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Liang D, Mu T, Yang Z, Giam X, Wang Y, Li J, Cai S, Zhang X, Wang Y, Liu Y, Wilcove DS. Assessing shorebird mortalities due to razor clam aquaculture at key migratory stopover sites in southeastern China. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2024; 38:e14185. [PMID: 37706237 DOI: 10.1111/cobi.14185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 09/03/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
Aquaculture can provide foraging habitat for birds, but it can also result in intentional and accidental mortality. We examined an overlooked conflict between razor clam (Sinonovacula spp.) aquaculture and declining shorebirds in southeastern China's Fujian and Zhejiang provinces. We surveyed 6 out of 11 internationally important stopover sites for these shorebirds and monitored shorebird mortality in 2 sites (Xinghua Bay, Yueqing Bay) with razor clam aquaculture. We visited an additional 32 sites in these 2 provinces to determine if there was netting in other razor clam farms. Approximately 8-9 km2 of intertidal foraging habitat was covered by horizontal nets to prevent birds from feeding on young razor clams at Xinghua Bay and Yueqing Bay. We conservatively estimated that 13,676 (2.5th-97.5th percentile 8,330-21,285) individual shorebirds were entangled in the nets at the 2 monitored sites in April and May 2021, including 2 endangered and 7 near-threatened species. Mortality of 5 species for which we had sufficient data accounted for 0.76% (black-tailed godwit [Limosa limosa]) to 4.27% (terek sandpiper [Xenus cinereus]) of their total flyway populations. This level of mortality could strongly affect their populations. We found netting at 17 additional razor clam farms, indicating a widespread threat to shorebirds. Although razor clams are typically harvested in late March to early April, nets are left on the mudflats throughout the spring and summer, including when the bulk of shorebird migration takes place. Immediately removing these nets after the clam harvest could prevent most of the spring mortality of shorebirds, although this is unlikely to happen without government regulations or economic incentives. To better assess and mitigate the impacts of this conflict, future research should quantify shorebird mortality at other razor clam farms, including during winter, explore less harmful deterrence methods, and assess the socioeconomic factors driving the conflict.
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Affiliation(s)
- Dan Liang
- Princeton School of Public and International Affairs, Princeton University, Princeton, New Jersey, USA
| | - Tong Mu
- Princeton School of Public and International Affairs, Princeton University, Princeton, New Jersey, USA
| | - Ziyou Yang
- Spoon-billed Sandpiper (Shanghai) Environmental Protection Technology Co., Ltd, Shanghai, China
| | - Xingli Giam
- Department of Ecology & Evolutionary Biology, The University of Tennessee, Knoxville, Tennessee, USA
| | - Yudi Wang
- Spoon-billed Sandpiper (Shanghai) Environmental Protection Technology Co., Ltd, Shanghai, China
| | - Jing Li
- Spoon-billed Sandpiper (Shanghai) Environmental Protection Technology Co., Ltd, Shanghai, China
| | - Shangxiao Cai
- Spoon-billed Sandpiper (Shanghai) Environmental Protection Technology Co., Ltd, Shanghai, China
| | - Xuelian Zhang
- Yunnan Wild Bird Association, Kunming, Yunnan, China
| | - Yixiao Wang
- Fujian Birdwatching Society, Fuzhou, Fujian, China
| | - Yang Liu
- School of Ecology, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - David S Wilcove
- Princeton School of Public and International Affairs, Princeton University, Princeton, New Jersey, USA
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
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de Oliveira YCBB, Nazareth Rivera D, Carramaschi de Alagão Querido L, da Silva Mourão J. Critical areas for sea turtles in Northeast Brazil: a participatory approach for a data-poor context. PeerJ 2024; 12:e17109. [PMID: 38549781 PMCID: PMC10977088 DOI: 10.7717/peerj.17109] [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: 01/26/2023] [Accepted: 02/23/2024] [Indexed: 04/02/2024] Open
Abstract
Fishing is one of the main threats to sea turtles due to the risk of entanglement in lost nets, vessel collision and mortality due to incidental catches. In Brazil, most of the studies regarding fishing interactions with sea turtles are focused on pelagic longline fisheries in the South and Southeast regions. However, their main reproductive areas in Southwest Atlantic RMU occur in Northeast Brazil, which overlaps small-scale coastal gillnet fisheries. Here, we aimed to use ethnobiology and participatory approaches as simple and cost-effective methods to identify areas for sea turtle conservation where impacts from small-scale fisheries are most likely. Expert captains were trained to recording sea turtle sightings during navigations from the landing port to the fishing grounds, informing their folk nomenclatures. By interpolation of environmental data (chlorophyll and bathymetry) and ecological data, we predicted habitats of 3,459.96 km² for Caretta caretta, Chelonia mydas, and Eretmochelys imbricata and fishing zones of 1,087 km² for management in 20 m and 50 m depths. Our results contributes to ongoing discussions of bycatch mitigation for sea turtle species and identification of habitats. We highlights the importance of considering particularities of overlapped areas in marine spatial planning and co-management arrangements.
