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Brönmark C, Hellström G, Baktoft H, Hansson LA, McCallum ES, Nilsson PA, Skov C, Brodin T, Hulthén K. Ponds as experimental arenas for studying animal movement: current research and future prospects. MOVEMENT ECOLOGY 2023; 11:68. [PMID: 37880741 PMCID: PMC10601242 DOI: 10.1186/s40462-023-00419-9] [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: 04/14/2023] [Accepted: 09/02/2023] [Indexed: 10/27/2023]
Abstract
Animal movement is a multifaceted process that occurs for multiple reasons with powerful consequences for food web and ecosystem dynamics. New paradigms and technical innovations have recently pervaded the field, providing increasingly powerful means to deliver fine-scale movement data, attracting renewed interest. Specifically in the aquatic environment, tracking with acoustic telemetry now provides integral spatiotemporal information to follow individual movements in the wild. Yet, this technology also holds great promise for experimental studies, enhancing our ability to truly establish cause-and-effect relationships. Here, we argue that ponds with well-defined borders (i.e. "islands in a sea of land") are particularly well suited for this purpose. To support our argument, we also discuss recent experiences from studies conducted in an innovative experimental infrastructure, composed of replicated ponds equipped with modern aquatic telemetry systems that allow for unparalleled insights into the movement patterns of individual animals.
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Affiliation(s)
- Christer Brönmark
- Department of Biology-Aquatic Ecology, Lund University, Ecology building, Sölvegatan 37 223 62, Lund, Sweden.
| | - Gustav Hellström
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Umeå, 90183, Sweden
| | - Henrik Baktoft
- National Institute of Aquatic Resources, Technical University of Denmark (DTU), Silkeborg, Denmark
| | - Lars-Anders Hansson
- Department of Biology-Aquatic Ecology, Lund University, Ecology building, Sölvegatan 37 223 62, Lund, Sweden
| | - Erin S McCallum
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Umeå, 90183, Sweden
| | - P Anders Nilsson
- Department of Biology-Aquatic Ecology, Lund University, Ecology building, Sölvegatan 37 223 62, Lund, Sweden
| | - Christian Skov
- National Institute of Aquatic Resources, Technical University of Denmark (DTU), Silkeborg, Denmark
| | - Tomas Brodin
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Umeå, 90183, Sweden
| | - Kaj Hulthén
- Department of Biology-Aquatic Ecology, Lund University, Ecology building, Sölvegatan 37 223 62, Lund, Sweden.
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2
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Audzijonyte A, Mateos-González F, Dainys J, Gundelund C, Skov C, Tyrell DeWeber J, Venturelli P, Vienožinskis V, Smith C. High-resolution app data reveal sustained increases in recreational fishing effort in Europe during and after COVID-19 lockdowns. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230408. [PMID: 37476517 PMCID: PMC10354473 DOI: 10.1098/rsos.230408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/27/2023] [Indexed: 07/22/2023]
Abstract
It is well recognized that COVID-19 lockdowns impacted human interactions with natural ecosystems. One example is recreational fishing, which, in developed countries, involves approximately 10% of people. Fishing licence sales and observations at angling locations suggest that recreational fishing effort increased substantially during lockdowns. However, the extent and duration of this increase remain largely unknown. We used four years (2018-2021) of high-resolution data from a personal fish-finder device to explore the impact of COVID-19 lockdowns on angling effort in four European countries. We show that relative device use and angling effort increased 1.2-3.8-fold during March-May 2020 and generally remained elevated even at the end of 2021. Fishing during the first lockdown also became more frequent on weekdays. Statistical models explained 50-70% of the variation, suggesting that device use and angling effort were relatively consistent and predictable through space and time. Our study demonstrates that recreational fishing behaviour can change substantially and rapidly in response to societal shifts, with profound ecological, human well-being and economic implications. We also show the potential of angler devices and smartphone applications for high-resolution fishing effort analysis and encourage more extensive science and industry collaborations to take advantage of this information.
