In October Skretting launched an upgraded Gemma Micro, which is a feed for marine fish hatcheries and replaces a live feed known as Artemia. The new feed represents a reliable supply of optimised nutrition, improving growth rates and reducing costs.

The upgraded Gemma Micro was trialled in several leading hatcheries in Spain, France and the USA during 2009 with impressive results. All hatcheries reported the diet is easy to use whether feeding by hand or by automated micro-feeders. It spreads readily on the water surface and sinks slowly. Fish larvae were quick to adapt to the feed. The patented formulation is based on pre-digested proteins and phospholipids with other ingredients such as a carefully selected blend of marine micro algae that give the feed a green colour. Eamonn O’Brien, Product Manager for Skretting Marine Hatchery Feeds, explains. “Marine larvae in the wild eat a wide range of organisms including marine algae. Our aim is to mimic this natural diet.”

In the hatchery trials, Gemma Micro led to significant improvements in growth rates compared with conventional Artemia diets. For example, at a hatchery in Spain sea bream at day 65 averaged 246 g compared with 176 g for Artemia-fed controls. Survival rates were the same or better; in some instances the improvement was substantial — up to 30% higher. O’Brien adds, “Overall, we saw greater consistency in production with the new formula Gemma Micro. Fry fed with Gemma Micro were more vigorous and moved readily into the next feeding phase, taking their growth momentum with them. Deformity rates were the same or better. Additionally, eliminating Artemia reduces the risk of introducing pathogenic bacteria and viruses to the rearing system and releases staff time for production of fish rather than live feed. The final benefits are the reliable quality of the dry feed and a shelf life of two years. Coupled with the improved performance, these factors reduced the overall cost of production in all trials.”

The quality of Artemia has become erratic in the recent past. Additionally, there are concerns over the sustainability and origin of Artemia. Further growth in aquaculture is inevitable as fish farmers seek to meet the increasing demand for fish from the expanding world population. The new Skretting feed will contribute to aquaculture’s ability to meet that demand sustainably in the years to come.

Photocaption

Cod at day 54: Artemia-fed control at the top, Gemma Micro-fed below