Fish environmental guilds as a tool for assessment of ecological condition of rivers

Abstract

The form, hydrology and functioning of rivers worldwide have been increasingly modified by a range of human activities. The impacts of these changes on the fish faunas of rivers need to be assessed for biodiversity conservation and fisheries management. Reliable and cost effective indicators of fish assemblage responses to hydrological, morphological and functional changes in a river are required. Given the large number of fish species present in many rivers, reliance on a single indicator species is problematic. The present paper proposes the use of environmental guilds for this purpose. Building on prior studies, we propose a series of environmental guilds based on common patterns of response by fish species to changes in river flow and geomorphology. A general framework consisting of two upland stream guilds, three lowland lentic guilds, four lowland lotic guilds, two generalist guilds and five estuarine guilds is proposed. Considering the large numbers of species present in many river and estuarine systems and the flexibility of their behaviour, many species will be difficult to classify. Further development of the proposed guild classification at the level of individual basins is anticipated, particularly in river systems with highly variable hydrology and many opportunistic species. Nevertheless, this general scheme would be easily and rapidly applied to a wide variety of local circumstance, as well as to the description of the general trends in fish population and assemblage structure occurring during river development.

Influences of environmental and chemical parameters on the spatial growth patterns of four riverine cyprinid fishes

“…Given that fish growth rates have been used widely to assess the influences of anthropogenic activities on aquatic environments (e.g. Harris, 1995;Welcomme et al, 2006), then these data assist assessment of how environmental changes might alter the growth rates of cyprinid fishes against a backdrop of influences of vairables such as temperature (latitude). Indeed, providing that toxicity thresholds are not exceeded then our outputs suggest that the expression of some aspects of the life history traits of these species, such as somatic growth rates, will shift and, potentially, accelerate.…”

“…Spatially, the influence of latitude on water temperature is recognised as a major determinant of fish growth rates in the northern hemisphere (Blanck and Lamouroux, 2007;Lappalainen et al, 2008;Carmona-Catot et al, 2011), with a general pattern of reduced growth with increased latitude due to lower temperatures and shorter growth seasons ( (Blanck and Lamouroux 2007;Lappalainen et al, 2008;Carmona-Catot et al, 2011). Nevertheless, anthropogenic activities that modify physical habitats and water quality can also strongly influence growth rates due to the shifts in geomorphic, hydrologic and chemical characteristics of rivers that result in significant changes in the structure and function of fish communities (Welcomme et al, 2006;Beardsley and Britton, 2012;Britton et al, 2013). Moreover, considerable interspecific differences are often evident (Magalhães et al, 2003;Šimková et al, 2006) with, for example, species such as roach Rutilus rutilus tending to grow faster and dominate lowland river fish communities receiving high nutrient loads (Willemsen, 1980;Beardsley and Britton, 2012), with species such as European barbel Barbus barbus increasing their growth rates and importance in communities as loadings decrease .…”

Factors affecting the distribution of fish during receding flood in lower Irtysh: effects of water level and diurnal cycle

“…Nonetheless, quite many of them always moved in the opposite direction: upstream. Whereas the roles of lateral and two-way migrations of fish in floodplain areas have been studied (Fernandes, 1997;Hohausova´et al, 2003;Welcomme et al, 2006;Nunn et al, 2010;Makrakis et al, 2012), mass upstream migration of juveniles appears unusual. Even though upstream migrations of juvenile fish have been occasionally documented (Yuma et al, 2000;Beckman and Larsen, 2005;Urabe, 2006), their mechanisms and adaptive significance are unclear.…”

“…(Rosso and Quiros, 2009;Jackson et al, 2001;Lucas et al, 2001). It is never static and involves continuous movements, drift and migrations at various scales which change over time (e.g., seasonally) and during the diurnal cycle (Welcomme et al, 2006;. Large floodplain rivers are characterized by particularly complex patterns of fish migrations.…”

“…Fish not only migrate longitudinally (up and down the main channel), but also laterally, i.e. in and out of the river tributaries, floodplain streams and various flooded areas (Welcomme et al, 2006;Nunn et al, 2010;Makrakis et al, 2012). Nonetheless, relatively little is known about the patterns and causes of fish distribution and their movements between the channel and lateral waterbodies (Hohausova´et al, 2003;Nunn et al, 2010).…”