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Lopes SM, Williamson JE, Lambreghts Y, Allen AP, Brown C. Predicting whaler shark presence and interactions with humans in southern Queensland, Australia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 934:172957. [PMID: 38719058 DOI: 10.1016/j.scitotenv.2024.172957] [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: 10/16/2023] [Revised: 04/28/2024] [Accepted: 05/01/2024] [Indexed: 05/25/2024]
Abstract
The Queensland Shark Control Program (QSCP) started in 1962 to reduce the number of shark-human incidents by deploying nets and drumlines across the most popular beaches. The program targets large shark species (white, tiger and bull sharks) that are potentially hazardous to bathers. However, this strategy is lethal for other sharks and marine wildlife, including threatened and endangered species. Thus, finding non-lethal strategies is a priority. To better manage shark-human interactions, establishing a better understanding of the factors that drive shark movement is key. Here we used sea surface temperature (SST), rainfall and distance to rivers as environmental variables to predict the presence of whaler sharks in southern Queensland based on 26 years of catch data from the QSCP. We found that SST is positively corelated to sharks caught by drumlines, while rainfall was associated with the number of sharks captured in shark nets. In addition, more sharks were captured by nets and drumlines further away from rivers, and nets captured roughly 10 times more sharks than drumlines over the period of study. In contrast to tiger sharks, the catch data indicate the number of whalers has not declined over the past 26 years. Our findings suggest that environmental variables can be used to predict the movement of large sharks and by incorporating this knowledge into management plans and public education programs, may ultimately reduce shark-human incidents.
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Affiliation(s)
- S M Lopes
- School of Natural Sciences, Macquarie University, NSW 2109, Australia.
| | - J E Williamson
- School of Natural Sciences, Macquarie University, NSW 2109, Australia
| | - Y Lambreghts
- School of Natural Sciences, Macquarie University, NSW 2109, Australia; School of Natural Sciences, University of Tasmania, Hobart, Tasmania 7005, Australia
| | - A P Allen
- School of Natural Sciences, Macquarie University, NSW 2109, Australia
| | - C Brown
- School of Natural Sciences, Macquarie University, NSW 2109, Australia
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2
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Lara-Lizardi F, Castro E, Leos Barajas V, Morales JM, Hoyos-Padilla EM, Ketchum J. Seasonal occurrence and individual variability of bull sharks, Carcharhinus leucas, in a marine reserve of the southwestern Gulf of California. PeerJ 2024; 12:e17192. [PMID: 38766482 PMCID: PMC11102736 DOI: 10.7717/peerj.17192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 03/13/2024] [Indexed: 05/22/2024] Open
Abstract
Background Studying how the bull sharks aggregate and how they can be driven by life history traits such as reproduction, prey availability, predator avoidance and social interaction in a National Park such as Cabo Pulmo, is key to understand and protect the species. Methods The occurrence variability of 32 bull sharks tracked with passive acoustic telemetry were investigated via a hierarchical logistic regression model, with inference conducted in a Bayesian framework, comparing sex, and their response to temperature and chlorophyll. Results Based on the fitted model, occurrence probability varied by sex and length. Juvenile females had the highest values, whereas adult males the lowest. A strong seasonality or day of the year was recorded, where sharks were generally absent during September-November. However, some sharks did not show the common pattern, being detected just for a short period. This is one of the first studies where the Bayesian framework is used to study passive acoustic telemetry proving the potential to be used in further studies.
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Affiliation(s)
- Frida Lara-Lizardi
- Pelagios Kakunjá, La Paz, Baja California Sur, Mexico
- Orgcas, La Paz, Baja California Sur, Mexico
- Migramar, Bodega Bay, CA, United States of America
| | - Eleazar Castro
- Centro Interdisciplinario en Ciencias Aplicadas de Baja California Sur A.C., La Paz, Baja California Sur, Mexico
| | - Vianey Leos Barajas
- Department of Statistical Sciences, University of Toronto, Toronto, Canada
- School of the Environment, University of Toronto, Toronto, Canada
- Department of Statistics, North Carolina State University, North Carolina, United States of America
- Department of Forestry and Environmental Resources, North Carolina State University, North Carolina, United States of America
| | - Juan Manuel Morales
- Grupo de Ecología Cuantitativa. INIBIOMA, Universidad Nacional del Comahue, Bariloche, Argentina
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, Scotland
| | - Edgar Mauricio Hoyos-Padilla
- Pelagios Kakunjá, La Paz, Baja California Sur, Mexico
- Migramar, Bodega Bay, CA, United States of America
- Fins attached: Marine Research and Conservation, Colorado Springs, CO, United States of America
| | - James Ketchum
- Pelagios Kakunjá, La Paz, Baja California Sur, Mexico
- Migramar, Bodega Bay, CA, United States of America
- Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, Mexico
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3
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Gayford JH, Whitehead DA, Jaquemet S. Ontogenetic shifts in body form in the bull shark Carcharhinus leucas. J Morphol 2024; 285:e21673. [PMID: 38361272 DOI: 10.1002/jmor.21673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 02/17/2024]
Abstract
Recent studies have uncovered mosaic patterns of allometric and isometric growth underlying ontogenetic shifts in the body form of elasmobranch species (shark and rays). It is thought that shifts in trophic and spatial ecology through ontogeny drive these morphological changes; however, additional hypotheses relating to developmental constraints have also been posed. The bull shark (Carcharhinus leucas) is a large-bodied coastal shark that exhibits strong ontogenetic shifts in trophic and spatial ecology. In this study, we utilise a large data set covering a large number of morphological structures to reveal ontogenetic shifts in the body form of C. leucas, stratifying analyses by sex and size classes to provide fine-scale, more ecomorphologically relevant results. Our results indicate shifts in functional demands across the body through ontogeny, driven by selective pressures relating to trophic and spatial ecology driving the evolution of allometry. We also find significant differences in scaling trends between life stages, and between the sexes, highlighting the importance of utilising large, diverse datasets that can be stratified in this way to improve our understanding of elasmobranch morphological evolution. Ultimately, we discuss the implications of these results for existing ecomorphological hypotheses regarding the evolution of specific morphological structures, and pose novel hypotheses where relevant.