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Affiliation(s)
- Asta Audzijonyte
- Institute for Marine and Antarctic Studies, University of Tasmania, Tasmania, Australia
- Nature Research Centre, Akademijos 2, Vilnius, Lithuania
- Centre for Marine Socioecology, Tasmania, Australia
| | - Fernando Mateos-González
- Institute for Marine and Antarctic Studies, University of Tasmania, Tasmania, Australia
- ALKA Wildlife, Lidéřovice, Czech Republic
| | - Justas Dainys
- Institute for Marine and Antarctic Studies, University of Tasmania, Tasmania, Australia
| | - Casper Gundelund
- Section of Freshwater Fisheries and Ecology, Technical University of Denmark, Denmark
| | - Christian Skov
- Section of Freshwater Fisheries and Ecology, Technical University of Denmark, Denmark
| | - J. Tyrell DeWeber
- Potsdam Institute of Inland Fisheries, Im Königswald 2, Potsdam, Germany
| | - Paul Venturelli
- Department of Biology, Ball State University, Muncie 47306, IN, USA
| | | | - Carl Smith
- Institute for Marine and Antarctic Studies, University of Tasmania, Tasmania, Australia
- Department of Ecology and Vertebrate Zoology, University of Łódź, Łódź, Poland
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Brno, Czech Republic
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3
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Darimont CT, Cooke R, Bourbonnais ML, Bryan HM, Carlson SM, Estes JA, Galetti M, Levi T, MacLean JL, McKechnie I, Paquet PC, Worm B. Humanity's diverse predatory niche and its ecological consequences. Commun Biol 2023; 6:609. [PMID: 37386144 PMCID: PMC10310721 DOI: 10.1038/s42003-023-04940-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 05/15/2023] [Indexed: 07/01/2023] Open
Abstract
Although humans have long been predators with enduring nutritive and cultural relationships with their prey, seldom have conservation ecologists considered the divergent predatory behavior of contemporary, industrialized humans. Recognizing that the number, strength and diversity of predator-prey relationships can profoundly influence biodiversity, here we analyze humanity's modern day predatory interactions with vertebrates and estimate their ecological consequences. Analysing IUCN 'use and trade' data for ~47,000 species, we show that fishers, hunters and other animal collectors prey on more than a third (~15,000 species) of Earth's vertebrates. Assessed over equivalent ranges, humans exploit up to 300 times more species than comparable non-human predators. Exploitation for the pet trade, medicine, and other uses now affects almost as many species as those targeted for food consumption, and almost 40% of exploited species are threatened by human use. Trait space analyses show that birds and mammals threatened by exploitation occupy a disproportionally large and unique region of ecological trait space, now at risk of loss. These patterns suggest far more species are subject to human-imposed ecological (e.g., landscapes of fear) and evolutionary (e.g., harvest selection) processes than previously considered. Moreover, continued overexploitation will likely bear profound consequences for biodiversity and ecosystem function.
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Affiliation(s)
- Chris T Darimont
- Department of Geography, University of Victoria, Victoria, BC, Canada.
- Raincoast Conservation Foundation, Sidney, BC, Canada.
| | - Rob Cooke
- UK Centre for Ecology & Hydrology, Wallingford, UK.
| | - Mathieu L Bourbonnais
- Department of Earth, Environmental, and Geographic Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Heather M Bryan
- Raincoast Conservation Foundation, Sidney, BC, Canada
- Department of Ecosystem Science and Management, University of Northern British Columbia, Prince George, BC, Canada
| | - Stephanie M Carlson
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
| | - James A Estes
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Mauro Galetti
- São Paulo State University (UNESP), Department of Biodiversity, Rio Claro, São Paulo, Brazil
- Kimberly Green Latin American and Caribbean Center, Florida International University (FIU), Miami, FL, USA
| | - Taal Levi
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Corvallis, OR, USA
| | - Jessica L MacLean
- Department of Geography, University of Victoria, Victoria, BC, Canada
- Raincoast Conservation Foundation, Sidney, BC, Canada
| | - Iain McKechnie
- Department of Anthropology, University of Victoria, Victoria, BC, Canada
- Hakai Institute, Heriot Bay, Quadra Island, BC, Canada
| | - Paul C Paquet
- Department of Geography, University of Victoria, Victoria, BC, Canada
- Raincoast Conservation Foundation, Sidney, BC, Canada
| | - Boris Worm
- Department of Biology, Dalhousie University, Halifax, NS, Canada
- Ocean Frontier Institute, Dalhousie University, Halifax, NS, Canada
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4
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Britton JR, Pinder AC, Alós J, Arlinghaus R, Danylchuk AJ, Edwards W, Freire KMF, Gundelund C, Hyder K, Jarić I, Lennox R, Lewin WC, Lynch AJ, Midway SR, Potts WM, Ryan KL, Skov C, Strehlow HV, Tracey SR, Tsuboi JI, Venturelli PA, Weir JL, Weltersbach MS, Cooke SJ. Global responses to the COVID-19 pandemic by recreational anglers: considerations for developing more resilient and sustainable fisheries. REVIEWS IN FISH BIOLOGY AND FISHERIES 2023:1-17. [PMID: 37360579 PMCID: PMC10227408 DOI: 10.1007/s11160-023-09784-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 05/01/2023] [Indexed: 06/28/2023]
Abstract
