Shrimp behavior in different substrates in light and dark phases of the day

Abstract

The objective of this work was to evaluate the effect of substrate type on the preference, burial, and natatory activity of shrimp (Litopenaeus vannamei). Juvenile (0.93±0.29 g) and adult males and females (10.05±1.18 g) were observed during 24 hours using the focal animal method, with instantaneous recording. The following soil granulometries (treatments) were tested: I, 100% C; II, 50% C + 50% B; III, 50% A + 50% C; IV, 100% B; V, 50% B + 50% A; and VI, 100% A, in which the letters reffer to particle mean diameter, A = 0.25–2.0 mm, B = 0.0625–0.25 mm, and C = <0.0625 mm. Six treatments were applied with 18 replicates for each category: juvenile, male, and female shrimp. Each individual was simultaneously exposed for 24 hours to the six types of substrates, and its behavior was observed in the light and dark phases of the day. Swimming occurred mainly during the dark phase, and burial in the light phase in substrate IV. The juvenile and adult shrimp (male or female) prefer substrate composed of fine and very fine sand (0.0625–0.25 mm), both for residence and for burial.