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Baker CJ, Class B, Dwyer RG, Franklin CE, Campbell HA, Irwin TR, Frère CH. Active crocodiles are less sociable. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220528. [PMID: 39230456 DOI: 10.1098/rstb.2022.0528] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/19/2024] [Accepted: 02/14/2024] [Indexed: 09/05/2024] Open
Abstract
How animals move and associate with conspecifics is rarely random, with a population's spatial structure forming the foundation on which the social behaviours of individuals form. Studies examining the spatial-social interface typically measure averaged behavioural differences between individuals; however, this neglects the inherent variation present within individuals and how it may impact the spatial-social interface. Here, we investigated differences in among-individual (co)variance in sociability, activity and site fidelity in a population of wild estuarine crocodiles, Crocodylus porosus, across a 10-year period. By monitoring 118 crocodiles using coded acoustic transmitters and an array of fixed underwater receivers, we discovered that not only did individual crocodiles repeatably differ (among-individual variation) in each behaviour measured but also in how consistently they expressed these behaviours through time (within-individual variation). As expected, crocodile activity and sociability formed a behavioural syndrome, with more active individuals being less sociable. Interestingly, we also found that individuals that were either more sociable or displayed greater site fidelity were also more specialized (lower within-individual variation) in these behaviours. Together, our results provide important empirical evidence for the interplay between spatial, temporal and social individual-level behavioural variation and how these contribute to forming behavioural niches. This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.
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Affiliation(s)
- Cameron J Baker
- Research Institute for Environment and Livelihoods, Charles Darwin University , Darwin, Northern Territory 0815, Australia
- The School of the Environment, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Barbara Class
- Ludwig-Maximilians-Universität München , Munich 80539, Germany
- School of Science, Technology and Engineering, University of the Sunshine Coast , Sippy Downs, Queensland 4556, Australia
| | - Ross G Dwyer
- School of Science, Technology and Engineering, University of the Sunshine Coast , Sippy Downs, Queensland 4556, Australia
| | - Craig E Franklin
- The School of the Environment, The University of Queensland , Brisbane, Queensland 4072, Australia
| | - Hamish A Campbell
- Research Institute for Environment and Livelihoods, Charles Darwin University , Darwin, Northern Territory 0815, Australia
| | - Terri R Irwin
- Australia Zoo, Steve Irwin Way , Beerwah, Queensland 4519, Australia
| | - Céline H Frère
- The School of the Environment, The University of Queensland , Brisbane, Queensland 4072, Australia
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2
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Chen S, Xiao Y, Xiao Z, Li J, Herrera-Ulloa A. Suitable habitat shifts and ecological niche overlay assessments among benthic Oplegnathus species in response to climate change. ENVIRONMENTAL RESEARCH 2024; 252:119129. [PMID: 38734292 DOI: 10.1016/j.envres.2024.119129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/22/2024] [Accepted: 05/09/2024] [Indexed: 05/13/2024]
Abstract
Climate change has had a significant impact on many marine organisms. To investigate the effects of environmental changes on deep-water benthic fishes, we selected the genus Oplegnathus and applied species distribution modeling and ecological niche modeling. From the last glacial maximum to the present, the three Oplegnathus species (O. conwayi, O. robinsoni, and O. peaolopesi) distributed in the Cape of Good Hope region of southern Africa experienced fitness zone fluctuations of 39.9%, 13%, and 5.7%, respectively. In contrast, O. fasciatus and O. punctatus, which were primarily distributed in the western Pacific Ocean, had fitness zone fluctuations of -6.5% and 11.7%, respectively. Neither the O. insignis nor the O. woodward varied by more than 5% over the period. Under future environmental conditions, the range of variation in fitness zones for the three southern African Oplegnathus species was expected to be between -30.8% and -26.5%, while the range of variation in fitness zones for the two western Pacific stonefish species was expected to remain below 13%. In addition, the range of variation in the fitness zones of the O. insignis was projected to be between -2.3% and 7.1%, and the range of variation in the fitness zones of the O. woodward is projected to be between -5.7% and -2%. The results indicated that O. fasciatus and O. punctatus had a wide distribution and high expansion potential, while Oplegnathus species might have originated in western Pacific waters. Our results showed that benthic fishes were highly adaptable to extreme environments, such as the last glacial maximum. The high ecological niche overlap between Oplegnathus species in the same region suggested that they competed with each other. Future research could explore the impacts of environmental change on marine organisms and make conservation and management recommendations.