The global COVID-19 pandemic resulted in many jurisdictions implementing orders restricting the movements of people to inhibit virus transmission, with recreational angling often either not permitted or access to fisheries and/or related infrastructure being prevented. Following the lifting of restrictions, initial angler surveys and licence sales suggested increased participation and effort, and altered angler demographics, but with evidence remaining limited. Here, we overcome this evidence gap by identifying temporal changes in angling interest, licence sales, and angling effort in world regions by comparing data in the 'pre-pandemic' (up to and including 2019); 'acute pandemic' (2020) and 'COVID-acclimated' (2021) periods. We then identified how changes can inform the development of more resilient and sustainable recreational fisheries. Interest in angling (measured here as angling-related internet search term volumes) increased substantially in all regions during 2020. Patterns in licence sales revealed marked increases in some countries during 2020 but not in others. Where licence sales increased, this was rarely sustained in 2021; where there were declines, these related to fewer tourist anglers due to movement restrictions. Data from most countries indicated a younger demographic of people who participated in angling in 2020, including in urban areas, but this was not sustained in 2021. These short-lived changes in recreational angling indicate efforts to retain younger anglers could increase overall participation levels, where efforts can target education in appropriate angling practices and create more urban angling opportunities. These efforts would then provide recreational fisheries with greater resilience to cope with future global crises, including facilitating the ability of people to access angling opportunities during periods of high societal stress. Supplementary Information The online version contains supplementary material available at 10.1007/s11160-023-09784-5.
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Affiliation(s)
- J. Robert Britton
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, BH12 5BB UK
| | - Adrian C. Pinder
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole, BH12 5BB UK
| | - Josep Alós
- Instituto Mediterráneo de Estudios Avanzados, IMEDEA (CSIC–UIB), Esporles, Spain
| | - Robert Arlinghaus
- Department of Fish Biology, Fisheries and Aquaculture, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany
- Division of Integrative Fisheries Management, Faculty of Life Sciences, Humboldt-Univesität zu Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
| | - Andy J. Danylchuk
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA 01003 USA
| | - Wendy Edwards
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT Suffolk UK
| | - Kátia M. F. Freire
- Department of Fisheries Engineering and Aquaculture, Universidade Federal de Sergipe, Cidade Universitária Prof. José Aloísio de Campos, Rua Mal. Rondon S/N, Jardim Rosa Elze São Cristóvão, Sergipe CEP 49100-000 Brazil
| | - Casper Gundelund
- Section of Freshwater Fisheries and Ecology, Technical University of Denmark, DTU Aqua, 8600 Silkeborg, Denmark
| | - Kieran Hyder
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT Suffolk UK
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ Norfolk UK
| | - Ivan Jarić
- Biology Centre of the Czech Academy of Sciences, Institute of Hydrobiology, Na Sádkách 702/7, 37005 České Budějovice, Czech Republic
- Université Paris-Saclay, CNRS, AgroParisTech, Ecologie Systématique Evolution, 12 Rue 128, 91190 Gif-Sur-Yvette, France
| | - Robert Lennox
- Norwegian Institute for Nature Research and at the Laboratory for Freshwater Ecology, Oslo, Norway
| | - Wolf-Christian Lewin
- Thünen Institute of Baltic Sea Fisheries, Alter Hafen Süd 2, 18069 Rostock, Germany
| | - Abigail J. Lynch
- U.S. Geological Survey, National Climate Adaptation Science Center, 12201 Sunrise Valley Drive MS 516, Reston, VA 20192 USA
| | - Stephen R. Midway
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA 70803 USA
| | - Warren M. Potts
- Department of Ichthyology and Fisheries Science, Rhodes University, P.O. Box 94, Makhanda, 6140 South Africa
| | - Karina L. Ryan
- Department of Primary Industries and Regional Development, Western Australian Fisheries and Marine Research Laboratories, 39 Northside Drive, Hillarys, WA 6025 Australia
| | - Christian Skov
- Section of Freshwater Fisheries and Ecology, Technical University of Denmark, DTU Aqua, 8600 Silkeborg, Denmark
| | - Harry V. Strehlow
- Thünen Institute of Baltic Sea Fisheries, Alter Hafen Süd 2, 18069 Rostock, Germany
| | - Sean R. Tracey
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 49, Hobart7001, TAS Australia
- Centre For Marine Socioecology, University of Tasmania, Private Bag 49, Hobart7001, TAS Australia
| | - Jun-ichi Tsuboi
- Research Center for Freshwater Fisheries, Japan Fish Res and Education Agency, Nikko, 321-1661 Japan
| | | | - Jessica L. Weir
- Department of Biology, Ball State University, Muncie, IN 47304 USA
| | | | - Steven J. Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON K1S 5B6 Canada
