Small fish in a big pond
we use to maintain the optimum dissolved oxygen levels through- out the hatchery.
What are the major challenges you face in maintaining water quality? The water quality on Harris is
generally pretty good. Perhaps the biggest issue is the low pH of the water here, the other is- sue is that we occasionally have prolonged dry periods, especially in the spring time, and a recircula- tion system will help me deal with
these two concerns. There needs to be consistency
in water quality parameters. This means we have alarms to warn us if there is any loss in power, oxygen or water quality. When an alarm goes off we’ve only got 15 minutes to respond and resolve the problem otherwise we could lose the fi sh. This does mean that, at times, we can never be further than 15 minutes from the farm. It’s quite a responsibility and one that
I prefer to do myself rather than delegate. Two of the advantages we have here are the fact that the winters
tend to be quite mild, so the smolts continue to grow well through the winters, while the extended daylight during the summer months is also useful for encouraging growth.
factor. Previously we were able to produce fry to the required size of about 7 grams between January and June but now I can’t sell January’s fi sh until the following April, which means there’s currently almost 15 months between payments.
What sort of system do you operate at the hatchery? We take eggs into an incubation shed which is fully
recirculated. With this system we can raise the ambient water temperature by 6°C without using any heating system. When the fry are ready to fi rst feed, we transfer them across to the tanks, which is a fl ow-through tank system. The fi sh are moved to freshwater lochs when they reach about 7 grams. However, I’m hoping to convert the hatchery to a
recirculation system by the time we start our 2015 production. I’ve been slowly building my own recircula- tion system over the last couple of years, but it has taken time as I’m doing most of it myself and struggle to fi nd the time between doing the work and looking after the fi sh. I save costs by doing many of the installation tasks, such as fi tting the pipework and digging the trenches myself, but I think that it’s important to buy top quality components for the system and I source most of my key parts – such as the drum fi lter, UV and grader – from Sterner Aquatech, with the counter coming from Vaki. Sterner have also supplied the OxyGuard Commander
www.fishfarmer-magazine.com
How has the move to using freshwater lochs been? I’m currently using one freshwater loch, but now have
Smolts from loch sites tend to adapt better when they’re transferred to sea cages
access to 7 on the island. This would be enough to expand production to about 800,000 smolts per year, which is what I’m aiming for and would mean that I could employ at least two more people, which would make things easier for me – it’s not always easy operat- ing alone.
Are you concerned by the Aquaculture Stewardship Council’s (ASC) stipulation that ASC-certifi ed smolts can’t be grown on in freshwater lochs? If all the salmon companies pledged to join the ASC’s
certifi cation scheme it would spell the end for my busi- ness because I’ve not got the funds available to produce smolts entirely in land-based facilities. However, I’m not overly concerned about it at the moment, in part because such a huge part of the Scottish industry relies on freshwater loch production and in part because there will always be a demand for smolts that have spent time in lochs – managers of seawater sites tell me that smolts that have spent time in lochs tend to adapt better to being transferred into seawater cages. It seems to be less of a culture shock for them compared to fi sh that have spent their whole lives in tanks. FF
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