Patterns and processes in the drift of early developmental stages of fish in rivers: a review

Abstract

Current-mediated downstream dispersal by the early developmental stages of fish in rivers is a common phenomenon. Knowledge of patterns and processes in the dispersal, or 'drift', of young fishes provides important information on spawning location and spawning success, habitat use, movement paths and flow-ecology relationships more generally, all of which are critical for effective river conservation and management. But despite the importance of such information, our understanding of the patterns and processes of the drift of the early life stages of riverine fishes is limited. Furthermore, riverine fish drift research has tended to occur in isolation from movement studies of other organisms, limiting its integration with higher level concepts and theory. This manuscript reviews the literature on the dispersal of young fishes in running waters. Relevant studies from all climatic zones and geographical regions are investigated, with particular attention given to the types and life history stages of fishes that drift and the seasonal and diel patterns of drifting. We then consider how fish enter the drift and their mode of drifting, attempting to reconcile a long-running discussion, under what we call the 'active-passive conundrum'. We argue that, aside from eggs, the early stages of fish are not exclusively either passive or active drifters, but usually a mixture of the two, which we term 'actipassive' drift. Finally, we evaluate existing knowledge in the context of a general conceptual framework for movement ecology, identifying gaps in our understanding of the roles of internal state, navigation capacity, motion capacity, external factors and internal factors in influencing the dispersal process.

Movement patterns and rheoreaction of larvae of a fluvial specialist (nase, Chondrostoma nasus): the role of active versus passive components of behaviour in dispersal

“…In marine fish ecology, the importance of larval behaviour for dispersal has been recognized during the past decade (Fiksen et al 2007;Gallego et al 2007;Leis 2007), and the need to break "the behavioural black box" has been realized (Pineda et al 2007). Moreover, basic behavioural features of fish larvae have already been successfully incorporated into elaborate 3D models of physical-biological interactions, which have increasingly become an integral tool for understanding larval fish dynamics in the sea (Gallego et al 2007), while in rivers these methods are in their infancy (Schludermann et al 2012;Lechner et al 2016). It has been recognized that certain "longterm" behavioural changes may considerably contribute to larval dispersion -these factors involve environmental stimuli such as odours, sounds and light, time of day, water temperature, salinity, food availability, or ontogeny -and act on time scales of hours, days, and weeks (Pineda et al 2007).…”

“…Minimal knowledge, however, exists on behavioural adaptation operating on scales of seconds to minutes, which responds to temporary "short-term" physical and biological triggers (Pineda et al 2007) or to factors that change rapidly in space (e.g., flow conditions, rheogradients) as fish larvae move. Lechner et al (2016) stated that the behavioural mode of drift or movement is rarely specified in field studies, and only very few studies sought to investigate movement behaviour in flume experiments. The behavioural mode and associated pattern of movement, however, is likely to ultimately determine the actual swimming trajectory, travel speed, and destination of dispersing fish larvae in rivers.…”

“…The behavioural mode and associated pattern of movement, however, is likely to ultimately determine the actual swimming trajectory, travel speed, and destination of dispersing fish larvae in rivers. Knowledge about these features is therefore indispensable when attempting to understand, model, or predict dispersal patterns of fish larvae in rivers and all other kinds of moving waters (Lechner et al 2016). The reduction of characteristic and native riverine fish fauna mainly due to pervasive habitat alteration is a worldwide phenomenon that has been acknowledged for decades (Schiemer and Spindler 1989), but is still ongoing (Moyle and Mount 2007).…”

Modelling the dispersal of riverine fish larvae: from a raster-based analysis of movement patterns within a racetrack flume to a rheoreaction-based correlated random walk (RCRW) model approach

“…Recent studies of fish larvae highlight the impact that active swimming behaviour has on their dispersal patterns in both freshwater (Lechner et al 2014b(Lechner et al , 2016Schludermann et al 2012) and marine environments (Leis 2006;Fisher et al 2000; Leis and Carson-Ewart 1997). Dispersal modes of fish during the crucial larval phase of their life cycle is an important factor in recruitment and is governed by abiotic triggers (e.g., hydrology and hydraulics: Pavlov (1994); and discharge: Lechner et al 2017;Korman et al (2004); Reichard and Jurajda (2004)), in combination with biotic triggers (e.g., physiology and behaviour: Gaudin and Sempeski (2001); Heggenes and Dokk (2001);Pavlov (1994)).…”

“…Willis (2011) suggests that track analysis and track replication within models to understand the factors influencing fish navigation should be a focus of future research. In addition, Lechner et al (2016) have encouraged further research into rheoreaction settlement cues for drifting fish larvae in running waters.…”