrated effects in the form of increasing migratory salmonid populations above man made obstacles. Stocking densities have reduced as a result of this more targeted approach as illustrated in Table 1. One component of the stocking process was not deemed a suitable option for inclusion in the reviewed protocol at this time. This was the utilization of the mainstem broodstock collection site. The current broodstock collection processes could have been modified to allow targeted stock collection from the tributaries to be stocked but this approach was not considered at this time. 6 P a g e
3. Discussion In the broadest sense stocking using hatcheries often divides fisheries managers into two camps those for and those against the process. Bearing in mind every situation should be considered on its own merits conclusions will be drawn upon the current approach in section 4. The following sections enable the Trust to evaluate the current approach and consider a series of viable alternatives to the stocking programme should they be deemed necessary. 3.1 Pros and Cons A number of issues with the current hatchery practices and its outputs have been defined in a series of bullet points below. To accompany this, a review of current literature outlines the basic pros and cons of generic salmonid stocking in table 2. Rehabilitation type stocking supplementing wild stock in the majority of areas stocked is not required Minimal area of upper catchment actually requiring any form of restoration type stocking Detrimental impacts to wild stock as a result of increased intraspecific competition. Broad brush approach to broodstock collection on mainstem Excessive progeny produced from 10x10 broodstock cross for areas required to be stocked Minimal return anticipated from hatchery stock in rod catch in relation to effort Relatively large volume of resources drawn upon to support programme Insignificant volume of eggs stocked in comparison with wild spawning Continual effort required to sustain hatchery effects Limited by natural carrying capacity at any given site Table 2. Some of the pros and cons associated with typical hatchery based stocking of salmonids. Pros Restoration or pump priming areas where man made obstacles have resulted in the loss of effective populations. Mitigate where populations have been lost on a permanent basis i.e. the presence of Hydro Impoundment. Enhancement where stocking aims to increase above carrying capacity i.e. the addition of smolts. Selection/manipulation of stocking locations Cons Scientific evidence illustrating poor return to rod catch as in Spey example Reduced survival/fitness compared to wild stock when stocked at various stages and densities. Negative impact upon genetics through forced matings, no natural mate selection, resulting in reduced genetic fitness. Increased competition, both inter and intra specific competition with wild salmonids. Not only reducing the 7 P a g e
survival of the stocked fish but also that of the wild fish. Increased survival of eggs in hatchery by eliminating; redd washout, egg predation and mortality due to siltation or pollution. Ability to sample populations for science and research. Educational tool to enable communities and schools to get hands on with adult fish and eggs. Increased predation upon wild fish as a result of stocking in inappropriate locations and densities. Lack of ability to accurately measure hatchery stock when mixed with wild stock to assess success/failure. Continued running costs to support programme primarily staff costs as in Table 2. Limited by habitat potential i.e. parr habitat carrying capacity. Hatchery eggs could be planted out in their millions but if the juvenile habitat only supports a fraction of this figure then the rest is wasted. Successive stocking programmes may be required to sustain populations. Only really effective at restoring populations when the volume of broodstock is low or at a bottleneck. Otherwise natural populations will be more effective. 8 P a g e
3. 2 Alternatives approaches. The main goal of any stocking programme is to maximize the natural production of smolts emigrating from the river as smolts. By maximizing the potential smolt output we are then maximizing the potential number of fish returning as adults which can in turn be exploited by the rod fishery. There are many alternatives to the rehabilitation type stocking currently undertaken here on the Don which either individually or combined could produce effective alternatives to this approach. Some of these alternative approaches do not require any direct manipulation of stocks but the physical habitat in which the stocks exist. Several short descriptions of those most appropriate for the Don s circumstances are as follows; Obstacles Easement Obvious restraints upon natural production of any catchment are the accessibility of natural spawning and juvenile habitat by migratory salmonids. If there are manmade or debris obstacles present these may restrict fish access to areas of the catchment and reduce the potential production of the catchment as a result. Habitat surveys have unveiled that approximately 21% of the Don catchment is above either partial or complete obstacles. By using information from spawning incidences or redd counts across tributaries a rough estimate