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Affiliation(s)
- Joel H Gayford
- Department of Life Sciences, Silwood Park Campus, Imperial College London, Berks, UK
| | | | - Sébastien Jaquemet
- Université de La Réunion, UMR Entropie (Univ. Réunion, IRD, CNRS, Ifremer, Univ. Nouvelle-Calédonie), Saint Denis Message Cedex 9, Ile de La Réunion, France
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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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5
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Erasmus JH, Smit NJ, Gerber R, Schaeffner BC, Nkabi N, Wepener V. Total mercury concentrations in sharks, skates and rays along the South African coast. MARINE POLLUTION BULLETIN 2022; 184:114142. [PMID: 36182787 DOI: 10.1016/j.marpolbul.2022.114142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/11/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
Global declines in elasmobranch populations resulting from several stressors raises conservation concern. Additionally, apex predators bioaccumulate high concentrations of total mercury (THg), due to biomagnification. Although South Africa is considered one of the top ten contributors of Hg emissions globally, information on Hg concentrations in elasmobranchs is limited. The aim of this study was to evaluate the THg concentrations in 22 species of elasmobranchs along the South African coastline. Concentrations ranged between 0.22 and 5.8 mg/kg in Haploblepharus pictus (dark shysharks) and Rostroraja alba (white skates) on the south coast, respectively. Along the east coast it ranged between 0.21 and 17.8 mg/kg in Mobula kuhlii (shortfin devil rays) and Sphyrna lewini (scalloped hammerheads), respectively. Mercury concentrations on the east coast were in the same range or higher compared to the same species sampled between 2005-10 from the same region, with generally higher concentrations compared to the same species sampled globally.
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Affiliation(s)
- J H Erasmus
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman Street, Potchefstroom 2520, South Africa.
| | - N J Smit
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman Street, Potchefstroom 2520, South Africa.
| | - R Gerber
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman Street, Potchefstroom 2520, South Africa; South African Shark Conservancy, Old Harbour, 22 Marine Drive, Hermanus 7200, South Africa.
| | - B C Schaeffner
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman Street, Potchefstroom 2520, South Africa; South African Shark Conservancy, Old Harbour, 22 Marine Drive, Hermanus 7200, South Africa; Institute for Experimental Pathology at Keldur, University of Iceland, Keldnavegur 3, 112 Reykjavík, Iceland.
| | - N Nkabi
- KwaZulu-Natal Sharks Board, 1a Herrwood Drive, Umhlanga Rocks 4320, South Africa.
| | - V Wepener
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, 11 Hoffman Street, Potchefstroom 2520, South Africa.
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Monteforte KIP, Butcher PA, Morris SG, Kelaher BP. The Relative Abundance and Occurrence of Sharks off Ocean Beaches of New South Wales, Australia. BIOLOGY 2022; 11:biology11101456. [PMID: 36290360 PMCID: PMC9599013 DOI: 10.3390/biology11101456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/15/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022]
Abstract
There is still limited information about the diversity, distribution, and abundance of sharks in and around the surf zones of ocean beaches. We used long-term and large-scale drone surveying techniques to test hypotheses about the relative abundance and occurrence of sharks off ocean beaches of New South Wales, Australia. We quantified sharks in 36,384 drone flights across 42 ocean beaches from 2017 to 2021. Overall, there were 347 chondrichthyans recorded, comprising 281 (81.0%) sharks, with observations occurring in <1% of flights. Whaler sharks (Carcharhinus spp.) had the highest number of observations (n = 158) recorded. There were 34 individuals observed for both white sharks (Carcharodon carcharias) and critically endangered greynurse sharks (Carcharias taurus). Bull sharks (Carcharhinus leucas), leopard sharks (Stegostoma tigrinum) and hammerhead species (Sphyrna spp.) recorded 29, eight and three individuals, respectively. Generalised additive models were used to identify environmental drivers for detection probability of white, bull, greynurse, and whaler sharks. Distances to the nearest estuary, headland, and island, as well as water temperature and wave height, were significant predictors of shark occurrence; however, this varied among species. Overall, we provide valuable information for evidence-based species-specific conservation and management strategies for coastal sharks.
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Affiliation(s)
- Kim I. P. Monteforte
- National Marine Science Centre, Southern Cross University, Coffs Harbour, NSW 2450, Australia
- Correspondence:
| | - Paul A. Butcher
- National Marine Science Centre, Southern Cross University, Coffs Harbour, NSW 2450, Australia
- NSW Department of Primary Industries, National Marine Science Centre, Coffs Harbour, NSW 2450, Australia
| | - Stephen G. Morris
- NSW Department of Primary Industries, Wollongbar, NSW 2477, Australia
| | - Brendan P. Kelaher
- National Marine Science Centre, Southern Cross University, Coffs Harbour, NSW 2450, Australia
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Goodman K, Niella Y, Bliss‐Henaghan T, Harcourt R, Smoothey AF, Peddemors VM. Ontogenetic changes in the tooth morphology of bull sharks (Carcharhinus leucas). JOURNAL OF FISH BIOLOGY 2022; 101:1033-1046. [PMID: 35848707 PMCID: PMC9804735 DOI: 10.1111/jfb.15170] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Teeth are an integral component of feeding ecology, with a clear link between tooth morphology and diet, as without suitable dentition prey cannot be captured nor broken down for consumption. Bull sharks, Carcharhinus leucas, undergo an ontogenetic niche shift from freshwater to marine habitats, which raises the question: does tooth morphology change with ontogeny? Tooth shape, surface area and thickness were measured using both morphometrics and elliptic Fourier analysis to determine if morphology varied with position in the jaw and if there was an ontogenetic change concordant with this niche shift. Significant ontogenetic differences in tooth morphology as a function of position in the jaw and shark total length were found, with upper and lower jaws of bull sharks presenting two different tooth morphologies. Tooth shape and thickness fell into two groupings, anterior and posterior, in both the upper and lower jaws. Tooth surface area, however, indicated three groupings, mesial, intermediate and distal, in both the upper and lower jaws. While tooth morphology changed significantly with size, showing an inflection at sharks of 135 cm total length, each morphological aspect retained the same tooth groupings throughout. These ontogenetic differences in tooth morphologies reflect tooth strength, prey handling and heterodonty.
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Affiliation(s)
- Kyle Goodman
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - Yuri Niella
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | | | - Robert Harcourt
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - Amy F. Smoothey
- NSW Department of Primary Industries, Fisheries ResearchSydney Institute of Marine ScienceMosmanNew South WalesAustralia
| | - Victor M. Peddemors
- NSW Department of Primary Industries, Fisheries ResearchSydney Institute of Marine ScienceMosmanNew South WalesAustralia
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8
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Matich P, Bigelow CL, Chambers B, Dodds JJ, Hebert JA, Lemieux A, Pittman CM, Trapp J, Bianco B, Cadena CP, Castillo EI, Castillo GI, Dawdy A, Dominguez AI, Dominique N, French DR, Glenn CF, Jackson ECH, Johnson B, Kohl G, Manka C, Martin JK, Pappas M, Reedholm AJ, Snead KM, Tyree MK, Fisher M. Delineation of blacktip shark (Carcharhinus limbatus) nursery habitats in the north-western Gulf of Mexico. JOURNAL OF FISH BIOLOGY 2022; 101:236-248. [PMID: 35591772 DOI: 10.1111/jfb.15103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Coevolution with predators leads to the use of low-risk habitats by many prey species, which promotes survival during early developmental phases. These nurseries are valued by conservation and management agencies because of their contributions to adult populations. However, the physical and geographic characteristics, like shallow depths and isolation from other marine habitats, that restrict access to predators and thereby reduce risk to juvenile animals can also limit scientific research. Consequently, many nursery habitats are still unidentified and understudied. Here we used gillnet monitoring from 1982 to 2018 to delineate blacktip shark (Carcharhinus limbatus) nurseries in the north-western Gulf of Mexico and elucidated their physical, environmental and biological characteristics. Nursery habitats within estuaries (<2% of spatial area) were proximate to the Gulf of Mexico and exhibited significantly lower variability in salinity than non-nurseries. However, relative abundances of predators and prey were not significant delineators of nursery habitats. As such, food and risk may not influence juvenile blacktip habitat use as expected. Alternatively, reduced osmoregulatory stress attributed to predictable environments likely provides advantageous conditions for blacktips to develop foraging and antipredator tactics, which is vital prior to the winter migration of juvenile sharks into the Gulf of Mexico.
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Affiliation(s)
| | - Camryn L Bigelow
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Barrett Chambers
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Jillian J Dodds
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Jessica A Hebert
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Alexis Lemieux
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Christy M Pittman
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Julianna Trapp
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Brooke Bianco
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Carolina P Cadena
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Emily I Castillo
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Gabriela I Castillo
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Alexandra Dawdy
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Alina I Dominguez
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Nicholas Dominique
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Donavon R French
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Callie F Glenn
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Elena C H Jackson
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Breidon Johnson
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Gunnar Kohl
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Cameron Manka
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Jared K Martin
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Matthew Pappas
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Audrey J Reedholm
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Kailey M Snead
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Matthew K Tyree
- Marine Biology Department, Texas A & M University at Galveston, Galveston, Texas, USA
| | - Mark Fisher
- Texas Parks and Wildlife Department, Coastal Fisheries Division, Rockport Marine Science Laboratory, Rockport, Texas, USA
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MAILLAUD C, TIRARD P, BORSA P, GUITTONNEAU AL, FOURNIER J, NOUR M. [Shark attacks in New Caledonia from 1958 to 2020: a review of cases]. MEDECINE TROPICALE ET SANTE INTERNATIONALE 2022; 2:mtsi.v2i1.2022.209. [PMID: 35685842 PMCID: PMC9128417 DOI: 10.48327/mtsi.v2i1.2022.209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 01/31/2022] [Indexed: 11/24/2022]
Abstract
Background and objectives Recent shark attacks in New Caledonia have prompted local authorities to elaborate a risk-management plan. The objective of the present paper is to produce detailed data on shark attacks that occurred in New Caledonian waters for the last few decades, as well as on the injuries of the victims, in order to inform rescue and medical services as well as authorities in charge of educating the public and providing security. Methods Incidents involving sharks and humans in New Caledonia for the last six decades were included into a database. Sharks were tentatively identified to species according to the shape, size and other external characteristics of injuries to the victims, together with witness accounts. The severity of shark bites was evaluated against the scale proposed by A.K. Lentz and co-authors (Am Surg. 2010;76:101-6). Results Sixty-seven shark-attack cases were recorded in New Caledonia from 1958 to 2020, of which 13 were lethal. The majority of the attacks concerned spearfishers and freedivers collecting invertebrates (58.5% of total). In the last decades, shark attacks may have increased towards bathers, swimmers and snorkelers (18.5%), and people taking part in water sports including surf, kitesurf, windsurf and SUP foil (14%). One scuba diver was also attacked (1.5%). Twenty attacks including 8 lethal ones were ascribed to the tiger shark Galeocerdo cuvier; 14 attacks including 2 lethal ones to the bull shark Carcharhinus leucas; 2 attacks including 1 lethal to the great white shark Carcharodon carcharías. The lethality of attacks was almost one in five, above the global average. Conclusions Feeding incentive appeared to be a frequent factor triggering attacks. The education of the public should be promoted as a preventive measure aiming to reduce the risk of such accidents.
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Affiliation(s)
- Claude MAILLAUD
- ISEA (Institut de sciences exactes et appliquées) (EA 7484), Université de la Nouvelle-Calédonie, BP R4, 98851 Nouméa, Nouvelle-Calédonie,*
| | - Philippe TIRARD
- 9 rue Émile Legrand - Anse Vata, Nouméa, 98800 Nouméa, Nouvelle-Calédonie
| | - Philippe BORSA
- Institut de recherche pour le développement, IRD-UMR 250 « Écologie marine tropicale des océans Pacifique et Indien », Centre IRD Occitanie, 911 avenue Agropolis, 34394 Montpellier Cedex 5, France
| | - Anne-Laure GUITTONNEAU
- SAMU/SMUR/SAU/UHCD, Centre hospitalier territorial de Nouvelle-Calédonie, BP J5, 98849 Nouméa, Nouvelle-Calédonie
| | - Joseph FOURNIER
- Service de Chirurgie orthopédique et traumatologique, Centre hospitalier territorial de Nouvelle-Calédonie, BP J5, 98849 Nouméa, Nouvelle-Calédonie
| | - Mohammed NOUR
- ISEA (Institut de sciences exactes et appliquées) (EA 7484), Université de la Nouvelle-Calédonie, BP R4, 98851 Nouméa, Nouvelle-Calédonie
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10
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Le Croizier G, Lorrain A, Sonke JE, Jaquemet S, Schaal G, Renedo M, Besnard L, Cherel Y, Point D. Mercury isotopes as tracers of ecology and metabolism in two sympatric shark species. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:114931. [PMID: 32590319 DOI: 10.1016/j.envpol.2020.114931] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/27/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
In coastal ecosystems, top predators are exposed to a wide variety of nutrient and contaminant sources due to the diversity of trophic webs within inshore marine habitats. Mercury contamination could represent an additional threat to shark populations that are declining worldwide. Here we measured total mercury, carbon and nitrogen isotopes, as well as mercury isotopes, in two co-occurring shark species (the bull shark Carcharhinus leucas and the tiger shark Galeocerdo cuvier) and their potential prey from a coastal ecosystem of the western Indian Ocean (La Réunion Island). Our primary goals were to (i) determine the main trophic Hg sources for sharks and (ii) better characterize their diet composition and foraging habitat. Hg isotope signatures (Δ199Hg and δ202Hg) of shark prey suggested that bull sharks were exposed to methylmercury (MeHg) produced in offshore epipelagic waters, while tiger sharks were exposed to offshore mesopelagic MeHg with additional microbial transformation in slope sediments. Δ199Hg values efficiently traced the ecology of the two predators, demonstrating that bull sharks targeted coastal prey in shallow waters while tiger sharks were mainly foraging on mesopelagic species in the deeper waters of the island slope. Unexpectedly, we found a positive shift in δ202Hg (>1‰) between sharks and their prey, leading to high δ202Hg values in the two shark species (e.g. 1.91 ± 0.52‰ in bull sharks). This large shift in δ202Hg indicates that sharks may display strong MeHg demethylation abilities, possibly reflecting evolutionary pathways for mitigating their MeHg contamination.
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Affiliation(s)
- Gaël Le Croizier
- Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées (OMP), UMR 5563 CNRS/IRD/Université Paul Sabatier, 14 avenue Edouard Belin, 31400, Toulouse, France.
| | - Anne Lorrain
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzané, France
| | - Jeroen E Sonke
- Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées (OMP), UMR 5563 CNRS/IRD/Université Paul Sabatier, 14 avenue Edouard Belin, 31400, Toulouse, France
| | - Sébastien Jaquemet
- Laboratoire ENTROPIE, UMR 9220 CNRS/IRD/Université de La Réunion, 15 Avenue René Cassin, BP 92003, 97744, Saint-Denis, La Réunion, France
| | - Gauthier Schaal
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzané, France
| | - Marina Renedo
- Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées (OMP), UMR 5563 CNRS/IRD/Université Paul Sabatier, 14 avenue Edouard Belin, 31400, Toulouse, France
| | - Lucien Besnard
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzané, France
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS-La Rochelle Université, 79360, Villiers-en-Bois, France
| | - David Point
- Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées (OMP), UMR 5563 CNRS/IRD/Université Paul Sabatier, 14 avenue Edouard Belin, 31400, Toulouse, France
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11
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DeGroot BC, Roskar G, Brewster L, Ajemian MJ. Fine-scale movement and habitat use of whitespotted eagle rays Aetobatus narinari in the Indian River Lagoon, Florida, USA. ENDANGER SPECIES RES 2020. [DOI: 10.3354/esr01047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Despite being crucial to the conservation of batoids (skates and rays), assessments of fine-scale movements and habitat use of these taxa are lacking in the scientific literature. Here we used active acoustic telemetry to characterize habitat use and movement behavior of the state-protected whitespotted eagle ray Aetobatus narinari in the Indian River Lagoon, Florida, USA. Seven mature individuals (6 males and 1 female) were individually tracked for a total of 119.6 h. Brownian bridge movement models of ray distribution showed the importance of habitats with high anthropogenic activity (i.e. boat traffic) such as inlets and channels, as well as clam aquaculture lease sites close to shore. This was supported by the significantly lower rates of movement in these habitats relative to other regions (offshore, open lagoon). Rate of movement significantly increased with temperature, suggesting that rays are more active during warmer periods. No tidal patterns in ray habitat use or distribution were evident. On average, rays used the deeper portions of the lagoon during the day and shallower portions during the night. While more extensive tracking is required to elucidate long-term movement patterns, this study is the first to characterize fine-scale habitat use by the whitespotted eagle ray in Florida while also identifying areas of potential interactions between this species and multiple anthropogenic threats.
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Affiliation(s)
- BC DeGroot
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, Florida 34946, USA
| | - G Roskar
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, Florida 34946, USA
| | - L Brewster
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, Florida 34946, USA
| | - MJ Ajemian
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Fort Pierce, Florida 34946, USA
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12
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Imaseki I, Wakabayashi M, Hara Y, Watanabe T, Takabe S, Kakumura K, Honda Y, Ueda K, Murakumo K, Matsumoto R, Matsumoto Y, Nakamura M, Takagi W, Kuraku S, Hyodo S. Comprehensive analysis of genes contributing to euryhalinity in the bull shark, Carcharhinus leucas; Na +-Cl - co-transporter is one of the key renal factors upregulated in acclimation to low-salinity environment. ACTA ACUST UNITED AC 2019; 222:jeb.201780. [PMID: 31138636 DOI: 10.1242/jeb.201780] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/18/2019] [Indexed: 11/20/2022]
Abstract
Most cartilaginous fishes live principally in seawater (SW) environments, but a limited number of species including the bull shark, Carcharhinus leucas, inhabit both SW and freshwater (FW) environments during their life cycle. Euryhaline elasmobranchs maintain high internal urea and ion levels even in FW environments, but little is known about the osmoregulatory mechanisms that enable them to maintain internal homeostasis in hypoosmotic environments. In the present study, we focused on the kidney because this is the only organ that can excrete excess water from the body in a hypoosmotic environment. We conducted a transfer experiment of bull sharks from SW to FW and performed differential gene expression analysis between the two conditions using RNA-sequencing. A search for genes upregulated in the FW-acclimated bull shark kidney indicated that the expression of the Na+-Cl- cotransporter (NCC; Slc12a3) was 10 times higher in the FW-acclimated sharks compared with that in SW sharks. In the kidney, apically located NCC was observed in the late distal tubule and in the anterior half of the collecting tubule, where basolateral Na+/K+-ATPase was also expressed, implying that these segments contribute to NaCl reabsorption from the filtrate for diluting the urine. This expression pattern was not observed in the houndshark, Triakis scyllium, which had been transferred to 30% SW; this species cannot survive in FW environments. The salinity transfer experiment combined with a comprehensive gene screening approach demonstrates that NCC is a key renal protein that contributes to the remarkable euryhaline ability of the bull shark.
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Affiliation(s)
- Itaru Imaseki
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Midori Wakabayashi
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Yuichiro Hara
- RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Taro Watanabe
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Souichirou Takabe
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Keigo Kakumura
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Yuki Honda
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Keiichi Ueda
- Okinawa Churaumi Aquarium, Motobu, Okinawa 905-0206, Japan
| | | | - Rui Matsumoto
- Okinawa Churaumi Aquarium, Motobu, Okinawa 905-0206, Japan
| | | | - Masaru Nakamura
- Okinawa Churashima Foundation, Motobu, Okinawa 905-0206, Japan
| | - Wataru Takagi
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Shigehiro Kuraku
- RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Susumu Hyodo
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
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13
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Werry JM, Sumpton W, Otway NM, Lee SY, Haig JA, Mayer DG. Rainfall and sea surface temperature: key drivers for occurrence of bull shark, Carcharhinus leucas, in beach areas. Glob Ecol Conserv 2018. [DOI: 10.1016/j.gecco.2018.e00430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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14
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Environmental and anthropogenic factors affecting the increasing occurrence of shark-human interactions around a fast-developing Indian Ocean island. Sci Rep 2018; 8:3676. [PMID: 29487378 PMCID: PMC5829236 DOI: 10.1038/s41598-018-21553-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 02/02/2018] [Indexed: 01/09/2023] Open
Abstract
Understanding the environmental drivers of interactions between predators and humans is critical for public safety and management purposes. In the marine environment, this issue is exemplified by shark-human interactions. The annual shark bite incidence rate (SBIR) in La Réunion (Indian Ocean) is among the highest in the world (up to 1 event per 24,000 hours of surfing) and has experienced a 23-fold increase over the 2005-2016 period. Since 1988, 86% of shark bite events on ocean-users involved surfers off the leeward coast, where 96% of surfing activities took place. We modeled the SBIR as a function of environmental variables, including benthic substrate, sea temperature and period of day. The SBIR peaked in winter, during the afternoon and dramatically increased on coral substrate since the mid-2000s. Seasonal patterns of increasing SBIR followed similar fluctuations of large coastal shark occurrences (particularly the bull shark Carcharhinus leucas), consistent with the hypothesis that higher shark presence may result in an increasing likelihood of shark bite events. Potential contributing factors and adaptation of ocean-users to the increasing shark bite hazard are discussed. This interdisciplinary research contributes to a better understanding of shark-human interactions. The modeling method is relevant for wildlife hazard management in general.
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15
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Niella YV, Afonso AS, Hazin FHV. Bioecology and movements of bull sharks, Carcharhinus leucas , caught in a long-term longline survey off northeastern Brazil. NEOTROPICAL ICHTHYOLOGY 2017. [DOI: 10.1590/1982-0224-20170106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT A robust understanding of habitat usage by coastal shark species, and how it overlaps with human presence in densely-populated regions is needed to inform the development of efficient conservation strategies for these important top predators. An intensive longline survey conducted in nearshore waters off northeastern Brazil from 2004 through 2014 caught a total of 18 bull sharks (Carcharhinus leucas) (male-female ratio = 0.63:1), which can be dangerous to humans. Although most sharks were sexually mature, there was no evidence that this region could be used as a parturition or nursery area. Prey items identified in the guts of the sharks comprised teleosts, mollusks and elasmobranchs. Additionally, one satellite-tagged bull shark covered a great distance (> 3,000 km) in 75 days at liberty, making most use of shallow waters (< 20 m depth) and presumably also entering an estuarine area. Although bull sharks are not an important fishery resource in this region, such a reduced abundance coupled with its affinity for coastal and inshore habitats highlights the potential vulnerability of C. leucas to deleterious anthropic interferences off northeastern Brazil.
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Affiliation(s)
- Yuri V. Niella
- Universidade Federal de Pernambuco, Brazil; Universidade Federal Rural de Pernambuco, Brazil
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16
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Vargas-Fonseca E, Olds AD, Gilby BL, Connolly RM, Schoeman DS, Huijbers CM, Hyndes GA, Schlacher TA. Combined effects of urbanization and connectivity on iconic coastal fishes. DIVERS DISTRIB 2016. [DOI: 10.1111/ddi.12495] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Elena Vargas-Fonseca
- School of Science and Engineering; University of the Sunshine Coast; Maroochydore DC Qld 4558 Australia
| | - Andrew D. Olds
- School of Science and Engineering; University of the Sunshine Coast; Maroochydore DC Qld 4558 Australia
| | - Ben L. Gilby
- School of Science and Engineering; University of the Sunshine Coast; Maroochydore DC Qld 4558 Australia
| | - Rod M. Connolly
- Australian Rivers Institute - Coast & Estuaries; School of Environment; Griffith University; Gold Coast Qld 4222 Australia
| | - David S. Schoeman
- School of Science and Engineering; University of the Sunshine Coast; Maroochydore DC Qld 4558 Australia
| | - Chantal M. Huijbers
- School of Science and Engineering; University of the Sunshine Coast; Maroochydore DC Qld 4558 Australia
- Australian Rivers Institute - Coast & Estuaries; School of Environment; Griffith University; Gold Coast Qld 4222 Australia
| | - Glenn A. Hyndes
- Centre for Marine Ecosystems Research; School of Natural Sciences; Edith Cowan University; Perth WA 6027 Australia
| | - Thomas A. Schlacher
- School of Science and Engineering; University of the Sunshine Coast; Maroochydore DC Qld 4558 Australia
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17
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Espinoza M, Heupel MR, Tobin AJ, Simpfendorfer CA. Evidence of Partial Migration in a Large Coastal Predator: Opportunistic Foraging and Reproduction as Key Drivers? PLoS One 2016; 11:e0147608. [PMID: 26841110 PMCID: PMC4740466 DOI: 10.1371/journal.pone.0147608] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 01/06/2016] [Indexed: 11/18/2022] Open
Abstract
Understanding animal movement decisions that involve migration is critical for evaluating population connectivity, and thus persistence. Recent work on sharks has shown that often only a portion of the adult population will undertake migrations, while the rest may be resident in an area for long periods. Defining the extent to which adult sharks use specific habitats and their migratory behaviour is essential for assessing their risk of exposure to threats such as fishing and habitat degradation. The present study used acoustic telemetry to examine residency patterns and migratory behaviour of adult bull sharks (Carcharhinus leucas) along the East coast of Australia. Fifty-six VR2W acoustic receivers were used to monitor the movements of 33 bull sharks in the central Great Barrier Reef (GBR). Both males and females were detected year-round, but their abundance and residency peaked between September and December across years (2012–2014). High individual variability in reef use patterns was apparent, with some individuals leaving the array for long periods, whereas others (36%) exhibited medium (0.20–0.40) or high residency (> 0.50). A large portion of the population (51%) undertook migrations of up to 1,400 km to other coral reefs and/or inshore coastal habitats in Queensland and New South Wales. Most of these individuals (76%) were mature females, and the timing of migrations coincided with the austral summer (Dec-Feb). All migrating individuals (except one) returned to the central GBR, highlighting its importance as a potential foraging ground. Our findings suggest that adult bull sharks appear to be highly dependent on coral reef resources and provide evidence of partial migration, where only a portion of the female population undertook seasonal migrations potentially to give birth. Given that estuarine habitats face constant anthropogenic pressures, understanding partial migration and habitat connectivity of large coastal predators should be a priority for their management.
