It cannot have escaped anyone’s attention that summer and autumn grilse numbers have been in steep decline across the whole of Scotland for several years now. The West Coast rivers, being primarily grilse fisheries, are being particularly badly affected.  There will be a range of reasons for the decline – many most likely the result of global climate change (perhaps cyclical, perhaps not) – but one of these is likely to be the  rapidly expanding pelagic fish stock throughout the whole of the salmon’s 2000 mile journey in the North East Atlantic. It would appear that mackerel in particular have mushroomed in number and spread over the last 5 years or so and present a very stark competitive and predation risk to small surface-swimming salmon smolts in their first year at sea. It would also seem that if the smolts can survive this dense proliferation of predatory competition then the pelagic fish themselves become their prey – hence possibly why we see the early MSW salmon in such great condition when they return from the sea, albeit the fewer numbers that survive the competition in their first year at sea.

At the moment the pelagic predation and competition threat is a hypothesis (see link below for the summary paper) but we are compelled by the seeming evidence at ‘river level’ and we are working closely with its author (the leading marine biologist and pelagic/salmon expert Jens Christian Holst) to try and facilitate international cooperation to facilitate further research into this field. As a key part of Dr Holst’s hypothesis suggests that the relevant authorities are using outdated models to assess the pelagic stock and set the fishing quotas for these species, the end goal of the research (should the hypothesis be shown unequivocally to be based on fact) will be to attain much much larger quotas for fishing vessels to harvest mackerel in the NE Atlantic. This may also include a ‘safe passage’ corridor along the known path of migrating salmon smolts on the ocean conveyor belt on the continental shelf edge west of Hebrides all the way up to the feeding grounds in the Norwegian Sea. The threat of salmon by-catch by pelagic trawlers remains very real but it seems likely that the ecosystem-sized problem of mackerel competition probably dwarfs the potential numbers involved in anthropomorphic by-catch (the AST are currently undertaking a project using eDNA to try and put a number on the by-catch issue which should report at the end of the year).

http://www.pelagisk.net/media/fm/9By4XvjHKl.pdf

Meanwhile there will be a host of other factors, both in freshwater and the sea, that will be impacting salmon numbers. We are closely involved with the Atlantic Salmon Trust’s new ‘Likely Suspects’ project that will be attempting to put some numbers on these factors both in a local and national context. These figures will hopefully then inform where action and resources can be most effectively delivered. In the case of the Lochy such factors will inevitably include hydro dams, winter floods, bird and seal predation, forestry and fish farms. All of these areas are being addressed on a constant basis through close stakeholder dialogue and practical action, but it will help to perhaps be able to put some of these risks into an overall relative context and where we need to concentrate our efforts.

Meanwhile on the ground we are making sure we have a very clear picture of how the freshwater phase of the Lochy salmon’s life cycle is performing – A very detailed habitat survey of all spawning and juvenile habitat in the entire catchment, including all the main stems of the Lochy/Spean/Roy and Arkaig and all their tributaries, gives us a very clear idea of how many spawning salmon is takes to fill each area of the catchment. Obviously with these drastic falling numbers of returning grilse some of these spawning targets are not now being met. Generally speaking the higher catchment is performing better than lower down in the system, which is what one would expect when the bulk of the run appears in the spring and early summer. An annual electro fishing survey allows us to put numbers on this and shows us where the main gaps are in the catchment.

Using these data we are able to respond using our hatchery and reseed barren areas of juvenile habitat with summer fry. Furthermore, due to the extensive facilities and skill base at the hatchery, we are also able to safeguard the future juvenile populations by growing indigenous captive broodstock in the hatchery for each area of the catchment and then releasing eyed ova from these broodstocks into redds in the gravel each winter (in streams where no redds were counted the previous winter).

There is little doubt though that the recent declines seen in returning salmon and grilse to the Lochy lies primarily in their marine phase and we see the job of organisations such as the Atlantic Salmon Trust as critical to the future of the species. Meanwhile all we can do at a local level is maximise the healthy output of the river (which is essentially just a ‘smolt factory’) through habitat improvement and protection, controlled adult exploitation and targeted restocking to allow each river and tributary to reach its  juvenile carrying potential.

 

Jon Gibb, River Lochy Association. 12th August 2018.

This is a fabulous new film about the full life-cycle of the Atlantic Salmon. Well worth watching to see all of the threats this amazing fish must overcome to complete its ultimate journey – to spawn back in the river of its birth. I hope you enjoy it much as I did.

