| 1. |
- Berggren, Matz S., 1950, et al.
(författare)
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Invasion routes, current and historical distribution of the Chinese mitten crab (Eriocheir sinensis H. Milne Edwards, 1853) in Sweden.
- 2010
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Ingår i: Aquatic Invasions. - 1818-5487. ; 5:4, s. 387-396
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Tidskriftsartikel (refereegranskat)abstract
- Single specimens of the Chinese mitten crab, Eriocheir sinensis H. Milne Edwards, 1853, have been regularly reported along the western and eastern coasts of Sweden since the 1930´s. The crab has most likely been brought from overseas via the transfer of ship’s ballast water or secondarily introduced from its key European distribution areas. Since 2001 a sharp increase in the occurrence of the mitten crab has been noticed in Swedish inland waters, but the dispersal routes and distribution of the species into Sweden remain poorly known. Here we document the current and historical distribution of the Chinese mitten crab in Sweden and assess possible invasion routes. A special focus is put on the historical occurrence of crabs in Lake Vänern, which empties into the Skagerrak/North Sea and Lake Mälaren, which connects to the Baltic Sea. The existing time series available for the mitten crab from the two lakes shows a large variation in dispersal pattern between different areas within each lake. In order to detect and monitor outbreaks of the mitten crab in Sweden, an internet based reporting system was created in 2007. Museum collections and reports from the general public throughout Sweden were compared with the known occurrence of mitten crabs in Lake Vänern and Lake Mälaren. During the study, the web-based reporting system was not advertised and the general public did not get paid for reporting the information. Population densities of the crab occurred “in peaks” and unevenly over the last decade in both lakes, suggesting a pulse invasion instead of a constant supply by migration. Significant difference in male and female occurrence together with few transport possibilities between lakes suggests different invasion routes for the crabs. Reports from the general public throughout Sweden coincide with the observations from local fishermen in Lake Mälaren and Lake Vänern. Data on occurrence and abundance are discussed in relation to a potential reproduction area on the western coast of Sweden.
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| 2. |
- Deldicq, Noémie, et al.
(författare)
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History of the introduction of a species resembling the benthic foraminifera Nonionella stella in the Oslofjord (Norway): morphological, molecular and paleo-ecological evidences
- 2019
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Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre Oy (REABIC). - 1818-5487. ; 14:2, s. 182-205
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Tidskriftsartikel (refereegranskat)abstract
- Specimens resembling the benthic foraminifera Nonionella stella (Cushman and Moyer, 1930), a morphospecies originally described from the San Pedro Basin, California, USA, were observed for the first time in the Oslofjord (Norway) in 2012. This study investigates the Oslofjord Nonionella population in order to confirm its nonindigenous species (NIS) status and assess its introduction time. Morphological characterisation based on SEM imaging complemented by molecular identification using small subunit (SSU) rDNA sequencing and assessment of the recent past record (sediment core), were performed on material collected in the Oslofjord in 2016. Examination of the dead fauna showed that specimens resembling N. stella only appeared recently in the Oslofjord, confirming the NIS status of this population. Moreover, DNA results indicate that the Oslofjord specimens differ genetically from N. stella sampled in the Santa Barbara Basin (California USA). Hence, we propose to use the name Nonionella sp. T1 for the specimens sampled in the Oslofjord for the time being. In the southern part of the Skagerrak, specimens morphologically similar to Nonionella sp. T1 were reported as NIS in the Gullmar fjord (Sweden) in 2011 and in the Skagerrak in 2015. Molecular data indicate that the two populations from Gullmar- and Oslofjords are identical, based on their SSU rDNA sequences. In addition, analyses of foraminiferal dead assemblages suggest that the population from the Gullmar fjord settled prior to the Oslofjord population, i.e. ~ 1985 and about 2010, respectively. This implies that Nonionella sp. T1 may have been transported from Sweden to Norway by northward coastal currents.
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| 3. |
- Drotz, M. K., et al.