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Affiliation(s)
- Shaohua Chen
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Qingdao Agricultural University, College of Life Sciences, Qingdao, China.
| | - Yongshuang Xiao
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology,Qingdao Marine Science and Technology Center, Qingdao, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao, China.
| | - Zhizhong Xiao
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology,Qingdao Marine Science and Technology Center, Qingdao, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao, China; Qingdao Agricultural University, College of Life Sciences, Qingdao, China.
| | - Jun Li
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology,Qingdao Marine Science and Technology Center, Qingdao, China; Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao, China.
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3
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Grant MI, Kyne PM, James J, Hu Y, Mukherji S, Amepou Y, Baje L, Chin A, Johnson G, Lee T, Mahan B, Wurster C, White WT, Simpfendorfer CA. Elemental analysis of vertebrae discerns diadromous movements of threatened non-marine elasmobranchs. JOURNAL OF FISH BIOLOGY 2023; 103:1357-1373. [PMID: 37632330 DOI: 10.1111/jfb.15537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 08/18/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
River sharks (Glyphis spp.) and some sawfishes (Pristidae) inhabit riverine environments, although their long-term habitat use patterns are poorly known. We investigated the diadromous movements of the northern river shark (Glyphis garricki), speartooth shark (Glyphis glyphis), narrow sawfish (Anoxypristis cuspidata), and largetooth sawfish (Pristis pristis) using in situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on vertebrae to recover elemental ratios over each individual's lifetime. We also measured elemental ratios for the bull shark (Carcharhinus leucas) and a range of inshore and offshore stenohaline marine species to assist in interpretation of results. Barium (Ba) was found to be an effective indicator of freshwater use, whereas lithium (Li) and strontium (Sr) were effective indicators of marine water use. The relationships between Ba and Li and Ba and Sr were negatively correlated, whereas the relationship between Li and Sr was positively correlated. Both river shark species had elemental signatures indicative of prolonged use of upper-estuarine environments, whereas adults appear to mainly use lower-estuarine environments rather than marine environments. Decreases in Li:Ba and Sr:Ba at the end of the prenatal growth zone of P. pristis samples indicated that parturition likely occurs in fresh water. There was limited evidence of prolonged riverine habitat use for A. cuspidata. The results of this study support elemental-environment relationships observed in teleost otoliths and indicate that in situ LA-ICP-MS elemental characterization is applicable to a wide range of elasmobranch species as a discriminator for use and movement across salinity gradients. A greater understanding of processes that lead to element incorporation in vertebrae, and relative concentrations in vertebrae with respect to the ambient environment, will improve the applicability of elemental analysis to understand movements across the life history of elasmobranchs into the future.
