Continental-scale network reveals cross-jurisdictional movements of sympatric sharks with implications for assessment and management

Authors

Charlie Huveneers, Flinders University, South Australia
Yuri Niella, Macquarie University
Michael Drew, Flinders University
Rory McAuley, University of Western Australia
Paul A. Butcher, New South Wales Department of Primary Industries
Victor Peddemors, New South Wales Department of Primary Industries
Daniela Waltrick, Department of Primary Industries and Regional Development, Western AustraliaFollow
Chris Dowling, Department of Primary Industries and Regional Development, Western AustraliaFollow
Silas Mountford, Department of Primary Industries and Regional Development, Western AustraliaFollow
Ian S. Keay, Department of Primary Industries and Regional DevelopmentFollow
Matias Braccini, Department of Primary Industries and Regional Development, Western AustraliaFollow

Document Type

Article

Publication Date

8-31-2021

Journal Title

Frontiers in Marine Science

ISSN

2296-7745

Keywords

shark fisheries, acoustic tracking, large-scale movement, dusky shark, bronze whaler, Carcharhinus obscurus, Carcharhinus brachyurus, fisheries management

Disciplines

Aquaculture and Fisheries | Natural Resources and Conservation

Abstract

Understanding the movement ecology of marine species and connectivity of populations is required for effective fisheries management. This is especially the case for species with wide-ranging distributions for which movement can span across several jurisdictions with different management regulations. We used the Australian national network of acoustic receivers facilitated by the Integrated Marine Observing System (IMOS) to describe the extent and frequency of movements for two large epipelagic shark species, the bronze whaler (Carcharhinus brachyurus) and dusky shark (Carcharhinus obscurus). A total of 210 sharks (117 bronze whalers and 93 dusky sharks) were tracked for a 10-year period during which 21% and 9% of detected bronze whalers and dusky sharks, respectively, moved between Australian states. Bronze whalers showed more variable inter-state movements, mostly between Western Australia and South Australia but also eastwards to New South Wales (NSW). Although no dusky sharks tagged in Western Australia undertook inter-state movements, ∼50% of the sharks tagged in South Australia went to Western Australia. Five of the 14 dusky sharks tagged in NSW (36%) were detected across different states but remained on the east and southeast coasts (Queensland, NSW, Victoria, and Tasmania). The IMOS receivers also detected six bronze whalers in Ningaloo Reef, representing an extension of the previously known Australian distribution. Our findings highlight the value of collaboration between researchers and the value of national infrastructure, by providing a more accurate understanding of inter-state movements. This new information will allow the development of more adequate population dynamic models for stock assessment and management advice, requiring collaboration among state agencies for coordinating research activities, sharing data and resources, and establishing appropriate cross-jurisdictional policies. This is essential to achieve successful management and conservation outcomes for highly migratory species.

Recommended Citation

Huveneers C, Niella Y, Drew M, McAuley R, Butcher P, Peddemors V, Waltrick D, Dowling C, Mountford S, Keay I and Braccini M (2021), Continental-Scale Network Reveals Cross-Jurisdictional Movements of Sympatric Sharks With Implications for Assessment and Management. Front. Mar. Sci. 8:697175. doi: 10.3389/fmars.2021.697175