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Affiliation(s)
- Mario Espinoza
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, 4811, Australia
- AIMS@JCU, Australian Institute of Marine Science, College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, 4811, Australia
- * E-mail:
| | - Michelle R. Heupel
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, 4811, Australia
- Australian Institute of Marine Science, PMB No 3, Townsville, Queensland, 4810, Australia
| | - Andrew J. Tobin
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Colin A. Simpfendorfer
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, 4811, Australia
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18
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Patterns of Occurrence of Sharks in Sydney Harbour, a Large Urbanised Estuary. PLoS One 2016; 11:e0146911. [PMID: 26824349 PMCID: PMC4732766 DOI: 10.1371/journal.pone.0146911] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 12/23/2015] [Indexed: 12/04/2022] Open
Abstract
Information about spatial and temporal variability in the distribution and abundance of shark-populations are required for their conservation, management and to update measures designed to mitigate human-shark interactions. However, because some species of sharks are mobile, migratory and occur in relatively small numbers, estimating their patterns of distribution and abundance can be very difficult. In this study, we used a hierarchical sampling design to examine differences in the composition of species, size- and sex-structures of sharks sampled with bottom-set longlines in three different areas with increasing distance from the entrance of Sydney Harbour, a large urbanised estuary. During two years of sampling, we obtained data for four species of sharks (Port Jackson, Heterodontus portusjacksoni; wobbegong, Orectolobus maculatus; dusky whaler, Carcharhinus obscurus and bull shark, Carcharhinus leucas). Only a few O. maculatus and C. obscurus were caught, all in the area closest to the entrance of the Harbour. O. maculatus were caught in all seasons, except summer, while C. obscurus was only caught in summer. Heterodontus portusjacksoni were the most abundant species, caught in the entrance location mostly between July to November, when water temperature was below 21.5°C. This pattern was consistent across both years. C. leucas, the second most abundant species, were captured in all areas of Sydney Harbour but only in summer and autumn when water temperatures were above 23°C. This study quantified, for this first time, how different species utilise different areas of Sydney Harbour, at different times of the year. This information has implications for the management of human-shark interactions, by enabling creation of education programs to modify human behaviour in times of increased risk of potentially dangerous sharks.
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19
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Smith KR, Scarpaci C, Louden BM, Otway NM. Behaviour of aggregated grey nurse sharks Carcharias taurus off eastern Australia: similarities and differences among life-history stages and sites. ENDANGER SPECIES RES 2015. [DOI: 10.3354/esr00652] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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20
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Chapman DD, Feldheim KA, Papastamatiou YP, Hueter RE. There and back again: a review of residency and return migrations in sharks, with implications for population structure and management. ANNUAL REVIEW OF MARINE SCIENCE 2015; 7:547-70. [PMID: 25251267 DOI: 10.1146/annurev-marine-010814-015730] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The overexploitation of sharks has become a global environmental issue in need of a comprehensive and multifaceted management response. Tracking studies are beginning to elucidate how shark movements shape the internal dynamics and structure of populations, which determine the most appropriate scale of these management efforts. Tracked sharks frequently either remain in a restricted geographic area for an extended period of time (residency) or return to a previously resided-in area after making long-distance movements (site fidelity). Genetic studies have shown that some individuals of certain species preferentially return to their exact birthplaces (natal philopatry) or birth regions (regional philopatry) for either parturition or mating, even though they make long-distance movements that would allow them to breed elsewhere. More than 80 peer-reviewed articles, constituting the majority of published shark tracking and population genetic studies, provide evidence of at least one of these behaviors in a combined 31 shark species from six of the eight extant orders. Residency, site fidelity, and philopatry can alone or in combination structure many coastal shark populations on finer geographic scales than expected based on their potential for dispersal. This information should therefore be used to scale and inform assessment, management, and conservation activities intended to restore depleted shark populations.
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Affiliation(s)
- Demian D Chapman
- Institute for Ocean Conservation Science and School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794-5000;
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21
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Drymon JM, Ajemian MJ, Powers SP. Distribution and dynamic habitat use of young bull sharks Carcharhinus leucas in a highly stratified northern Gulf of Mexico estuary. PLoS One 2014; 9:e97124. [PMID: 24841925 PMCID: PMC4026320 DOI: 10.1371/journal.pone.0097124] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 04/14/2014] [Indexed: 11/19/2022] Open
Abstract
Understanding how animals alter habitat use in response to changing abiotic conditions is important for effective conservation management. For bull sharks (Carcharhinus leucas), habitat use has been widely examined in the eastern and western Gulf of Mexico; however, knowledge of their movements and the factors influencing them is lacking for populations in the more temperate north-central Gulf of Mexico. To examine how changes in hydrographic conditions affected the presence of young bull sharks in Mobile Bay, Alabama, thirty-five sharks were fitted with internal acoustic transmitters and monitored with an acoustic monitoring array consisting of thirty-three receivers between June 2009 and December 2010. Tagged sharks ranged in size from 60 to 114 cm fork length and were detected between the upper and lower portions of Mobile Bay. Despite a variety of freshwater sources associated with this highly productive estuary, sharks were most consistently detected at the largest input to the system--the Mobile and Tensaw Rivers. Our findings suggest a combination of hydrographic factors interact to influence the distribution of juvenile bull sharks in Mobile Bay. The factors affecting the probability of detecting at least one bull shark varied both temporally (2009 vs 2010) and spatially (upper vs lower bay). Electivity analysis demonstrated that bull sharks showed highest affinity for warm water (29-32 °C), moderate salinities (10-11 psu) and normoxic waters (5-7 mg/l), although these patterns were not consistent between regions or across years. We suggest future studies coupling telemetry and hydrographic variables should, when possible, consider the interactions of multiple environmental parameters when defining the dynamic factors explaining the spatial distribution of coastal sharks.
