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Tigert LR, Porteus CS. Invited review - the effects of anthropogenic abiotic stressors on the sensory systems of fishes. Comp Biochem Physiol A Mol Integr Physiol 2023; 277:111366. [PMID: 36586568 DOI: 10.1016/j.cbpa.2022.111366] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 12/04/2022] [Accepted: 12/27/2022] [Indexed: 12/30/2022]
Abstract
Climate change is a growing global issue with many countries and institutions declaring a climate state of emergency. Excess CO2 from anthropogenic sources and changes in land use practices are contributing to many detrimental changes, including increased global temperatures, ocean acidification and hypoxic zones along coastal habitats. All senses are important for aquatic animals, as it is how they can perceive and respond to their environment. Some of these environmental challenges have been shown to impair their sensory systems, including the olfactory, visual, and auditory systems. While most of the research is focused on how ocean acidification affects olfaction, there is also evidence that it negatively affects vision and hearing. The effects that temperature and hypoxia have on the senses have also been investigated, but to a much lesser extent in comparison to ocean acidification. This review assembles the known information on how these anthropogenic challenges affect the sensory systems of fishes, but also highlights what gaps in knowledge remain with suggestions for immediate action. Olfaction, vision, otolith, pH, freshwater, seawater, marine, central nervous system, electrophysiology, mechanism.
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Affiliation(s)
- Liam R Tigert
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada.
| | - Cosima S Porteus
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada. https://twitter.com/cosimaporteus
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2
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Queiroz APN, Araújo MLG, Hussey NE, Lessa RPT. Trophic ecology of three stingrays (Myliobatoidei: Dasyatidae) off the Brazilian north-eastern coast: Habitat use and resource partitioning. JOURNAL OF FISH BIOLOGY 2023; 102:27-43. [PMID: 36153814 DOI: 10.1111/jfb.15226] [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: 06/23/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
Understanding the ecological role of species with overlapping distributions is central to inform ecosystem management. Here we describe the diet, trophic level and habitat use of three sympatric stingrays, Hypanus guttatus, H. marianae and H. berthalutzae, through combined stomach content and stable isotope (δ13 C and δ15 N) analyses. Our integrated approach revealed that H. guttatus is a mesopredator that feeds on a diverse diet of benthic and epibenthic marine and estuarine organisms, principally bivalve molluscs, Alpheus shrimp and teleost fishes. Isotopic data supported movement of this species between marine and estuarine environments. H. berthalutzae is also a marine generalist feeder, but feeds primarily on teleost fishes and cephalopods, and consequently occupies a higher trophic level. In contrast, H. marianae is a mesopredator specialized on shrimps and polychaetas occurring only in the marine environment and occupying a low niche breadth. While niche overlap occurred, the three stingrays utilized the same prey resources at different rates and occupied distinct trophic niches, potentially limiting competition for resources and promoting coexistence. These combined data demonstrate that these three mesopredators perform different ecological roles in the ecosystems they occupy, limiting functional redundancy.
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Affiliation(s)
- Aristóteles Philippe Nunes Queiroz
- Programa de Pós-graduação em Biologia Animal, Universidade Federal de Pernambuco, Recife, Brazil
- Laboratório de Dinâmica de Populações Marinhas - DIMAR, Departamento de Pesca e Aquicultura, Universidade Federal Rural de Pernambuco, Recife, Brazil
| | - Maria Lúcia Góes Araújo
- Laboratório de Dinâmica de Populações Marinhas - DIMAR, Departamento de Pesca e Aquicultura, Universidade Federal Rural de Pernambuco, Recife, Brazil
| | - Nigel E Hussey
- Department of Integrative Biology, University of Windsor, Windsor, Ontario, Canada
| | - Rosângela P T Lessa
- Laboratório de Dinâmica de Populações Marinhas - DIMAR, Departamento de Pesca e Aquicultura, Universidade Federal Rural de Pernambuco, Recife, Brazil
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3
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Bottaro M. Sixth sense in the deep-sea: the electrosensory system in ghost shark Chimaera monstrosa. Sci Rep 2022; 12:9848. [PMID: 35701513 PMCID: PMC9198096 DOI: 10.1038/s41598-022-14076-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 06/01/2022] [Indexed: 11/25/2022] Open
Abstract
Animals that continually live in deep sea habitats face unique challenges and require adaptive specializations solutions in order to locate and identify food, predators, and conspecifics. The Ampullae of Lorenzini are specialized electroreceptors used by chondrichthyans for important biological functions. Ampullary organs of the ghost shark Chimaera monstrosa, a deep-sea species commonly captured as by-catch in the bottom trawl fishery, are here described for the first time using macroscopic, ultrastructural and histological approaches. The number of ampullary pores in C. monstrosa is about 700, distributed into the whole cephalic section of C. monstrosa, and organized in12 pore clusters and they are arranged into different configurations and form a distinct morphological pattern for this species, showing some anatomical peculiarities never described before in others cartilaginous fishes and may constitute an evolutionary adaptation of this ancient chondrichthyan species to the extreme environmental conditions of its deep sea niche.
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Affiliation(s)
- Massimiliano Bottaro
- Department of Integrative Marine Ecology (EMI), Genoa Marine Centre (GMC), Stazione Zoologica Anton Dohrn - Italian National Institute of Marine Biology, Ecology and Biotechnology, Villa del Principe, Piazza del Principe 4, 16126, Genoa, Italy.
