R

Rotifers — Group of microscopic, primarily aquatic, animals belonging to a distinct class of the phylum Aschelminthes. They are characterized by a corona at the anterior end, which bears rufts of cilia used for feeding and locomotion. Rotifers are important live-food organisms in the rearing of marine fish larvae in hatcheries.

U

Umbrella stage — Developmental stage of the brine shrimp embryo, when it hangs underneath the empty cyst shell after the breaking stage and completes its development into a nauplius.

W

Weaning — Process in which an animal’s dependence on its mother, directly or indirectly (e.g. yolk sac) for food or protection comes to an end. In aquaculture, also used to refer to the transition from live food to processed feed for small larval fish.

Z

Zoea (pl. zoeae) — Larval stage of crustaceans following metamorphosis from the nauplius larva.  it may be referred to as protozoea where differentiation between the nauplius and mysis (or postlarva stage of          development) is difficult.

Zooplankton — The animal component of plankton.