THE DUNBEATH WATER:
RIVER MANAGEMENT REPORT
In 2008, following review, a small salmon hatchery was implemented on the Dunbeath Water. Motivation for investing in a salmon hatchery was threefold: (i) to stabilise and increase the salmon population in the Dunbeath Water; (ii) to improve our understanding of Dunbeath salmon and the river’s wider ecology; and (iii) to improve public engagement and understanding of wild Atlantic salmon. Additional to these important drivers, the hatchery was an excellent opportunity to make use of the old Dunbeath Corn Mill, which is sited next to the lower stretches of the river. The Mill traditionally drew water from the Dunbeath, so it was possible to continue a reliable and high-
The hatchery’s key role was to allow a small subset of Dunbeath salmon to be reared within the protected environment of the hatchery, thereby insuring against an increasingly severe set of complex pressures facing wild salmon in the river and sea. Although the hatchery environment is necessarily benign by comparison with selection from the wild, and there is evidence that hatchery-
The intention of the hatchery program was not to swamp the river with salmon for the benefit of anglers, potentially creating density-
The Dunbeath Water has been historically stocked with fed fry, but the Dunbeath Management Plan wished to implement its own hatchery so that direct control could be exerted over a number of restocking variables, including: (a) the source and genetic background of any hatchery broodstock from within the Dunbeath system, (b) the number of broodstock, (c) their husbandry, (d) the method of artificial fertilisation and parentage, (e) the numbers of offspring re-
The hatchery has now been operating since 2008, so we report on its progress across four general areas: 1) hatchery activity, 2) salmon catch statistics, 3) monitoring, management and research, and 4) education and engagement.
1. HATCHERY ACTIVITY
Dunbeath salmon hatchery increased its activities from 2008, and in 2011 became fully operational. Since 2011, the hatchery has been operating according to the Dunbeath Water Management Plan, aiming to strip and rear eggs from 5% of the adult hens in the river, which local expertise has given their best estimate to be 10 hens per annum. Broodstock are caught at the end of the fishing season using permitted methods, and then maintained in mixed-
Each year, the 10 stripped hens have typically produced ~50,000 eggs for restocking. The hatchery has achieved good success rates through fertilisation and rearing: ~95% of stripped eggs are fertile and successfully hatch. If retaining hatchlings instead of restocking, 10-
The restocking strategy is deliberately flexible, and designed to react to areas of the river where adult spawning or juvenile surveys suggest reduced numbers, and/or habitat has a high carrying capacity. The core approach has been to return unfed fry to prime juvenile habitat, especially areas where previous spawning surveys have revealed lower numbers of adults than expected from local knowledge. Electric fishing surveys of these sites that have been stocked show healthy numbers of fry and parr present. Fry are returned to the river in April, over a three to four week period (commensurate with when different groups hatched). Restocking takes place using genetically mixed families at any one site, avoiding the creation of genetic structuring which could lead to future inbreeding. Fry are carefully introduced along a suitable stretch of juvenile habitat, spreading out the introduction at a typical rate of 2000 fish per km of stream section, and avoiding extreme weather or flow conditions. In addition to unfed fry, some early-
2. SALMON CATCH STATISTICS
We expect any hatchery contribution to adult returning salmon to have begun from 2012. The average annual catch of salmon in the Dunbeath Water between 2000 and 2011 was 56. Although this number can be influenced by a number of factors in addition to the size of the population of adult salmon running the river, there were years when records show only 6 and 7 salmon were caught, in 2000 and 2003 respectively. These figures were a major concern, presenting risks of Allee effects, and therefore motivating more proactive and responsible management, to include the hatchery. Since 2012, annual catches have increased more than two-
The contribution of the hatchery to this improvement is difficult to confirm exactly, but two pieces of evidence indicate that the management plan and hatchery have played significant roles:
(i) Despite low flow, difficult angling conditions, and some evidence of Saprolegnia fungus on adults in the holding pools, the minimum catch figure since 2012 has been 58 (in 2013), a ten-
(ii) Between 2012 and 2016, 1500 of the largest grown-
We cannot calculate the exact contribution of the hatchery to the number of returning adults because: i) the fin-
Of particular note, in May 2017, two large, fresh-
Figure 2. Spring salmon caught in May 2017 on the Dunbeath Water and marked without adipose fin as being reared in the hatchery and released as a smolt in 2015.
