First Summer
The larvae spend all of their first summer in the early rearing ponds normally at very high densities. Because of the competition for natural food we need to add supplementary feed to the fish after about 3 or 4 weeks. We do this by introducing increasing amounts of artificial food via clockwork, vibrator, or auger feeders.
Experience has shown that trout pellets are not an ideal diet for coarse fish. Ideally, the food should contain approximately 35% protein, have an oil content of less than 8%, and have an ascorbic acid availability of at least 1000mg/kg.
As the fish grow, the size and ration of the food is increased correspondingly until, by September, they are feeding on 1.5mm to 2.0mm pellets. At this stage the barbel should be at least 5 or 6cm, the chub at least 4cm and the dace 5cm in length. Growth rates can be doubled if the fish are grown at very low densities.
Second Summer
At first, growth is rapid due to the abundance of natural food. However, after 3 or 4 weeks, the majority of the natural food has been consumed and supplementary feeding must commence.
Food is introduced via "sector spreader" feeders mounted on floating platforms, which broadcast the food over a wide area. Each feeder is operated by its own 12 volt controller and can therefore be adjusted to suit requirements of individual ponds, for example: stock densities, specific species requirements, species mixture, oxygen levels, water quality and water temperature. The controllers also incorporate a photo-electric cell, which switches the unit off automatically during the night and recommences feeding at first light. Feeding rates vary greatly due to the reasons outlined above but tend to be in the range of 2% and 5% body weight/day.
Growth rates vary between the species. Barbel may reach 18cm+ at the end of the second summer, chub will easily reach 12cm to 15cm, and roach and dace reach 10cm to 12cm over the same period.
We have found that survival rates for all three species are good, ranging from an average of 82% for the dace, to 98% for the barbel.
Production figures range from 2,500kg/ha to 4,000kg/ha with an average of approximately 3,500kg/ha.