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Affiliation(s)
- Michael I Grant
- Centre for Sustainable Tropical Fisheries and Aquaculture and College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- Piku Biodiversity Network, National Research Institute, Port Moresby, Papua New Guinea
| | - Peter M Kyne
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Julie James
- ARC Centre of Excellence for Australian Biodiversity and Heritage, College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Yi Hu
- Advanced Analytical Centre, James Cook University, Townsville, Queensland, Australia
| | - Sushmita Mukherji
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Yolarnie Amepou
- Piku Biodiversity Network, National Research Institute, Port Moresby, Papua New Guinea
| | - Leontine Baje
- National Oceanic Resource Management Authority, Palikir, Pohnpei State, Federated States of Micronesia
| | - Andrew Chin
- Centre for Sustainable Tropical Fisheries and Aquaculture and College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Grant Johnson
- Fisheries Division, Northern Territory Department of Industry, Tourism and Trade, Berrimah, Northern Territory, Australia
| | - Tegan Lee
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Perth, Western Australia, Australia
| | - Brandon Mahan
- IsoTropics Geochemistry Laboratory, James Cook University, Townsville, Queensland, Australia
| | - Christopher Wurster
- ARC Centre of Excellence for Australian Biodiversity and Heritage, College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - William T White
- CSIRO Oceans and Atmosphere, Castray Esplanade, Hobart, Tasmania, Australia
- Australian National Fish Collection, CSIRO National Research Collections Australia, Hobart, Tasmania, Australia
| | - Colin A Simpfendorfer
- Centre for Sustainable Tropical Fisheries and Aquaculture and College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
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4
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Jacoby DMP, Piper AT. What acoustic telemetry can and cannot tell us about fish biology. JOURNAL OF FISH BIOLOGY 2023. [PMID: 37837176 DOI: 10.1111/jfb.15588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 09/29/2023] [Accepted: 10/11/2023] [Indexed: 10/15/2023]
Abstract
Acoustic telemetry (AT) has become ubiquitous in aquatic monitoring and fish biology, conservation, and management. Since the early use of active ultrasonic tracking that required researchers to follow at a distance their species of interest, the field has diversified considerably, with exciting advances in both hydrophone and transmitter technology. Once a highly specialized methodology, however, AT is fast becoming a generalist tool for those wishing to study or conserve fishes, leading to diversifying application by non-specialists. With this transition in mind, we evaluate exactly what AT has become useful for, discussing how the technological and analytical advances around AT can address important questions within fish biology. In doing so, we highlight the key ecological and applied research areas where AT continues to reveal crucial new insights and, in particular, when combined with complimentary research approaches. We provide a comprehensive breakdown of the state of the art for applications of AT, discussing the ongoing challenges, where its strengths lie, and how future developments may revolutionize fisheries management, behavioral ecology and species protection. Through selected papers we illustrate specific applications across the broad spectrum of fish biology. By bringing together the recent and future developments in this field under categories designed to broadly capture many aspects of fish biology, we hope to offer a useful guide for the non-specialist practitioner as they attempt to navigate the dizzying array of considerations and ongoing developments within this diverse toolkit.
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Affiliation(s)
- David M P Jacoby
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
- Institute of Zoology, Zoological Society of London, London, UK
| | - Adam T Piper
- Institute of Zoology, Zoological Society of London, London, UK
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Smoothey AF, Niella Y, Brand C, Peddemors VM, Butcher PA. Bull Shark ( Carcharhinus leucas) Occurrence along Beaches of South-Eastern Australia: Understanding Where, When and Why. BIOLOGY 2023; 12:1189. [PMID: 37759589 PMCID: PMC10526001 DOI: 10.3390/biology12091189] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/14/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023]
Abstract
Unprovoked shark bites have increased over the last three decades, yet they are still relatively rare. Bull sharks are globally distributed throughout rivers, estuaries, nearshore areas and continental shelf waters, and are capable of making long distance movements between tropical and temperate regions. As this species is implicated in shark bites throughout their range, knowledge of the environmental drivers of bull shark movements are important for better predicting the likelihood of their occurrence at ocean beaches and potentially assist in reducing shark bites. Using the largest dataset of acoustically tagged bull sharks in the world, we examined the spatial ecology of 233 juvenile and large (including sub-adult and adult) bull sharks acoustically tagged and monitored over a 5.5-year period (2017-2023) using an array of real-time acoustic listening stations off 21 beaches along the coast of New South Wales, Australia. Bull sharks were detected more in coastal areas of northern NSW (<32° S) but they travelled southwards during the austral summer and autumn. Juveniles were not detected on shark listening stations until they reached 157 cm and stayed north of 31.98° S (Old Bar). Intra-specific diel patterns of occurrence were observed, with juveniles exhibiting higher nearshore presence between 20:00 and 03:00, whilst the presence of large sharks was greatest from midday through to 04:00. The results of generalised additive models revealed that large sharks were more often found when water temperatures were higher than 20 °C, after >45 mm of rain and when swell heights were between 1.8 and 2.8 m. Understanding the influence that environmental variables have on the occurrence of bull sharks in the coastal areas of NSW will facilitate better education and could drive shark smart behaviour amongst coastal water users.