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4
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Net illumination reduces fisheries bycatch, maintains catch value, and increases operational efficiency. Curr Biol 2022; 32:911-918.e2. [PMID: 35063121 DOI: 10.1016/j.cub.2021.12.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/04/2021] [Accepted: 12/17/2021] [Indexed: 11/20/2022]
Abstract
Small-scale fisheries are vital for food security, nutrition, and livelihoods in coastal areas throughout the world's oceans.1-9 As intricately linked social-ecological systems, small-scale fisheries require management approaches that help ensure both ecological and socioeconomic sustainability.7,10-14 Given their ease of use and lucrative nature, coastal gillnet fisheries are globally ubiquitous.10,15 However, these fisheries often result in high discarded capture of non-target organisms (bycatch) that can lead to significant cascading effects throughout trophic chains16-18 and costly fisheries restrictions that result in important revenue losses in coastal communities with scarce economic alternatives.19,20 Despite these challenges, few solutions have been developed and broadly adopted to decrease bycatch in coastal gillnet fisheries, particularly in developing nations.5,21 Here we used controlled experiments along Mexico's Baja California peninsula to show that illuminating gillnets with green LED lights-an emerging technology originally developed to mitigate sea turtle bycatch-significantly reduced mean rates of total discarded bycatch biomass by 63%, which included significant decreases in elasmobranch (95%), Humboldt squid (81%), and unwanted finfish (48%). Moreover, illuminated nets significantly reduced the mean time required to retrieve and disentangle nets by 57%. In contrast, there were no significant differences in target fish catch or value. These findings advance our understanding of how artificial illumination affects operational efficiency and changes in catch rates in coastal gillnet fisheries, while illustrating the value of assessing broad-scale ecological and socioeconomic effects of species-specific conservation strategies.
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6
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Abrantes K, Barnett A, Soetaert M, Kyne PM, Laird A, Squire L, Seymour J, Wueringer BE, Sleeman J, Huveneers C. Potential of electric fields to reduce bycatch of highly threatened sawfishes. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Sawfishes are among the most threatened families of marine fishes and are susceptible to incidental capture in net fisheries. Since bycatch reduction devices currently used in trawl fisheries are not effective at reducing sawfish catches, new methods to minimise sawfish bycatch are needed. Ideally, these should affect sawfish behaviour and prevent contact with the fishing gear. We tested the effects of electric fields on sawfish behaviour to assess the potential of electric pulses in mitigating sawfish bycatch. Experiments were conducted in a tank where 2 electrodes were suspended in the water column, connected to a pulse generator, and placed across the swimming path of sawfish. Two largetooth sawfish Pristis pristis were tested in control conditions, in the presence of a baseline pulse, and of 5 variations of that pulse where 1 parameter (polarity, voltage, frequency, pulse shape, pulse duration) was altered at a time. Conditional inference trees were used to identify the effects of various parameters (e.g. treatment, individual) on reaction type, reaction distance, twitching presence and duration, and inter-approach times. Sawfish reacted to electric fields, but reaction distances were small (typically <1.2 m), and no field tested consistently led to reactions conducive to escaping from moving nets. The following parameters induced the most response in both individuals: bipolar current, rectangular shaped, 5-10 Hz, ~1500 µs duration, and 100 V. We recommend further research focussing on moving nets, testing a V-shaped electric array preceding the net mouth by at least 5 m, and testing a setup similar to electrotrawling.
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Affiliation(s)
- K Abrantes
- College of Science and Engineering, James Cook University, Townsville, Qld 4811, Australia
- Biopixel Oceans Foundation, Cairns, Qld 4870, Australia
| | - A Barnett
- College of Science and Engineering, James Cook University, Townsville, Qld 4811, Australia
- Biopixel Oceans Foundation, Cairns, Qld 4870, Australia
| | - M Soetaert
- Institute for Agricultural and Fisheries Research, Animal Sciences - Fisheries, Ankerstraat 1, 8400 Oostende, Belgium
| | - PM Kyne
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, NT 0815, Australia
| | - A Laird
- Northern Prawn Fishery Industry Pty Ltd, Caloundra, Qld 4551, Australia
| | - L Squire
- Cairns Marine, Cairns, Qld 4870, Australia
| | - J Seymour
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld 4870, Australia
| | - BE Wueringer
- Sharks and Rays Australia, PO Box 575, Bungalow, Cairns, Qld 4870, Australia
| | - J Sleeman
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Qld 4870, Australia
| | - C Huveneers
- College of Science and Engineering, Flinders University, Bedford Park, Adelaide, SA 5042, Australia
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Elmer LK, Madliger CL, Blumstein DT, Elvidge CK, Fernández-Juricic E, Horodysky AZ, Johnson NS, McGuire LP, Swaisgood RR, Cooke SJ. Exploiting common senses: sensory ecology meets wildlife conservation and management. CONSERVATION PHYSIOLOGY 2021; 9:coab002. [PMID: 33815799 PMCID: PMC8009554 DOI: 10.1093/conphys/coab002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 10/27/2020] [Accepted: 01/06/2021] [Indexed: 05/21/2023]
Abstract
Multidisciplinary approaches to conservation and wildlife management are often effective in addressing complex, multi-factor problems. Emerging fields such as conservation physiology and conservation behaviour can provide innovative solutions and management strategies for target species and systems. Sensory ecology combines the study of 'how animals acquire' and process sensory stimuli from their environments, and the ecological and evolutionary significance of 'how animals respond' to this information. We review the benefits that sensory ecology can bring to wildlife conservation and management by discussing case studies across major taxa and sensory modalities. Conservation practices informed by a sensory ecology approach include the amelioration of sensory traps, control of invasive species, reduction of human-wildlife conflicts and relocation and establishment of new populations of endangered species. We illustrate that sensory ecology can facilitate the understanding of mechanistic ecological and physiological explanations underlying particular conservation issues and also can help develop innovative solutions to ameliorate conservation problems.
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Affiliation(s)
- Laura K Elmer
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Christine L Madliger
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Daniel T Blumstein
- Department of Ecology and Evolutionary Biology, Institute of the Environment and Sustainability, University of California, Los Angeles, Los Angeles, CA 90095-1606, USA
| | - Chris K Elvidge
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, Ottawa, ON K1S 5B6, Canada
| | | | - Andrij Z Horodysky
- Department of Marine and Environmental Science, Hampton University, Hampton, VA 23668, USA
| | - Nicholas S Johnson
- USGS, Great Lakes Science Center, Hammond Bay Biological Station, Millersburg, MI 49759, USA
| | - Liam P McGuire
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Ronald R Swaisgood
- Institute for Conservation Research, San Diego Zoo Global, San Diego, CA 92027-7000, USA
| | - Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, Ottawa, ON K1S 5B6, Canada
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Smith JA, Gaynor KM, Suraci JP. Mismatch Between Risk and Response May Amplify Lethal and Non-lethal Effects of Humans on Wild Animal Populations. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.604973] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Human activity has rapidly transformed the planet, leading to declines of animal populations around the world through a range of direct and indirect pathways. Humans have strong numerical effects on wild animal populations, as highly efficient hunters and through unintentional impacts of human activity and development. Human disturbance also induces costly non-lethal effects by changing the behavior of risk-averse animals. Here, we suggest that the unique strength of these lethal and non-lethal effects is amplified by mismatches between the nature of risk associated with anthropogenic stimuli and the corresponding response by wild animals. We discuss the unique characteristics of cues associated with anthropogenic stimuli in the context of animal ecology and evolutionary history to explore why and when animals fail to appropriately (a) detect, (b) assess, and (c) respond to both benign and lethal stimuli. We then explore the costs of over-response to a benign stimulus (Type I error) and under-response to a lethal stimulus (Type II error), which can scale up to affect individual fitness and ultimately drive population dynamics and shape ecological interactions. Finally, we highlight avenues for future research and discuss conservation measures that can better align animal perception and response with risk to mitigate unintended consequences of human disturbance.
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9
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Swimmer Y, Zollett EA, Gutierrez A. Bycatch mitigation of protected and threatened species in tuna purse seine and longline fisheries. ENDANGER SPECIES RES 2020. [DOI: 10.3354/esr01069] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bycatch and mortality in fishing gear poses a conservation threat worldwide to many marine species. Resource managers and conservation scientists face challenges in identifying bycatch mitigation solutions that work for multiple taxa while maintaining acceptable levels of target fish catch. The most successful mitigation measures to address bycatch concerns are those that (1) minimize bycatch with limited or no impact on target species catch, (2) have been proven through at-sea experimental research, (3) are practical, affordable, and easy to use, and (4) do not risk the safety of the fishing vessel crew or the bycaught animals. We conducted a review of mitigation measures in fishing gears that target tuna and tuna-like species and that either prevent capture of non-target species in fishing gear or facilitate alive post-capture release, and evaluated these against 4 defined criteria: effective, proven, practical, and safe. This paper outlines the most effective bycatch mitigation measures, as based upon the best scientific information available, in commercial and artisanal pelagic longline and purse seine fisheries, specifically those that target tuna and tuna-like species. This review includes information on gear and operational changes to fishing practices that reduce bycatch for protected and threatened species across taxonomic groups, with a focus on cetaceans, sea turtles, seabirds, sharks, and istiophorid billfishes. The information provided can guide future research and management efforts in Regional Fisheries Management Organizations that are specific to tuna fishing and that aim to minimize impacts to protected and threatened species while maintaining viable commercial fisheries.