Jon Gibb

 

 

It’s been a busy last few months at the hatchery and in our representational work at a national level.

The winter was particularly cold this year and this meant that both stripping of broodstock and the development of ova was a good 3 weeks behind normal due to the lower than usual water temperatures. At times the snow was quite a challenge…


Nevertheless we successfully grew on all of the eyed ova required for outside contract work (currently the Ness DSFB project to restore the Upper Garry is the largest of these) as well as growing on all of the Lochy eggs with near 98% survival through to alevin.


The first of the alevins are now only now just beginning to absorb their yolk sacs and they will be introduced to feed over the next few weeks. These fish will be stocked as fed fry based on an electro-fishing survey being undertaken in July to identify poorly populated areas of the catchment.

Meanwhile stocking of fin clipped smolts was undertaken in April and early May. 15,000 fin clipped smolts were released in the Roy and 50,000 fin clipped smolts were released in the main stem River Lochy. The latter fish were treated with the infeed anti-sealice medicine SLICE which should give them 6 weeks protection from infestation as they find their way out to sea.

Probably the most important event of the last few months for us has been the Scottish Government’s enquiry into salmon farming. This is due to report some time this summer. We have made sure that the Lochy and surrounding rivers have been at the forefront of their considerations and, as well as written representations, I was invited to give evidence as a witness to the Committee as part of their enquiry. Following this I hosted a site visit for the REC Committee to the River Lochy and Drimsallie Hatchery. These were both very good opportunities to express the view that, while we view fish farming as critically important to the West Coast economy, we do not believe that it is currently being undertaken in suitable locations or that regulation is tight enough to protect migratory fish. So we now all wait to see whether the MSP’s will be brave enough to tackle the problem head on and introduce new measures to see the genuinely sustainable expansion of the fish farming industry.

So as a new season starts we all wait to see what it will bring. Will the spring and early summer run continue the trend of recent years (2017 aside) and continue to increase? Or will the summer and autumn grilse runs improve on recent years? We won’t know unless we are out there with a fly in the water.. so I wish all visiting and local anglers Tight Lines for the season ahead…..and don’t forget to check for those adipose fin clips!

Jon Gibb, Hatchery and Restoration Manager.

Just about all of the fisheries management world is now agreed that we are currently entering a MSW salmon cycle and are fast coming out of a 1SW grilse cycle. If history repeats itself, it may last up to 60 years! We are at a pinch-point in that transition and all it takes in any given year is for a poor MSW salmon run (as happens frequently, even in normal times) and the whole season collapses, as the salmon component of any annual run in a river is always far less numerous than grilse. I suggest this is probably exactly what we saw in rivers such as the Awe and the Lochy in 2017.

We are still fortunate though that the Lochy, compared to most west coast rivers, supports a strong genetic strain of large MSW salmon. Their time to shine might well be about to happen! It can be certainly no coincidence that only last season (2016) we had the best MSW spring salmon run for decades but the poorest grilse run in recent memory…

The reason for this grilse to salmon shift appears to be a warming sea (especially in the western edge of the NE Atlantic) and the complex changes it is having on (parts) of the ocean. Some areas of the NE Atlantic are still fairly stable, probably due to lesser impacts from shifting warmer currents (there is a known ‘cold blob’ just west of Norway for instance) but in other areas the lack of ‘grilse sized’ food is catastrophic: West of UK and South of Iceland being 2 examples. This is probably the reason for the northern Scottish rivers holding up particularly well and the southern and western rivers on the point of collapse in some cases. In times of grilse abundance (1960’s to 1990’s) the much cooler ocean would have held food uniformly all over – nowadays the food supply (and temperature) is highly patchy.

Sand-eel numbers have spiralled downwards due in part to the explosion in numbers and the unprecedented geographic spread of mackerel and other pelagic fish as waters have warmed. Grilse require abundant sand-seels to grow strong enough to survive their first winter at sea. A post-smolt salmon is a relatively rare creature in the vast ocean and the competition from any super-abundance of any marine species such as mackerel will completely swamp the vulnerable post smolt’s ability to compete for the same food source.

Conversely, MSW salmon travel further north for food where the problem is less pronounced. MSW salmon may also benefit if they can survive the first winter at sea and grow big enough to predate on the mackerel themselves. Possibly why, in amongst the current declines of most salmon rivers, some MSW salmon are returning at huge sizes (you grow fat quickly if you become big enough to eat mackerel!)