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Affiliation(s)
| | - Douglas Nazareth Rivera
- Programa de Pós-Graduação em Conservação da Fauna, Universidade Federal de São Carlos, São Carlos, São Paulo, Brazil
| | | | - José da Silva Mourão
- Departamento de Biologia, Universidade Estadual da Paraíba, Campina Grande, Paraiba, Brazil
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Rouxel Y, Arnardóttir H, Oppel S. Looming-eyes buoys fail to reduce seabird bycatch in the Icelandic lumpfish fishery: depth-based fishing restrictions are an alternative. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230783. [PMID: 37885979 PMCID: PMC10598418 DOI: 10.1098/rsos.230783] [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: 06/08/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023]
Abstract
Bycatch in gillnets from lumpfish (Cyclopterus lumpus) fisheries is an important conservation issue in the north Atlantic, with up to 30 000 seabirds potentially killed each year. To date, no technical solutions exist to reduce the bycatch of seabirds in gillnet fisheries, but research on above-water bird deterrents as a form of bycatch mitigation has shown promising results. Here, we tested whether a floating device called 'looming-eyes buoy' (LEB) would consistently reduce the bycatch of seabirds in the Icelandic lumpfish fishery. We conducted 61 controlled trials with sets of normal gillnets and experimental nets equipped with LEBs. We compared both fish catch and bycatch between net types while accounting for exposure time, water depth and season, and found no effect of LEBs on both target lumpfish catch and bycatch. Our analysis indicated however a strong correlation between bycatch rates and fishing depths, suggesting that depth-based fishing restrictions could virtually eliminate the bycatch of seabirds in this fishery. We estimated that limiting fishing to waters more than 50 m deep could save between 5000 and 9300 seabirds every year, arrest the population decline of endangered black guillemots in Iceland, while having only a marginal effect on target fish catch.
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Affiliation(s)
- Yann Rouxel
- BirdLife International Marine Programme, the Royal Society for the Protection of Birds Scotland, Glasgow, UK
| | | | - Steffen Oppel
- RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, UK
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Araujo SCDE, Beneditto APMDI, Gatts CEN, Moreira SC, Domit C, Gama RM, Martins AS, Zappes CA. Local ecological knowledge of fishers from southern and southeastern Brazil about the franciscana dolphin Pontoporia blainvillei: Strategies for conservation. AN ACAD BRAS CIENC 2023; 95:e20201111. [PMID: 37222356 DOI: 10.1590/0001-3765202320201111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/05/2020] [Indexed: 05/25/2023] Open
Abstract
This study compares local ecological knowledge (LEK) of fishers from the Southwest Atlantic Ocean (SWAO), Brazil, related to the franciscana dolphin (Pontoporia blainvillei). We conducted 330 ethnographic interviews in ten fishing communities in southern and southeastern Brazil between 2012 and 2018. Boolean or Classic Logic was used to identify 95 fishers who were able to recognize the franciscana dolphin accordingly to the taxonomic entity P. blainvillei: 23 in northern Espírito Santo state, one in southern Espírito Santo, 20 in northern Rio de Janeiro state, and 51 in northern Paraná state. Among these 95 fishers, 87.4% (n = 83) reported incidental captures in fishing nets. Among these, 52 (54.7%) did not know any solution to this problem. Interviews revealed that the fishers usually discard carcasses in the sea after fat and muscle tissue are removed so that they can be used as bait for shark fishing or as food. In Southeastern Brazil, fishers LEK related to their ability to identify franciscana dolphin varied from 'no identification' and 'extremely low identification' to 'partial' and 'good identification,' while in southern Brazil, fishers mainly presented a 'good identification' of the dolphins. We propose comanagement actions to conserve the franciscana dolphin in the SWAO.