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Affiliation(s)
- Amy F. Smoothey
- NSW Department of Primary Industries, Fisheries Research, Sydney Institute of Marine Science, Mosman, NSW 2088, Australia;
| | - Yuri Niella
- Department of Biological Sciences, Macquarie University, North Ryde, Sydney, NSW 2113, Australia;
| | - Craig Brand
- NSW Department of Primary Industries, Fisheries Research, National Marine Science Centre, Coffs Harbour, NSW 2450, Australia; (C.B.); (P.A.B.)
| | - Victor M. Peddemors
- NSW Department of Primary Industries, Fisheries Research, Sydney Institute of Marine Science, Mosman, NSW 2088, Australia;
| | - Paul A. Butcher
- NSW Department of Primary Industries, Fisheries Research, National Marine Science Centre, Coffs Harbour, NSW 2450, Australia; (C.B.); (P.A.B.)
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6
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Bielmyer-Fraser GK, Franks B, Somerville R, Hueter R, Newton AL, Fischer C. Tissue metal concentrations and antioxidant enzyme activity in western north Atlantic white sharks (Carcharodon carcharias). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 261:106641. [PMID: 37506482 DOI: 10.1016/j.aquatox.2023.106641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/17/2023] [Accepted: 07/23/2023] [Indexed: 07/30/2023]
Abstract
Anthropogenic practices have increased metal contamination in marine ecosystems. Most sharks have long lifespans, occupy an important ecological position at the top of marine food webs, and can accumulate metals. However, reference levels of metal contaminants in the tissues of sharks, particularly, apex predators such as the white shark (Carcharodon carcharias), are lacking. In this study, concentrations of copper (Cu), cadmium (Cd), nickel (Ni), lead (Pb), silver (Ag), and zinc (Zn) were measured in the muscle tissue of white (n = 42) and tiger (Galeocerdo cuvier; n = 3) sharks. Metal exposure in various species, including sharks, has been correlated with increased oxidative stress. Therefore, the main objectives of this study were to assess metal accumulation and antioxidant enzyme activity (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) in the muscle tissue of the population of white sharks and tiger sharks inhabiting the Western North Atlantic. The measured parameters were qualitatively compared between species. The small sample size of tiger sharks (collected from only one site) limited statistical analyses, therefore, white sharks were the primary focus of this study. Differences in tissue metal (Cu, Cd, Ni, and Zn) concentrations and antioxidant enzyme activities were detected based on collection site, with significant positive correlations between Cd and enzymes, SOD and CAT, and Zn and enzymes, SOD and GPx in C. carcharias. Differences in Ni concentration were detected based on sex, with females having higher Ni levels. Additionally, plasma osmolality was not correlated with tissue metal concentrations; however, osmolality decreased with increasing length in C. carcharias. This study is the first to report baseline levels of Cu, Zn, Cd, Ni, Ag, and Pb in muscle of North Atlantic white sharks and provides new insights into oxidative stress responses of these sensitive species to metal contaminants.
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Affiliation(s)
| | - Bryan Franks
- Jacksonville University, 2800 University Blvd. North, Jacksonville, FL 32211, USA
| | - Rachel Somerville
- Jacksonville University, 2800 University Blvd. North, Jacksonville, FL 32211, USA
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Tresguerres M, Kwan GT, Weinrauch A. Evolving views of ionic, osmotic and acid-base regulation in aquatic animals. J Exp Biol 2023; 226:jeb245747. [PMID: 37522267 DOI: 10.1242/jeb.245747] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
The regulation of ionic, osmotic and acid-base (IOAB) conditions in biological fluids is among the most fundamental functions in all organisms; being surrounded by water uniquely shapes the IOAB regulatory strategies of water-breathing animals. Throughout its centennial history, Journal of Experimental Biology has established itself as a premier venue for publication of comparative, environmental and evolutionary studies on IOAB regulation. This Review provides a synopsis of IOAB regulation in aquatic animals, some of the most significant research milestones in the field, and evolving views about the underlying cellular mechanisms and their evolutionary implications. It also identifies promising areas for future research and proposes ideas for enhancing the impact of aquatic IOAB research.