Anyway, all of the above is having an equal impact of sand-eel eating seabirds such as kittiwakes (doing very badly) but is favouring deep diving fish eaters such as gannets (doing very well). I cannot recommend highly enough the following programme which explains all of these oceanic changes on seabirds (and salmon) far better than I can. The mechanisms at play for both species are exactly the same.

http://www.bbc.co.uk/iplayer/episode/b072wwv9

Jon Gibb, Hatchery Manager.

 

Jon Gibb.     The rationale behind the agreed 3-year stocking plan

It may be helpful to recap the advantages of various stocking strategies and why (even when marine survival rates are at all-time lows) it is still worth removing a small amount of the overall spawning adults from the river to maximise the future benefit the progeny of those fish bring to the population.

The table below uses accepted wild salmon survival rates (Mills and Shelton, AST, 1986) at all life cycle stages, compared to the survival rates of reared hatchery smolts. Clearly it makes sense to take a small proportion of your spawning fish and utilise them in this way as the eggs generate proportionally far more returning adults. However, any such activity must be done within the bounds of what is an acceptable risk to genetic variation (this is why we stock only 50,000 smolts as opposed to a million!)

In terms of which life stage to stock at, it makes the most sense to stock smolts…. if you can afford to do so. In our case it makes perfect sense to do so as, due to funding, it costs the RLA a fraction of the normal price of running a smolt hatchery (normal cost for 50,000 smolts = £100,000pa @£2 per smolt)

This next table shows a comparison of 2 different stocking strategies – smolt stocking and fry stocking.  It demonstrates why the most productive strategy is smolt stocking, even when marine survival rates have collapsed (as they almost certainly did these last 2 years). It is also why the 3-year hatchery plan (agreed in February 2017) is to stock both smolts and fry if enough broodstock can be obtained.

Fundamentally though, until marine survival rates of both stocked/wild smolts return to their recent range (circa 4% for wild, 1.5% for stocked) then the hatchery will not be likely to be benefiting fishermen in the short-term, but the long-term benefits of extra egg deposition remains. Importantly, it takes a very small shift upwards in survival rates to have a very large impact on returning numbers (including those to the rod). Meantime, using the hatchery, we can create significantly more eggs deposits than if we had left the fish in the river, and hope for a turnaround very soon in marine survival.

 

Sea Lice from local fish farms 50,000 fin clipped smolt release in Lochy – even balance on all 4 private beats and river mouth.

Treated against lice when necessary based on late winter lice figures

Ongoing liaison with fish farm industry, Highland Council and Marine Scotland about the relocation of the inshore fish farms to deep-water locations (short term) or to land-based or closed containment units (eventual goal).

Declining 1sw grilse numbers Undertake an annual 16 site electro-fishing survey to identify areas of poor recruitment

50,000 – 100,000 fed fry released in areas identified by the electro-fishing survey

200,000 from 2019 onwards due to additional captive broodstock maturing in hatchery

Improved access to some smaller tributaries including working with LFT to install new fish passes on barriers on the Inverlochy and Distillery burns

Roy/Spean below min spawning target 25,000 fin clipped pre-smolts released in October 2017

From April 2018 onwards release of 25,000 fin clipped full smolts

Ongoing talks with Braeroy re bankside fencing

Predation in river Responsible person to deliver a predation control plan including goosanders, gulls and trout

eg. YEAR-ROUND goosander target = 1 birds per 24 acres (research by Dr PF Elson)

Mucomir Counter below min spawning target New smolt trapping, captive broodstock and eyed ova stocking programme agreed with SSE and Lochiel estates. Starts in April 2018

Ongoing negotiation with SSE in to improve downstream and upstream fish passage at Mucomir including the design of a new operating regime using the new turbines and floodgate control


 

 

 

 

 

 

50,000 Spring stocked fin clipped smolts main stem River Lochy April 2017

 

 

 

 

 

 

25,000 Late autumn parr stocked into Roy Catchment

 

 

 

 

 

 

 

 

 

 

One of our young helpers!

Please note that ALL FIN CLIPPED FISH MUST BE KILLED IN 2016. As part of a Marine Scotland study into the fecundity of returned hatchery fish on the Lochy, all of the ghillies will be carrying equipment to extract and store the ovaries of all hen fin clipped salmon and grilse and take scale samples of all fish. All fin clipped fish caught on the club beats should be reported immediately to the River Manager.

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