Recruitment and abundance of an invasive fish, the common carp, is driven by its propensity to invade and reproduce in basins that experience winter-time hypoxia in interconnected lakes

Abstract

Although the common carp is globally distributed, it only reaches extreme densities in certain regions. We hypothesized that this phenomenon might be linked to recruitment bottlenecks which carp overcome where environmental conditions create unstable peripheral areas that it can access for spawning and nursery habitat. To test this hypothesis, the abundance, movement and reproductive success of carp was determined in two systems of inter-connected lakes in the North American Midwest whose shallow basins frequently experience winterhypoxia ('winterkill'). Radio-tracking demonstrated that while adult carp overwinter in deep lakes that do not winterkill, they aggressively move into winterkill-prone shallow regions in the spring to spawn. The significance of this behavior was demonstrated by ageing analyses which found that carp recruit only in interconnected shallow lakes and then only in years following severe winter hypoxia. Presumably this strategy allows carp to exploit nursery habitat that is relatively free of predators. It likely evolved in response to seasonally variable conditions in the carp's native habitat in the Ponto-Caspian region. This life history may also explain the carp's abundance in other unstable regions such as southern Australia and could potentially be exploited to control this damaging invasive.

Age determination in common carp Cyprinus carpio: history, relative utility of ageing structures, precision and accuracy

“…Flower 1935;Einsele 1956), hence in habitat conditions that are likely to differ profoundly from those of populations in the wild. Also, findings about carp longevity in some cold-climate water bodies of North America (Köppen-Geiger climate class D: Peel et al 2007), albeit most likely not as pronounced as that of some marine species, are relatively recent (Bajer and Sorensen 2010) and may have therefore been responsible for the lack of adoption (as originally suggested by Vilizzi 1997) of the more advanced methods of otolith sectioning (possibly coupled with bomb radiocarbon dating) in this species so far.…”

“…Black et al 2005;Tracey et al 2016). With regard to longevity, estimated ages of 35 (Bajer and Sorensen 2010) and 23 years (Brown et al 2003) have been reported for carp based on otolith sections, although the oldest (mark-recapture validated) age using this method has been up to 14 years ). On the other hand, published otolith-based age-growth data on carp have so far been limited to the 1-19 years old range (Vilizzi and Copp 2017), indicating the need for further research (especially regarding validation) into this ageing method.…”

“…With regard to the otolith and vertebra, the former was found to be more useful in a comparative study (Phelps et al 2007), whereas in another study both structures were considered of similar utility (Yılmaz and Polat 2008). On the other hand, the majority of (recent) studies focusing on the use of otoliths alone have been able to age successfully carp with estimated (albeit not validated) ages over 20 years (Brown et al 2003;Bajer and Sorensen 2010), even though there have been disagreements as to the value of using either whole or sectioned asterisci. In this respect, confidently and successfully aged carp using otolith sections, hence without facing the problems relating to the crowding of annuli at the edge (in older fish) as emphasised in other studies (Vilizzi and Walker 1999;Winker et al 2010).…”

Attracting Common Carp to a bait site with food reveals strong positive relationships between fish density, feeding activity, environmental DNA, and sex pheromone release that could be used in invasive fish management

“…First, we knew from an ongoing mark–recapture study using electrofishing that it contained ~2,900 adult Common Carp (95% CI: 1,915–3,857) (Swanson, 2017), with a total biomass of about 150 kg/ha, a relatively modest, but not atypical density of Carp (Bajer & Sorensen, 2010, 2012), Second, the plant, animal, and fish communities in Lake Steiger (http://www.dnr.state.mn.us/lakefind/lake.html?id=10004500) are typical of other lakes in the Upper Mississippi River Basin. Third, aquatic habitat in the lake is also relatively typical and uniform with floating patches of cattail marsh and a heavy infestation of Eurasian milfoil.…”

“…A previous study showed that this approach (“Judas fish”) can be used to accurately describe overall Carp distribution and abundance (Bajer, Chizinski, & Sorensen, 2011). We re‐located these Carp 3 weeks later from a small boat using radio‐telemetry (manual bi‐angulation, a technique with an accuracy of about 20 m; Bajer & Sorensen, 2010) to confirm their health (all survived) and to pick a site that lacked Carp that could be used as a bait site. We selected the northern corner of the lake as a bait site.…”