of the potential production can be concluded. Take for instance the Esset Burn a tributary of ~33km in length presently inaccessible due to man made obstacles. If we were to utlise redd count data from a neighbouring (<5km away) and geological similar tributary the Leochel ~66km in length we could estimate the anticipated number of returning adult fish to the Esset once a suitable period of continued accessibility was achieved. In this case the Leochel Burn is approximately twice the size of the Esset Burn and therefore we would anticipate twice the number of redds to be cut in the Leochel compared to the Esset. Previous redd counts from the Leochel burn over a twenty year period range from 43-192 redds with an average of 109 redds per season. At a typical redd cutting rate of 1.4redds/female we would anticipate that there are 78 females spawning in the Leochel on an average year. Therefore using this rough estimation we could anticipate that the Esset at half this value would support 39 spawning females. These females could be expected to lay 171,054 eggs in total. Work to restore the natural accessibility of the catchment to migratory salmonids would only have a positive benefit upon the stock and could make considerable positive differences to the production of the catchment. The RDT and DDSFB are already undertaking easements of obstacles across the catchment and with the aid of RAFTS and SEPA s Restoration Fund. Obstacle easement work should be considered an essential component to the arsenal of restoration options available to the River Don. Work such as this would again outweigh any approach offered by a hatchery in terms of potential return, but hatchery restoration stocking complements this approach and may be required to pump prime areas following easement in order to expediate recolonisation by migratory salmonids. 9 P a g e
Habitat Restoration Consideration from the outset must be given to the potential carrying capacity of area to be stocked. If the site is already at carrying capacity then additional stocking asides from the introduction of smolts would have no benefit. This is where the tool of habitat restoration comes into its own. The habitat and electro fishing surveys have also discovered areas of the catchment where the stocks are not at their full carrying capacity. This is often the result of poorer quality habitat, through degradation such as dredging or siltation from livestock poaching. Spawning gravels can become silted with fines from poaching and result in poor survival of eggs in redds. Parr habitat can be lost by the continued dredging and removal of substrates from watercourses by farmers in order to improve drainage. These and many other examples can often be rectified by restoration projects which include, installing buffer strips where the banksides are fenced off, inputting Large Woody Debris to increase cover and hydraulic diversity etc. A buffer strip reduces the volume of diffuse pollution entering a watercourse by restricting access by livestock whilst also acting as a natural filter from agricultural applications on the farmland adjacent. Once buffer strips are established the addition of substrate to restore specific habitats can be undertaken, for example Boulder Addition will improve parr numbers by providing cover and increasing the number of territories available for parr, often a limiting factor. These restoration examples will increase the potential carrying capacity of an area and as a result the potential smolt production. Both Obstacle Easing and Habitat Restoration offer durable, sustainable solutions to the issues associated with improving migratory fish populations. Whilst resources and costs may initially be high these are often only required once as opposed to the continued requirement of a hatchery to maintain stock. This is a cheaper sustainable option and when the potential grants and funding to support these works are realised the prospect becomes even more cost effective. Asides from the finances these options also offer other benefits such as the ability to directly measure and quantify success/failure through research and monitoring, often a tricky proposition when using a hatchery). These approaches also benefit a wider range of species as opposed to just migratory fish alone and are often more appealing to the wider public due to the visibility across the whole catchment. Most importantly these approaches allow natural selection to take place, which removes any inappropriate matings and the reduction in genetic fitness as a result often encountered with hatcheries. Catch and Release The Don DSFB s conservation code has enabled the development of a catch and release policy on the river Don for several years now. Current return rates averaged across the 2011 season for salmon and grilse are 82% on equal footing with the Spey and surpassed only by the Dee and Esk on the East coast rivers. The relationship between the number of wild fish, hatchery and caught and released fish in the catchment and the volume of eggs they are attributing to the fishery is displayed in Table 3. 10 P a g e
