Editorial. Bridging the gap between fish behaviour, performance and hydrodynamics: an ecohydraulics approach to fish passage research

Kemp, Paul S. (2012) Editorial. Bridging the gap between fish behaviour, performance and hydrodynamics: an ecohydraulics approach to fish passage research. [in special issue: Fish passage: an ecohydraulics approach] River Research and Applications, 28 (4), 403-406. (doi:10.1002/rra.1599).

Record type: Editorial

Abstract

Development of the world's rivers has long been associated with the disruption of ecological processes and degradation of physical and chemical habitat quality. A substantial and growing literature documents large-scale environmental impact associated with the construction of physical barriers such as dams and road crossings. One of the dominant effects of these barriers is the obstruction and delay of movements of aquatic biota. The resulting fragmentation of habitats leads to a broad-scale reduction in habitat quality and ultimately to the loss of diversity and abundance both upstream and downstream of the barrier.

Mitigation technology and strategies to ameliorate these impacts are widely employed and include provision of alternative routes of migration (e.g. fishways), transportation systems that carry fish past obstructions, screens that divert fish to less hazardous areas, hatcheries intended to compensate for lost natural production or in some cases the removal of the offending structure. Mitigation is not always successful, however, and efficiency of the approach adopted often fails to meet management objectives. As a consequence, ecological condition deteriorates, and population abundance and resilience continue to decline.

There may be several explanations for these failures. Mitigation options are not always considered during the design and planning phase of projects and hence if applied then retrospectively are sometimes based on a process of ‘trial-and-error’ (Kemp et al., 2008, Williams et al., 2012). As a result, efficiency is dictated by site-specific characteristics (Bunt et al., 2012) and can be highly variable. Even when the requirement to mitigate for environmental impacts is recognized at the planning stage, socio-economic factors may impede or prevent application of appropriate solutions. The primary cause for ineffective mitigation, however, is perhaps due to a lack of understanding of biological motivators, cues and constraints and lack of meaningful performance evaluations of structures once they are built (Bernhardt et al., 2005; Castro-Santos et al., 2009; Palmer et al., 2005).

This special edition presents the results of an initiative to advance understanding of fish behaviour and performance in relation to hydrodynamics, a first step to improving fish passage design for multiple species. A network of international participants funded by the Leverhulme Trust was formed with the aim to bridge five key gaps to address the challenge posed. These gaps were (1) between disciplines, including the behavioural ecology of fish, fluid dynamics and engineering; (2) between approaches and methodologies, for example, empirical experimental and field-based research and modelling; (3) between theoretical and applied science; (4) among regions, with participants representing North and South America, Europe and Asia; and (5) among generations, with senior researchers working closely with those in the early stages of their career. The network held three annual workshops in Southampton (UK, 2008), Nashville (USA, 2009) and Winnipeg (Canada, 2010), during which an interdisciplinary ecohydraulics-focused approach was adopted to identify current and future challenges in river restoration, concentrating mainly on fish passage. Some of the results of the meetings are presented in this special edition as a series of papers that highlight the challenges identified and provide recommendations for potential solutions.

This record has no associated files available for download.