Datas - visual acuity and contrast sensitivity of the Pacific white shrimp, Penaeus vannamei

Visual acuity (VA) refers to the ability to distinguish two separate points at a distance and is an important dimension of an animal’s vision. It can be affected by several visual properties, including contrast sensitivity (CS), which represents the ability to detect differences in luminance. Although the Pacific white shrimp <i>Penaeus vannamei</i> is the most bred shrimp species worldwide, little is known about its visual capacities. The aim of this study was to assess its VA and CS using the optokinetic response (OKR) in a rotating drum apparatus. VA was evaluated by presenting moving grey and white striped patterns of increasing angular width: 0 (uniform grey); 0.3; 4.0; 7.8; 11.3; 15.0; 18.0 and 22.5 °, to identify the smallest angle eliciting significant OKR (αmin). We found that αmin was 11.3 °. CS was assessed by presenting moving black and white striped patterns of constant angular width (22.5 °) at varying differences of contrast: 0 (uniform white), 10, 20, 40, 60, 80 and 100 %. The number of OKR increased with contrast, and even a contrast of 10 % elicited more OKR than 0 % contrast, indicating a CS of at least 90 % at this angular width. Further studies are needed to assess their CS to striped patterns of various angular width, to determine their contrast sensitivity function. These findings highlight that <i>P. vannamei</i> possess poor visual capacities, which is in accordance with their dim and turbid aquatic environment, where visibility is reduced.