BioInvasions Records (2020) Volume 9, Issue 1: 127–132

CORRECTED PROOF

Rapid Communication Continuing expansion of non-indigenous species in Northern : first established spiny-cheek crayfish limosus (Refinesque, 1817) population in Estonia

Katrin Kaldre*, Tiit Paaver, Margo Hurt and Riho Gross Estonian University of Life Sciences, Institute of Veterinary Medicine and Sciences, Chair of Aquaculture, Kreutzwaldi 46A, 51006 Tartu, Estonia Author e-mails: [email protected] (KK), [email protected] (MH), [email protected] (RG) *Corresponding author

Citation: Kaldre K, Paaver T, Hurt M, Gross R (2020) Continuing expansion of Abstract non-indigenous crayfish species in Northern Europe: first established spiny- First sighting of the non-indigenous spiny-cheek crayfish Faxonius limosus cheek crayfish Faxonius limosus (Refinesque, 1817) in Estonia was registered in October 2017 in the pre-estuary of (Refinesque, 1817) population in Estonia. the Pärnu River which flows into the Baltic Sea. This indicates the continuing BioInvasions Records 9(1): 127–132, expansion of this species in Northern Europe. The detection site is about 70 km https://doi.org/10.3391/bir.2020.9.1.17 from the border of Latvia, a country where F. limosus is already present, but in the Received: 8 April 2019 studied rivers which flow to the Gulf of Riga between the Pärnu River and Latvian Accepted: 22 November 2019 border, no F. limosus was found. This suggests that a human-assisted introduction Published: 6 January 2020 of the species into the Pärnu River is very likely. Handling editor: David Hudson Key words: invasive crayfish, alien crayfish, NICS, , Aphanomyces Copyright: © Kaldre et al. astaci This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International - CC BY 4.0). Introduction OPEN ACCESS. The noble crayfish Astacus astacus (Linnaeus, 1758) is the only indigenous crayfish species (ICS) in Estonia. Until 2008, Estonia was one of the few countries in Europe where non-indigenous crayfish species (NICS) were not recorded (Kaldre et al. 2017). However, a number of NICS have been detected since then: Pacifastacus leniusculus (Dana, 1852) in 2008 (Kaldre et al. 2017), marbled crayfish Procambarus virginalis (Lyko, 2017) in 2018 (Ercoli et al. 2019) and in the current article the first sighting of spiny-cheek crayfish Faxonius limosus (Rafinesque, 1817) is reported. The introduction of NICS is one of the major causes of extinction of ICS in European freshwaters (Holdich et al. 2009). Faxonius limosus is native to the eastern USA and is one of the most common NICS in European inland waters after it was first introduced from into a fish farm pond in Poland in 1890 (Souty-Grosset et al. 2006). By 2014, F. limosus was already present in 20 European countries including Latvia, which is the neighbouring country to Estonia (Kouba et al. 2014). Faxonius limosus inhabits similar environments to ICS (Kouba et al. 2014), but is adaptable to a wide variety of environmental conditions (Holdich et al. 2009). This species

Kaldre et al. (2020), BioInvasions Records 9(1): 127–132, https://doi.org/10.3391/bir.2020.9.1.17 127 First established Faxonius limosus population in Estonia

Figure 1. Updated distribution map of the non-indigenous F. limosus in Europe (Kouba et al. 2014, upper left insert) and its detection sites in Estonia (A). The field sampling sites in the Pärnu River (4–19, 21), Sauga River (1, 2, 3) and Reiu River (20) are indicated by numbers in lower left insert (B), and the sampling locations with only A. astacus detected are represented as black boxes, whereas the empty rings denote that no crayfish were detected. The study sites are in small Estonian rivers that feed the Gulf of Riga between The Pärnu River and Latvian border (C).

is an active migrator (Holdich and Black 2007) and can live and reproduce in brackish waters with salinity up to 10‰ (Leppäkoski and Olenin 2000). NICS of North American (NA) origin are more aggressive, fertile and tolerant to environmental changes than native European crayfish species (Souty-Grosset et al. 2006) and can drive out the native species. NICS most devastating effect on the ICS stocks, however, is that they are chronic carriers of the crayfish plague agent Aphanomyces astaci (Unestam 1972) that is lethal to the ICS in Europe (Alderman et al. 1990). Thus, the F. limosus is a potential threat to the Estonian native noble crayfish populations and its monitoring and prevention of spreading is essential.