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Affiliation(s)
- J. Marcus Drymon
- Department of Marine Sciences, University of South Alabama, Mobile, Alabama, United States of America
- Center for Ecosystem Based Fishery Management, Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America
- * E-mail:
| | - Matthew J. Ajemian
- Department of Marine Sciences, University of South Alabama, Mobile, Alabama, United States of America
- Center for Ecosystem Based Fishery Management, Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America
| | - Sean P. Powers
- Department of Marine Sciences, University of South Alabama, Mobile, Alabama, United States of America
- Center for Ecosystem Based Fishery Management, Dauphin Island Sea Lab, Dauphin Island, Alabama, United States of America
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22
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Werry JM, Planes S, Berumen ML, Lee KA, Braun CD, Clua E. Reef-fidelity and migration of tiger sharks, Galeocerdo cuvier, across the Coral Sea. PLoS One 2014; 9:e83249. [PMID: 24421879 PMCID: PMC3885424 DOI: 10.1371/journal.pone.0083249] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 10/25/2013] [Indexed: 12/30/2022] Open
Abstract
Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark–human interactions. Here we compare movement, reef-fidelity, and ocean migration for tiger sharks, Galeocerdo cuvier, across the Coral Sea, with an emphasis on New Caledonia. Thirty-three tiger sharks (1.54 to 3.9 m total length) were tagged with passive acoustic transmitters and their localised movements monitored on receiver arrays in New Caledonia, the Chesterfield and Lord Howe Islands in the Coral Sea, and the east coast of Queensland, Australia. Satellite tags were also used to determine habitat use and movements among habitats across the Coral Sea. Sub-adults and one male adult tiger shark displayed year-round residency in the Chesterfields with two females tagged in the Chesterfields and detected on the Great Barrier Reef, Australia, after 591 and 842 days respectively. In coastal barrier reefs, tiger sharks were transient at acoustic arrays and each individual demonstrated a unique pattern of occurrence. From 2009 to 2013, fourteen sharks with satellite and acoustic tags undertook wide-ranging movements up to 1114 km across the Coral Sea with eight detected back on acoustic arrays up to 405 days after being tagged. Tiger sharks dove 1136 m and utilised three-dimensional activity spaces averaged at 2360 km3. The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks. Management strategies need to consider the wide-ranging movements of large (sub-adult and adult) male and female tiger sharks at the individual level, whereas fidelity to specific coastal reefs may be consistent across groups of individuals. Coastal barrier reef MPAs, however, only afford brief protection for large tiger sharks, therefore determining the importance of other oceanic Coral Sea reefs should be a priority for future research.
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Affiliation(s)
- Jonathan M. Werry
- Australian Rivers Institute and School of Environment, Griffith University, Gold Coast, Queensland, Australia
- Ocean and Coast Research, Gold Coast, Queensland, Australia
- * E-mail:
| | - Serge Planes
- Centre de recherches insulaires et observatoire de l’environnement (CRIOBE), Moorea, French Polynesia
| | - Michael L. Berumen
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Biology Department, Woods Hole Oceanographic Department, Woods Hole, Massachusetts, United States of America
| | - Kate A. Lee
- Marine Mammal Research Group, Graduate School of Environment, Macquarie University, New South Wales, Australia
| | - Camrin D. Braun
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Eric Clua
- Secretariat of the Pacific Community, CRISP Programme, Noumea, New Caledonia
- French ministry of Agriculture and Fisheries, Paris, France
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Daly R, Froneman PW, Smale MJ. Comparative feeding ecology of bull sharks (Carcharhinus leucas) in the coastal waters of the southwest Indian Ocean inferred from stable isotope analysis. PLoS One 2013; 8:e78229. [PMID: 24205168 PMCID: PMC3804608 DOI: 10.1371/journal.pone.0078229] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 09/10/2013] [Indexed: 11/24/2022] Open
Abstract
As apex predators, sharks play an important role shaping their respective marine communities through predation and associated risk effects. Understanding the predatory dynamics of sharks within communities is, therefore, necessary to establish effective ecologically based conservation strategies. We employed non-lethal sampling methods to investigate the feeding ecology of bull sharks (Carcharhinus leucas) using stable isotope analysis within a subtropical marine community in the southwest Indian Ocean. The main objectives of this study were to investigate and compare the predatory role that sub-adult and adult bull sharks play within a top predatory teleost fish community. Bull sharks had significantly broader niche widths compared to top predatory teleost assemblages with a wide and relatively enriched range of δ13C values relative to the local marine community. This suggests that bull sharks forage from a more diverse range of δ13C sources over a wider geographical range than the predatory teleost community. Adult bull sharks appeared to exhibit a shift towards consistently higher trophic level prey from an expanded foraging range compared to sub-adults, possibly due to increased mobility linked with size. Although predatory teleost fish are also capable of substantial migrations, bull sharks may have the ability to exploit a more diverse range of habitats and appeared to prey on a wider diversity of larger prey. This suggests that bull sharks play an important predatory role within their respective marine communities and adult sharks in particular may shape and link ecological processes of a variety of marine communities over a broad range.
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Affiliation(s)
- Ryan Daly
- Department of Zoology & Entomology, Rhodes University, Grahamstown, Eastern Cape, South Africa
- * E-mail:
| | - Pierre W. Froneman
- Department of Zoology & Entomology, Rhodes University, Grahamstown, Eastern Cape, South Africa
| | - Malcolm J. Smale
- Port Elizabeth Museum at Bayworld, Port Elizabeth, Eastern Cape, South Africa
- Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth, Eastern Cape, South Africa
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