Effect of the lipid droplet adherence on growth and survival of the European hake (Merluccius merluccius) larvae

The effect of the adherence of the lipid droplet in the yolk-sac on the growth and survival of the European hake (Merluccius merluccius) larvae was studied under starved and feeding conditions. Recently hatched hake larvae with adhered and non-adhered lipid droplet (ALD and non-ALD) were maintained during 8 days under starvation conditions. The adherence of the lipid droplet positively affected larval survival during starvation. At the end of the yolk consumption period (7–8 days after hatching), 90% of the surviving larvae had an ALD, while 10% of the survivors had a non-ALD and showed a higher mortality rate. In a month feeding experiment, results show that the presence of non-ALD in newly hatched hake larvae negatively affected their growth and survival. Dry weight and length (TL) of 20-days-old larvae with ALD were significantly higher than those with non-ALD. Furthermore, lifespan of those larvae with non-adhered lipid droplet was shorter, with most of them dying during the first 15–20 days of culture. As conclusion, the percentage of the lipid droplet adherence at hatching could be used as an indicator of ‘quality’ for European hake larvae: the greater the number of larvae with adhered lipid droplet, the better larval growth and survival.