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Affiliation(s)
- Samanta C DE Araujo
- Programa de Pós-Graduação em Oceanografia Ambiental, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, 29075-900 Vitória, ES, Brazil
- Universidade Federal do Espírito Santo, Grupo de Pesquisa Ecologia Humana do Oceano, Laboratório de Oceanografia Socioambiental, Av. Fernando Ferrari, 514, 29075-910 Vitória, ES, Brazil
| | - Ana Paula M DI Beneditto
- Universidade Estadual do Norte Fluminense Darcy Ribeiro, Av. Alberto Lamego, 2000, Parque Califórnia, 28013-602 Campos dos Goytacazes, RJ, Brazil
- Universidade Federal do Espírito Santo, Grupo de Pesquisa Ecologia Humana do Oceano, Laboratório de Oceanografia Socioambiental, Av. Fernando Ferrari, 514, 29075-910 Vitória, ES, Brazil
| | - Carlos Eduardo N Gatts
- Universidade Estadual do Norte Fluminense Darcy Ribeiro, Centro de Ciência e Tecnologia, Laboratório de Ciências Físicas, Av. Alberto Lamego, 2000, Parque Califórnia, Campos dos Goytacazes, 28013-602 Rio de Janeiro, RJ, Brazil
| | - Sérgio C Moreira
- Universidade Federal do Rio de Janeiro, Laboratório de Bioacústica e Ecologia de Cetáceos, Av. Carlos Chagas Filho, 373, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil
- Universidade Federal do Espírito Santo, Grupo de Pesquisa Ecologia Humana do Oceano, Laboratório de Oceanografia Socioambiental, Av. Fernando Ferrari, 514, 29075-910 Vitória, ES, Brazil
| | - Camila Domit
- Universidade Federal do Paraná, Centro de Estudos do Mar, Laboratório de Ecologia e Conservação, Av. Beira Mar, s/n, Caixa Postal 6, 83255-000 Pontal do Sul, Paraná, Brazil
- Universidade Federal do Espírito Santo, Grupo de Pesquisa Ecologia Humana do Oceano, Laboratório de Oceanografia Socioambiental, Av. Fernando Ferrari, 514, 29075-910 Vitória, ES, Brazil
| | - Renata M Gama
- Universidade Federal do Espírito Santo, Grupo de Pesquisa Ecologia Humana do Oceano, Laboratório de Oceanografia Socioambiental, Av. Fernando Ferrari, 514, 29075-910 Vitória, ES, Brazil
| | - Agnaldo S Martins
- Programa de Pós-Graduação em Oceanografia Ambiental, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, 29075-900 Vitória, ES, Brazil
| | - Camilah A Zappes
- Programa de Pós-Graduação em Oceanografia Ambiental, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, 29075-900 Vitória, ES, Brazil
- Universidade Federal do Espírito Santo, Grupo de Pesquisa Ecologia Humana do Oceano, Laboratório de Oceanografia Socioambiental, Av. Fernando Ferrari, 514, 29075-910 Vitória, ES, Brazil
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Post S, Merkel F, Bak-Jensen Z, Koch C, Hedeholm RB. Bycatch mitigation in the West Greenland lumpfish ( Cyclopterus lumpus) fishery using modified gillnets. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221536. [PMID: 37035295 PMCID: PMC10073906 DOI: 10.1098/rsos.221536] [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: 12/05/2022] [Accepted: 03/13/2023] [Indexed: 06/19/2023]
Abstract
Bycatch in gillnets is a global issue and mitigation measures that balance target species catch rates, bycatch reduction and fisher support are scarce. In the North Atlantic lumpfish fisheries, bycatch includes marine mammals and seabirds, and there are no permanent technical initiatives to reduce the bycatch. In the West Greenland fishery, common eider bycatch is several thousand individuals annually. We explored if bycatch in this fishery could be reduced by modifying standard lumpfish gillnets by adding a 45 cm high small-meshed net panel to the bottom part of the net. We tested the nets in combination with standard nets and estimated catch rates in a controlled setting in 2021 and in the commercial fishery in 2022. The modified nets had a 71% reduced bycatch rate for common eider and a 25% reduced catch rate for female lumpfish. A combination of the panel and increased seaweed entanglement was the most likely explanation for the effect. In addition to the effect of the net modification, the common eider bycatch decreased significantly during the season, and we recommend studying the net effect further and exploring the option of postponing the fishing season as a simpler way of reducing bycatch.
