Effective Monitoring of Freshwater Fish
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Received: 20 October 2018 | Revised: 14 April 2019 | Accepted: 16 April 2019 DOI: 10.1111/faf.12373 ORIGINAL ARTICLE Effective monitoring of freshwater fish Johannes Radinger1 | J. Robert Britton2 | Stephanie M. Carlson3 | Anne E. Magurran4 | Juan Diego Alcaraz‐Hernández1 | Ana Almodóvar5 | Lluís Benejam6 | Carlos Fernández‐Delgado7 | Graciela G. Nicola8 | Francisco J. Oliva‐Paterna9 | Mar Torralva9 | Emili García‐Berthou1 1GRECO, Institute of Aquatic Ecology, University of Girona, Girona, Spain Abstract 2Faculty of Science and Freshwater ecosystems constitute only a small fraction of the planet's water re‐ Technology, Bournemouth University, Poole, sources, yet support much of its diversity, with freshwater fish accounting for more Dorset, UK 3Department of Environmental Science, species than birds, mammals, amphibians or reptiles. Fresh waters are, however, par‐ Policy, and Management, University of ticularly vulnerable to anthropogenic impacts, including habitat loss, climate and land California, Berkeley, California use change, pollution and biological invasions. This environmental degradation, com‐ 4Centre for Biological Diversity, School of Biology, University of St Andrews, St bined with unprecedented rates of biodiversity change, highlights the importance Andrews, UK of robust and replicable programmes to monitor freshwater fish. Such monitoring 5Department of Biodiversity, Ecology and programmes can have diverse aims, including confirming the presence of a single Evolution, Complutense University of Madrid, Madrid, Spain species (e.g., early detection of alien species), tracking changes in the abundance of 6 Aquatic Ecology Group, University of Vic – threatened species, or documenting long‐term temporal changes in entire communi‐ Central University of Catalonia, Vic, Spain ties. Irrespective of their motivation, monitoring programmes are only fit for purpose 7Departamento de Zoología, Facultad de Ciencias, Universidad de Córdoba, Córdoba, if they have clearly articulated aims and collect data that can meet those aims. This Spain review, therefore, highlights the importance of identifying the key aims in monitor‐ 8Department of Environmental Sciences, University of Castilla‐La Mancha, ing programmes and outlines the different methods of sampling freshwater fish that Toledo, Spain can be used to meet these aims. We emphasize that investigators must address is‐ 9 Departamento de Zoología y Antropología sues around sampling design, statistical power, species’ detectability, taxonomy and Física, Universidad de Murcia, Murcia, Spain ethics in their monitoring programmes. Additionally, programmes must ensure that Correspondence high‐quality monitoring data are properly curated and deposited in repositories that Johannes Radinger, GRECO, Institute of Aquatic Ecology, University of Girona, will endure. Through fostering improved practice in freshwater fish monitoring, this 17003 Girona, Spain. review aims to help programmes improve understanding of the processes that shape Email: [email protected] the Earth's freshwater ecosystems and help protect these systems in face of rapid Funding information environmental change. Government of Catalonia, Grant/Award Number: 2014 SGR 484 and 2017 SGR 548; Spanish Ministry of Science, Innovation KEYWORDS and Universities, Grant/Award Number: biodiversity targets, ecological monitoring, environmental assessment, environmental BiodivERsA3‐2015‐26, CGL2015‐69311‐ management, rivers and lakes, sampling design REDT, CGL2016‐80820‐R and PCIN‐2016‐ 168 Fish and Fisheries. 2019;20:729–747. wileyonlinelibrary.com/journal/faf © 2019 John Wiley & Sons Ltd | 729 730 | RADINGER ET AL. 1 | INTRODUCTION 1 Introduction 730 Human‐driven environmental changes continue to raise sub‐ 2 History of fish monitoring 731 stantial concerns for biodiversity conservation and have led to 3 Aims of effective monitoring 731 the development and implementation of many ecological moni‐ 4 Different questions lead to different monitoring 731 toring programmes around the world (Nichols & Williams, 2006). approaches These programmes generally aim to understand and manage the 5 Sampling and network design, and statistical models 732 interactions of environmental change with biodiversity (Fölster, 6 Approaches to fish monitoring 735 Johnson, Futter, & Wilander, 2014). Given the increasing serious‐ 6.1 Monitoring questions versus sampling methods 735 ness of environmental degradation, the need for effective eco‐ 6.2 Capture techniques and application within moni‐ 735 logical and biodiversity monitoring programmes has never been toring programmes higher (Lindenmayer & Likens, 2010). Freshwater ecosystems are 6.3 Capture and release methods 735 particularly imperilled by anthropogenic activities worldwide. 