In this study, the structure and ultrastructure of the digestive system are compared in the early larval stages (nauplii I and II) of two copepod calanoid species, Acartia clausi Giesbrecht, 1889 and Hemidiaptomus roubaui Richard, 1888. The nauplii I of both species have no functional digestive tract, which is represented initially only by a blind esophageal slit and yolky endodermal cells, whi...

the aims of this study were to investigate the effect of photoperiod and light intensity on egg production and hatching rate in acartia clausi in laboratory conditions. this zooplankton was collected from caspian coastal waters of mazandaran province by the use of a 100µ net. all tests were performed in five light treatments (photoperiod) namely 24:00, 18:06, 12:12, 06:18, 00:24 (light / dark),...