Diurnal active photolocation enhances predator detection in a marine fishMatteo Santon, Pierre-Paul Bitton, Jasha Dehm, Roland Fritsch,  Ulrike K. Harant, Nils Anthes,  Nico K. Michielsdoi: https://doi.org/10.1101/324202     Who we are:We are a group of zoologists at different career stages with a diverse background. We have started a preprint review journal club in order to discuss topics across our different areas of concentration to stay up-to-date with the latest research and get practice writing reviews. We selected this preprint, “Diurnal active photolocation enhances predator detection in a marine fish,” by Matteo Santon et al. due to the interesting experimental design and general interest of the topic. This manuscript built upon a body of previous work in a logical, easy-to-read way. The authors demonstrate experimentally that diurnal active photolocation exists in diurnal fish and that it aids in predator detection. We were generally impressed by the experimental design and the thorough treatment of the topic. We do, however, have a few questions that we could not answer by reading the manuscript and also some comments on the presentation of the information. Questions:For the lab experiment: a. What kind of glass was used for the partition between the triplet and the predator? This is explicitly stated for the field experiment (spectrally neutral Evotron Plexiglas), but we were wondering if the same glass was used in the laboratory experiments?b. What is the purpose of the “sub-optimal substrate” strip of gravel along the long side of the tank and why is it not included in the schematic drawing of the setup? c. In lines 200-201, the authors state, “Both stimuli were simultaneously present in the tank, but only one was visible to the triplefins.” Here we would like to know how they prevented visibility of one stimulus and suggest that the spatial relationship be stated or illustrated more clearly.