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Novel Use of Pop-Up Satellite Archival Telemetry in Sawsharks

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Novel Use of Pop-Up Satellite Archival Telemetry in Sawsharks Burke et al. Anim Biotelemetry (2020) 8:33 https://doi.org/10.1186/s40317-020-00222-y Animal Biotelemetry TELEMETRY CASE REPORT Open Access Novel use of pop-up satellite archival telemetry in sawsharks: insights into the movement of the common sawshark Pristiophorus cirratus (Pristiophoridae) Patrick J. Burke1* , Johann Mourier1,2, Troy F. Gaston3 and Jane E. Williamson1,4 Abstract Background: Understanding movement patterns of a species is vital for optimising conservation and management strategies. This information is often difcult to obtain in the marine realm for species that regularly occur at depth. The common sawshark (Pristiophorus cirratus) is a small, benthic-associated elasmobranch species that occurs from shallow to deep-sea environments. No information is known regarding its movement ecology. Despite this, P. cirrata are still regularly landed as nontargeted catch in the south eastern Australian fsheries. Three individuals were tagged with pop-up satellite archival tags (PSATs) of the coast of Tasmania, Australia, to test the viability of satellite tagging on these small elasmobranchs and to provide novel insights into their movement. Results: Tags were successfully retained for up to 3 weeks, but movement difered on an individual basis. All three individuals displayed a post-release response to tagging and limited vertical movement was observed for up to 5–7 days post-tagging. Temperature loggers on the tags suggest the animals were not stationary but moved horizon- tally during this time, presumably in a fight response. After this response, continuous wavelet transformations identi- fed diel vertical movements in one individual at cyclical intervals of 12- and 24-hour periods; however, two others did not display as clear a pattern. Temperature was not signifcantly correlated with movement in the study period. The deepest depths recorded during the deployments for all individuals was approximately 120 m and the shallowest was 5 m. Conclusions: This study demonstrates that sawsharks can be successfully tagged by pop-up satellite archival tags. The data presented here show that sawsharks regularly move both horizontally and vertically in the water column, which was an unexpected result for this small benthic species. Additional research aimed at resolving the trophic ecology will help identify the drivers of these movements and help to better defne the ecological, behavioural and physiological roles of these sharks in their ecosystems. These data describe a substantial ability to move in the com- mon sawshark that was previously unknown and provides the frst account of movement ecology on the family of sawsharks: Pristiophoridae. Keywords: Elasmobranch, Satellite telemetry, Diel vertical migration, Tagging, Pristiophoridae, Australia, Movement Background Organisms in the deep-sea biome present various envi- *Correspondence: [email protected] ronmental challenges for study even with the most 1 Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia technologically advanced equipment [1]. Despite Full list of author information is available at the end of the article a lack of biological information for many deep-sea © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creat iveco mmons .org/licen ses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creat iveco mmons .org/publi cdoma in/ zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Burke et al. Anim Biotelemetry (2020) 8:33 Page 2 of 11 inhabitants, habitat within the deep-sea biome are fshing there remains a dearth of biological data on P. cir- increasingly targeted for harvest by expanding fsher- ratus, particularly in movement ecology. ies [2, 3]. Deep-sea sharks (species that predominantly Understanding animal movement is key if meaningful occur below 200 m) remain one of the more poorly management and conservation eforts are to be efec- understood group of elasmobranchs but continue to be tively employed [30]. Te scope of an animal’s ability to regularly caught in fsheries [4, 5]. In areas where deep- disperse infuences population dynamics, nutrient distri- sea sharks are targeted, dramatic population declines bution, productivity, resilience and other ecosystem level have been observed [5, 6]. Te impacts of harvesting processes [31]. For example, the frst marine protected such species are usually unknown but may have long area located entirely in the high seas was partially justi- lasting consequences because of the low productivity fed by movements of the Adélie penguins (Pygoscelis and low intrinsic rebound potential observed in many adeliae) during their energy-intensive premoult period deep-sea chondrichthyans [4]. [32]. Furthermore, many human activities pose serious Sharks play a crucial role in ecosystem function- threats to the ecology of marine life [33, 34]. Examples ing and stability [7–9]. Many species perform critical include increased fshing pressure [35, 36], pollution roles in structuring biological communities through [37, 38] and oil and gas extraction or exploration [39, predation by exhibiting top–down controls thus allow- 40]. Knowledge of movement patterns can provide data ing lower trophic levels to maintain viable diversity essential for the identifcation and mitigation of poten- [10, 11]. As such, the presence, abundance and health tial impacts [31]. Until recently, collecting this informa- of such predators have been used as indicators of the tion for small deep-sea sharks was very challenging [41]. overall health of ecosystems [10, 12, 13]. In addition, However, miniaturization of satellite telemetry tags and indirect efects of predators can be observed through their ability to record location and abiotic factors has prey response to the predators [14]. Such efects made such data collection more feasible for these spe- involve prey actively avoiding certain areas or habitats cies, including smaller bodied sharks [41]. In this study, associated with sharks or high shark abundance [14, we tested the efcacy of pop-up satellite archival tags on 15]. Tese result in increased time and energy spent on the common sawshark as an initial assessment into the predator avoidance, which could impact the ftness of applicability of using such tags for tracking movement of prey species [16]. Consequently, these efects substan- smaller deep-sea sharks, and to assess short-term move- tially infuence species and communities throughout ment in relation to depth for this sawshark species. Tis the predator’s distribution. study provides the frst baseline data on movement ecol- Sawsharks (Pristiophoridae) share many of the typi- ogy from satellite tagging for any Pristiophorid species. cal characteristics of deep-sea sharks and are also relatively understudied [4, 17]. Most of the informa- Results tion known about this group is derived from fsher- Tree PSATS were deployed and all three sawsharks ies-dependent sources [18–22]. Tese data often lack swam away strongly on release. Tag retention durations location of fshing grounds, species-specifc informa- were 14 days (Tags 167263 and 167264) and 23 days (Tag tion for nontarget catch, and inherent bias introduced 167262) (Table 1). Te percent of archived data success- by a commercially driven feet [23]. As such, the true fully transmitted to the ARGOS satellite network was demographics and population structure of these animals 64% for tag 167262 and 93% for tag 167264. Tag 167263 are generally unknown [4]. Tis is problematic as many was recovered, allowing the entire uncompressed dataset populations are continually fshed. Undoubtedly, fsh- to be downloaded. Initial deployment location with the eries management needs a broad understanding of spe- date and location of frst transmission paired with cor- cies-specifc information to make informed decisions on responding depth profles and bathymetry were used to management strategies [24]. indicate a rough path of movement (Fig. 1). Te data did Te common sawshark Pristiophorus cirratus (Latham, not allow for traditional light-based geolocation methods 1794) is a small, benthic-associated shark endemic to given limitations imposed by tag type (Tag 167264) and south eastern Australia and occurs from shallow to deep- by failures in light level data collection (Tags 167262 and sea environments [25]. Very little information is known 167263). about this species and what is known is primarily from recent studies relating to aspects of their diet [26], lon- Horizontal movements gevity concerns [27], and biological features [28, 29]. Data from all three tags suggest a southward movement Tese animals are a regular facet of nontarget catch in the after release using frst transmission
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