Diel Feeding, Laminarinase Activity, and Phytoplankton Consumption by Euphausiids

Three corroborative techniques—stomach fullness, gut fluorescence, and digestive enzyme activity (laminarinase)—were used to examine the feeding ecology of two common euphausiid species off the California coast. Euphausia pacifica showed a diel feeding periodicity: stomach fullness, gut pigment levels, and laminarinase activity increased at night when this species entered the surface waters (< 80 m). In situ phytoplankton consumption by E....