(författare)
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Distribution patterns of the Chinese mitten crab (Eriocheir sinensis H. Milne Edwards, 1853) in Lake Vanern, Sweden
- 2012
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Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre Oy (REABIC). - 1798-6540 .- 1818-5487. ; 7:2, s. 243-249
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Tidskriftsartikel (refereegranskat)abstract
- The catadromous Chinese mitten crab (CMC), Eriocheir sinensis is well known for its extensive invasion routes across the world. However, little is known about both adult and juvenile behaviour after they arrive to a new region. Particularly if the CMC has utilised freight ship ballast tanks as its invasion vector to new freshwater areas like coastal connected larger lakes. The Swedish Lake Vanern, Europe's third largest freshwater lake, offers a suitable study area since only a handful of CMC had been reported between its first record in 1954 and 2004. Hence, the increased catch of of CMC in the mid 2000s was unexpected and provided a rare opportunity to study the initial phase of a biological invasion. Fortunately local fishermen have traditionally, since the mid 1970s, utilised large stationary fish trap nets, evenly distributed from the inlet to the harbour of Lidkoping outward into the main part of the lake. During the peak occurrence in 2005 the traps captured CMC frequently for 90 days starting on August 10. Daily catch increased from September 19th to October 17th. Thereafter the number decreased until November 7th when the last crab was captured. Only one crab out of the 21 caught in the two traps furthest away from the harbour inlet was caught before September 19th. The number of caught CMC differed significantly between the trap nets. Almost half (48.4 %) of all CMC were caught in the two traps closest to the harbour inlet and 41.9% in the second trap-line, consisting of two traps 6 km from the harbour inlet. The remaining crabs were caught in the traps furthest away. Catch pattern from this unique invasion event is discussed in relation to CMC dispersal/migration, invading sample size, behavioural traits and catch efficiency of traps.
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| 4. |
- Granhag, Lena, 1974, et al.
(författare)
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First recordings of the ctenophore Euplokamis sp. (Ctenophora, Cydippida) in Swedish coastal waters and molecular identification of this genus
- 2012
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Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre Oy (REABIC). - 1818-5487 .- 1798-6540. ; 7:4, s. 455-463
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Tidskriftsartikel (refereegranskat)abstract
- The ctenophore Euplokamis sp. was observed and collected in the Gullmar fjord on the west coast of Sweden in April-August 2011 during regular jellyfish and zooplankton monitoring. In April-May 2011, both larval and adult Euplokamis sp. were collected in the surface water of the fjord and in June-August in the deep part of the fjord at 110-100 m. The typical morphological and behavioral characters of Euplokamis sp. were observed (i.e. coiled tentacle side branches and rapid swimming both in forward and reverse). With no published sequence data from the ctenophore family Euplokamidae, molecular identification using the nuclear 18S rRNA gene and internal transcribed spacer region I region (ITS1) revealed that Euplokamis sp. individuals were closely related to the morphologically similar ctenophore family Mertensiidae. Therefore, morphological and molecular data support the identification as Euplokamis. Euplokamis sp. densities in the deep water of the Gullmar fjord in June 2011 reached similar densities as the local ctenophore Beroe spp. The presence of Euplokamis sp. and other ctenophores in the area is discussed together with the importance of continuous monitoring of gelatinous forms to include detection of less frequent and more fragile ctenophore species. We also discuss the importance of molecular identification for ctenophore larvae and adult ctenophores of small size.
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| 5. |
- Katsanevakis, Stelios, et al.
(författare)
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Impacts of invasive alien marine species on ecosystem services and biodiversity: a pan-European review
- 2014
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Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre Oy (REABIC). - 1818-5487. ; 9:4, s. 391-423
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Forskningsöversikt (refereegranskat)abstract
- A good understanding of the mechanisms and magnitude of the impact of invasive alien species on ecosystem services and biodiversity is a prerequisite for the efficient prioritisation of actions to prevent new invasions or for developing mitigation measures. In this review, we identified alien marine species that have a high impact on ecosystem services and biodiversity in European seas, classified the mechanisms of impact, commented on the methods applied for assessing the impact and the related inferential strength, and reported on gaps in available information. Furthermore, we have proposed an updated inventory of 87 marine species in Europe, representing 13 phyla, which have a documented high impact on ecosystem services or biodiversity. Food provision was the ecosystem service that was impacted by the greatest number of alien species (in terms of both positive and negative impacts). Following food provision, the ecosystem services that were negatively affected by the highest number of alien species were ocean nourishment, recreation and tourism, and lifecycle maintenance, while the ecosystem services that were most often positively impacted were cognitive benefits, water purification, and climate regulation. In many cases, marine aliens were found to impact keystone/protected species and habitats. Thirty percent of the assessed species had an impact on entire ecosystem processes or wider ecosystem functioning, more often in a negative fashion. Forty-nine of the assessed species were reported as being ecosystem engineers, which fundamentally modify, create, or define habitats by altering their physical or chemical properties. The positive impacts of alien species are probably underestimated, as there is often a perception bias against alien species. Among the species herein assessed as high-impact species, 17 had only negative and 7 only positive impacts; for the majority (63 species), both negative and positive impacts were reported; the overall balance was often unknown. Although there is no doubt that invasive species have modified marine ecosystems, evidence for most of the reported impacts is weak, as it is based on expert judgement or dubious correlations, while only 13% of the reported impacts were inferred via manipulative or natural experiments. A need for stronger inference is evident, to improve our knowledge base of marine biological invasions and better inform environmental managers.