Table 3. Illustrates the volume of eggs deposited within the catchment highlighting the differences in scale by several orders of magnitude between the hatchery processes, caught and released fish and natural spawning. A target catch and release figure has been included for illustration Number fish caught in the Don (10yr Ave) Number fish released (82%) Actual Catch & Release 82%** Target Catch & Release 86% Hatchery Process* 1942 1942 Estimated run of wild fish to River Don*** 1592 1670 Number of hens (50%) 796 835 Number of hens(50%) 4855 Number of eggs per hen (Mills 1990) Number of eggs deposited. Hatchery process volume comparison 4386 4386 Number of eggs per hen (Mills 1990) 3,492,220 3,662,573 160,000 Number of eggs deposited. 0.045% 0.043% 100% Hatchery volume comparison *Hatchery Process figures 2011-12. **Average Catch and Release rate over the whole season for the Don is 82% as of 2011 this figure relates to the number of eggs deposited by caught and released fish. ***Assumes rod catch exploitation rate of 20% Wild Fish 9710 4386 21,294,030 0.008% The figures from Table 3 have been prepared using the 2011, 10 year average run of Salmon for the River Don which is estimated at 9,710 from a conservative 20% exploitation from the rod catch. It s anticipated that half would be females with an average weight of 6lb producing 4386 eggs (Mills 1990). The total volume of eggs potentially deposited by wild spawners would then be equal 21,294,030. To put the volume of eggs produced by the hatchery into perspective this figure equates to 0.045% of the total salmon eggs deposited by caught and released fish. This figure decreases further to 0.008% of the total salmon eggs deposited when compared with wild fish. It s apparent that the volume of hatchery related eggs are insignificant when compared to the potential natural production of caught and released and also wild spawners. The volume of the caught and released fish egg deposition (3,492,220) far exceeds anything which would be possible with a hatchery. Increasing the catch and release rate by 4% from the average of 82% to an average of 86%, would enable a further 170,353 eggs laid down by the 4% of additional released fish which would exceed the current hatchery contribution of eggs to the catchment and could be argued that this approach would be far more sustainable than running a hatchery. 11 P a g e A limit upon this approach is that those fish released to spawn, do so at their own discretion and cannot be targeted to specific areas of the catchment where perhaps stock is required, but again these fish spawn under the most natural conditions possible which offer better survival than hatchery stock.
Mitigation or Restoration stocking The RDT believes that mitigation stocking can be appropriate and effective, but only under the right circumstances and if applied in a sustainable way. The potential to stock the catchment with green or preferably eyed eggs on an ad hoc basis would provide the Don DSFB with the option to stock areas above man made obstacles which are to be eased to pump prime a tributary or to mitigate for losses as a result of pollution events etc. The methodology of collecting broodstock in the field is used by other DSFB s and provides a more appropriate approach to selecting stock for crossing than is presently undertaken. The resulting broodstock can be striped on site assuming that they are ripe, these eggs can be then be fertilized and planted out after a period of water hardening for green eggs. This approach is however not as successful as planting out eyed eggs, but benefits from the reduction in labour and costs associated with maintaining a hatchery. Alternatively broodstock can be collected and retained and the fish stripped when ripe. The eggs can then be fertilised and laid down in troughs, the process of eyeing can take 30 to 50 days depending upon the water temperature and the eggs would typically be eyed by Christmas. Utlising eyed eggs is a more robust and successful stocking approach although it does require facilities and resources to be attributed to the holding and rearing of the eggs until they are eyed and ready to be planted out. A different approach, should there be sufficient wild stock locally is the relocation of eyed eggs. This approach harvests eggs from redds identified earlier in the season. The redds can be carefully dug up following eyeing and then transported and placed in an artificial redd with little negative impact upon the eggs survival. This approach was initially designed to smooth out the patchy distribution of salmonids spawning and underutilisation of juvenile habitat as a result. Field tests indicate that this approach is feasible, cost effective and efficient and requires no specialist skills of hatchery facilities and is well suited to the small scale enhancement of local salmonid populations which may be desirable on the Don (Youngson and Malcom 1998). Each of these approaches enables the targeted stocking of the catchment where it is deemed appropriate or necessary, established skills can be utilised but the requirement for existing resources and facilities are reduced or omitted altogether depending upon the approach. Hatchery practices in the field can be attractive but whilst they are cost and time effective they can also be prone to poorer survival due to increased environmental factors as a result of the removal of the relatively safe incubation periods experienced in normal hatchery programmes. Each approach has its limitations but anyone may be considered appropriate depending upon the mitigation or restoration stocking programme identified. 12 P a g e