Materials and methods The field samplings were carried out in a total of 21 sites in a 4 km section in the pre-estuary of the Pärnu River (catchment area ~ 6800 km2) and its tributaries in the middle of Pärnu City between 2016–2018 in order to monitor the spread of another NICS, P. leniusculus population, which was recorded for the first time in this river in 2016, just within the Pärnu City (Supplementary material Table S1, Figure 1). The field samplings were carried out with cylindrical traps (dimensions 60 × 30 cm and 12 mm mesh

Kaldre et al. (2020), BioInvasions Records 9(1): 127–132, https://doi.org/10.3391/bir.2020.9.1.17 128 First established Faxonius limosus population in Estonia

size) with two entrances (d 5 cm) applied in lines in every 10 meters and kept in the water overnight (~12 hours). Total of 20 traps were applied in every study site, except in study site 5 in 2017 when 30 traps were used. Frozen fish (Rutilus rutilus or Abramis brama, ~ 50–100 g per trap) was used as bait. For every trapping session, catch per unit effort (CPUE) was recorded at each site (Figure 1). In 2018, all small coastal rivers which flow into the Gulf of Riga between the Pärnu River and the Latvian border were studied using the same field sampling methodology as in the Pärnu River to assess the possibility of natural spreading of F. limosus along the coast to the Pärnu River (Figure 1). Six individuals of F. limosus (caught in 2017) were analysed for the presence of crayfish plague agent A. astaci by the quantitative TaqMan® MGB real- time PCR method (qPCR) using the protocol developed by Vrålstad et al. (2009) and an Applied Biosystems 7500 Fast Instrument. Soft abdominal cuticle and uropod tissue samples were collected from each individual from which DNA was isolated by NucleoSpin® Plant II kit. The prevalence of A. astaci and its 95% confidence interval in the studied population was estimated using the function binom.test in the statistical package R 3.5.3.

Results During the field samplings in 2016 16 P. leniusculus were caught from the Pärnu River and one A. astacus was caught from the Sauga River in the middle of Pärnu City (Pärnu County). There were no F. limosus collected in 2016. In 2017, a total of ten individuals of F. limosus with mean total length (TL) of 92.9 mm ± 14.3 SD were caught from four study sites in the Pärnu River (Table S1, Figures 1 and 2). Further field sampling in 2018 confirmed the presence of F. limosus in the Pärnu River, a total of 48 specimens with mean TL of 89.4 mm ± 12.5 SD were caught from five study sites (Table S1, Figures 1 and 2). No F. limosus individuals were found in the study sites in small Estonian rivers that feed the Gulf of Riga between the Pärnu River and the Latvian border (Figure 1). The qPCR based molecular test did not detect any presence of crayfish plague agent A. astaci in tissue samples of six F. limosus specimens collected in 2017. The pathogen prevalence in samples was 0% with 95% confidence interval (0.0%, 45.9%). Thus, due to the small sample size the absence of the pathogen in the Pärnu River samples cannot be considered as a confident evidence for its absence in the whole population.

Discussion The spread of F. limosus in Europe has been fast and seems to continue towards the North. In the Baltic Sea region, it has spread from the Polish coastal waters to Lithuania and Latvia (Pieplow 1938; Burba 2008; Briede

Kaldre et al. (2020), BioInvasions Records 9(1): 127–132, https://doi.org/10.3391/bir.2020.9.1.17 129 First established Faxonius limosus population in Estonia

2017 8 A Female Male 7 6 5 4 3

No of individuals 2 1 0

Total length, mm

2018 8 B Female Male 7 6 5 4 3 2 No of individuals 1 0

Total length, mm Figure 2. The total lengths of female and male F. limosus in the Pärnu River in 2017 (A) and 2018 (B).