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| 6. |
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| 8. |
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| 9. |
- Mattila, Johanna
(författare)
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A laboratory study of potential effects of the invasive round goby on nearshore fauna of the Baltic Sea
- 2016
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Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre Oy (REABIC). - 1798-6540 .- 1818-5487. ; 11, s. 327–335-
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Tidskriftsartikel (refereegranskat)abstract
- In the Baltic Sea, species diversity is relatively low and the introduction of new predator species can have large direct and indirect impacts on native species - both prey and potential competitors. The alien round goby Neogobius melanostomus Pallas, 1811 was introduced to the Baltic Sea in the early 1990s and is now well-established. We examined the feeding habits of male round gobies from the Åland Islands, Finland, where round gobies were first recorded in 2011. Specifically, we tested whether small round gobies (≤165 mm TL) showed size and/or species preferences (using Manly's selectivity index) for two abundant bivalve prey items, the blue mussel Mytilus trossulus Gould, 1850 and the Baltic clam Macoma balthica Linnaeus, 1758. When offered two sizes of clams, small round gobies did not show a prey preference. When offered two sizes of mussels, round gobies selected for small mussels (6 - 9 mm) and against large (10 - 13 mm) mussels. When offered both bivalve species and sizes simultaneously (four prey options), round gobies selected for small blue mussels and against large clams. Combined, these results suggest that small round gobies will selectively feed on the preferred prey if available and if not, their feeding will reflect the availability of various prey items in the environment. In addition, round gobies consumed small (≤ 38 mm TL) individuals of the native flounder Platichthys flesus Linnaeus, 1758. Round goby and flounder have the potential to overlap in habitat use and previous literature has suggested a diet overlap between the two; however, this is the first evidence of direct predation on flounder by round gobies.
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| 10. |
- Piccolo, John, 1964-, et al.
(författare)
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A biological risk assessment for an Atlantic salmon (Salmo salar) invasion in Alaskan waters
- 2012
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Ingår i: Aquatic Invasions. - : Regional Euro-Asian Biological Invasions Centre. - 1798-6540 .- 1818-5487. ; 7:2, s. 259-270
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Tidskriftsartikel (refereegranskat)abstract
- We present an event-tree biological risk assessment for a non-native Atlantic salmon (Salmo salar) invasion into Alaskan waters. Atlanticsalmon farming is prohibited in Alaska, USA, but large numbers of them are reared in ocean net-pens in Washinton (WA) USA, and BritishColumbia (BC), Canada. Large numbers of Atlantic salmon escape each year, and they have been recovered in both saltwater and freshwaterin WA, BC, and Alaska. There is limited evidence of successful spawning and rearing in BC, but none from Alaska. No stream-reared smoltsare known to have returned successfully from ocean migrations, but survey efforts for escaped adults and reared juveniles in streams havebeen very limited in time and space. Given recurring, large-scale escape events, propagule pressure could be great enough in any given yearfor a successful invasion. To date, such large numbers of adults have not been recorded ascending Alaskan streams, but again, monitoring isvery limited. Atlantic salmon could most likely successfully spawn and rear in Alaskan streams, so successful ocean migration appears to bethe factor most likely to limit their success. Successful invasion of BC waters, where propagule pressure is greater, followed by a subsequentinvasion of a pre-adapted stock by straying to Alaskan waters, may pose the greatest risk. The lack of adequate surveys, under-reporting ofescapes and recoveries, and inherent ecosystem variation, make it impossible to assign meaningful probabilities to the risk of an invasion ofAlaskan waters. We conclude that the short-term risk of invasion generally appears low, but that it might increase over time. We also notethat invasion is only part of the ecological risk of Atlantic salmon farming in Pacific waters. Disease, parasites, and pollution may also poserisks to local ecosystems – we do not assess these risks here.
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