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Affiliation(s)
- Y Swimmer
- NOAA Fisheries, Pacific Islands Fisheries Science Center, Honolulu, Hawaii 96818, USA
| | - EA Zollett
- Environmental Leadership Incubator, University of California, Santa Barbara, California 93106, USA
| | - A Gutierrez
- NOAA Fisheries, Office of Protected Resources, Silver Spring, Maryland 20910, USA
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10
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Lyons K, Bigman JS, Kacev D, Mull CG, Carlisle AB, Imhoff JL, Anderson JM, Weng KC, Galloway AS, Cave E, Gunn TR, Lowe CG, Brill RW, Bedore CN. Bridging disciplines to advance elasmobranch conservation: applications of physiological ecology. CONSERVATION PHYSIOLOGY 2019; 7:coz011. [PMID: 31110763 PMCID: PMC6519003 DOI: 10.1093/conphys/coz011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 02/02/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
A strength of physiological ecology is its incorporation of aspects of both species' ecology and physiology; this holistic approach is needed to address current and future anthropogenic stressors affecting elasmobranch fishes that range from overexploitation to the effects of climate change. For example, physiology is one of several key determinants of an organism's ecological niche (along with evolutionary constraints and ecological interactions). The fundamental role of physiology in niche determination led to the development of the field of physiological ecology. This approach considers physiological mechanisms in the context of the environment to understand mechanistic variations that beget ecological trends. Physiological ecology, as an integrative discipline, has recently experienced a resurgence with respect to conservation applications, largely in conjunction with technological advances that extended physiological work from the lab into the natural world. This is of critical importance for species such as elasmobranchs (sharks, skates and rays), which are an especially understudied and threatened group of vertebrates. In 2017, at the American Elasmobranch Society meeting in Austin, Texas, the symposium entitled `Applications of Physiological Ecology in Elasmobranch Research' provided a platform for researchers to showcase work in which ecological questions were examined through a physiological lens. Here, we highlight the research presented at this symposium, which emphasized the strength of linking physiological tools with ecological questions. We also demonstrate the applicability of using physiological ecology research as a method to approach conservation issues, and advocate for a more available framework whereby results are more easily accessible for their implementation into management practices.
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Affiliation(s)
- K Lyons
- Georgia Aquarium, Atlanta, GA, USA
| | - J S Bigman
- Simon Fraser University, Burnaby, Canada
| | - D Kacev
- Southwest Fisheries Science Center, La Jolla, CA, USA
| | - C G Mull
- Simon Fraser University, Burnaby, Canada
| | | | - J L Imhoff
- Florida State University Coastal and Marine Laboratory, St. Teresa, FL, USA
| | - J M Anderson
- University of Hawai`i at Mānoa, Honolulu, HI, USA
| | - K C Weng
- Virginia Institute of Marine Science, Gloucester Point, VA, USA
| | - A S Galloway
- South Carolina Department of Natural Resources, SC, USA
| | - E Cave
- Florida Atlantic University, Boca Raton, FL, USA
| | - T R Gunn
- Georgia Southern University, Statesboro, GA USA
| | - C G Lowe
- California State University Long Beach, Long Beach, CA, USA
| | - R W Brill
- Virginia Institute of Marine Science, Gloucester Point, VA, USA
| | - C N Bedore
- Georgia Southern University, Statesboro, GA USA
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11
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Sloman KA, Bouyoucos IA, Brooks EJ, Sneddon LU. Ethical considerations in fish research. JOURNAL OF FISH BIOLOGY 2019; 94:556-577. [PMID: 30838660 DOI: 10.1111/jfb.13946] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
Fishes are used in a wide range of scientific studies, from conservation research with potential benefits to the species used to biomedical research with potential human benefits. Fish research can take place in both laboratories and field environments and methods used represent a continuum from non-invasive observations, handling, through to experimental manipulation. While some countries have legislation or guidance regarding the use of fish in research, many do not and there exists a diversity of scientific opinions on the sentience of fish and how we determine welfare. Nevertheless, there is a growing pressure on the scientific community to take more responsibility for the animals they work with through maximising the benefits of their research to humans or animals while minimising welfare or survival costs to their study animals. In this review, we focus primarily on the refinement of common methods used in fish research based on emerging knowledge with the aim of improving the welfare of fish used in scientific studies. We consider the use of anaesthetics and analgesics and how we mark individuals for identification purposes. We highlight the main ethical concerns facing researchers in both laboratory and field environments and identify areas that need urgent future research. We hope that this review will help inform those who wish to refine their ethical practices and stimulate thought among fish researchers for further avenues of refinement. Improved ethics and welfare of fishes will inevitably lead to increased scientific rigour and is in the best interests of both fishes and scientists.
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Affiliation(s)
- Katherine A Sloman
- School of Health and Life Sciences, University of the West of Scotland, Paisley, UK
| | - Ian A Bouyoucos
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia
- PSL Research University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan, Perpignan Cedex, France
| | - Edward J Brooks
- Cape Eleuthera Island School, Rock Sound, Eleuthera, The Bahamas
| | - Lynne U Sneddon
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
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12
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Egeberg CA, Kempster RM, Hart NS, Ryan L, Chapuis L, Kerr CC, Schmidt C, Gennari E, Yopak KE, Collin SP. Not all electric shark deterrents are made equal: Effects of a commercial electric anklet deterrent on white shark behaviour. PLoS One 2019; 14:e0212851. [PMID: 30856187 PMCID: PMC6411110 DOI: 10.1371/journal.pone.0212851] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 02/11/2019] [Indexed: 11/18/2022] Open
Abstract
Personal shark deterrents offer the potential of a non-lethal solution to protect individuals from negative interactions with sharks, but the claims of effectiveness of most deterrents are based on theory rather than robust testing of the devices themselves. Therefore, there is a clear need for thorough testing of commercially available shark deterrents to provide the public with information on their effectiveness. Using a modified stereo-camera system, we quantified behavioural interactions between Carcharodon carcharias (white sharks) and a baited target in the presence of a commercially available electric anklet shark deterrent, the Electronic Shark Defense System (ESDS). The stereo-camera system enabled accurate assessment of the behavioural responses of C. carcharias when approaching an ESDS. We found that the ESDS had limited meaningful effect on the behaviour of C. carcharias, with no significant reduction in the proportion of sharks interacting with the bait in the presence of the active device. At close proximity (< 15.5 cm), the active ESDS did show a significant reduction in the number of sharks biting the bait, but this was countered by an increase in other, less aggressive, interactions. The ESDS discharged at a frequency of 7.8 Hz every 5.1 s for 2.5 s, followed by an inactive interval of 2.6 s. As a result, many sharks may have encountered the device in its inactive state, resulting in a reduced behavioural response. Consequently, decreasing the inactive interval between pulses may improve the overall effectiveness of the device, but this would not improve the effective deterrent range of the device, which is primarily a factor of the voltage gradient rather than the stimulus frequency. In conclusion, given the very short effective range of the ESDS and its unreliable deterrent effect, combined with the fact that shark-bite incidents are very rare, it is unlikely that the current device would significantly reduce the risk of a negative interaction with C. carcharias.