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Affiliation(s)
- Martin Tresguerres
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037, USA
| | - Garfield T Kwan
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, Davis, CA 95616, USA
| | - Alyssa Weinrauch
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2M5, Canada
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Baker CJ, Frère CH, Franklin CE, Campbell HA, Irwin TR, Dwyer RG. Long-term tracking reveals a dynamic crocodylian social system. Anim Behav 2023. [DOI: 10.1016/j.anbehav.2023.02.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
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Conditional alternative movement tactics in male crocodiles. Behav Ecol Sociobiol 2023. [DOI: 10.1007/s00265-023-03303-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Abstract
In species where conflict is costly, individuals adopt alternative movement tactics to minimise the risk of competitive interactions. Dominant males often maintain defined territories, while less competitive males may be forced to adopt alternative tactics to maximise fitness and reduce conflict. However, the extent to which males switch tactics according to current social or physiological status is poorly understood. Using implanted acoustic tags and a fixed array of tracking receivers, we investigated how the behaviour of 78 male estuarine crocodiles (Crocodylus porosus) shifted over an 11-year period in relation to ontogeny, body condition, and the extent of physical injuries. We discovered that male crocodiles sorted into three common movement classes, with 51% of males maintaining the same movement class across consecutive years (max = 9 years). Males > 4 m in total length maintained confined territories both within and across years and had the greatest extent of injuries and the highest condition score, indicative of territory holders. In contrast, smaller males sorted into high movement roamer or low movement site-philopatric tactics, where the tactic an individual adopted was less stable between years and did not correlate with condition or external injuries. Our study reveals the socio-biological mechanisms by which estuarine crocodiles coexist within a restricted habitat.
Significance statement
Identifying individual-level differences in movement helps us predict which individuals are more likely to be involved in human-wildlife interactions. However, studying long-term shifts in movement is challenging, as large datasets of co-occurring individuals tracked in their natural environment over multiple years are required. We tracked a population of 78 male estuarine crocodiles (1030–4687 mm total length) in a shared environment over 11 years and assessed how eight movement traits were linked to body size and physical condition. At the population level, males sorted into different movement tactics according to ontogeny, with large territorial males having better body condition yet a greater incidence of injury. However, 49% of males showed variability across years, suggesting that tactics were conditional relative to environmental variability and a male’s own status. Our study provides insights into the mechanisms and costs of movement tactics in wild crocodile populations.
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Baker CJ, Frère CH, Franklin CE, Campbell HA, Irwin TR, Dwyer RG. Crocodile social environments dictated by male philopatry. Behav Ecol 2021. [DOI: 10.1093/beheco/arab120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Examining the social behaviors of solitary species can be challenging due to the rarity in which interactions occur and the large and often inaccessible areas which these animals inhabit. As shared space-use is a prerequisite for the expression of social behaviors, we can gain insights into the social environments of solitary species by examining the degree of spatial overlap between individuals. Over a 10-year period, we examined how spatial overlap amongst 105 estuarine crocodiles Crocodylus porosus was influenced by season, sex, and movement tactic. We discovered that crocodiles displayed highly consistent spatial overlaps with conspecifics between months and across years. Furthermore, male crocodiles that exhibited a greater degree of site fidelity displayed more stable social environments, while females and males that were less site-attached had more dynamic social environments with spatial overlaps between conspecifics peaking during the mating season. Our results demonstrate how long-term tracking of multiple individuals within the same population can be used to quantify the spatial structure and social environment of cryptic and solitary species.
