tSurvival estimates were obtained for the Norway lobster, Nephrops norvegicus, retained and escapingfrom a standard 70 mm mesh size diamond and a modified 55 mm square mesh codend, on board acommercial vessel in fishing grounds off the Portuguese south coast. Ten hauls were carried out, fivewith each experimental codend, plus three creel sets for the capture of a control group in an adjacentnon-trawled area. A total of 571 lobsters were sampled upon arrival on vessel deck, either captured in thecodend or retained in the codend cover. In addition, a total of 25 individuals were caught with creels. Theywere assessed for physical damage and vitality and subsequently placed in cages which were deployedin the same adjacent area for 48 h. Average survival rates were 0.18 and 0.17 for retained individuals and0.17 and 0.30, for individuals escaping through diamond and square meshes, respectively, and 0.84 forcreeled individuals. A discussion is carried out stressing the difficulty in disentangling the influence ofthe different factors contributing to condition and mortality of individual lobsters.