| | Clear Water Tank CultureFor information on live feed culture techniques please refer to the Department of Fisheries publication titled "Live Feed for Aquaculture" within the AquaInfo series. Involves the culture of larvae in a controlled environment, such as an indoor hatchery, where the fish larvae are supplied with zooplankton which are also cultured under controlled conditions. The intensive system requires dedicated facilities, considerable labour and a high degree of technological skill otherwise health or nutritional problems may arise. A typical schedule for rearing barramundi in clear water would consist of: Table1: Clear Water Tank Culture | Day | Regime | | 0 | Fertilised eggs are removed from broodstock tanks and placed into 1000 litre conical bottom tanks with flow through water (1,200 eggs per litre). | | 1 | Eggs hatch after 14-17 hours at 28 o C and 32ppt. Stock tanks initially at 30 larvae / litre, reduce to 15/L on day 10, then to 6/L on day 21. | | 2-14 | Larvae are fed on rotifers at 15-20/mL. | | 12-15 | Larvae are fed on rotifers at 0.5/mL and enriched brine shrimp nauplii at 2/mL. | | 15-26 | Larvae are fed on enriched brine shrimp nauplii and adults at 5-10/ml. | | 21 | Larvae are weaned onto a suitable dry onwards crumble. | | Reference: Castanos (1997) and Barlow et al (1996). |
Green Water Tank Culture Rearing tank maintenance is significantly lower in green water tank culture compared with clear water tank culture, with growth comparable in both methods. Larval survival is often up to 50 per cent higher than clear water culture. Growing larvae in green water would involve the following: Table2: Green Water Tank Culture | Day | Regime | | 0 | 5000 litre (or larger) rearing tanks are filled with 1200 litres of 5 micron (µm) filtered seawater and 600 litres of dense (>5 x 10 ø cells/mL) Nanochloropsis oculata algae culture. Rotifers are then added at 20 per millilitre (mL). | | 0 | Fertilised eggs are removed from broodstock tanks and placed into 1000 litre conical bottom tanks with flow through water. | | 1 | Larvae are stocked in pre-prepared tanks at a density of 50-170 larvae per litre. | | 1-9 | Rotifer densities should be monitored daily with numbers maintained at 20 per mL. | | 2 | Add a microencapsulated nutritional booster such as Frippack™ (2.5-20µm particle size) on a daily basis at a rate of 10 grams per tank. | | 4 | Add 600 litres of N. oculata to each rearing tank. | 6,10,
12,13 | Add 600 litres of filtered seawater to each rearing tank. | | 8-10 | Newly hatched brine shrimp (nauplii) are added at 2 per mL | | 10-15 | Brine shrimp nauplii are increased to 4 per mL. | | 13 | One third of brine shrimp added to each tank should be on-grown for 24 hours. | | 15 | Two 50 per cent water changes in each tank is conducted to reduce ammonia levels in preparation for harvest the following day. | | 16 | Tanks harvested, larvae can be on-grown in tanks, ponds or sea cages. | | Reference: Palmer et al (1992) |
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