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Affiliation(s)
- Søren Post
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
| | - Flemming Merkel
- Greenland Institute of Natural Resources, 3900 Nuuk, Greenland
- Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark
| | - Zita Bak-Jensen
- DTU Aqua, Technical University of Denmark, 9850 Hirtshals, Denmark
| | - Christoffer Koch
- DTU Aqua, Technical University of Denmark, 2800 Kgs, Lyngby, Denmark
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McGrew KA, Crowell SE, Fiely JL, Berlin AM, Olsen GH, James J, Hopkins H, Williams CK. Underwater hearing in sea ducks with applications for reducing gillnet bycatch through acoustic deterrence. J Exp Biol 2022; 225:jeb243953. [PMID: 36305674 PMCID: PMC10658911 DOI: 10.1242/jeb.243953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
As diving foragers, sea ducks are vulnerable to underwater anthropogenic activity, including ships, underwater construction, seismic surveys and gillnet fisheries. Bycatch in gillnets is a contributing source of mortality for sea ducks, killing hundreds of thousands of individuals annually. We researched underwater hearing in sea duck species to increase knowledge of underwater avian acoustic sensitivity and to assist with possible development of gillnet bycatch mitigation strategies that include auditory deterrent devices. We used both psychoacoustic and electrophysiological techniques to investigate underwater duck hearing in several species including the long-tailed duck (Clangula hyemalis), surf scoter (Melanitta perspicillata) and common eider (Somateria mollissima). Psychoacoustic results demonstrated that all species tested share a common range of maximum auditory sensitivity of 1.0-3.0 kHz, with the long-tailed ducks and common eiders at the high end of that range (2.96 kHz), and surf scoters at the low end (1.0 kHz). In addition, our electrophysiological results from 4 surf scoters and 2 long-tailed ducks, while only tested at 0.5, 1 and 2 kHz, generally agree with the audiogram shape from our psychoacoustic testing. The results from this study are applicable to the development of effective acoustic deterrent devices or pingers in the 2-3 kHz range to deter sea ducks from anthropogenic threats.
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Affiliation(s)
- Kathleen A. McGrew
- Virginia Maryland College of Veterinary Medicine, 205 Duck Pond Drive, Blacksburg, VA 24060, USA
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
- Department of Entomology and Wildlife Ecology, University of Delaware, 531 South College Ave, Newark, DE 19716, USA
| | - Sarah E. Crowell
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
| | - Jonathan L. Fiely
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
| | - Alicia M. Berlin
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
| | - Glenn H. Olsen
- US Geological Survey, Eastern Ecological Science Center, 12100 Beech Forest Road, Laurel, MD 20708, USA
| | - Jennifer James
- Department of Entomology and Wildlife Ecology, University of Delaware, 531 South College Ave, Newark, DE 19716, USA
| | - Heather Hopkins
- Department of Entomology and Wildlife Ecology, University of Delaware, 531 South College Ave, Newark, DE 19716, USA
| | - Christopher K. Williams
- Naval Undersea Warfare Center, Newport Division, Mission Environmental Planning, 1176 Howell St, Newport, RI 02841, USA
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Kolipakam V, Jacob M, Gayathri A, Deori S, Sarma H, Tasfia ST, Rokade A, Negi R, Wakid A, Qureshi Q. Pingers are effective in reducing net entanglement of river dolphins. Sci Rep 2022; 12:9382. [PMID: 35672330 PMCID: PMC9174236 DOI: 10.1038/s41598-022-12670-y] [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: 01/07/2022] [Accepted: 05/13/2022] [Indexed: 11/17/2022] Open
Abstract
Ganges River dolphins echolocate, but this mechanism is inadequate for poor sonar-echoing objects such as the monofilament gillnets, causing considerable net entanglement related mortalities. Net entanglement related deaths are one of the major causes of cetacean population decline around the world. Experiments were carried out to understand the use of pingers—an acoustic deterrent, in aiding the deterrence of dolphins from fishing nets. Based on the dolphin clicks recorded, in an experimental setup spanning 36 days, a 90% deterrence was found; 22.87 ± 0.71 SE dolphin detection positive minutes per hour near non-pingered nets versus 2.20 ± 0.33 SE per hour near pingered net. Within 30 m radii of nets, visual encounters of non-calf reduced by 52% and calf by 9%, in the presence of pingers. No evidence of habituation to pingers, habitat avoidance in dolphins after pinger removal or a change in fish catch in nets because of pingers was found during the study. While the effectiveness of pingers on calves and fish catch needs further experimentation, the use of pingers to minimize net entanglement mortalities in the Ganges River dolphins seems to be the most promising solution currently available. These results have critical implications for the conservation of other species of river dolphins around the world.
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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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Rouxel Y, Crawford R, Cleasby IR, Kibel P, Owen E, Volke V, Schnell AK, Oppel S. Buoys with looming eyes deter seaducks and could potentially reduce seabird bycatch in gillnets. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210225. [PMID: 33981446 PMCID: PMC8103233 DOI: 10.1098/rsos.210225] [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: 02/08/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Bycatch of seabirds in gillnet fisheries is a global conservation issue with an estimated 400 000 seabirds killed each year. To date, no underwater deterrents trialled have consistently reduced seabird bycatch across operational fisheries. Using a combination of insights from land-based strategies, seabirds' diving behaviours and their cognitive abilities, we developed a floating device exploring the effect of large eyespots and looming movement to prevent vulnerable seabirds from diving into gillnets. Here, we tested whether this novel above-water device called 'Looming eyes buoy' (LEB) would consistently deter vulnerable seaducks from a focal area. We counted the number of birds present in areas with and without LEBs in a controlled experimental setting. We show that long-tailed duck Clangula hyemalis abundance declined by approximately 20-30% within a 50 m radius of the LEB and that the presence of LEBs was the most important variable explaining this decline. We found no evidence for a memory effect on long-tailed ducks but found some habituation to the LEB within the time frame of the project (62 days). While further research is needed, our preliminary trials indicate that above-water visual devices could potentially contribute to reduce seabird bycatch if appropriately deployed in coordination with other management measures.
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Affiliation(s)
- Yann Rouxel
- BirdLife International Marine Programme, c/o the Royal Society for the Protection of Birds Scotland, 10 Park Quadrant, Glasgow, UK
| | - Rory Crawford
- BirdLife International Marine Programme, c/o the Royal Society for the Protection of Birds Scotland, 10 Park Quadrant, Glasgow, UK
| | - Ian R. Cleasby
- RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, UK
| | - Pete Kibel
- Fishtek Marine, Webbers Way, Dartington, Devon, UK
| | - Ellie Owen
- RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, UK
| | - Veljo Volke
- Estonian Ornithological Society, Veski 4, Tartu, Estonia
| | | | - Steffen Oppel
- RSPB Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, UK
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Cantlay JC, Bond AL, Wells-Berlin AM, Crawford R, Martin GR, Rouxel Y, Peregoy S, McGrew KA, Portugal SJ. Ineffectiveness of light emitting diodes as underwater deterrents for Long-tailed Ducks Clangula hyemalis. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Zaluski S, Soanes LM, Bright JA, George A, Jodice PGR, Meyer K, Woodfield-Pascoe N, Green JA. Potential threats facing a globally important population of the magnificent frigatebird Fregata magnificens. TROPICAL ZOOLOGY 2019. [DOI: 10.1080/03946975.2019.1682352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Susan Zaluski
- Jost Van Dykes Preservation Society, Jost Van Dyke, British Virgin Islands
| | - Louise M. Soanes
- School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom
- Life Sciences, University of Roehampton, London, United Kingdom
| | - Jenny A. Bright
- Royal Society for the Protection of Birds, The Lodge, Bedfordshire, United Kingdom
| | - Atoya George
- Conservation and Fisheries Department, British Virgin Islands Government, Road Town, Tortola, British Virgin Islands
| | - Patrick G. R. Jodice
- U.S. Geological Survey, South Carolina Cooperative Fish and Wildlife Research Unit, Clemson University, Clemson, South Carolina, USA
| | - Ken Meyer
- Avian Research and Conservation Institute, 411 N.E 7th Street, Gainesville, Florida 32601, USA
| | | | - Jonathan A. Green
- School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom
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Field R, Crawford R, Enever R, Linkowski T, Martin G, Morkūnas J, Morkūnė R, Rouxel Y, Oppel S. High contrast panels and lights do not reduce bird bycatch in Baltic Sea gillnet fisheries. Glob Ecol Conserv 2019. [DOI: 10.1016/j.gecco.2019.e00602] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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13
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Spatial and temporal variations in seabird bycatch: Incidental bycatch in the Norwegian coastal gillnet-fishery. PLoS One 2019; 14:e0212786. [PMID: 30865723 PMCID: PMC6415787 DOI: 10.1371/journal.pone.0212786] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/08/2019] [Indexed: 11/21/2022] Open
Abstract
The general decline of seabird populations worldwide raises large concerns. Although multiple factors are interacting to cause the observed trends, increased mortality from incidental bycatch in fisheries has proven to be important for many species. However, the bulk of published knowledge is derived from longline fisheries, whereas bycatch in gillnet fisheries is less studied and even overlooked in some areas. We present seabird bycatch data from a 10-year time-series of fishery data from the large fleet of small-vessels fishing with gillnets along the Norwegian coast—a large area and fishery with no prior estimates of seabird bycatch. In general, we document high rates of incidental bycatch (averaging 0.0023 seabirds/net, or approximately 0.08 seabirds/fishing trip). This results in an estimated annual bycatch between 1580 and 11500 (95% CI) birds in this fishery. There was a surprisingly high percentage (43%) of surface-feeding seabirds in the bycatch, with northern fulmar being the most common species. Among the diving seabirds caught, common guillemot was most numerous. Our findings suggest that coastal gillnet fisheries represent a more general threat to a wider range of seabird populations, as opposed to longline fisheries where surface-feeding seabird species seem to dominate the bycatch. The bycatch estimates for the Norwegian gillnet-fishery varied in time, between areas, and with fishing depth and distance from the coast, but we found no clear trends in relation to the type of gillnets used. The results enabled us to identify important spatio-temporal trends in the seabird bycatch, which can allow for the development and implementation of more specific mitigation measures. While specific time closures might be an efficient option to reduce bycatch for diving seabirds, measures such as gear modification and reduction in release of wastewater during fishing operation are probably a more effective mitigation approach for reducing bycatch of surface-feeding seabirds.
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Radar detectors carried by Cape gannets reveal surprisingly few fishing vessel encounters. PLoS One 2019; 14:e0210328. [PMID: 30726223 PMCID: PMC6364876 DOI: 10.1371/journal.pone.0210328] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 12/20/2018] [Indexed: 11/30/2022] Open
Abstract
Fisheries compete with seabirds for vanishing marine resources, but also produce fishery waste consumed by seabirds. Marine birds may therefore avoid or seek fishing vessels, and have evolved complex, plastic behavioural responses to vessel presence. Understanding these responses is essential to the conservation of a globally declining seabird community. We studied Cape gannets (Morus capensis), which compete with fisheries for reduced sardine (Sardinops sagax) resources in the Benguela upwelling region off South Africa. Using bird-borne GPS trackers coupled with newly-developed ship-radar detectors we show that foraging gannets seldom attended fishing vessels. Rather, they switched from eating scarce sardines or energetically-poor fishery waste to targeting locally abundant saury (Scomberesox saurus). This pelagic fish is brought into the seascape by warm water influx, and is not commercially exploited by fisheries. Cape gannets thereby show dietary plasticity, allowing them to maintain adult body condition and chick growth rates. This diet switch is a strong indicator that Cape gannets forage in an ecologically perturbed marine environment.
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