Case studies on eradicating the Asiatic cyprinid Pseudorasbora parva from fishing lakes in England to prevent their riverine dispersal

Abstract

ABSTRACT1. The topmouth gudgeon Pseudorasbora parva has proved to be a highly invasive pest fish species in mainland Europe following introduction from Asia, and was first recorded in the wild in the UK in 1996. Distribution has increased markedly since 2002, with recordings now from 32 sites, the majority being lakes.2. In infested UK lakes, populations establish rapidly and become dominant in the fish community (often >97% by number); densities to over 60 m À2 have been recorded, with the majority of individuals 570 mm. The species also hosts a novel pathogen not previously recorded in the UK. It has, therefore, been identified as a significant concern to native fish communities and deserving of an appropriate response by regulatory authorities.3. Where populations have been detected in lakes with connection to river catchments, actions have been taken to prevent riverine dispersal. Control measures are put in place, and eradication programmes designed and initiated. This paper details case studies on three completed eradication operations, two that utilized the piscicide rotenone, the other, de-watering and disinfection.4. Each case study has, so far, been successful in eradicating the topmouth gudgeon population and has resulted in approximately 280 km of river length being protected from their dispersal. Application of rotenone was the most cost-effective eradication method at approximately £2 per m 2 of water area treated. 5. These case studies demonstrate that riverine dispersal of invasive fish from infested connected lakes can be prevented by eradication. Outputs can be used to develop a strategy to manage the increasing distribution of topmouth gudgeon } and other invasive, pest fish } in the UK.

Alien Fish Species in France with Emphasis on the Recent Invasion of Gobies

“…Today, it would be a futile and potentially a controversial exercise to try to eradicate these two species and more generally already established alien fish species because of high expense, difficulty of success, and the likelihood of imposing substantial collateral damage [56,64].…”

“…It still continues today to expand its range, and represent one of the most common alien species in France [49]. Similarly, following its introduction into lakes in the UK in 1996, populations appear to establish rapidly and become dominant in the fish community (often >97% by number) [64]. The reason for its success is its very high reproductive rate, which gives rise to dense populations of fish that compete with fry of other species [65].…”

“…[65]. It was also described that populations of Leucapius delineatus decreased when topmouth gudgeon increased, the latter being a vector of a lethal pathogen for the former [49,64,65]. More generally, their high abundance provokes concerns of detrimental ecological impacts through, for example, high competition for resources such as food and spawning habitat, and they become a pest species to anglers [64].…”

Recreational fisheries in the UK: natural capital, ecosystem services, threats, and management

“…The removal of introduced populations is extremely difficult in most rivers and lakes, although some success has been achieved in England in smaller standing waters from which the invasive cyprinid topmouth gudgeon (Pseudorasbora parva) has been successfully removed by the controlled use of rotenone [59,60]. Nevertheless, the best management option is undoubtedly to prevent undesirable introductions from being made in the first place, and to this end all fish introductions to the UK are now subjected to sophisticated risk analyses [61].…”

Biological conservation of aquatic inland habitats: these are better days

“…With some notable exceptions such as the removal of non-native fish species from relatively small water bodies (Britton et al, 2008), preventative action in the form of biosecurity measures is the only way in which this issue can be managed at a significant scale. Such species introductions can occur entirely accidentally, as is the case with a range of relatively small species such as the diatom Didymosphenia geminate (lyngbye) (Reid et al, 2012) inadvertently transported by water users and other vectors.…”