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Letty BA, Hart TGB, Murugan S, Naidoo T, Rai S, Thiam D, Zake J, Sershen, Annor-Frempong I. A critical comparative review of evidence on alternative instruments for supporting research and innovation in agri-food systems in the Global South. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2022. [DOI: 10.3389/fsufs.2022.1013156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Financial support is a critical enabling factor for healthy agri-food innovation systems, particularly within resource-limited settings, though additional forms of support are also necessary. This motivated a critical comparative review of evidence in peer-reviewed and gray literature on the range of instruments that support innovation in agri-food systems in the Global South, toward achieving sustainable agriculture intensification. The main aim is to provide recommendations to innovation managers on the choice of different instruments for supporting innovation. The key guiding questions for the comparative analysis were whether the instrument fosters uptake of innovation and whether it promotes inclusive development. A review of the literature was supplemented with a scan of websites for sources of peer-reviewed and gray literature documenting the application of the 12 selected instruments. The study revealed three categories of instruments: (Type A) those that support entrepreneurship; (Type B) those that primarily finance innovation; and (Type C) those that support innovation in real-life contexts. Our analysis indicates that innovation managers and funders need to select instruments that are likely to fit the specific context as well as to address the mandates of their organizations, and in so doing, they must consider how to ensure the sustainability of their investments and meet the needs of their beneficiaries. This review represents one of a handful that have compared the use of multiple instruments across multiple continents in the Global South, and can serve as an important decision-making tool for investors and funders looking to invest in agri-food innovation systems.
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Calderwood J. Smartphone application use in commercial wild capture fisheries. REVIEWS IN FISH BIOLOGY AND FISHERIES 2022; 32:1063-1083. [PMID: 36124315 PMCID: PMC9476459 DOI: 10.1007/s11160-022-09727-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
UNLABELLED Smartphones are increasingly the most common type of mobile phone used throughout the world, offering users the ability to browse the internet and access mobile applications. Smartphones are also often equipped with high definition digital cameras, accelerometers, gyroscopes, and GPS. They can, therefore, facilitate the collection and dissemination of data, often through purpose designed applications (apps). As a result, numerous apps have been developed for use in wild capture fisheries. These apps have been designed for a number of purposes including for data collection, providing information to fishers, being linked to value chains and post-harvest practices and for uses linked to employment, legislation and safety. These apps are used across the world from large commercialized fisheries to small scale fisheries. In the latter, apps have the potential to bridge a technology gap, possibly replicating the functions of multiple pieces of hardware such as are used on larger vessels. This paper presents results from a narrative literature review to provide a synthesis of smart phone apps currently available for use by commercial fishers. 84 smartphone apps were identified as being currently available for use in commercial wild capture fisheries throughout the world. Smartphone apps were available for a number of uses but they were predominantly used for data collection and reporting. While this review provides an important overview of the extent of app use in commercial wild capture fisheries there remains potential for future work to improve understanding of how beneficial app use is and what it is that encourages app use and determines an app as being 'successful'. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s11160-022-09727-6.
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Affiliation(s)
- Julia Calderwood
- Marine Institute, Rinville, Oranmore, County Galway, H91 R673 Ireland
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Thomas FL, Forys EA. The Role of Fishing Piers in Brown Pelican ( Pelecanus occidentalis) Entanglement. Animals (Basel) 2022; 12:ani12182352. [PMID: 36139212 PMCID: PMC9495162 DOI: 10.3390/ani12182352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/04/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
Throughout their range, Brown Pelicans (Pelecanus occidentalis) are one of the most common species to become entangled in fishing gear. We surveyed four piers every other week for one year (6/2019−5/2020) in the Tampa Bay region, FL, USA, to determine frequency of pelican entanglement associated with fishing piers, and explored factors that might influence the rate of entanglement. We conducted a generalized linear model (GLM) to determine the influence that pier, pier closure due to COVID-19, time of day and season, number of anglers, and presence of human behaviors that might attract pelicans to the pier had on the number of entangled pelicans. We conducted 144 surveys and counted 3766 pelicans of which 254 (7%) were entangled. The variables significantly associated (p < 0.05) with entanglement were the pier, time of day, and pier closure status, while the number and behavior of anglers were not significant. The two piers that most significantly influenced the number of entanglements both had extensive perches within 10 m of the fishing pier. The management action most likely to reduce the number of entangled pelicans appears to be deterring pelicans from perching near piers or decreasing fishing near perching structures.
