Final Technical Report part 3 - ACP Fish II

Elaboration of an aquaculture development strategy forst. kitts and nevis – Aquaculture situation appraisalfrom easterly directions. They are in average over the year between 9 – 14 knots (4.59 – 7.20m/s),which is similar to a moderate breeze. It is suggested to use this directly for pumping water into alarge reservoir. This reservoir could be compared with the same function as a battery has ifproducing electricity and that is to store the energy if the wind is too weak or if somemaintenance is done. Most windmills are of course used for pumping freshwater so they wouldneed to be adapted for seawater. There are however also windmill models which are movingwater by an air pump. On e.g. the website internet www.ironmanwindmill.com pumps as arequoted to have capacity of pumping more than 1.3 m 3 /minute (Figure 33). That would of coursedepend on the head that the water is to be moved.Figure 33: Windmills are first of all being used forpumping of water. Picture is showing an Ironmanwindmill from USAIf to use a windmill for pumping seawater the best conditions are likely found if having the farmon the Atlantic Coast of the islands.Due to nature of the soil, “traditional” earthen ponds are not feasible and instead tanks have to beconstructed either by GRP, concrete or plastic liner.The only aquaculture farm on SKN – the SNAPPER tilapia farm – is using plastic liner andraceways.However it is suggested to use circular tanks as they have several advantages because of betterhydraulics i.e. circular water flow pattern concentrating dirt in the middle due to slowest current.• Significant better water quality (O 2 and CO 2 ) in the whole volume of the tank giving an evendistribution of fish and thus ability for higher stocking density per cubic unit• High self-cleaning effect of the tank floor (of faeces) even at low biomass and water flow• Easier to install automatic harvesting (i.e. secured for future)• For construction purpose the tanks can be modified into square tanks but with round innercorners, thus the tanks have some shared walls (like raceways)which make them cheaper inconstruction and less area demanding – but still keeping the hydraulic benefits• If having sloping land area which is not feasible to level the circular tanks can easily beconstructed at different levels, while raceways would need larger level area.This project is financed by the European Union Project implemented by pg. 67RTF pg. 139/204