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Affiliation(s)
- Cameron J Baker
- The School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Céline H Frère
- Global Change Ecology Research Group, University of the Sunshine Coast, Sippy Downs, Australia
| | - Craig E Franklin
- The School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Hamish A Campbell
- Research Institute for Environment & Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
| | - Terri R Irwin
- Australia Zoo, 1638 Steve Irwin Way, Beerwah, Australia
| | - Ross G Dwyer
- The School of Biological Sciences, The University of Queensland, Brisbane, Australia
- Global Change Ecology Research Group, University of the Sunshine Coast, Sippy Downs, Australia
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Grant MI, White WT, Amepou Y, Appleyard SA, Baje L, Devloo-Delva F, Feutry P, Ibana D, Jogo DJ, Jogo S, Kyne PM, Mana R, Mapmani N, Nagul A, Roeger D, Simpfendorfer CA, Chin A. Papua New Guinea: A Potential Refuge for Threatened Indo–Pacific River Sharks and Sawfishes. FRONTIERS IN CONSERVATION SCIENCE 2021. [DOI: 10.3389/fcosc.2021.719981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The conservation of threatened elasmobranchs in tropical regions is challenging due to high local reliance on aquatic and marine resources. Due primarily to fishing pressure, river sharks (Glyphis) and sawfishes (Pristidae) have experienced large population declines in the Indo-Pacific. Papua New Guinea (PNG) may offer a refuge for these species, as human population density is low, and river shark and sawfish populations are thought to persist. However, few data are available on these species in PNG, and risk posed by small-scale fishers is poorly understood. This study observed elasmobranch catches in small-scale fisheries in riverine and coastal environments in the East Sepik (northern region), Gulf, and Western Provinces (southern region) of PNG. Surveys were conducted over a period of weeks to months in each region, during the dry season across seven field trips from 2017 to 2020. We observed a total of 783 elasmobranchs encompassing 38 species from 10 families. River sharks made up 29.4% of observations in the southern region, while sawfishes made up 14.8 and 20.3% in the northern and southern regions, respectively. River sharks were commonly caught by small-scale fishers in lower riverine environments in southern PNG, while sawfishes were generally less common and mainly observed through dried rostra. The primary threat to river shark and sawfish populations is their capture by small-scale fishers targeting teleosts for swim bladder. Persisting populations of river sharks and sawfishes indicate that PNG is the second known nation with viable populations of multiple species in the Indo-Pacific. However, populations are declining or at high risk of decline, and fisheries management and conservation are required to realize the potential of PNG as a long-term refuge.
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Lear KO, Whitney NM, Morris JJ, Gleiss AC. Temporal niche partitioning as a novel mechanism promoting co-existence of sympatric predators in marine systems. Proc Biol Sci 2021; 288:20210816. [PMID: 34229487 PMCID: PMC8261200 DOI: 10.1098/rspb.2021.0816] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Niche partitioning of time, space or resources is considered the key to allowing the coexistence of competitor species, and particularly guilds of predators. However, the extent to which these processes occur in marine systems is poorly understood due to the difficulty in studying fine-scale movements and activity patterns in mobile underwater species. Here, we used acceleration data-loggers to investigate temporal partitioning in a guild of marine predators. Six species of co-occurring large coastal sharks demonstrated distinct diel patterns of activity, providing evidence of strong temporal partitioning of foraging times. This is the first instance of diel temporal niche partitioning described in a marine predator guild, and is probably driven by a combination of physiological constraints in diel timing of activity (e.g. sensory adaptations) and interference competition (hierarchical predation within the guild), which may force less dominant predators to suboptimal foraging times to avoid agonistic interactions. Temporal partitioning is often thought to be rare compared to other partitioning mechanisms, but the occurrence of temporal partitioning here and similar characteristics in many other marine ecosystems (multiple predators simultaneously present in the same space with dietary overlap) introduces the question of whether this is a common mechanism of resource division in marine systems.
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Affiliation(s)
- Karissa O Lear
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Nicholas M Whitney
- Anderson Cabot Center for Ocean Life, New England Aquarium, 1 Central Wharf, Boston, MA 02110, USA
| | - John J Morris
- Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA
| | - Adrian C Gleiss
- Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia.,Environmental and Conservation Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
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13
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Bolotov IN, Aksenova OV, Vikhrev IV, Konopleva ES, Chapurina YE, Kondakov AV. A new fossil piddock (Bivalvia: Pholadidae) may indicate estuarine to freshwater environments near Cretaceous amber-producing forests in Myanmar. Sci Rep 2021; 11:6646. [PMID: 33758318 PMCID: PMC7988128 DOI: 10.1038/s41598-021-86241-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 03/12/2021] [Indexed: 11/10/2022] Open
Abstract
The lower Cenomanian Kachin amber from Myanmar contains a species-rich assemblage with numerous plant and animal fossils. Terrestrial and, to a lesser degree, freshwater species predominate in this assemblage, while a few taxa with marine affinities were also discovered, e.g. isopods, ammonites, and piddocks. Here, we describe the Kachin amber piddock †Palaeolignopholas kachinensis gen. & sp. nov. It appears to be an ancestral stem lineage of the recent Lignopholas piddocks, which are estuarine to freshwater bivalves, boring into wood and mudstone rocks. Frequent occurrences and high abundance of †Palaeolignopholas borings and preserved shells in the Kachin amber could indicate that the resin-producing forest was partly situated near a downstream (estuarine to freshwater) section of a river. Multiple records of freshwater invertebrates (caddisflies, mayflies, stoneflies, odonates, and chironomids) in this amber could also manifest in favor of our paleo-environmental reconstruction, although a variety of local freshwater environments is known to occur in coastal settings.
