Phenotypic plasticity in the spawning traits of bigheaded carp (Hypophthalmichthys spp.) in novel ecosystems

Abstract

Summary 1. Bigheaded carp, including both silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp, are successful invasive fishes that threaten global freshwater biodiversity. High phenotypic plasticity probably contributes to their success in novel ecosystems, although evidence of plasticity in several spawning traits has hitherto been largely anecdotal or speculative. 2. We collected drifting eggs from a Midwestern U.S.A. river from June to September 2011 and from April to June 2012 to investigate the spawning traits of bigheaded carp in novel ecosystems. 3. Unlike reports from the native range, the presence of drifting bigheaded carp eggs was not related to changes in hydrological regime or mean daily water temperature. Bigheaded carp also exhibited protracted spawning, since we found drifting eggs throughout the summer and as late as 1 September 2011. Finally, we detected bigheaded carp eggs in a river reach where the channel is c. 30 m wide with a catchment area of 4579 km2, the smallest stream in which spawning has yet been documented. 4. Taken with previous observations of spawning traits that depart from those observed within the native ranges of both bighead and silver carp, our findings provide direct evidence that bigheaded carp exhibit plastic spawning traits in novel ecosystems that may facilitate invasion and establishment in a wider range of river conditions than previously envisaged.

Quantification of eDNA shedding rates from invasive bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix

“…Samples were run using the appropriate species' primer/probe set (Coulter et al, 2013). Primer/probe sets were initially tested using DNA extracted from both tissue and environmental (water) samples, and sequencing of amplification product verified their specificity.…”

Phenotypic Shifts in Life History Traits Influence Invasion Success of Goldfish in the Yarlung Tsangpo River, Tibet

“…Predicting the potential spread of invasive species remains a core goal in conservation biology (Vander Zanden and Olden 2008), and life history traits continue to show utility in this regard (Feiner et al 2012;Coulter et al 2013). Our study suggests that shifts in the timing of spawning and growth rates play an important role in the invasion success of Goldfish in extreme cold climates.…”

Trophic ecology and persistence of invasive silver carpHypophthalmichthys molitrixin an oligotrophic South African impoundment

“…The latter may indicate a level of phenotypic plasticity that is not considered in previous modeling approaches (Cooke 2015). Hypophthalmichthys molitrix have been observed to spawn at the confluence of the Elands and Olifants River in FBD (Brits 2009) (Figure 1), and this represents one of the few cases that H. molitrix has been observed to spawn in small and short rivers (see also Aliev 1976 andCoulter et al (2013)). …”

“…Although H. molitrix can persist in lotic environments (Kolar et al 2007), they are incapable of maintaining self-sustained feral populations in isolated reservoirs without continuous stocking, as observed in other impoundments (Spatura and Gophen 1985, Kamilov 2014, Gophen and Snovsky 2015. Their specialist planktivorous diet further suggests that they are incapable of persisting in environments with low algal biomass, such as the Laurentian Great Lakes of North America The recruitment success of H. molitrix is associated with access to long (> 80 -100 km) freeflowing rivers with a suitable hydrology (Kolar et al 2007, Kocovsky et al 2012), although differences in spawning requirements (phenotypic plasticity) between their native and invaded ranges have recently been observed in several studies (Kocovsky et al 2012, Coulter et al 2013, Deters et al 2013, reviewed in Cooke 2015. Irrespectively, H.molitrix developed an atypical, persistent and reproducing population in an oligotrophic impoundment in South Africa (Brits 2009, Lübcker et al 2014) with limited access to rivers considered suitable for spawning ( Figure 1).…”