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Affiliation(s)
- Fairl L. Thomas
- Environmental Studies Discipline, Eckerd College, St. Petersburg, FL 33711, USA
| | - Elizabeth A. Forys
- Environmental Studies and Biology Disciplines, Eckerd College, St. Petersburg, FL 33711, USA
- Correspondence:
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Britton JR, Cucherousset J, Dominguez Almela V. Novel trophic subsidies from recreational angling transform the trophic ecology of freshwater fishes. J Appl Ecol 2022. [DOI: 10.1111/1365-2664.14237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Robert Britton
- Department of Life and Environmental Sciences, Faculty of Science and Technology Bournemouth University Dorset United Kingdom
| | - Julien Cucherousset
- CNRS, Université Paul Sabatier; UMR 5174 EDB (Laboratoire Évolution & Diversité Biologique) Toulouse France
| | - Victoria Dominguez Almela
- Department of Life and Environmental Sciences, Faculty of Science and Technology Bournemouth University Dorset United Kingdom
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9
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Chang YC, Zhang X, Khan MI. The impact of the COVID-19 on China's fisheries sector and its countermeasures. OCEAN & COASTAL MANAGEMENT 2022; 216:105975. [PMID: 34840439 PMCID: PMC8610844 DOI: 10.1016/j.ocecoaman.2021.105975] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 05/19/2023]
Abstract
The COVID-19 pandemic has affected China's economic development, international exchanges and other aspects to varying degrees, among which the impact on China's fishery development should not be underestimated. The fishery is a traditional and vast industry in China. The ongoing COVID-19 outbreak has also exposed potential problems in China's fishery development, such as the lack of specialised aquatic product quality and safety supervision and testing institutions. New problems have also arisen, such as the decline in the market demand for fish and aquatic products, affecting fishers' income, livelihood and so on. These deficiencies require China to establish a matching legal system to correspondingly solve the current legal and political problems. This paper will systematically discuss the impact of the COVID-19 on China's fisheries sector from the perspectives of 'fishers' and 'aquatic products' after the outbreak of the COVID-19 pandemic and analyse how to deal with various problems by referring to relevant experience in light of China's national conditions and characteristics.
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Affiliation(s)
- Yen-Chiang Chang
- School of Law, Dalian Maritime University, China, Research Fellow, Institute of Shenzhen Studies, Dalian Maritime University, China, Dean, Institute of Yellow Sea and Bohai Sea Studies, Dalian Maritime University, China
| | - Xu Zhang
- Institute of Yellow Sea and Bohai Sea Studies, Dalian Maritime University, China, Juris Doctor (JD) Graduate from the University of Melbourne, Australia
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Application of Feature Point Matching Technology to Identify Images of Free-Swimming Tuna Schools in a Purse Seine Fishery. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2021. [DOI: 10.3390/jmse9121357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tuna fish school detection provides information on the fishing decisions of purse seine fleets. Here, we present a recognition system that included fish shoal image acquisition, point extraction, point matching, and data storage. Points are a crucial characteristic for images of free-swimming tuna schools, and point algorithm analysis and point matching were studied for their applications in fish shoal recognition. The feature points were obtained by using one of the best point algorithms (scale invariant feature transform, speeded up robust features, oriented fast and rotated brief). The k-nearest neighbors (KNN) algorithm uses ‘feature similarity’ to predict the values of new points, which means that new data points will be assigned a value based on how closely they match the points that exist in the database. Finally, we tested the model, and the experimental results show that the proposed method can accurately and effectively recognize tuna free-swimming schools.
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11
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Coulson PG, Moore GI. A rare capture of two Japanese rubyfish (Erythrocles schlegelii) (Richardson, 1846) off southern Western Australia, including their otolith characteristics and age. AUST J ZOOL 2020. [DOI: 10.1071/zo21020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Due to advances in fish-finding equipment and vessel capabilities, commercial and recreational fishers are now regularly accessing deep waters off the edge of the continental shelf and catching fish species that are rarely encountered in shallower waters or that have not previously been caught. This study details the capture of two Japanese rubyfish (Erythrocles schlegelii) in deep, offshore waters on the south coast of Western Australia, and in waters further south than previously encountered. This study also provides the first age estimates from counts of growth (opaque) zones in sectioned sagittal otoliths. The estimated ages of 8 years for both individuals, one female and the other male, are much lower than what would have been expected based on age estimates for this species derived from scales undertaken in an earlier study. Understanding the biological characteristics of these deepwater fish species will assist in future management of these resources.
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