Use of acoustic telemetry for spatial management of southern calamary Sepioteuthis australis, a highly mobile inshore squid species

Abstract

The use of temporal and/or spatial fish- ing exclusions is a common approach in managing impacts of squid fisheries targeting spawning aggre- gations, although there are limited data for assessing closed areas as a management tool. We evaluated the degree of protection that 2 closed areas were providing to individual spawning Sepioteuthis aus- tralis and assessed the extent of exchange between these coastal regions, separated by only 25 to 32 km. VR2 acoustic receivers were placed along the bound- aries of closed areas on the east coast of Tasmania, Australia, across smaller bays within these areas, and on individual seagrass beds. Over 77 000 detection events were obtained from 46 individuals over dura- tions of up to 129 d, demonstrating that individuals spawn over several months, traveling 100s of km within the spawning areas during this time. Squid were detected at closed area boundaries; however, most were detected again on other receivers within the closed area, indicating that although squid had moved within boundary vicinities, they had not actually left the protected area. Closures of critical spawning regions during times of heightened repro- ductive activity will therefore achieve the desired effect of protecting spawners and will allow for egg- laying. Clearly, inshore squid species can be highly mobile during an extended spawning phase and any assessment of the management benefits of closed areas needs to explicitly consider the temporal and spatial scales of the closed area in question.