2011; Szaniawaska et al. 2017). In this study we recorded the first introduced population of F. limosus in Estonia, which is currently the northernmost country in its distribution range in Europe. The ongoing spread of F. limosus is a combination of natural expansion and human- assisted introductions which may be both deliberate and accidental (Peay and Füreder 2011). In our case, natural migration along the seacoast to the Pärnu River is unlikely as the discovery site in the river mouth is about 70 km from the border of Latvia. Furthermore, we could not detect F. limosus in any of the small Estonian rivers which flow to the Gulf of Riga between the Pärnu River and the Latvian border. However, F. limosus can live and reproduce in the freshwater and brackish waters (Leppäkoski and Olenin 2000); therefore, further studies in the coastal waters of the Baltic Sea between Pärnu and Latvia are necessary. It is very likely that F. limosus could spread to Estonia by illegal human- assisted introductions similar to how the signal crayfish were introduced (Kaldre et al. 2017). Many people cannot discriminate F. limosus from A. astacus because of their similar appearance. This may facilitate non- deliberate import of this alien species despite the fact that F. limosus has no

Kaldre et al. (2020), BioInvasions Records 9(1): 127–132, https://doi.org/10.3391/bir.2020.9.1.17 130 First established Faxonius limosus population in Estonia

commercial value and its introduction poses danger to the ICS. Therefore, it is important to raise public awareness and educate people about the alien crayfish species threat to ICS populations. Not only in Estonia but also in other countries where this is a potential environmental issue. Accidental introduction of F. limosus by ballast water of ships is also possible. In the Pärnu City, there is a large harbour in the estuary of the Pärnu River with intensive international shipping traffic, therefore accidental introduction of F. limosus into the Pärnu River cannot be excluded. The NICS of North American origin are frequently chronic carriers of the crayfish plague, being generally more resistant to infection themselves (Persson and Söderhäll 1983; Alderman et al. 1990). Crayfish plague is the most destructive disease of European native crayfish species as it is highly infectious and can eradicate the whole crayfish population (Cerenius et al. 2009). In the 2017 sample, the analysed individuals of F. limosus from the Pärnu River population did not indicate the presence of A. astaci. However, the possibility that other specimens can spread the crayfish plague cannot be excluded. Proper screening for the presence of crayfish plague agent in NICS populations is warranted to assess the potential threat of NICS to native noble crayfish populations in Estonia. Faxonius limosus is able to adapt easily to different types of environmental conditions and can tolerate low water temperatures (Souty-Grosset et al. 2006). Due to their rapid maturation, short-lifespan, high fecundity and second mating period they have fast population growth and invasive capabilities (Kozák et al. 2006). The maximum total length of female F. limosus in the Pärnu River was 118 and 115 mm, which shows their good growth in Estonian climatic conditions. Due to the similar climatic and habitat conditions to Estonia, further spread of F. limosus by deliberate or accidental human assisted introductions is possible into neighbouring countries like Finland, Sweden and also Russia. The qPCR based molecular test did not reveal any presence of crayfish plague agent A. astaci in tested six F. limosus specimens. However, due to a small sample size, we cannot conclude that the crayfish plague is absent from the Pärnu River population and therefore, a bigger sample sizes are needed to evaluate the prevalence of A. astaci in the F. limosus population in the Pärnu River. Even in the absence of the crayfish plague agent in the Pärnu River, F. limosus is a serious threat to the A. astacus populations because of its biological advantages and migrating activity. The Pärnu River is one of the biggest rivers in Estonia with ~ 6800 km2 catchment area. There are no obstacles to NICS spread in upstream and its tributaries. So far, no good eradication methods of NICS which do not cause environmental contamination or have serious impact on other water biota have been found in the Pärnu River. Only physical control by trapping has been applied so far. New emerging techniques for detecting, controlling and eradicating NICS such as eDNA and others (Manfrin et al. 2019) should be considered for further management actions.

Kaldre et al. (2020), BioInvasions Records 9(1): 127–132, https://doi.org/10.3391/bir.2020.9.1.17 131 First established Faxonius limosus population in Estonia

Acknowledgements

This study was funded by the Estonian Environmental Investment Centre projects “Action Plan for Management and Protection of Noble Crayfish Resources” in 2017 and 2018, and supported by the Estonian Ministry of Education and Research (institutional research funding project IUT8-2 to Riho Gross). We thank the anonymous reviewers whose comments and suggestions helped improve and clarify this manuscript.

