The Free Online Aquaculture Dictionary

Y

Yellowtail

Common name for Seriola quinqueradiata. Species of the tuna family, farmed in intensive cages in Japan and some other Far East countries.

 

Yolk

Store of food material, mainly protein and fat. Used for egg and embryo development see also yolk sac

Yolk Sac

Membrane containing yolk which hangs from the ventral surface of the embryo / animal. Supplies all the embryos and alevin's nutritional needs until it is exhausted. the time taken to exhaust is dependant on species, temperature and activity. Salmonids have large yolk sacs which will last several weeks, whilst carps have very small ones which may only last a few hours. It is essential that as the yolk sac nears the end of it's supply, that other food is available for the fish - see first feeding

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