Reducing Artemia use in the culture of Atlantic cod ( Gadus morhua)

Abstract

The acquisition and production of Artemia for the feeding of larval marine fish can constitute a significant portion of total fry culturing costs. The availability and price of Artemia can vary widely from year to year and, recently, Artemia cysts attained record high prices. This experiment was conducted to examine early weaning of cod ( Gadus morhua) larvae followed by supplementing microparticulate diet (MPD) with reduced Artemia rations. The objective was to determine whether Artemia use could be minimized while maintaining high growth and survival through supplementation of the MPD diet. Eggs were volumetrically counted to achieve a stocking density of 75 larvae l −1. The experiment consisted of a control group (100% A), which was fed live food during the experimental period, and three experimental treatments. All treatments were run in triplicate. The three experimental treatments received MPD and 50% of the amount Artemia in the 100% A treatment (50% A), MPD and 25% of the amount Artemia in the 100% A treatment (25% A), and MPD only (MPD). Standard lengths and dry weights were collected at hatch, 8, 22, 36, 50 and 64 days post-hatch (dph). Survival was calculated by counting all remaining fish at the conclusion of the experiment. The results indicate that the 100% A, 50% A and 25% A treatments did not differ significantly in standard length, dry weight, specific growth rate or survival. The MPD treatment had lower growth and survival than any of the treatments receiving Artemia. This study supports that, when Artemia prices are high (>US$50/kg), significant savings are possible for marine larval fish culture by using co-feeding strategies similar to those presented here.