Landbase & Recirculation – Jacob Bregnballe resource in many regions.
Seen from an environmental point of view, the limited amount of water used in
recirculation is of course
beneficial as water has become a limited
Also, the limited use of water makes it much easier and cheaper to remove the nutrients excreted from the fish as the volume of discharged water is much lower than that discharged from a traditional fish farm. Recirculation aquaculture
considered the most environmentally friendly way of producing fish at a commercially viable level.
‘I
was brought up on the Danish Trout Culture Research Station, where my father was a director
for more than thirty years, so you could say I’ve been feeding fi sh ever since I could walk’, laughs Jacob Bregnballe. ‘My fi rst “real job” was on a fi sh farm in Yorkshire, working with Nicholas Horton-Fawkes, who is a direct descendent of Guy Fawkes.’ Bregnballe later studied biology at Copenhagen University, before running his own farm – land-based recirculation and sea cage – for twenty-fi ve years. ‘I sold them off about ten years ago’, he explains, along with another business concern, Danaq, which I sold to AKVA Group around six years ago. Since then I’ve worked with AKVA Group as Director of its Land Based Aquaculture division. I have also been the chairman of the Danish Aquaculture Producer’s Organisation.
‘When I farmed it was mainly
trout, but also turbot and some salmon’, he continues. ‘I produced large 3-5kg trout in seawater, and I also had land-based seawater tanks as well as a freshwater Recircu- lating Aquaculture System (RAS) that used cooling water from one of the biggest power stations in Denmark. Closed recirculation systems have come a long way since they began in Denmark in the eel farming business. ‘They needed the water temper-
ature to be higher for the eels, so they began attempts at recycling the water. At around the same time Danish trout farmers realised that they too could benefi t from
66 HAVING SPENT A LIFETIME WORKING ON FISH can therefore be
of the water, oxygen levels, o and and
leaves drifting blocking
the inlet
down s
On dry land
etc. In a recirculated system external factors are eliminated completely or partly, depend the degree of recirculation a construction of the plant.
Recirculation enables the farmer to completely
cont
FARMS, HALF OF IT ON LAND-BASED SITES, JACOB BREGNBALLE KNOWS A THING OR TWO ABOUT RECIRCULATING AQUACULTURE SYSTEMS
the parameters in the prod and the skillfulness of the to operate the recirculation itself becomes just as impor his ability to take care of the fi
A Guide to Recirculated Aquaculture
Most interesting though, is the fact that the limited use of water gives a huge benefit to the production inside the fish farm. Traditional fish farming
recycling the water for the pro- duction of fry and fi ngerlings. That’s how it all started,’ he continues. Bregnballe admits that to begin with he was very sceptical about
Figure 1.2 An outdoor recirculation farm.
ammonia are excreted from the gills into the water. Thus fish consume oxygen and feed, and as a result the water in the system is polluted with faeces, carbon dioxide and ammonia.
RAS. ‘I had experienced all the mis- takes and disasters of RAS when I was at the Research Station, so I was not confi dent that it would be successful’. These ‘mistakes and
is totally Faeces dependent on
external conditions such as the water temperature of the river, cleanliness
feed to a minimum. The conversion rate (FCR), describing how many kilos of feed you use for every kilo of fish you produce, is improved, and the farmer gets a higher production Controlling
disasters’, he explains, were very rarely anything to do with power failures or technical faults. ‘In fact, Danish eel farmers always pay a lower insurance premium for
parameters su
water temperature, oxygen le daylight for that matter, give and optimal conditions for th which again gives less
Feed Ammonia from gills - 8 - stre
better growth. These stable con result in a steady and fores
Uneaten feed
Figure 2.2 Eating feed and using oxygen results in fish growth and excretion of waste products.
www.fishfarmer-magazine.com
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