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Affiliation(s)
- Channing A. Egeberg
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
| | - Ryan M. Kempster
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
- * E-mail:
| | - Nathan S. Hart
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Laura Ryan
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Lucille Chapuis
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
| | - Caroline C. Kerr
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
| | - Carl Schmidt
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
| | - Enrico Gennari
- Oceans Research, Mossel Bay, South Africa
- South African Institute for Aquatic Biodiversity, Grahamstown, South Africa
| | - Kara E. Yopak
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
- Department of Biology and Marine Biology, UNCW Center for Marine Science, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
| | - Shaun P. Collin
- The UWA Oceans Institute and the Oceans Graduate School, The University of Western Australia, Crawley, Western Australia, Australia
- School of Life Sciences, La Trobe University, Bundoora, Victoria, Australia
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13
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Mangel JC, Wang J, Alfaro-Shigueto J, Pingo S, Jimenez A, Carvalho F, Swimmer Y, Godley BJ. Illuminating gillnets to save seabirds and the potential for multi-taxa bycatch mitigation. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180254. [PMID: 30109081 PMCID: PMC6083706 DOI: 10.1098/rsos.180254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/04/2018] [Indexed: 05/31/2023]
Abstract
Bycatch in net fisheries is recognized as a major source of mortality for many marine species, including seabirds. Few mitigation solutions, however, have been identified. We assessed the effectiveness of illuminating fishing nets with green light emitting diodes (LEDs) to reduce the incidental capture of seabirds. Experiments were conducted in the demersal, set gillnet fishery of Constante, Peru and compared 114 pairs of control and illuminated nets. We observed captures of a total of 45 guanay cormorants (Phalacrocorax bougainvillii), with 39 caught in control nets and six caught in illuminated nets. Seabird bycatch in terms of catch-per-unit-effort was significantly (p < 0.05) higher in control nets than in illuminated nets, representing an 85.1% decline in the cormorant bycatch rate. This study, showing that net illumination reduces seabird bycatch and previous studies showing reductions in sea turtle bycatch without reducing target catch, indicates that net illumination can be an effective multi-taxa bycatch mitigation technique. This finding has broad implications for bycatch mitigation in net fisheries given LED technology's relatively low cost, the global ubiquity of net fisheries and the current paucity of bycatch mitigation solutions.
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Affiliation(s)
- Jeffrey C. Mangel
- ProDelphinus, Jose Galvez 780-E, Miraflores, Lima 18, Peru
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
| | - John Wang
- NOAA, National Marine Fisheries Service, Pacific Islands Fisheries Science Center, Honolulu, HI 96818, USA
| | - Joanna Alfaro-Shigueto
- ProDelphinus, Jose Galvez 780-E, Miraflores, Lima 18, Peru
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
- Facultad de Biologia Marina, Universidad Cientifica del Sur, Panamericana Sur Km 19, Villa, Lima, Peru
| | - Sergio Pingo
- ProDelphinus, Jose Galvez 780-E, Miraflores, Lima 18, Peru
| | - Astrid Jimenez
- ProDelphinus, Jose Galvez 780-E, Miraflores, Lima 18, Peru
| | - Felipe Carvalho
- NOAA, National Marine Fisheries Service, Pacific Islands Fisheries Science Center, Honolulu, HI 96818, USA
| | - Yonat Swimmer
- NOAA, National Marine Fisheries Service, Pacific Islands Fisheries Science Center, Honolulu, HI 96818, USA
| | - Brendan J. Godley
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, UK
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14
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Ellis JR, McCully Phillips SR, Poisson F. A review of capture and post-release mortality of elasmobranchs. JOURNAL OF FISH BIOLOGY 2017; 90:653-722. [PMID: 27864942 DOI: 10.1111/jfb.13197] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/27/2016] [Indexed: 06/06/2023]
Abstract
There is a need to better understand the survivorship of discarded fishes, both for commercial stocks and species of conservation concern. Within European waters, the landing obligations that are currently being phased in as part of the European Union's reformed common fisheries policy means that an increasing number of fish stocks, with certain exceptions, should not be discarded unless it can be demonstrated that there is a high probability of survival. This study reviews the various approaches that have been used to examine the discard survival of elasmobranchs, both in terms of at-vessel mortality (AVM) and post-release mortality (PRM), with relevant findings summarized for both the main types of fishing gear used and by taxonomic group. Discard survival varies with a range of biological attributes (species, size, sex and mode of gill ventilation) as well as the range of factors associated with capture (e.g. gear type, soak time, catch mass and composition, handling practices and the degree of exposure to air and any associated change in ambient temperature). In general, demersal species with buccal-pump ventilation have a higher survival than obligate ram ventilators. Several studies have indicated that females may have a higher survival than males. Certain taxa (including hammerhead sharks Sphyrna spp. and thresher sharks Alopias spp.) may be particularly prone to higher rates of mortality when caught.