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Affiliation(s)
- Ivan N Bolotov
- Northern Arctic Federal University, Northern Dvina Emb. 17, 163002, Arkhangelsk, Russia.
- N. Laverov Federal Center for Integrated Arctic Research, Ural Branch, Russian Academy of Sciences, Northern Dvina Emb. 23, 163000, Arkhangelsk, Russia.
| | - Olga V Aksenova
- Northern Arctic Federal University, Northern Dvina Emb. 17, 163002, Arkhangelsk, Russia
- N. Laverov Federal Center for Integrated Arctic Research, Ural Branch, Russian Academy of Sciences, Northern Dvina Emb. 23, 163000, Arkhangelsk, Russia
| | - Ilya V Vikhrev
- Northern Arctic Federal University, Northern Dvina Emb. 17, 163002, Arkhangelsk, Russia
- N. Laverov Federal Center for Integrated Arctic Research, Ural Branch, Russian Academy of Sciences, Northern Dvina Emb. 23, 163000, Arkhangelsk, Russia
| | - Ekaterina S Konopleva
- Northern Arctic Federal University, Northern Dvina Emb. 17, 163002, Arkhangelsk, Russia
- N. Laverov Federal Center for Integrated Arctic Research, Ural Branch, Russian Academy of Sciences, Northern Dvina Emb. 23, 163000, Arkhangelsk, Russia
| | - Yulia E Chapurina
- Northern Arctic Federal University, Northern Dvina Emb. 17, 163002, Arkhangelsk, Russia
- N. Laverov Federal Center for Integrated Arctic Research, Ural Branch, Russian Academy of Sciences, Northern Dvina Emb. 23, 163000, Arkhangelsk, Russia
| | - Alexander V Kondakov
- Northern Arctic Federal University, Northern Dvina Emb. 17, 163002, Arkhangelsk, Russia
- N. Laverov Federal Center for Integrated Arctic Research, Ural Branch, Russian Academy of Sciences, Northern Dvina Emb. 23, 163000, Arkhangelsk, Russia
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Dwyer RG, Campbell HA, Cramp RL, Burke CL, Micheli‐Campbell MA, Pillans RD, Lyon BJ, Franklin CE. Niche partitioning between river shark species is driven by seasonal fluctuations in environmental salinity. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13626] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Ross G. Dwyer
- School of Biological Sciences The University of Queensland Brisbane QLD Australia
- Global Change Ecology Research Group University of the Sunshine Coast Maroochydore QLD Australia
| | - Hamish A. Campbell
- Research Institute for the Environment and Livelihoods College of Engineering, IT & Environment Charles Darwin University Darwin NT Australia
| | - Rebecca L. Cramp
- School of Biological Sciences The University of Queensland Brisbane QLD Australia
| | - Colin L. Burke
- School of Biological Sciences The University of Queensland Brisbane QLD Australia
| | - Mariana A. Micheli‐Campbell
- Research Institute for the Environment and Livelihoods College of Engineering, IT & Environment Charles Darwin University Darwin NT Australia
| | | | - Barry J. Lyon
- School of Biological Sciences The University of Queensland Brisbane QLD Australia
| | - Craig E. Franklin
- School of Biological Sciences The University of Queensland Brisbane QLD Australia
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