Consistency in the life history traits of four invasive pseudorasbora parva populations in Southern England

Abstract

Life history plasticity can be a strong predictor of the establishment and invasion success of introduced fishes. Here, the life‐history traits of four P. parva populations in adjacent ponds in Southern England were measured throughout 2013 to determine the timing and length of their reproductive season and the extent of trait plasticity. The relative abundance of the populations (as catch per unit effort) was similar, with low variability in their traits relating to reproductive effort and somatic growth. All the populations were male dominated. Both sexes matured at small body sizes, with fish as small as 30 mm being mature in both sexes, with the age at maturity for both sexes being age 1+ years. The peak spawning period, characterised by female fish investing heavily in reproduction when their gonado‐somatic index (GSI) values were highest and declined thereafter, occurred in May and June, and after a mean of 212 ± 24 degree‐days >12°C, and with water temperatures being 13.2–14.6°C. There were no further peaks in GSI, despite the species being considered to have prolonged spawning periods across spring and summer. These results also suggest that whilst the expression of life‐history traits of invasive fishes often vary with density, they can be highly consistent between populations at similar abundances and locations.

Population structure and dietary plasticity of four invasive populations of the topmouth gudgeon Pseudorasbora parva

“…However, individuals belonging to older age classes (2+, 3+, 4+, and 5+) were caught in decreasing numbers, representing the natural mortality within populations. All sampled populations, except one, had a sex ratio biased towards males, as also found for invasive populations in England (Britton et al, 2007; Davies & Robert Britton, 2021). However, it should be stressed that for the population with the most unbalanced sex ratio (Firenze), only males were caught during the summer, leveraging the extreme sex ratio found.…”

“…The long reproductive period starts as early as April and lasts at least until late June. Previous studies showed that the annual gonadic cycle of P. parva has usually only one seasonal reproductive peak, corresponding to the warmest period of the year, but this period is considerably prolonged in both sexes, confirming a long reproductive season for this species, which also includes multiple depositions (Davies & Robert Britton, 2021; Gozlan et al, 2010; Záhorská & Kováč, 2009). Nevertheless, earlier spawning in spring and later spawning in autumn is not uncommon (Gozlan et al, 2010).…”

“…According to previous studies (Davies & Robert Britton, 2021; Záhorská & Kováč, 2009), P. parva typically reaches sexual maturity at age of 1 year or older. The pattern of GSI values we observed across age classes in our study sites supports this finding (Supporting Information: Figure ).…”

Fish Assemblage Shift after Japanese Smelt (Hypomesus nipponensis McAllister, 1963) Invasion in Lake Erhai, a Subtropical Plateau Lake in China

“…Topmouth gudgeon is an omnivorous fish [52][53][54], which feeds mainly on zooplankton and benthic animals in Lake Erhai [61]. The reproduction of the Japanese smelt population in Lake Erhai occurs mainly from January to April [47], which is earlier than that of the topmouth gudgeon [62]. Like most other fishes that have a zooplanktivores stage in their early life history [56], the full utilization of food during the reproductive stage of the Japanese smelt may reduce the growth of the topmouth gudgeon.…”

Morphological variability in a successful invasive species originating from habitats experiencing different levels of disturbance

“…Non-native fish species can change receiving ecosystems through, e.g. increased predation pressure and competition for resources that can lead to shifts in ecosystem function and alteration of food webs (Gozlan et al 2010, Davies & Britton 2021). However, not all newcomers impose such changes, therefore, it is important to determine the traits that predict them to become successful invaders.…”