Chemical degumming increases larvae size and facilitates the commercial production of Lumpfish (Cyclopterus lumpus) eggs

Abstract

AbstractMany fishes produce adhesive eggs that confer protection from currents and predators in the wild, but that are more difficult to disinfect and aerate under aquaculture conditions. Removing egg adhesiveness (‘degumming’) has proved beneficial in the culture of many fish, and a recent gap analysis identified this as a potential way of increasing hatching success and minimize the risk of infectious diseases in the culture of lumpfish (Cyclopteurs lumpus), a novel species to aquaculture. We tested the efficacy of the enzyme alcalase (0.02%, 0.2%, 2%) as a degumming agent for lumpfish eggs, and examined its effects on hatching success, survival, and larvae size under laboratory and commercial conditions. A five-minute exposure to 0.2% and 2% alcalase decreased chorion thickness by 14% and resulted in 61-75% degumming rates, without any negative effects on hatching rate, larval survival, or incidence of embryo malformations. Degummed eggs hatched earlier than controls and resulted in larger larvae, which may confer some benefits under aquaculture conditions. A cost-benefit analysis indicates that the benefits of egg degumming compensate the costs of chemical treatment under most conditions, and that the optimal alcalase concentration is around 0.2%. We therefore recommend egg degumming as a way of making the lumpfish industry more efficient and sustainable.Statement of relevanceImproving the commercial production of lumpfish