Institute for Environmental Protection and Research (ISPRA) 1 article published in JoVE Environment Long-term Video Tracking of Cohoused Aquatic Animals: A Case Study of the Daily Locomotor Activity of the Norway Lobster (Nephrops norvegicus) Jose A. Garcia*1,2, Valerio Sbragaglia*3,4, David Masip1, Jacopo Aguzzi2 1Universitat Oberta de Catalunya, 2Institute of Marine Sciences, Spanish National Research Council (CSIC), 3Institute for Environmental Protection and Research (ISPRA), 4Department of Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries Here we present a protocol to individually track animals over a long period of time. It uses computer vision methods to identify a set of manually constructed tags by using a group of lobsters as case study, simultaneously providing information on how to house, manipulate, and mark the lobsters.