3. MONITORING, MANAGEMENT AND RESEARCH
The Dunbeath Water management team and members of the Angling Club have been active in monitoring and managing the river at a number of levels beyond the hatchery. Overall fisheries’ management of the county of Caithness is guided by the Caithness District Salmon Fishery Board, a statutory body created by Parliament in the 1860s. This board, together with the Northern District Salmon Fishery Board, has taken the initiative of forming a charitable trust called the Flow Country Rivers Trust, the purpose of which is to advance for the public benefit the conservation of all fish species within the Flow Country catchment together with the flora and fauna proximate to the rivers and stillwaters. The Dunbeath Water Management Team work closely with the Flow Country Rivers Trust. The current Dunbeath Management Team consists of: S.W.M. Threipland (Owner), Professor Matthew Gage (University of East Anglia), J.R. Fleming (Chair, Flow Country Fisheries Trust), Henry Young (Head Water Bailiff). The group meets formally twice a year, informally on numerous occasions, and is in active communication with members of the Dunbeath Angling Club.
Each year, annual rod catch statistics are collated and the fishing club rules and regulations are reviewed. The river bailiff monitors the river full time, and poaching incidents have been minimised and policed. Croys and banks have been maintained, and bankside vegetation has been managed to prevent overgrowing and maintain shading and protection. The Dunbeath Water has two traditional hatches on Loch Dubh and Loch Braec, which have been used to allow small improvements in water flow during times of drought.
Unusual catches, such as potential farm fish, are required to be reported to the bailiff, and the club is watchful for other invasives such as Pacific salmon species; neither of these have yet to be seen in the Dunbeath, despite Pink salmon (a Pacific species) being caught in July 2017 from the Helmsdale and Thurso either side. Scale readings are submitted for unusual fish, such as the hatchery-
Annual juvenile surveys have been conducted at historical sites along the Dunbeath by independent SFCC-
The Dunbeath Water management team actively engages with SEPA to enable ongoing hydrological monitoring, and the data are passed back for inspection and storage. During the breeding season, traditional redds are monitored for presence of spawning adults. A spring dipper survey of the entire river has been conducted, indicating nesting only in the lower reaches. Each year, all broodstock used in the hatchery restocking program have a DNA sample taken and stored, so we have initiated a Dunbeath Water salmon genebank, which could be important for future assessments of genetic change, and/or more refined measures of the contribution that the hatchery makes to the wild population.
The river and hatchery has also enabled a number of specific research projects. A genetic survey of 49 hatchery-
Figure 3. By tracking eggs from fertilisation through to hatch and alevin development, research at Dunbeath Hatchery has shown that ‘dry’ fertilisation methods are as effective as ‘wet’ for encouraging egg development and juvenile development, with no difference in triploidy incidence.
Another specific research test has been conducted with the hatchery: exploring whether greater carrying capacities exist for juvenile salmon in prime habitat on the river. By using the results of past electric fishing surveys, and before targeted restocking had been implemented, survey sites were deliberately stocked to a high density (Figure 4), in order to determine whether a greater juvenile carrying capacity exists. Future surveys will examine whether juvenile densities have increased, and therefore whether higher juvenile carrying capacity can exist in the river which restocking could take advantage of.
Figure 4. Experimental ‘over-
Figure 1. Annual rod catch of salmon on the Dunbeath Water from 1997 to 2019. Figures combine grilse and salmon. Blue arrow indicates start of Dunbeath Hatchery. Red arrow indicates start of possible hatchery contribution to catch.
RIVER MANAGEMENT AND SALMON HATCHERY REPORT
2018 was a very difficult year with minimum water throughout the season. The rains came in October by which time it is thought that many of our fish had -
Some 1250 were counted over their fish counter in a night! However late spawning activity was seen by our stalkers on the Redds in mid to late October. So ……..!
Catch Record -
Dunbeath Water was returned to Grade 1 for 2019 having suffered Scottish Marine's moment of madness by degrading us to Grade 3 for 2018 -
THE DUNBEATH WATER:
RIVER MANAGEMENT REPORT