References Alderman DJ, Holdich D, Reeve I (1990) Signal Crayfish as vectors in crayfish plague in Britain. Aquaculture 86: 3–6, https://doi.org/10.1016/0044-8486(90)90216-A Briede I (2011) Crayfish in Latvia. Acta Biolica Universitatis Daugavpiliensis 11: 83–87 Burba A (2008) limosus found along the Lithuanian coastal zone of the Baltic Sea. Crayfish News: IAA Newsletter 30(2): 6–7 Cerenius L, Andersson MG, Söderhäll K (2009) Aphanomyces astaci and . In: Lamour K, Kamoun S (eds), Oomycete Genetics and Genomics: Diversity, Interactions and Research Tools. John Wiley & Sons, Inc., Hoboken, NJ, pp 425–433, https://doi.org/10.1002/ 9780470475898.ch21 Ercoli F, Kaldre K, Paaver T, Gross R (2019) First record of an established marbled crayfish (Procambarus virginalis) population in Estonia. Bioinvasions Records 8: 675–683, https://doi.org/10.3391/bir.2019.8.3.25 Holdich DM, Black J (2007) The spiny-cheek crayfish, (Rafinesque, 1817) [Crustacea: : ], digs into the UK. Aquatic Invasions 2: 1–16, https://doi.org/10.3391/ai.2007.2.1.1 Holdich DM, Reynolds JD, Souty-Grosset C, Sibley PJ (2009) A review of the ever increasing threat to European crayfish from non-indigenous crayfish species. Knowledge and Management of Aquatic Ecosystems 11: 394–395, https://doi.org/10.1051/kmae/2009025 Kaldre K, Paaver T, Hurt M, Grandjean, F (2017) First records of the non-indigenous signal crayfish (Pacifastacus leniusculus) and its threat to noble crayfish (Astacus astacus) populations in Estonia. Biological Invasions 19: 2771–2776, https://doi.org/10.1007/s10530- 017-1496-z Kouba A, Petrusek A, Kozák P (2014) Continental-wide distribution of crayfish species in Europe: update and maps. Knowledge and Management of Aquatic Ecosystems 413: 05, https://doi.org/10.1051/kmae/2014007 Kozák P, Buřič M, Policar T (2006) The fecundity, time of egg development and juvenile production in spiny-cheek crayfish (Orconectes limosus) under controlled conditions. Bulletin français de la pêche et de la pisciculture 380–381: 1171–1182, https://doi.org/10. 1051/kmae:2006019 Leppäkoski E, Olenin S (2000) Non-native species and rates of spread: lessons from the brackish Baltic Sea. Biological Invasions 2: 151–163, https://doi.org/10.1023/A:1010052809567 Manfrin C, Souty-Grosset C, Anastácio PM, Reynolds J, Giulianini PG (2019) Detection and Control of Invasive Freshwater Crayfish: From Traditional to Innovative Methods. Diversity 11: 5, https://doi.org/10.1051/kmae/2018007 Peay S, Füreder L (2011) Two indigenous European crayfish under threat - how can we retain them in aquatic ecosystems for the future? Knowledge and Management of Aquatic Ecosystems 401: 33, https://doi.org/10.1051/kmae/2011062 Persson M, Söderhäll K (1983) Pacifastacus leniusculus (Dana) and its resistance to the parasitic fungus Aphanomyces astaci Schikora. Freshwater Crayfish 5: 292–298 Pieplow I (1938) Fischereiwissenschäftliche Monographie von Cambarus affinis Say. Zeitschrift Fischerei 34B: 349–440 Souty-Grosset C, Holdich DM, Noel PY, Reynolds JD, Haffner P (2006) Atlas of crayfish in Europe. Muséum national d’Histoire naturelle, Paris, France, 187 pp Szaniawaska A, Dobrzycka-Krahel A, Jaszczolt J (2017) Spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) on its way to the open coastal waters of the Baltic Sea. Oceanological and Hydrobiological Studies 46: 451–463, https://doi.org/10.1515/ohs-2017-0044 Unestam T (1972) On the host range and origin of the crayfish plague fungus. Report: Institute of Fresh-water Research, Drottningholm 52: 192–198 Vrålstad T, Knutsen AK, Tengs T, Holst-Jensen A (2009) A quantitative TaqMan1 MGB real- time polymerase chain reaction based assay for detection of the causative agent of crayfish plague Aphanomyces astaci. Veterinary Microbiology 137: 146–155, https://doi.org/10.1016/j. vetmic.2008.12.022 Supplementary material The following supplementary material is available for this article: Table S1. The field sampling sites with number of study sites on Figure 1 map, geographic coordinates of sampling sites, CPUE and caught species in a 4 km section in the estuary of the Pärnu River and its tributaries in the middle of Pärnu City during the years 2016–2018. This material is available as part of online article from: http://www.reabic.net/journals/bir/2020/Supplements/BIR_2020_Kaldre_etal_Table_S1.xlsx

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