Editorial |
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Sudeep Chandra and Almut Gerhardt
Invasive species in aquatic ecosystems: issue of global concern (pp 1-2)
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Research articles |
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Thomas Horvath
Economically viable strategy for prevention of invasive species introduction: Case study of Otsego Lake, New York (pp 3-9)
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The literature is full of examples detailing ecological impacts of invasive species
and predictions of which and where species will invade next. Many fewer examples
of effective prevention strategies are known. Prevention of aquatic invasive species (AIS)
to inland lakes should be easily established because most AIS are initially introduced into
watersheds by recreational boating activities, especially in North America. The Watershed
Management Plan for Otsego Lake, a central New York glacial lake, provides for prevention
of AIS via a stringent boat inspection and washing program (BIP). All boats entering Otsego
Lake at the public launch are visually inspected and those deemed likely to harbor AIS are
required to power wash before launching. However, other sites are available to launch boats.
BIP expenses average $30,000 per year, much of which has been covered by collecting a launch fee.
After implementation of the BIP, only one boat was refused access, and less than 1% required
washing before allowed access, however, zebra mussels (Dreissena polymorpha) and water
chestnut (Trapa natans) have since been found in the lake. The BIP continues to be
supported because other AIS may have been prevented or may be prevented in the future.
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Tore Lindholm, Eeva Rönnholm and Kerstin Häggqvist
Changes due to invasion of Myriophyllum sibiricum in a shallow lake in Åland, SW Finland
(pp 10-13)
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Lake Österträsk, a shallow, 25 ha lake in Åland, SW Finland, was invaded by the common watermilfoil,
Myriophyllum sibiricumKomarov, 1914 (Magnoliophyta: Haloragaceae), in the 1990s. In summer 2006
the dense vegetation, up to 2.5 m tall, richly branching Myriophyllum shoots, caused pH values
of about 10 and oxygen supersaturation near the surface. Deeper layers were hypoxic throughout the season.
The surface water Chlorophyll a values were about 10 µg L-1. Shoot formation from the turions was
temperature dependent and enhanced by nutrient as well as sediment addition. Decaying plants release
nutrients to the water, produce organic sediments, and cause bottom oxygen depletion, changing the chemistry,
nutrient dynamics and plant structure of the lake.
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Tara M. Higgins, Jon M. Grennan and T. Kieran McCarthy
Effects of recent zebra mussel invasion on water chemistry and phytoplankton production in a small Irish lake (pp 14-20)
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Lough Doon is a dual basin lake in the west of Ireland, split into an upper and lower basin
that are morphometrically and physiochemically similar. Zebra mussels (Dreissena polymorpha Pallas, 1771) were introduced
in the lower basin in 1998 and are now well established there. A survey in July 2007 involving scuba dive transects and dredging
revealed a population of 5.5 x 108 zebra mussels (4.9 x 105 kg) in the lower basin, while just 3 zebra mussels were recorded
in the upper basin. To assess the effects of Dreissena infestation on suspended solids, algal production and nutrient
concentrations, near-surface water samples from Lough Doon were analysed from January-July 2007 (n = 12) for selected chemical
and biological parameters. Sampling revealed marked differences in seston load between the two basins, with the infested lower
basin exhibiting significantly reduced concentrations of suspended solids, chlorophyll-a and phytoplankton biovolumes and,
conversely, greater Secchi transparency. Total phosphorus concentrations were lower in the lower basin but concentrations
of ammonium and, particularly, nitrate were significantly higher. Inter-basin differences in Lough Doon mirror the post-invasion
changes observed in other, larger European and North American lakes and reflect the effectiveness of coupled filter feeding-excretion
by zebra mussels in reducing seston load and converting particulate nutrients into soluble forms. The data provide initial evidence
that modest zebra mussel populations can significantly alter water chemistry in a small well-mixed lough, with implications for water
quality management as the zebra mussel continues its rapid range extension in Ireland.
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Bart T. De Stasio, Michael B. Schrimpf, Ashley E. Beranek and William C. Daniels
Increased Chlorophyll a, phytoplankton abundance,
and cyanobacteria occurrence following invasion of Green Bay,
Lake Michigan by dreissenid mussels (pp 21-27)
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The invasion of freshwater ecosystems in North America by the zebra mussel,
Dreissena polymorpha (Pallas, 1769), has repeatedly led to rapid
changes in water clarity and phytoplankton abundance. Examining cases where
a successful invasion has occurred but where rapid changes do not occur can
help us understand the full range of responses of ecosystems to invasions.
