Morphological responses of a stream fish to water impoundment

Abstract

Water impoundment imposes fundamental changes on natural landscapes by transforming rivers into reservoirs. The dramatic shift in physical conditions accompanying the loss of flow creates novel ecological and evolutionary challenges for native species. In this study, we compared the body shape of Cyprinella venusta collected from eight pairs of river and reservoir sites across the Mobile River Basin (USA). Geometric morphometric analysis of the body shape showed that river populations differ from reservoir populations. Individuals inhabiting reservoirs are deep-bodied and have a smaller head, a more anterior dorsal fin, a shorter dorsal fin base and a more ventral position of the eye than C. venusta in streams. The direction of shape divergence within reservoir–river pairs was consistent among pairs of sites, and the shape of C. venusta in reservoirs is strongly correlated with reservoir size. These findings show that physical characteristics of reservoirs drive changes in the morphological attributes of native fish populations, indicating that water impoundment may be an important, yet largely unrecognized, evolutionary driver acting on aquatic biodiversity.

Shared and unique morphological responses of stream fishes to anthropogenic habitat alteration

“…decreased head depth and increased caudal area) is consistent with morphologies associated with lower sustained swimming abilities and higher burst-swimming performance in lentic habitats [18]. These shape changes were also qualitatively similar to morphological shifts in reservoirs observed by Haas et al [13] and Franssen [14] in C. venusta and red shiner C. lutrensis, respectively. Based on the diversity of fishes investigated here, such a relatively strong, shared response by all species was rather unexpected (habitat explained nearly twice as much variation as basin in the global MANCOVA).…”

Objectively measuring subjectively described traits: geographic variation in body shape and caudal coloration pattern within Vieja melanura (Teleostei: Cichlidae)

“…The main pattern observed regarding body shape variation in V. melanura indicates that specimens from drainages in Belize are significantly distinct from those in Guatemala and México. We hypothesize these morphological shape differences are likely due to differences in habitat variables such as river flow, which has been documented in other groups of fishes (Haas, Blum, & Heins, 2010). The freshwater systems in Belize where this species occurs are smaller and possess more flow than the more expansive and slower flowing (e.g.…”

Swimming and jumping ability of 10 Great Plains fish species

“…Water velocity was found to have altered the height to length ratio of the carapace of the turtle, Pseudemys concinna (Rivera 2008) and also changed growth rates and body condition of freshwater drum Aplodinotus grunniens (Rypel et al 2006). Morphological differences were found in blacktail shiner Cyprinella venusta as lentic individuals had deeper bodies and a shorter dorsal fin base that was located more anterior than lotic individuals (Haas et al 2010). An effort to identify differences in swimming and jumping ability within a species that reside in variable water velocities has not been conducted.…”