Finfish production in a static, inland saline water body using a Semi-Intensive Floating Tank System (SIFTS)

Abstract

Using a newly developed culture technology known as the Semi-Intensive Floating Tank System (SIFTS), rainbow trout ( Oncorhynchus mykiss), mulloway ( Argyrosomus japonicus) and barramundi ( Lates calcarifer) were produced in a 0.13 ha static, inland saline water body over a period of 292 days, yielding the equivalent of 26 tonnes/(ha year). Rainbow trout were grown with an FCR of 0.97 from 83 to 697 g over 111 days (specific growth rate (SGR), 1.91%/day) between June and September, when average daily water temperatures ranged from 12.3 to 18.2 °C. Over the same time period, mulloway grew only from 100 to 116 g, however, once temperatures increased to approximately 21 °C in October, food intake increased and mulloway grew to an average size of 384 g over 174 days with an SGR and FCR of 0.68%/day and 1.39, respectively. Barramundi stocked in November with an average weight of 40 g increased to 435 g in 138 days (SGR 1.73%/day) with an FCR of 0.90. The SIFTS significantly reduced nutrient input into the pond by removing settleable wastes as a thick sludge with a dry matter content of 5–10%. The total quantity of dry waste removed over the culture period was 527 kg (5 tonnes/(ha year)), which was calculated to contain 15 kg of nitrogen (144 kg/(ha year)) and 16 kg of phosphorus (153 kg/(ha year)). The release of soluble nutrients into the pond resulted in blooms of macro- and micro-algae which caused large and potentially lethal diurnal fluctuations in dissolved oxygen within the pond, however, comparatively stable levels of dissolved oxygen were maintained within each SIFT 1 1 The acronym SIFTS describes the Semi-Intensive Floating Tank System which is comprised of a number of Semi-Intensive Floating Tanks (SIFTs). through the use of air lift pumps.