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Stock Assessment in Inland Fisheries: a Foundation for Sustainable Use and Conservation

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Stock Assessment in Inland Fisheries: a Foundation for Sustainable Use and Conservation See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/303808362 Stock assessment in inland fisheries: a foundation for sustainable use and conservation Article in Reviews in Fish Biology and Fisheries · June 2016 DOI: 10.1007/s11160-016-9435-0 READS 614 12 authors, including: Ian G Cowx John D. Koehn University of Hull Arthur Rylah Institute for Environment… 239 PUBLICATIONS 5,579 CITATIONS 120 PUBLICATIONS 1,948 CITATIONS SEE PROFILE SEE PROFILE David B. Bunnell Shannon D. Bower United States Geological Survey Carleton University 95 PUBLICATIONS 1,260 CITATIONS 14 PUBLICATIONS 20 CITATIONS SEE PROFILE SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, Available from: Kai Lorenzen letting you access and read them immediately. Retrieved on: 22 August 2016 Rev Fish Biol Fisheries (2016) 26:405–440 DOI 10.1007/s11160-016-9435-0 REVIEWS Stock assessment in inland fisheries: a foundation for sustainable use and conservation K. Lorenzen . I. G. Cowx . R. E. M. Entsua-Mensah . N. P. Lester . J. D. Koehn . R. G. Randall . N. So . S. A. Bonar . D. B. Bunnell . P. Venturelli . S. D. Bower . S. J. Cooke Received: 27 July 2015 / Accepted: 18 May 2016 / Published online: 4 June 2016 Ó Springer International Publishing Switzerland 2016 Abstract Fisheries stock assessments are essential widespread presence of non-native species and the for science-based fisheries management. Inland fish- frequent use of enhancement and restoration measures eries pose challenges, but also provide opportunities such as stocking affect stock dynamics. This paper for biological assessments that differ from those outlines various stock assessment and data collection encountered in large marine fisheries for which many approaches that can be adapted to a wide range of of our assessment methods have been developed. different inland fisheries and management challenges. These include the number and diversity of fisheries, Although this paper identifies challenges in assess- high levels of ecological and environmental variation, ment, it focuses on solutions that are practical, scalable and relative lack of institutional capacity for assess- and transferrable. A path forward is suggested in ment. In addition, anthropogenic impacts on habitats, which biological assessment generates some of the K. Lorenzen R. G. Randall Fisheries and Aquatic Sciences, School of Forest Great Lakes Laboratory for Aquatic Science, Canadian Resource and Conservation, University of Florida, Centre for Inland Waters, Fisheries and Oceans Canada, Gainesville, FL, USA Burlington, ON, Canada I. G. Cowx N. So Hull International Fisheries Institute, University of Hull, Mekong River Commission, Phnom Penh, Cambodia Hull, UK S. A. Bonar R. E. M. Entsua-Mensah U.S. Geological Survey Arizona Cooperative Fish and Water Research Institute, Council for Scientific and Wildlife Research Unit, University of Arizona, Tucson, Industrial Research, Accra, Ghana AZ, USA N. P. Lester D. B. Bunnell Science and Research Branch, Ontario Ministry of Natural U.S. Geological Survey, Great Lakes Science Center, Resources and Forestry, Peterborough, ON, Canada Ann Arbor, MI, USA J. D. Koehn P. Venturelli Applied Aquatic Ecology, Arthur Rylah Institute for Department of Fisheries, Wildlife, and Conservation Environmental Research, Heidelberg, VIC, Biology, University of Minnesota, St Paul, MN, USA Australia 123 406 Rev Fish Biol Fisheries (2016) 26:405–440 critical information needed by fisheries managers to typically in a quantitative form, is the aim of fisheries make effective decisions that benefit the resource and stock assessment (Hilborn and Walters 1992; Cowx stakeholders. 1996; Walters and Martell 2004). Use of assessments allows managers to be predictive rather than reactive Keywords Assessment tools Á Fisheries with their actions, such as setting catch regulations and management Á Inland fisheries Á Sustainable fisheries initiating enhancement or restoration measures. When assessment is conducted over long time scales (mon- itoring) such data can be used to identify factors related to changes in fishery productivity (e.g., envi- Introduction ronmental degradation or change, effort dynamics; Vaughan et al. 2001). Inland capture fisheries extract fish and other living Perhaps surprisingly, many freshwater fisheries organisms from surface waters inland of the coastline are managed without use of stock assessments, even (Welcomme et al. 2010). Inland fisheries deliver where capacity for data collection and analysis nutritional security and income to hundreds of exists. Management of such fisheries is likely to millions of rural households (Cooke et al. in