6.4 Non‐capture monitoring techniques 737 Although fresh waters cover less than 1% of the earth's surface, 6.5 Anglers’ data and data mining 737 they support high levels of biodiversity (Dudgeon et al., 2006; 6.6 Complementarity of capture and non‐capture 738 Strayer & Dudgeon, 2010). Extinction rates of freshwater taxa methods are considerably higher than terrestrial species (Sala et al., 2000), 7 Major challenges in fish monitoring 738 due to issues including habitat loss, climate and land use change, 7.1 Detectability 738 pollution and biological invasions (Ormerod, Dobson, Hildrew, & 7.2 Taxonomy 738 Townsend, 2010; Stendera et al., 2012). At approximately 13,000 7.3 Economic costs 739 species, freshwater fish represent 40%–45% of global fish diver‐ 7.4 Fish welfare and ethics in monitoring 739 sity (Lévêque, Oberdorff, Paugy, Stiassny, & Tedesco, 2008), with this highly diverse group including some of the most imperilled 8 Management of monitoring data 740 animals on the planet (Cooke, Paukert, & Hogan, 2012). 9 Conclusions 740 Freshwater fishes also provide ecosystem services of major eco‐ Acknowledgments 740 nomic, nutritional, scientific, historical and cultural importance (IUCN References 741 FFSG, 2015). For example, freshwater and marine fisheries jointly constitute the largest extractive use of wildlife in the world and status in rivers and lakes (e.g., Counihan et al., 2018; Holmgren, contribute to overall economic well‐being by means of export com‐ Degerman, Petersson, & Bergquist, 2016; Wagner, Deweber, Detar, modity trade, tourism and recreation (Santhanam, 2015). Freshwater Kristine, & Sweka, 2014), played a central role in fish‐based assess‐ fish provide a major source of protein for humans and support the ment systems (e.g., for the European Water Framework Directive, livelihoods of many people (Holmlund & Hammer, 1999), particularly Pont, Hugueny, & Rogers, 2007), and resulted in guidelines on stan‐ in the Global South. However, there are serious threats to this valu‐ dardized fish sampling methods (e.g., Bonar, Hubert, & Willis, 2009). able resource related to over‐exploitation and other anthropogenic There remains a series of issues and knowledge gaps with how stressors (Allan et al., 2005; de Kerckhove, Minns, & Chu, 2015). these programmes are designed and implemented. In particular, The wide range of responses of freshwater fishes to anthropogenic freshwater fish monitoring that has been poorly planned and lacks stressors make fish valuable indicators for assessing the biological and focus results in ineffective programmes that rarely meet their aims ecological integrity of fresh waters and their catchments (Fausch, Karr, (Lindenmayer & Likens, 2009, 2010; Marsh & Trenham, 2008; Nichols & Yant, 1984; Magurran et al., 2018; Schiemer, 2000). The breadth of & Williams, 2006). Moreover, there is considerable disparity across fundamental information on ecology and taxonomy, combined with developed and developing regions in how monitoring schemes are im‐ their higher societal importance compared to other freshwater taxa, plemented. This is an acute problem, as developing regions are often makes freshwater fish a popular target taxon in assessments of eco‐ characterized by high levels of fish diversity but limited resources logical integrity (Simon & Evans, 2017). Correspondingly, freshwater for research (e.g., Vörösmarty et al., 2010). Where monitoring pro‐ fishes are commonly used for evaluating the functioning and status of grammes are in place, there are almost inevitably trade‐offs in tempo‐ freshwater ecosystems and habitat quality. These assessments, how‐ ral and spatial scales of measurement (Pollock et al., 2002), but these ever, are only as good as the data that underpin them. For this reason, trade‐offs are often poorly quantified or justified, resulting in long‐ effective and meaningful monitoring of fish populations and commu‐ term data lacking statistical power. Finally, there are inherent issues nities in freshwater habitats is essential. over programmes being either question driven or mandated, with the The need for effective monitoring in ecological research is well‐ latter often lacking rigour in design resulting in their provision of only recognized and there are many monitoring programmes that have coarse‐level summaries of change (Lindenmayer & Likens, 2010). provided important scientific advances and crucial information for en‐ In this review, we examine these issues and knowledge gaps and vironmental policy (Lovett et al., 2007). For example, freshwater fish make recommendations about how they can be addressed within monitoring has highlighted changes in species diversity and species monitoring programmes. Our aim is to foster improved practices RADINGER ET AL. | 731 by: