Unusual Species Feature On Feeds List

The Fish Site
by The Fish Site
2 July 2010, at 1:00am

NORWAY - Claiming to feed over 50 species of aquaculture fish means Skretting has some less usual species on its list. Among the more interesting are wrasse and besugo or blackspot sea bream (Pagellus bogaraveo), both benefiting from European funding.

Wrasse, in this case Ballan wrasse (Labrus bergylta), is unusual in that it is being bred and grown to eat sea lice rather than for eating. Several teams in Norway, also in Scotland, Ireland and Russia, are working to develop commercial rearing of this species with funding from Ecofish, a part of the European Union (EU) Northern Periphery Programme that is encouraging environment-friendly fish farming.

The objective of rearing the wrasse is to introduce small numbers into pens with Atlantic salmon as a biological control, contributing to effective management of sea lice. Skretting is involved at each end of the cycle, with feeds for the broodstocks being established starting in 2009 and for the larvae they produce.

Ballan wrasse is the largest of the family; adults grow to more than 60 cm, around 3.5 kg, and it has proved to be the most effective species at eating the sea lice, which is why it was selected for this project. Also, it can withstand low water temperatures.

Kathrine Lunde, a Skretting Product Manager in Norway, gives an insight: “Taste is important in preparing feed for wrasse, which are shy feeders and scare easily. For the broodstock we are using our Vitalis Cal and Vitalis Repro feeds, already established for cod and halibut broodstock.

"We are binding the feed pellets into small blocks, with extra moisture and ingredients to increase the attraction. For the larvae we tried several feeds and our latest range of Gemma marine hatchery feeds with algal ingredients works well, potentially replacing rotifers in the protocol.

"Their high protein content seems to suit the wrasse, which is a relatively low fat fish. Hatcheries begin with Gemma Micro and progress through the sequence to Gemma Wean then Gemma Diamond after metamorphosis. When the pellet size reaches about 1.5 mm we are again adding attractants and making a moister version of the feed, as for the broodstock.”

The blackspot sea bream is a deep water fish popular for eating in several countries, especially around the Mediterranean. Yields from the wild catch were dropping, and are subject to quotas, which encouraged one company in Spain, Isidro de la Cal, to try farming it.

However, it proved more difficult than its relative the gilthead sea bream. Attempts to overcome the problems, with support from the EU EUREKA project, led the company to look for external expertise, including its own hatchery company Luso Hispaña de Acuicultura and feed company Skretting.

Fernando Sanz, the commercial manager of Skretting España introduced them to Skretting ARC. Skretting specialists in Spain and Norway then ran a series of trials with feeds based a variety of raw materials.

“The result,” says Mr Sanz, “is a high energy formulation that enables the blackspot bream to grow faster than in the wild. We named it Blackspot Power and are producing it as a commercial product.”

The farm is now supplying black spot bream at competitive prices to supermarkets in Spain.