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Affiliation(s)
- J R Ellis
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk, NR33 0HT, U.K
| | - S R McCully Phillips
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk, NR33 0HT, U.K
| | - F Poisson
- Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre de Recherche Halieutique UMR MARBEC (MARine Biodiversity Exploitation and Conservation), Avenue Jean Monnet, CS 30171, 34203 Sète, France
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15
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Uchoa M, O’Connell C, Goreau T. The effects of Biorock-associated electric fields on the Caribbean reef shark (Carcharhinus perezi) and the bull shark (Carcharhinus leucas). ANIM BIOL 2017. [DOI: 10.1163/15707563-00002531] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Healthy coral reefs are biologically diverse and provide vital ecosystem services. However, decreasing water quality and global warming are key contributors to coral reef decline, which poses substantial environmental threats. In response to this degradation, an innovative coral reef restoration technology, called Biorock, utilizes weak direct current electric fields to cause limestone deposition on conductive materials, inevitably inducing prolific coral reef growth. Although expediting coral growth, research on how the associated electric fields may impact the behavioural patterns of teleosts and/or organisms (i.e. elasmobranchs) possessing electroreception capabilities is lacking. Therefore, we studied the behavioural responses of two shark species, the bull shark (Carcharhinus leucas) and the Caribbean reef shark (Carcharhinus perezi) and multiple teleost species towards weak direct current electric fields in Bimini, Bahamas. Generalized linear mixed model analyses based on 90 trials illustrate that both the feeding and avoidance behaviors of C. leucas and C. perezi were significantly associated with treatment type, with the weak experimental electrode treatments resulting in the greatest quantity of avoidances and fewest feedings for both species. However, data analyses illustrate that teleost feeding behavior was not observably impacted by experimental treatments. Although the Biorock technology exhibits promise in coral reef restoration, the findings from this study illustrate a need for future large-scale studies assessing shark behavioral patterns around these devices, since the deterrence of apex predators may impact ecosystem balance.
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Affiliation(s)
- Marcella P. Uchoa
- 1O’Seas Conservation Foundation, 3636 Waldo Ave, Apt 2B, Bronx, NY 10463, USA
| | - Craig P. O’Connell
- 1O’Seas Conservation Foundation, 3636 Waldo Ave, Apt 2B, Bronx, NY 10463, USA
| | - Thomas J. Goreau
- 2Global Coral Reef Alliance, 37 Pleasant St, Cambridge, MA 02139, USA
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16
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Lopes K, Passos L, Rodrigues JG, Koenen F, Stiebens V, Székely T, Dutra A. Sea Turtle, Shark, and Dolphin Bycatch Rates by Artisanal and Semi-Industrial Fishers in Maio Island, Cape Verde. CHELONIAN CONSERVATION AND BIOLOGY 2016. [DOI: 10.2744/cb-1213.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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Kempster RM, Egeberg CA, Hart NS, Ryan L, Chapuis L, Kerr CC, Schmidt C, Huveneers C, Gennari E, Yopak KE, Meeuwig JJ, Collin SP. How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour. PLoS One 2016; 11:e0157717. [PMID: 27368059 PMCID: PMC4930202 DOI: 10.1371/journal.pone.0157717] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 06/05/2016] [Indexed: 12/02/2022] Open
Abstract
Sharks play a vital role in the health of marine ecosystems, but the potential threat that sharks pose to humans is a reminder of our vulnerability when entering the ocean. Personal shark deterrents are being marketed as the solution to mitigate the threat that sharks pose. However, the effectiveness claims of many personal deterrents are based on our knowledge of shark sensory biology rather than robust testing of the devices themselves, as most have not been subjected to independent scientific studies. Therefore, there is a clear need for thorough testing of commercially available shark deterrents to provide the public with recommendations of their effectiveness. Using a modified stereo-camera system, we quantified behavioural interactions between white sharks (Carcharodon carcharias) and a baited target in the presence of a commercially available, personal electric shark deterrent (Shark Shield Freedom7™). The stereo-camera system enabled an accurate assessment of the behavioural responses of C. carcharias when encountering a non-lethal electric field many times stronger than what they would naturally experience. Upon their first observed encounter, all C. carcharias were repelled at a mean (± std. error) proximity of 131 (± 10.3) cm, which corresponded to a mean voltage gradient of 9.7 (± 0.9) V/m. With each subsequent encounter, their proximity decreased by an average of 11.6 cm, which corresponded to an increase in tolerance to the electric field by an average of 2.6 (± 0.5) V/m per encounter. Despite the increase in tolerance, sharks continued to be deterred from interacting for the duration of each trial when in the presence of an active Shark Shield™. Furthermore, the findings provide no support to the theory that electric deterrents attract sharks. The results of this study provide quantitative evidence of the effectiveness of a non-lethal electric shark deterrent, its influence on the behaviour of C. carcharias, and an accurate method for testing other shark deterrent technologies.
