Development of a novel T-bar anchor tag for massive fish release and benefit assessments in the coastal water off Taiwan

Abstract

Stock enhancement has been one of the major practices routinely utilized to enhance and restore coastal fisheries resources in Taiwan. Over the past two decades, at least 100 million of hatchery-produced fish have been routinely released into the coastal water off Taiwan. However, the consequence of these hatchery-produced fish in natural environments are rarely characterized and poorly understood due to the lack of effective monitoring and tracking systems. Recently, a 4-years research project entitled fish fry releasing and its benefit assessment in Taiwan was launched to address the above issues. In the present study, we aimed to develop a novel T-bar anchor tag system for massive tagging and fish release. The effects of novel T-bar anchor tags on the retention, survival, and growth of 5 major fish species, Acanthopagrus schlegelii, A. latus, Lutjanus argentimaculatus, Rhabdosargus sarba, and Trachinotus blochii, routinely used for the stock enhancement programs in Taiwan were examined. Tag retention rates of 5 different fish species were consistently high (95-100%). All 5 different fish species with novel T-bar anchor tags also exhibited high survival rates (96.7-100%). The delayed increase of body weight was evident in 4 tagged fish species, but completely absent after 2 weeks of tagging experiments. Taken together, we have developed a novel tag anchor tag cost effective for massive tagging-release-recapture experiments that allow us to collect the recapture information for better understanding of the consequence of hatchery-produced fish after being released into the coastal water off Taiwan.