Crangon septemspinosa

Lore & Background

Sand shrimp is a nocturnal species, more active in dark environments and at higher temperatures, with respiration increasing at 20°C, where it adopts a bimodal activity pattern. As a prey resource for many predators, it has limited prey availability but compensates with an unspecialized, diverse diet; when more active, it may shift to carnivorous feeding on animal tissues for higher energy. Hydration levels are inversely proportional to satiety, with water replacing tissues lost to metabolism.

Reader's Guide

The species has two major reproductive periods, though their timing varies by location. In the Mystic River estuary, these occur in early spring and late autumn; in the Southern Gulf of St. Lawrence estuary, they occur in spring and late summer, with additional smaller reproductive rates in summer and early fall, suggesting a more continuous cycle in southern populations. Mature two- or three-year-old sand shrimp immigrate from offshore to shallow shorelines in early spring to mate. Temperature strongly influences growth: in the Gulf of Maine, shrimp hatched in warmer seasons grow faster (0.42–1.25 mm/week) than those in colder seasons (0.31–0.83 mm/week). However, in Rhode Island (summer average 20°C), growth rates are up to four times higher than in Delaware Bay (summer average 27°C), indicating optimal temperatures vary by habitat. Eggs hatch when water temperatures are optimal.

Did You Know?

• Sand shrimp can reach depths of up to 450 m.
• At 20°C, the species adopts a bimodal activity pattern rather than a uni-modal one.
• Spring reproductive periods produce about twice as many eggs as autumn periods.
• Growth rates in Rhode Island can be four times higher than in Delaware Bay.