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Affiliation(s)
- Ryan M. Kempster
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
- * E-mail:
| | - Channing A. Egeberg
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Nathan S. Hart
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Laura Ryan
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Lucille Chapuis
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Caroline C. Kerr
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Carl Schmidt
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Charlie Huveneers
- School of Biological Sciences, Flinders University, Bedford Park, South Australia, Australia
| | - Enrico Gennari
- Oceans Research, Mossel Bay, South Africa
- South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown, South Africa
| | - Kara E. Yopak
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Jessica J. Meeuwig
- The Oceans Institute and the Centre for Marine Futures, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Shaun P. Collin
- The Oceans Institute and the School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
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18
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Horodysky AZ, Cooke SJ, Graves JE, Brill RW. Fisheries conservation on the high seas: linking conservation physiology and fisheries ecology for the management of large pelagic fishes. CONSERVATION PHYSIOLOGY 2016; 4:cov059. [PMID: 27382467 PMCID: PMC4922246 DOI: 10.1093/conphys/cov059] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 11/09/2015] [Accepted: 11/15/2015] [Indexed: 05/26/2023]
Abstract
Populations of tunas, billfishes and pelagic sharks are fished at or over capacity in many regions of the world. They are captured by directed commercial and recreational fisheries (the latter of which often promote catch and release) or as incidental catch or bycatch in commercial fisheries. Population assessments of pelagic fishes typically incorporate catch-per-unit-effort time-series data from commercial and recreational fisheries; however, there have been notable changes in target species, areas fished and depth-specific gear deployments over the years that may have affected catchability. Some regional fisheries management organizations take into account the effects of time- and area-specific changes in the behaviours of fish and fishers, as well as fishing gear, to standardize catch-per-unit-effort indices and refine population estimates. However, estimates of changes in stock size over time may be very sensitive to underlying assumptions of the effects of oceanographic conditions and prey distribution on the horizontal and vertical movement patterns and distribution of pelagic fishes. Effective management and successful conservation of pelagic fishes requires a mechanistic understanding of their physiological and behavioural responses to environmental variability, potential for interaction with commercial and recreational fishing gear, and the capture process. The interdisciplinary field of conservation physiology can provide insights into pelagic fish demography and ecology (including environmental relationships and interspecific interactions) by uniting the complementary expertise and skills of fish physiologists and fisheries scientists. The iterative testing by one discipline of hypotheses generated by the other can span the fundamental-applied science continuum, leading to the development of robust insights supporting informed management. The resulting species-specific understanding of physiological abilities and tolerances can help to improve stock assessments, develop effective bycatch-reduction strategies, predict rates of post-release mortality, and forecast the population effects of environmental change. In this synthesis, we review several examples of these interdisciplinary collaborations that currently benefit pelagic fisheries management.
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Affiliation(s)
- Andrij Z. Horodysky
- Department of Marine and Environmental Science, Hampton University, 100 East Queen Street, Hampton, VA 23668, USA
| | - Steven J. Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Drive, Ottawa, ON, Canada K1S 5B6
| | - John E. Graves
- Department of Fisheries Science, Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, VA 23062, USA
| | - Richard W. Brill
- Department of Fisheries Science, Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, VA 23062, USA
- Behavioral Ecology Branch, James J. Howard Marine Sciences Laboratory, Northeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Highlands, NJ 07732, USA
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19
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Madliger CL, Cooke SJ, Crespi EJ, Funk JL, Hultine KR, Hunt KE, Rohr JR, Sinclair BJ, Suski CD, Willis CKR, Love OP. Success stories and emerging themes in conservation physiology. CONSERVATION PHYSIOLOGY 2016; 4:cov057. [PMID: 27382466 PMCID: PMC4922248 DOI: 10.1093/conphys/cov057] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 11/05/2015] [Accepted: 11/09/2015] [Indexed: 05/21/2023]
Abstract
The potential benefits of physiology for conservation are well established and include greater specificity of management techniques, determination of cause-effect relationships, increased sensitivity of health and disturbance monitoring and greater capacity for predicting future change. While descriptions of the specific avenues in which conservation and physiology can be integrated are readily available and important to the continuing expansion of the discipline of 'conservation physiology', to date there has been no assessment of how the field has specifically contributed to conservation success. However, the goal of conservation physiology is to foster conservation solutions and it is therefore important to assess whether physiological approaches contribute to downstream conservation outcomes and management decisions. Here, we present eight areas of conservation concern, ranging from chemical contamination to invasive species to ecotourism, where physiological approaches have led to beneficial changes in human behaviour, management or policy. We also discuss the shared characteristics of these successes, identifying emerging themes in the discipline. Specifically, we conclude that conservation physiology: (i) goes beyond documenting change to provide solutions; (ii) offers a diversity of physiological metrics beyond glucocorticoids (stress hormones); (iii) includes approaches that are transferable among species, locations and times; (iv) simultaneously allows for human use and benefits to wildlife; and (v) is characterized by successes that can be difficult to find in the primary literature. Overall, we submit that the field of conservation physiology has a strong foundation of achievements characterized by a diversity of conservation issues, taxa, physiological traits, ecosystem types and spatial scales. We hope that these concrete successes will encourage the continued evolution and use of physiological tools within conservation-based research and management plans.
