An ecomorphological framework for the coexistence of two cyprinid fish and their hybrids in a novel environment

Abstract

Niche variation between hybrid taxa and their parental species has been deemed imperative to the persistence of hybrid populations in nature. However, the ecological factors promoting hybrid establishment remain poorly understood. Through the application of a multidisciplinary approach integrating genetics, morphometry, life- history, and trophic ecology, we studied the hybrids of roach (Rutilus rutilus L.) and bream (Abramis brama L.), and their parental species inhabiting an Irish lake. The roach ¥ bream hybrid exhibited a body shape intermediate of that of the parental species. Diet analyses depicted the hybrid as a generalist, feeding on all prey items consumed by either parental species. Stable isotope data confirm the trophic niche breadth of hybrids. A significant correlation between body shape and diet was detected, suggesting that the intermediate phenotype of hybrids might play a role in their feeding abilities, resulting in the utilization of a broader trophic spectrum than the parental species. Growth and age class structure analyses also yielded a scenario that is consistent with the ecological success of hybrids. Genetic analyses suggest that the majority of hybrids result from first-generation crosses between the parental species; however, a potentially significant proportion of back-crosses with bream were also detected. The recent introduction of roach and bream into Irish waters, as well as the climatic and ecological features of the colonized habitats, can explain the remarkable success of the roach ¥ bream hybrid in Ireland. The adaptive significance of hybridization and its demographic consequences for the parental species are discussed

Does invasive Chondrostoma nasus shift the parasite community structure of endemic Parachondrostoma toxostoma in sympatric zones?

“…[19-21]) and some of them form hybrid zones [22,23]. In cyprinids, several previous cases involving introduction of new species have led to the endangerment of native species.…”

Use of geometric morphometrics to identify ecophenotypic variation of juvenile Persian sturgeon <em>Acipenser persicus</em>

“…Several studies have stated that body shape should be attributed to genetic differences and environmental effects (Albertson et al 2003, Toscano et al 2010, Cadrin 2014. Although gene flow between the western and eastern stocks of Persian sturgeon in the Iranian waters of the Caspian Sea (Khoshkholgh et al 2011) occurs, our findings showed that juvenile sturgeon from the different regions were well segregated by body shape analysis.…”

Trophic dynamics within a hybrid zone - interactions between an abundant cyprinid hybrid and sympatric parental species

“…Previous authors have reported similarities in diet between hybrids and both roach (Fahy et al, 1988) and bream (Cowx, 1983), although a recent account indicated that hybrids may exhibit a broader trophic niche than either roach or bream in eutrophic conditions (Toscano et al, 2010). In spite of this, evidence of trophic interactions within the hybrid zone remains sparse, and this study is the first to incorporate a multisystem sample design to investigate trophic ecology.…”