Abstract

Alvarez de Quevedo et al. (2013; Mar Ecol Prog Ser 489:225-234) tagged 26 by-caught loggerhead sea turtles, released them with the hook and 40 cm of line, tracked them for 90 d, and concluded that the Spanish longline fleet in the southwestern Mediterranean Sea has an annual by-catch of 10 656 loggerhead turtles, resulting in 3421 to 4028 turtle deaths. We consider the methodology and results in Alvarez de Quevedo et al. (2013) to be correct overall, but based on the loggerhead CPUE (per 1000 hooks) in the 2006-2007 period, we estimate that only 6060 ind. (SE: +/- 40%) are captured annually; this would lead to a lower estimate of turtle mortality of 1945 to 2290 ind. (+/- 40%).