How is the daytime reduced activity state of shrimp often described?

As a state of energy conservation or low-profile maintenance.

The way shrimp manage their energy reserves and activity patterns during daylight hours differs fundamentally from mammalian sleep patterns. They do not experience clear-cut sleep/wake cycles like humans. Instead, when the bright overhead lights are on, they enter periods of reduced movement. This inactivity is best characterized as a phase dedicated to energy conservation, perhaps interspersed with necessary maintenance activities like cleaning their gills, or simply resting stationary on substrate elements like rocks or leaves, waiting for the lower visual risk associated with darkness.