4. Discussion & Conclusion Discussion As recommended by ASFB/RAFTS in their policy document any stocking programme should undergo a process of assessment to firstly ascertain what type of stocking programme is required and then the cost, benefit and risks associated with this stocking programme should be assessed. Justification for this programme can then be made upon this basis and if it is deemed acceptable then an appropriate monitoring programme can also be developed at this stage in order to assess the efficacy of the programme. Where costs are concerned this approach can also be considered in the assessment. The RDT recognises that whilst it s typically only biological and not financial risks which are of concern to Fishery Trust the same could not be said for a DSFB. Under the current circumstances the RDT has noted attempted to quantify the costs associated with the current hatchery process due to the limited data available to the RDT from the Board. Many figures for the costs attributed to stocking programmes have been quantified in scientific literature; Aprahamain 2003 provides a synopsis of the typical costs should further assessment be required. It s recommended that where present a local fishery Trust should provide scientific advice to the Board on this process. The Trust have effectively be undertaking this process with the Board over the past three years in the form of the Stocking Briefing notes prepared annually and now in the delivery of this evaluation of the hatchery programme. The evaluation of the hatchery process has enabled the Trust to make a subjective assessment of the hatchery programme. The recommendations from this evaluation will enable the Don DSFB to make informed decisions on the future of the hatchery process within the Don catchment. The stocking of eyed ova has been shown to be successful in the Upper Don catchment following the assessment of areas inaccessible to migratory fish though electro fishing surveys. These areas have established fry and parr populations as a result of the stocking programme and illustrate the success of restoration type or pump prime stocking prior to obstacle easement. It must be remembered that artificial reproduction will not lead to recovery unless the fundamental problems that cause the population decline are addressed (Jonsson et al 1999). It is therefore paramount to remove these obstacles in order for the natural spawning to occur in place of the continued requirement or hatchery stocking. In those areas where we undertook supplemental stocking (i.e. where interspecific competition with wild stock is present) we did not experience increased abundances of salmonids as these areas were already believed to be at their carrying capacity as a result of wild stock abundances alone. The approach of supplemental stocking is therefore considered to be ineffective due to the relatively pristine condition of the Upper Don Catchment tributaries. The requirement for alternative approaches is apparent here; easing obstacles and where appropriate improving and restoring habitats will enable natural production of areas to be increased, as the factors limiting the production are often not addressed in stocking programmes. 13 P a g e
Furthermore the current practice of collecting broodstock at the mainstem site by the Newe weir, whilst convenient is not considered to be best practice. These fish could be destined for any part of the 190km tributaries and mainstem upstream of this point which is accessible. By removing fish from this location and making crossings in the hatchery there can be no rationale for appropriate forced crossings and the approach may have deleterious effects upon the wild stock as well as that of the hatchery progeny when it comes to survival following planting out. Reduced genetic fitness and diversity may be having serious implications upon the hatchery stocks ability to adapt to the local environment. Whilst genetic analysis of the Don fish stocks did not find any significant structuring (Coulson 2011) the negative impact of the forced crossings may be having upon the genetic diversity and fitness of the stock has been well documented and should not be overlooked. It s apparent from Table 4 that the volume of hatchery related eggs are insignificant when compared to the potential natural production of wild spawners. The ability of these fish to then contribute to the natural stock far exceeds anything which would be possible with a hatchery. Using current survival rates a rough estimate of the potential returning adult fish to the rod catch from the hatchery volume of 140,000 eyed ova would be in the region of 2-3 fish. This is as a result of the low survival of hatchery reared stock both in the fresh water (<1% survive to smolt) and marine environments (<1% survive to return as adults). Considerations for the presence of inter and intraspecific competition would only serve to reduce this figure further. Stephens 2012, makes the point that biologically and statistically there is no good reason to operate hatcheries for general fishery enhancement or rehabilitation, especially