Introduced alien signal crayfish (<i>Pacifastacus leniusculus</i>) in Finland − uncontrollable expansion despite numerous crayfisheries strategies

Ruokonen, Timo; Sjövik, Rosanna; Erkamo, Esa; Tulonen, Jouni; Ercoli, Fabio; Kokko, Hanna; Jussila, Japo

doi:10.1051/kmae/2018016

Cited by 11 publications

(29 citation statements)

References 38 publications

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“…However, signal crayfish has spread throughout other parts of Europe e.g. 2 , 30 , and there is little doubt that many more Italian lakes and streams will be under threat in the future. The high temperature and water scarce in summer, typical of Mediterranean streams, might influence the trophic ecology of this invasive cold-water crayfish species 31 .…”

Section: Introductionmentioning

confidence: 99%

Diet and trophic niche of the invasive signal crayfish in the first invaded Italian stream ecosystem

Ercoli

Ghia

Gruppuso

et al. 2021

Sci Rep

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The occurrence of the signal crayfish Pacifastacus leniusculus in the Valla Stream was the first established population of this invasive species recorded in an Italian stream ecosystem. We evaluated the seasonality of diet and trophic niche of invasive signal crayfish in order to estimate the ecological role and effects on native communities of the stream ecosystem. We studied the differences in food source use between sexes, life stages and seasons using carbon and nitrogen stable isotope analyses. To supplement stable isotope analyses, we evaluated food source usage using traditional stomach content analysis. We tested the hypothesis that juveniles have a different diet, showing different trophic niches, compared to adults. Results indicated that signal crayfish adult and juvenile diets mainly rely on macroinvertebrates and periphyton in summer, shifting to mostly periphyton in autumn. Although the two age classes occupied an equivalent trophic niche, juveniles showed slightly different carbon isotope values, suggesting a somewhat ontogenetic shift consistent among seasons. No significant differences were found in adult and juvenile diets between summer and autumn seasons. Our findings suggest that signal crayfish juveniles and adults exhibited seasonal feeding habits, probably due to ecological behaviour rather than food resource availability, and that both are likely to impose similar effects on macroinvertebrate communities in this and similar stream ecosystems.

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Section: Introductionmentioning

confidence: 99%

Diet and trophic niche of the invasive signal crayfish in the first invaded Italian stream ecosystem

Ercoli

Ghia

Gruppuso

et al. 2021

Sci Rep

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“…Soon after the introduction of P. leniusculus to Fennoscandia, it was discovered that even the most sophisticated stockling production systems might produce P. leniusculus that were carriers of A. astaci (e.g., Makkonen et al, 2010), while some P. leniusculus stocks remained in disease-free status for a while once established from farm raised stocklings. This did not halt the stocking of the disease carrying P. leniusculus into numerous water bodies, even though there were strict national regulations banning introductions of diseased organisms into the wild (e.g., Fiskeriverket, 1993;Ruokonen et al, 2018;Jussila and Edsman, 2020): a case of fisheries administration favoring the distribution of an alien species even if it was suspected or known to carry and spread A. astaci (e.g., Kilpinen, 2003). The relaxed attitude among fisheries administrators, even an attitude that favors alien species over native ones (e.g., Ruokonen et al, 2018;Jussila and Edsman, 2020), is bound to cause devastation of the native crayfish, even when it is already claimed to be vulnerable and threatened, as has been the case in Sweden (Bohman and Edsman, 2011).…”

Section: Promotion Of the Harmful Alien Species Is Not Conservation Of The Native Species: Cases From Fennoscandiamentioning

confidence: 99%

“…The designated area for the introductions of the alien P. leniusculus in Sweden was originally limited to the southeastern part of the country (Bohman et al, 2006). The designated area in Finland was originally only the great lakes in southern Finland, too (Ruokonen et al, 2018). Due to intensive promotion of P. leniusculus as a commercially lucrative species and initial good development of the introduced stocks (e.g., Ackefors, 1999;Kirjavainen and Sipponen, 2004), the illegal introductions of P. leniusculus northwards were commonplace (Bohman et al, 2006;Bohman and Edsman, 2011;Ruokonen et al, 2018).…”

Section: Promotion Of the Harmful Alien Species Is Not Conservation Of The Native Species: Cases From Fennoscandiamentioning

confidence: 99%

“…The designated area in Finland was originally only the great lakes in southern Finland, too (Ruokonen et al, 2018). Due to intensive promotion of P. leniusculus as a commercially lucrative species and initial good development of the introduced stocks (e.g., Ackefors, 1999;Kirjavainen and Sipponen, 2004), the illegal introductions of P. leniusculus northwards were commonplace (Bohman et al, 2006;Bohman and Edsman, 2011;Ruokonen et al, 2018). In Finland, fisheries administration, instead of taking a firm stand against illegal introductions, drafted several crayfishery strategies, which all included the regions of illegal introductions within the newly designated region for P. leniusculus (Ruokonen et al, 2018).…”