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Affiliation(s)
- Christine L. Madliger
- Department of Biological Sciences, University of Windsor, Windsor, ON, Canada N9B 3P4
- Corresponding author: Department of Biological Sciences, University of Windsor, 401 Sunset Avenue, Windsor, ON, Canada N9B 3P4. Tel: +1 519 253 3000.
| | - Steven J. Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON, Canada K1S 5B6
| | - Erica J. Crespi
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - Jennifer L. Funk
- Schmid College of Science and Technology, Chapman University, Orange, CA 92866, USA
| | - Kevin R. Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - Kathleen E. Hunt
- John H. Prescott Marine Laboratory, Research Department, New England Aquarium, Boston, MA 02110, USA
| | - Jason R. Rohr
- Integrative Biology, University of South Florida, Tampa, FL 33620, USA
| | - Brent J. Sinclair
- Department of Biology, Western University, London, ON, Canada N6A 5B7
| | - Cory D. Suski
- Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Craig K. R. Willis
- Department of Biology and Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, MB, Canada R3B 2E9
| | - Oliver P. Love
- Department of Biological Sciences, University of Windsor, Windsor, ON, Canada N9B 3P4
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada N9B 3P4
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20
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O’Connell CP, Hyun SY, Gruber SH, He P. Effects of barium-ferrite permanent magnets on great hammerhead shark Sphyrna mokarran behavior and implications for future conservation technologies. ENDANGER SPECIES RES 2015. [DOI: 10.3354/esr00629] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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21
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Affiliation(s)
- Nathan S. HART
- School of Animal Biology and the Oceans Institute; The University of Western Australia; Crawley Perth Australia
| | - Shaun P. COLLIN
- School of Animal Biology and the Oceans Institute; The University of Western Australia; Crawley Perth Australia
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22
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Gallagher A, Orbesen E, Hammerschlag N, Serafy J. Vulnerability of oceanic sharks as pelagic longline bycatch. Glob Ecol Conserv 2014. [DOI: 10.1016/j.gecco.2014.06.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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23
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Affiliation(s)
- Csilla Ari
- Foundation for the Oceans of the Future; Budapest 1108 Hungary
- Hyperbaric Biomedical Research Laboratory; Department of Molecular Pharmacology and Physiology; University of South Florida; Tampa FL 33612 USA
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24
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Barbosa-Filho MLV, Schiavetti A, Alarcon DT, Costa-Neto EM. "Shark is the man!": ethnoknowledge of Brazil's South Bahia fishermen regarding shark behaviors. JOURNAL OF ETHNOBIOLOGY AND ETHNOMEDICINE 2014; 10:54. [PMID: 24994466 PMCID: PMC4131805 DOI: 10.1186/1746-4269-10-54] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 06/14/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Fishermen's knowledge is a source of indispensable information in decision-making processes related to efforts to stimulate the management and conservation of fishing resources, especially in developing countries. This study analyzed the knowledge of fishermen from three municipal areas of Bahia in northeast Brazil regarding the behavior repertoire of sharks and the possible influence that these perceptions may have on the inclination to preserve these animals. This is a pioneering study on the ethnobiological aspects of elasmobranchs in Brazil. METHODS Open, semi-structured interviews with shark fishing specialists were conducted between September 2011 and October 2012. The interviews addressed the fishermen's profile, fishing techniques and knowledge about sharks, focusing on the behaviours exhibited by sharks. The data were analysed with quantitative approach and conducted with the use of descriptive statistical techniques. RESULTS Sixty-five fishermen were interviewed. They descend from the rafting subculture of Brazil's northeast, which has historically been disregarded by public policies addressing the management and conservation of fishing resources. The fishing fleet involved in shark fishing includes rafts, fishing boats and lobster boats equipped with fishing lines, gillnets, longlines and "esperas". The informers classified sharks' behaviour repertoire into 19 ethological categories, related especially to feeding, reproduction, and social and migratory behaviours. Because they identify sharks as predators, the detailed recognition of the behaviours exhibited is crucial both for an efficient catch and to avoid accidents. Therefore, this knowledge is doubly adaptive as it contributes to safer, more lucrative fishing. A feeling of respect for sharks predominates, since informers recognize the ecological role of these animals in marine ecosystems, attributing them the status of leader (or "the man") in the sea. CONCLUSIONS This work demonstrates the complexity and robustness of artisanal fishermen's ichthyological knowledge of sharks. Therefore, we suggest that such knowledge should be considered to develop public policies for the control of the fishing activity, as well as to develop and consolidate the National Action Plan for the Conservation of Shark and Ray Species (PAN - Tubarões e Raias).
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Affiliation(s)
- Márcio Luiz Vargas Barbosa-Filho
- Departamento de Ciências Biológicas (DCB), Programa de Pós-graduação em Zoologia, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, Km 16, Bairro Salobrinho, Ilhéus, Bahia, Brazil
| | - Alexandre Schiavetti
- Departamento de Ciências Agrárias e Ambientais (DCAA), Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, Km 16, Bairro Salobrinho, Ilhéus, Bahia, Brazil
| | - Daniela Trigueirinho Alarcon
- Programa de Doutorado em Desenvolvimento e Meio Ambiente, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, Km 16, Bairro Salobrinho, Ilhéus, Bahia, Brazil
| | - Eraldo Medeiros Costa-Neto
- Departamento de Ciências Biológicas, Universidade Estadual de Feira de Santana, Avenida Transnordestina S/N, Novo Horizonte, Feira de Santana, Bahia, Brazil
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Affiliation(s)
- Steven J Cooke
- Editor-in-Chief, Conservation Physiology Canada Research Chair, Carleton University, Ottawa, Ontario, Canada
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