Injuries to Barramundi Lates calcarifer Resulting from Lip-Gripping Devices in the Laboratory

Abstract

The barramundi Lates calcarifer (also known as barramundi perch) is a renowned recreational sport fish that is the target of considerable catch-and-release fishing effort. Mechanical lip-gripping devices (lip grippers) are often used to handle barramundi because they allow the angler to easily and safely lift their catch, remove the hooks, and return it to the water while minimizing contact between the fish and other surfaces. The effects of these devices on the fish are largely unknown and to date have only been specifically quantified for bonefish Albula spp., which suffered serious injuries as a result of being handled with lip grippers. To investigate the effects of these grips on barramundi of a range of sizes, we held 21 fish (53–102 cm total length) above the water using lip grippers—10 without any additional support, and 11 with a hand holding them in a horizontal position—and compared survival and sublethal effects with those of 10 fish that had been held in landing nets for the same period of time (20 s). Two fish (7%) died 10 d posttreatment, but death could not be attributed directly to any handling treatment. All fish held with lip grippers and receiving no additional support had small holes in the membranes of the lower jaw, compared with 81% of fish that were held with lip grippers and supported by a hand. X-rays showed that lifting fish with lip grippers altered the alignment of the vertebrae, which did not return to normal after 3 weeks.