press). lose out on quantitative information that can They supply protein and essential macro-nutrients support decision making on issues ranging from (Youn et al. 2014) and support livelihoods (Smith et al. the sustainability of fisheries exploitation (Isaac and 2005) through a diverse range of fisheries exploitation Ruffino 1996; Pitcher 2016), to the development of strategies (Welcomme et al. 2010). In 2008, inland effective stocking and harvesting strategies for capture fisheries produced an estimated 10 million enhanced fisheries (Lorenzen et al. 1998a, b)or tonnes of fish and crustaceans (FAO Fishstat 2010— fisheries impacts of agricultural water management see http://www.fao.org/fishery/statistics/software/ in river-floodplain systems (Shankar et al. 2005). fishstat/en). Inland fish resources also provide a wide Many inland fisheries scientists and managers are range of other ecosystem services (Holmlund and unaware of the power of stock assessment methods Hammer 1999; Cowx and Portocarrero 2011; Lynch even in relatively data-limited situations and are et al. 2016). unfamiliar with the methods, data requirements, and Inland fisheries are managed for a variety of options for tailoring such methods to specific objectives and by multiple means. The objectives are problems and contexts. Stock assessment experts, usually related to the types of use as well as socio- on the other hand, are often unaware of the economic factors connected with the associated particular issues involved in applying assessments stakeholders. The means by which this is done include in inland systems. Our aim with this paper is to the management of exploitation (e.g., by catch, fishing break this impasse and inform inland fisheries effort or size limits), the management of fish habitat scientist and managers about their options for stock (e.g., river flow regulation, management of aquatic assessment, and stock assessment scientists about vegetation, etc.), and the use of fisheries enhancements the context of inland fisheries and its implications (e.g., stocking of hatchery fish) (Welcomme et al. for stock assessment approaches. 2010; Arlinghaus et al. 2016). Effective management The development and use of quantitative stock decision making requires knowledge of the state of the assessment methods has been spearheaded in large- fishery relative to management targets or limits, and of scale, commercial marine fisheries that rely on the likely responses of the fishery to alternative extensive and long-term data collection, complex management options. Providing such knowledge, and skill-intensive analytical procedures, clear and uniform performance indicators, and frequent updat- ing of assessments and adjustment of management measure to keep fishing within sustainable limits S. D. Bower Á S. J. Cooke (&) (Beverton and Holt 1957; Hilborn and Walters Fish Ecology and Conservation Physiology Laboratory, 1992). Even though most stock assessment methods Department of Biology and Institute of Environmental Science, Carleton University, Ottawa, ON, Canada are equally suited for use in inland and marine e-mail: [email protected] fisheries (Pitcher 2016), only a small proportion of 123 Rev Fish Biol Fisheries (2016) 26:405–440 407 inland fisheries are being systematically assessed. Stock assessment and management basics Reasons for this are likely to include the much smaller scale of most inland fisheries and the Stock assessment corresponding, relative scarcity of resources and expertise that can be applied to individual inland In a nutshell, stock assessment entails the development fisheries. However, inland fisheries are not simply of mathematical models of the fishery and their equivalent to data- and capacity-poor marine fish- confrontation with data in order to determine how eries, the assessment of which is a very active management practices (i.e., fishing input and output research area (Carruthers et al. 2014; Chrysafi and controls, stocking) and environmental forcing influ- Kuparinen 2016). Rather, inland fisheries pose ence the state of fisheries. The role of models in challenges, but also opportunities for assessment fisheries assessment is threefold: they provide a clear that are different from, and more diverse than those conceptual and mathematical-statistical basis for syn- encountered in large-scale marine fisheries. These thesizing and interpreting information, allow the challenges relate to the nature and diversity of estimation of theory-based reference points such as management objectives, anthropogenic impacts on Maximum Sustainable Yield (MSY) (which cannot be freshwater habitats and fisheries, and tools for directly observed), and predict responses to different managing and enhancing fisheries. Traditional stock management options. Assessment models must be assessment methods may not address the range of confronted with
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