considering the number of extra eggs laid in Scottish rivers thanks to catch and release. Again utilising alternative approaches to hatchery stocking may be as successful in this example. Coupling the catch and release approach with easing obstacles would produce much more significant returns to the rod catch than hatcheries, with minimal overall resource requirements. Whilst we are aware of the positive and negative impacts of hatcheries in particular upon stock genetics, a full assessment of the impacts relative to our circumstances here on the Don has not been possible due to resources. Our neighbouring catchment the Spey District Salmon Fishery Board on the other hand has been able to utlise genetic tools and its detailed stocking and crossing records in an attempt to ascertain parentage of rod caught fish which are attributed to the hatchery. The use of genetic samples enabled markers from hatchery broodstock to be identified and analysed with rod caught fish. In summary the outcome was that the return rate to the fishery from hatchery stocking was in the region of 0.5% of rod caught fish (Coulson 2012) equating to 40 fish for a hatchery volume effort equivalent to ten times that of the current approach on the Don. This low return rate illustrates a local example which employs significantly advanced targeted collection and crossing procedures compared to current practices of the Don DSFB and puts in question the current programme. 14 P a g e
Conclusion The existing approach of rehabilitation stocking or the supplementing of wild stock is unnecessary and has only been maintained as a result of the minimum 10x10 crosses required for stocking in recent years. Whilst we recognise that there are inadequacies with the present hatchery protocols and further recommendations could be proposed to remedy these, they would still not overcome the fact that the hatchery programme s contribution is trivial on the catchment scale. Alternative styles of stocking may be more appropriate given the potential approaches of habitat restoration and obstacle easement but presently, the current stocking programme is not required. It is recommended that the current rehabilitation type stocking be ceased indefinitely and that any future stocking programmes undergo a strict assessment following the criteria identified in the ASFB/RAFTS policy document. Alternative approaches such as obstacle easement and habitat restoration are more resourceful approaches with better results, which also address the root cause of population limits as opposed to supplementary stocking and should be utilised as an alternative to the existing stocking programme. The potential for restoration stocking or to pump prime areas of the catchment prior to or following obstacle easement should be considered as one such approach for future evaluation, particularly as this approach can be more effective on the tributary scale and has illustrated success within the catchment already. 15 P a g e
5. References Aprahamian, M.W., Martin Smith, K., McGinnity, P., McKelvey, S. and Taylor, J., 2003. Restocking of salmonids opportunities and limitations. Fisheries Research 62, 211-227 Coulson, M W., Webster, L M I., Urquhart, J., Armstrong, A., Cauwelier, E., Stradmeyer, L., Gilbey, J., Sinclair, C., & Verspoor, E., An Overview of Population Genetic Structuring in the River Don. Marine Scotland Science Report 02/2012 Coulson, M W. & Knight, R. 2012. Genetics Testing of Stocking Effects on the River Spey. ASFB and RAFTS Annual Review 2012 p7. Mills, D 1989, Ecology and Management of Atlantic Salmon, Chapman and Hall, London (1989), p. 351 Stephens, A. 2012 Catch and Release Compared to Stocking. ASFB and RAFTS Annual Review 2012 p8. Jonsson, B. & Jonsson, N. 1999. Restoration and Enhancement of Salmonid Populations and Habitats with Special Reference to Atlantic Salmon. American Fisheries Society Symposium 69:000 000, 2009 Youngson, A. and Malcom, I, S. 1998. Relocation of naturally spawned salmonid ova as a countermeasure to patchiness in adult distribution at spawning. Scottish Fisheries Research Report No.61 1998 MSS Guidance Documents Salmon and sea trout: to stock or not? 2003. Scottish Fisheries Information Pamphlet No. 22. Scotland s Freshwater Fish Populations: Stocking, Genetics and Broodstock Management 2004 Youngson, A., 2007.Hatchery work in Support of Salmon Fisheries. Scottish Fisheries Research Report No.65 2007 Environment Agency Guidance Document Schemes to stock rivers with salmon, sea and brown trout from locally sourced populations 2011. Operational Instruction 570_11. 16 P a g e
Appendix 1. Don Stocking Protocols RDT suggested Broodstock Collection, Crossing and Planting-Out Protocols - June 2010 It is recommended that these guidance notes be used as best practice procedures for hatchery based work on the River Don catchment. Introduction As with most other East coast salmon rivers in Scotland it is expected the spring component of the stock spawns in the upper reaches of the river. Current advice is that stock for any enhancement should be taken from higher part of the system, which at present is viewed as fish spawning upstream of the fish trap at mill of Newe. These fish are all either 2+ or 3+ fish that enter the freshwater before June (it is unlikely many if any 4+ sea age fish are present). The 1 sea winter component (grilse) enter the river during summer and autumn and it is generally not viewed these stocks need any assistance. Only 2SW fish should be chosen, all fish under 70cm (27.5 ) should be floy tagged and placed above weir. All fish trapped at weir should be tagged, as it is completely unknown at present the number of fish they drop back and then attempt to re ascend. Although late running grilse may be of this size the numbers can be determined by scale readings. Rearing of juveniles to parr stage is counterproductive as the survival rates of these fish once released is extremely low and the numbers that would be required to make even a 10% increase in catches would be prohibitive. Hence the policy of artificial redds should be adhered to whenever possible. To ensure good genetic diversity is maintained in hatchery derived stock specific protocols are given below that should be followed during broodstock collection and stripping. Hatchery It is also recommended that the hatchery facility remains in its current situation, due to the available untreated and unpolluted water supply, which adequately mimics the natural water conditions of the intended hatchery stock release sites, therefore enabling the accurate timings of wild fish egg incubation to be replicated and result in appropriate timings of hatching of reared fish in relation to food availability in intended stocking sites. It would be suggested that the current level of stocking is greater than required and until the appropriate information is gathered to determine the extent of stocking required, a conservative number of broodstock be collected to increase efficacy of the hatchery under its recently limited workspace. It is suggested that the incubation hall be moved to the ground floor to facilitate hatchery works to continue in light of H&S requirements and that a smaller number of stock reared as a result. It is also recognised that the value of the hatchery as an educational facility is valuable, both for site visits to illustrate hatchery procedure and Don DSFB work and to provide stock for Salmon/Trout in the Classroom projects. 17 P a g e
Stocking Protocols Methods Reason Collection Stripping/Crossing 18 P a g e 1. Using electro fishing, habitat, redd count and previous hatchery stock placement data to determine number of broodstock. 2. Collect broodstock at Newe weir 3. Collect most valuable stock component for broodstock i.e. fish over 70cm. 4. Floy tag all fish caught during broodstock collection process at Newe weir. 5. Ensure that scale and genetic samples are collected from broodstock used. 6. Floy tag, scale and genetic sample spawning brown/sea trout 1. Cross males and females which are ripe on the same day. 2. Divide spawners into groups of approx ten each i.e. ten females and ten males. 3. Strip all females separately and then mix eggs into one tub. 4. Divide eggs into batches, equal to number of males to be used (i.e. 10 Females x10 Males.) 5. Use single individual males to fertilise each batch of eggs. 6. Follow current incubation procedures with intent to release as eyed ova 1. Determine the number of broodstock required for stocking system at carrying capacity. 2. Due to current practice and lack of potential for direct broodstock capture from spawning sites. 3. Valuable broodstock is interpreted as MSW fish or those fish assumed by physical characteristics to be of spring or summer run types, later confirmed by scale reading. 4. To ascertain number of fish which re ascend weir and drop back. 5. To identify life history and genetic information for each fish. 6. To ascertain further information on life history, genetics and relate to anglers potential catch records for future projects. 1. Minimise inbreeding, reducing family effects. 2. Straightforward practice and easy handling of individual fish. 3. As above. 4. Enabling separate crosses to be performed and recorded. 5. Prevent mixing of milt and sperm competition. 6. Best practice, cost effective and best survival.
Planting Out 1. Using electro fishing, habitat, redd count and previous hatchery stock placement data to determine locations for planting out. 2. Only release hatchery stock within the potential natural range of wild spawners. 3. Plant out as eyed ova in artificial redds in appropriate densities at multiple sites.(info to follow) 4. Eggs planted out as early as viably possible and at period when hatchery temperature mimic s possible stocking location s. 5. If planted out as unfed or fed fry use appropriate densities at multiple sites as for artificial redds. 1. Identify the best possible location for hatchery stock to prevent competition with existing wild fish and increase chance of hatchery stock survival. 2. Reduce detrimental impacts to native trout stocks above natural obstructions. 3. Best survival rates, minimal husbandry and easily transportable. 4. Reduces the mismatch of natural timings relating to egg hatching and food availability. 5. Reduces competition and also predator affects which may also adversely impact wild fish. 19 P a g e
Appendix 2. ASFB/RAFTS policy document on salmonid stocking. The document can be found at this link http://www.asfb.org.uk/wp-content/uploads/2011/04/asfb-rafts-salmon-stocking-policy-paper.pdf 20 P a g e