Size‐Mediated Effects of Water‐Flow Velocity on Riverine Fish Species

Abstract

We applied species sensitivity distributions (SSDs), commonly used in chemical risk assessment, to quantify the impact of water-flow velocity on the presence of fish species in a river. SSDs for water-flow velocity were derived from observational field data (maximal velocity at which species occur, V max ) and laboratory measurements (critical swimming velocity, V crit ). By calculating the potentially affected fraction of the fish species of the river Rhine, effects of water-flow velocity on different life stages and guilds were estimated. V max values for adults were significantly higher than those for juveniles and larvae. At water-flow velocity of 60 cm s À1 , half of the adults were affected, while half of the non-adult life stages were affected at velocities of 25 to 29 cm s À1 . There was a positive correlation between body size and fish tolerance to water-flow. As expected, rheophilic species tolerated higher water-flow velocities than eurytopic and limnophilic species. Maximal velocities measured in littoral zones of the Rhine were, on average, 10 cm s À1 , corresponding to an affected fraction of 2%. An increase in water-flow velocity up to 120 cm s À1 as a result of passing vessels caused an increase in affected species to 75%. For a successful ecological river management, the SSD method can be used to quantify the trait-mediated effects of water-flow alterations on occurring species enabling to compare and rank the effects of chemical and physical stress.

Penja fish (Genus: Sicyopterus) from Karama River, West Sulawesi, Indonesia: Growth Pattern and Habitat Characteristics

“…The slender body will make easiness to hide in the substrate gap from predator attacks, like a fish-eating bird, crab, and shrimp. There is allometric relation between fish body size and water-flow velocity (Hockley et al 2014;Del Signore et al 2016) which interpreted the slender body of Sicyopterus will help to improve the swimming velocity and swimming ability through the rocky substrate. Based on water-flow velocity, four sites on Karama River are classified as low (10-25 cm.s -1 ) to high (>100 cm.s -1 ) current velocities, respectively; 20, 140, 160, and 80.…”

Sensitivity of native and alien freshwater bivalve species in Europe to climate‐related environmental factors

“…For instance, shipping‐induced variability in flow velocity in littoral zones of regulated rivers can be mitigated by replacing groynes by longitudinal training dams (Del Signore et al. , Collas et al. ).…”

“…The habitat suitability of freshwater ecosystems for bivalve species can be optimized using the SSDs to guide the physical reconstruction and management of habitats. For instance, shipping-induced variability in flow velocity in littoral zones of regulated rivers can be mitigated by replacing groynes by longitudinal training dams (Del Signore et al 2016b, Collas et al 2018. At a species-specific level, the same approach can be used to a priori optimize habitats or to mitigate dominance of invasive bivalve species by taking the species-specific sensitivities for environmental conditions into account.…”

Wave and tide‐driven flow act on multiple scales to shape the distribution of a juvenile fish (Albula vulpes) in shallow nearshore habitats

“…It is not surprising then that juvenile fishes exposed to elevated flow velocities exhibit comparatively large *Correspondence: chrishaak@gmail.com Additional Supporting Information may be found in the online version of this article. reductions in prey capture success (Flore and Keckeis 1998), greater rates of flow refuging Johansen et al 2008), and can be disproportionately affected by extreme flow events (Lassig 1983;Del Signore et al 2014). Collectively, these impacts may lead to the exclusion of smaller fishes from wave-or current-swept environments (Sagnes et al 1997;Depczynski and Bellwood 2005;Eggertsen et al 2016), placing major constraints on habitat utilization.…”

“…Small fishes achieve lower absolute swimming speeds than larger‐bodied individuals, limiting the water velocities they are capable of negotiating (Brett ; Beamish ), and are subject to disturbance by a broader range of turbulence scales, increasing their susceptibility to the destabilizing effects of unsteady flows (Lupandin ; Webb et al ). It is not surprising then that juvenile fishes exposed to elevated flow velocities exhibit comparatively large reductions in prey capture success (Flore and Keckeis ), greater rates of flow refuging (Fulton and Bellwood ; Johansen et al ), and can be disproportionately affected by extreme flow events (Lassig ; Del Signore et al ). Collectively, these impacts may lead to the exclusion of smaller fishes from wave‐ or current‐swept environments (Sagnes et al ; Depczynski and Bellwood ; Eggertsen et al ), placing major constraints on habitat utilization.…”