In the past year marine biologist Siri Myhren of lumpfish supplier Tjeldbergodden Rensefisk has had overall responsibility for coordinating a study that has compared two different diets for lumpfish - one comprised of live feed and the other of dry feed.
The ongoing project is a long-term study by companies Tjeldbergodden Rensefisk and C-Feed. The copepods, Acartia tonsa, which have been used in connection with the study, are supplied by both C-Feed and Planktonic.
Bigger survival rate
“C-Feed offers copepods that are bred, while Planktonic offers copepods that are fished and cryopreserved,” Myhren tells Fish Farming Expert’s Norwegian sister site, Kyst.no.
The lumpfish were hatched in mid-January 2018, and were then divided into two groups to be fed with either live feed or dry feed.
Myhren points out that the results of the experiment show that live feed provides a much bigger survival rate, and significantly greater growth.
“The growth was equal for the first six weeks, and then the live feed group grew better. In addition, there is a great difference in survival after vaccination,” she says.
The marine biologist points out that, combined, this will mean that the production time will decrease.
When it comes to mortality, she says that 31 weeks after hatching the difference in the accumulated mortality in the groups is 35.77%.
The group of fish fed live feed also had a great advantage in connection with vaccination.
“After 13 weeks there was a big difference between the accumulated mortality,” says Myhren, pointing out that the accumulated mortality after vaccination is now 7 percentage points in the live feed group, while it is 13.39 percentage points for the dry feed group.
“This gives a difference of 47.4%,” she emphasises.
Less cleaning, less stress on fish
Myhren points out that one of the benefits of live feeds is that she doesn’t need to clean the tanks so often, therefore reducing stress on the fish.
“The dedicated operating engineers at the plant have also done their best to make the experiment go as well as it has gone,” she concludes.
C-Feed marketing director Björn Ronge says that the experiments show very good results.
“New experiments carried out show that it is almost 40% more profitability when using Norwegian-produced copepods in lumpfish production. Despite a relatively short start-up period, the group shows that they have a double survival rate with copepods,” says Ronge.
Difference in sales price
Tjeldbergodden Rensefisk points out that with its production figures this represents an increased profitability of 39%.
Ronge points out that the results clearly show that using live feed initially affects the fish throughout the production cycle. The difference in mortality throughout production means that more fish have been vaccinated in the live feed group than in the dry feed group.
“This makes a big difference in the sales price of the fish. Although the cost of live feed is greater than dry feed, we will get it back in the long run,” argues Ronge.