Five experiments were conducted during the year 2000 haddock spawning season on larval haddock. Live feed enrichments, larval stocking density, lighting intensity, and the influence of greenwater on growth and survival were tested. In addition, a weaning protocol for the transition from live to inert diet was investigated.

Experiment 1 examined the affect of different nutritional enrichments on survival and growth of haddock larvae. This experiment ended prematurely due to high mortality from siphoning the bottom of the tanks at 1dph. No growth data or survival data was obtained during this experiment.

Experiment 2 examined the affect of light intensity on survival. A high light intensity between 53lux-62lux was examined along with a low light intensity between 15lux-20lux. Insufficient data was retrieved for growth analysis. The experiment ran from 0 dph to16 dph. The range of survival for all tanks at high and low light intensities was 1% - 12%.

Experiment 3 examined the affect of light intensity, rearing density and greenwater on survival and growth. A high light intensity between 95lux-105lux was examined as well as a low light intensity between 8lux-12lux. Two rearing densities of 100larvae/L and 50larvae/L were investigated. Two recirculating systems were used in this experiment. One system was filled with greenwater and the other system had no greenwater. Nannochloropsis oculata paste was used for greenwater. The experiment ran from 0dph-25dph. Survival for all tanks ranged between 0%-3.3%. Growth data was obtained but dry weights are still in process.

Experiment 4 investigated the affect of light intensity and aeration treatments on survival and growth. A high light intensity between 8lux-10lux was examined as well as a low light intensity between 3lux-4lux. Treatments of aeration and no aeration were examined. The experiment ran from 0dph to 24dph.

Experiment 5 investigated an early weaning protocol for larval haddock. Eggs were obtained near the tail-bud stage from Department of Fisheries and Oceans laboratories in St. Andrews Canada. The eggs were transported to U. Maine and were incubated in complete darkness at 70 C at 32 ppt salinity. Just prior to hatch, 3,125 eggs were counted volumetrically into 8, 22 liter blue tanks. The resulting larval stocking density was 150 larvae/ liter. The blue tanks were arranged in a re-circulating culture system containing artificial seawater, receiving 200ml water exchange per minute. The tanks were aerated to ensure consistent motion within the tanks. Larvae were reared under 24-hr light (100 lux) at 90 C at 32 ppt salinity. Beginning at 2 days post hatch, larvae were fed enriched rotifers 6 times daily (200,000/tank/feeding). Rotifers were enriched with equal portions of DHA Selco, algae paste and Algamac for 12 hours prior to feeding.

The 8 tanks were randomly assigned to one of two treatments (n=4). Four tanks were weaned onto a microparticulate diet (Biokyowa 250-A) and four tanks received rotifers throughout the study. A two week co-feeding/weaning period was utilized beginning at day 7. The weaning tanks received 10mg of Biokyowa 250 every half hour between the hours of 7am and 10pm in addition to the regularly scheduled feedings of rotifers. During this two-week period, the quantity of rotifers offered to the weaning tanks at each feeding was reduced by 7% day-1. By day 21 the tanks receiving Biokyowa were completely weaned. On day 2, 7, 14, 21, and 31, 20 larvae from each tank were sampled for standard length and dry weight measurements. On day 31 survival was calculated by counting all the remaining fish in each tank. Data are summarized in the following table: