Internal monofilament tags used to identify juvenile Penaeus monodon: tag retention and effects on growth and survival

Abstract Juvenile Penaeus monodon were tagged with internal monofilament tags to determine if this method was suitable for identifying small prawns through a 1–2 month experiment. Two size categories of prawns, small (0.36−1.04 g), and large (1.66−2.60 g), were placed in separate experimental systems. Half in each category were tagged with internal, coloured monofilament tags injected between the integument and the muscle on the ventral surface of the sixth abdominal segment. Tagging did not significantly affect growth or survival. All tags were retained for the duration of the experiment, and colour codes remained easy to identify. Intermal monofilament tags are easy and cheap to use, and do not appear to have any adverse effects on juvenile P. monodon .