Section: Promotion Of the Harmful Alien Species Is Not Conservation Of The Native Species: Cases From Fennoscandiamentioning

confidence: 99%

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Money Kills Native Ecosystems: European Crayfish as an Example

et al. 2021

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Native European crayfish conservation was triggered by invasion of crayfish plague disease agent, Aphanomyces astaci, starting 1860s in Northern Italy. Resulting crayfish plague epidemics quickly spread over Continental Europe, then to Finland, Sweden and finally, after running amok around Europe, A. astaci was discovered also in Iberian Peninsula, Norway, Ireland, and United Kingdom in 1970s and 1980s. By that time significant proportion of native crayfish stocks had been lost, and while crayfish plague epidemics were still recorded, also industrialization and waterways construction were causing damage to remaining native crayfish stocks. While alien crayfish introductions, at least Faxonius limosus, already gave rise to first wave of crayfish plague epidemics in late 19th century, later in 1960s it was decided that introductions of alien Pacifastacus leniusculus should be initiated to replace native European crayfish populations. Decisions were based on presumed advantages for fishery, suitable habitat requirements and supposed immunity against A. astaci. Furthermore, conservation of native European crayfish species was sidelined and focus shifted toward alien crayfish stocking routine and consumption. Alien crayfish species introductions resulted in repeated waves of crayfish plague epidemics among remaining native crayfish stocks. It was soon discovered that alien crayfish of North American origin were, as suspected, permanent reservoirs for A. astaci, that some of those alien species were losing their resistance against selected strains of A. astaci and struggled in European aquatic ecosystems. In this article, we introduce numerous motives behind grand mistake of introducing alien crayfish species to Europe and then promoting their stocks instead of focusing on conservation of native crayfish species. We outline how false economical, biological and ecologic assumptions were used to justify a hasty introduction of alien crayfish, which has further devastated native crayfish and also permanently changed European aquatic ecosystems, both with disastrous consequences. Lesson to be learnt is that science-based warnings about alien species damage to native ecosystems and native crayfish must be taken with utmost caution. Protection of native European crayfish should be core issue, not commercial activities. Finally, we summarize main threats and actions needed to protect remaining native freshwater crayfish fauna in Europe.

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“…Pacifastacus leniusculus is endemic to North America west of the Rocky Mountains and has been introduced to aquaculture facilities in over 20 countries in Europe since 1959. It is now considered to be the most prevalent non-indigenous crayfish species in Europe (Kouba et al, 2015;Ruokonen et al, 2018). All P. leniusculus individuals used in the experiments were collected using baited traps from Gaddesby Brook (Twyford, Leicestershire, UK, 52°68 0 40 0 ' N., -0.9°19 0 95 00 W) during June 2017 ca.…”

Section: Animals Used In the Experimentsmentioning

confidence: 99%

Substrate mediated predator–prey interactions between invasive crayfish and indigenous and non-native amphipods

et al. 2020

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The increasing number of taxa being translocated across the globe is leading to many nonnative species encountering indigenous taxa as well as other non-native species. Environmental heterogeneity may strongly influence the spatial distribution, habitat use and refuge availability for these taxa. Using a series of 24-h mesocosm experiments we examined the predator-prey interactions between an invasive crayfish (Pacifastacus leniusculus) and four amphipod taxa, one indigenous (Gammarus pulex) and three non-native species (Crangonyx pseudogracilis, Dikerogammarus villosus and Gammarus tigrinus) to Great Britain. The potential mediating effect of physical habitat on predator-prey interactions was examined via the use of different substrate particle sizes; cobbles, gravels and, sand. Survivorship of amphipods in response to crayfish predation varied significantly with the highest rates recorded for the non-native species D. villosus, followed by G. tigrinus, and C. pseudogracilis, with the lowest survivorship recorded for the indigenous species G. pulex for all substrates except cobble. However, total biomass consumption of the indigenous G. pulex and the nonnative D. villosus by P. leniusculus were similar suggesting that crayfish may have been satiated by larger D. villosus individuals. Substrate size had a significant influence on the predation success of P. leniusculus, with larger substrate clasts typically resulting in increased survivorship rates for all species except C. pseudogracilis, which displayed lower predation rates for sand substrates. The findings of this study highlight the risks that naïve indigenous taxa may face from new invasive species and the importance of characterising physical habitat (complexity and refugia potential) when considering the potential ecological effects of invaders on predation success.

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Introduced alien signal crayfish (Pacifastacus leniusculus) in Finland − uncontrollable expansion despite numerous crayfisheries strategies

Cited by 11 publications

References 38 publications

Diet and trophic niche of the invasive signal crayfish in the first invaded Italian stream ecosystem

Diet and trophic niche of the invasive signal crayfish in the first invaded Italian stream ecosystem

Money Kills Native Ecosystems: European Crayfish as an Example

Substrate mediated predator–prey interactions between invasive crayfish and indigenous and non-native amphipods

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