Goerger Alice, Darmaillacq Anne-Sophie, Shashar Nadav, Dickel Ludovic
Normandie Univ., UNICAEN, Ethos (Ethologie Animale et Humaine) UMR 6552, Caen, France.
Department of Life Sciences, Ben Gurion University of the Negev, Eilat, Israel.
Front Physiol. 2021 Feb 10;12:622126. doi: 10.3389/fphys.2021.622126. eCollection 2021.
In La Manche (English Channel) the level of turbidity changes, not only seasonally and daily in seawater but also along the coast. As a consequence, vision in marine species is limited when based only on contrast-intensity. It is hypothesized that polarization sensitivity (PS) may help individuals detect preys and predators in turbid environments. In the cuttlefish, , to date, all behavioral studies have been conducted on animals reared in clear water. But the cuttlefish sensory system is adapted to a range of turbid environments. Our hypothesis was that rearing cuttlefish in clear water may affect the development of their visual system, and potentially affect their visually guided behaviors. To test this, newly-hatched cuttlefish, from eggs laid by females brought in from the wild, were reared for 1 month under three different conditions: clear water (C group), low turbidity (0.1 g / l of clay, 50-80 NTU, LT group) and high turbidity (0.5 g / l of clay, 300-400 NTU, HT group). The visual capacities of cuttlefish were tested with an optomotor apparatus at 7 days and at 1 month post-hatching. Optomotor responses of juveniles were measured by using three screen patterns (black and white stripes, linearly polarized stripes set at different orientations, and a uniform gray screen). Optomotor responses of juveniles suggest that exposure to turbid water improves the development of their PS when tested in clear water (especially in LT group) but not when tested in turbid water. We suggest that the use of slightly turbid water in rearing systems may improve the development of vision in young cuttlefish with no detrimental effect to their survival rate. Future research will consider water turbidity as a possible factor for the improvement of cuttlefish well-being in artificial rearing systems.
在拉芒什海峡（英吉利海峡），海水的浑浊度不仅随季节和每日变化，而且沿海岸线也有所不同。因此，仅基于对比度强度时，海洋物种的视觉会受到限制。据推测，偏振敏感性（PS）可能有助于个体在浑浊环境中探测猎物和捕食者。对于乌贼，迄今为止，所有行为研究都是在清水中饲养的动物上进行的。但乌贼的感官系统适应一系列浑浊环境。我们的假设是，在清水中饲养乌贼可能会影响其视觉系统的发育，并可能影响其视觉引导行为。为了验证这一点，将从野外带回的雌性乌贼所产的新孵化乌贼，在三种不同条件下饲养1个月：清水（C组）、低浑浊度（0.1克/升粘土，50 - 80 NTU，LT组）和高浑浊度（0.5克/升粘土，300 - 400 NTU，HT组）。在孵化后7天和1个月时，用视动仪测试乌贼的视觉能力。通过使用三种屏幕图案（黑白条纹、设置为不同方向的线性偏振条纹以及均匀灰色屏幕）来测量幼体的视动反应。幼体的视动反应表明，在清水中测试时，暴露于浑浊水可改善其PS的发育（特别是在LT组），但在浑浊水中测试时则不然。我们建议在饲养系统中使用轻度浑浊的水可能会改善幼乌贼视觉的发育，而对其存活率没有不利影响。未来的研究将把水的浑浊度视为改善人工饲养系统中乌贼健康状况的一个可能因素。