We re-sampled established sampling locations in Green Bay, Lake Michigan
during four years of the post-invasion period. We determined Secchi depths,
Chlorophyll-a concentrations, and phytoplankton composition and
biovolume at five stations along a previously documented trophic gradient.
Our data support the continued existence of a strong trophic gradient
between lower and middle bay areas of Green Bay. Secchi depth did not
significantly change following invasion at either lower bay or middle bay
locations. Responses to invasion were stronger at middle bay than lower
bay for both Chlorophyll-a and phytoplankton biovolume.
Chlorophyll-a was significantly greater in the post-invasion period
at both locations, while phytoplankton biovolume was significantly higher
following invasion in middle bay. Along with these increases in abundance
there was a significant shift to higher and more frequent dominance
of the phytoplankton community by cyanobacteria. The increased phytoplankton
abundance during the post-invasion period is likely explained by selective
feeding and increased nutrient recycling by zebra mussels under high turbidity
conditions in this highly productive embayment of Lake Michigan.
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Meghan E. Brown and Melissa A. Balk
The potential link between lake productivity and the invasive zooplankter Cercopagis pengoi in Owasco Lake (New York, USA)
(pp 28-34)
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The fishhook water flea (Cercopagis pengoi Ostroumov, 1891)
is an invasive zooplankter that can decrease the abundance and diversity
of cladocerans and rotifers, which theoretically could release phytoplankton
from grazing pressure and increase algal primary productivity. In the last
decade, C. pengoi established and primary productivity increased
concurrently in Owasco Lake (New York, USA). We studied plankton density,
primary productivity, and standard limnological conditions in Owasco Lake
during summer 2007 (1) to document summer densities of invertebrate predators,
(2) to investigate correlations between C. pengoi and the abiotic environment,
and (3) to examine the relationships among C. pengoi, native zooplankton,
and productivity. Although the maximum abundance of C. pengoi observed
(245 ind./m3) far exceeded that of any native invertebrate predator, at most
locations and dates unimodal density peaks between 35-60 ind./m3 were typical
and comparable to Leptodora kindtii (Focke, 1844), the most common native
planktivore. Abiotic conditions were suitable for growth and reproduction
throughout the sampling period, but were not linearly correlated with
C. pengoi abundance. We observed reciprocal trends between predacious
cladoceran density (both C. pengoi and L. kindtii) and herbivorous
cladoceran density, and between herbivorous cladoceran density and Chlorophyll a
concentration. Although these trends are only corollary, they support the possibility
that C. pengoi may affect the trophy of Owasco Lake by reducing grazing
zooplankton beyond the level of the native planktivores. Further study is needed
to quantify the relative contributions of C. pengoi and L. kindtii
to seasonal changes in the herbivorous cladoceran assemblage.
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Marcy Kamerath, Sudeep Chandra, and Brant C. Allen
Distribution and impacts of warm water invasive fish in Lake Tahoe, USA (pp 35-41)
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In the last 125 years numerous invasive species have been introduced into Lake Tahoe.
In recent years there has been an invasion of warm water fishes including largemouth bass
[Micropterus salmoides (Lacepède, 1802)], and bluegill [Lepomis macrochirus
(Rafinesque, 1820)]. These species threaten to displace and decrease native fish populations,
and reduce nearshore water clarity. It is believed, with the help of climate change increasing
lake temperature, these species are spreading to other areas from established populations
on the south shore. Our objective was to determine current distribution and the potential
impacts of warm water nonnative fishes. Snorkel surveys were conducted bi-weekly from May
to November 2006 and electrofishing was conducted four times within the snorkel survey period
at locations where warm water species are already established. Snorkel surveys and electro-fishing
revealed that 57% of monitored sites contained warm water nonnative fish species. At electro-fish
sites, number of native fish decreased with increasing nonnative fish species. Comparing historical
and current diet data of natives and nonnatives indicated the latter are consuming the same diet
items that native fish consumed historically. As a result, where nonnative and native fish habitats
overlap, predation on and competition with native fish is likely. Current distributions of nonnative
species found during this study are where the next established populations can be expected if their
spread is not controlled.
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Trinidad Ruiz Téllez, Elsa Martín de Rodrigo López,
Gloria Lorenzo Granado, Eva Albano Pérez, Ricardo Morán López and
Juan Manuel Sánchez Guzmán
The Water Hyacinth, Eichhornia crassipes: an invasive plant in the Guadiana River Basin (Spain)
(pp 42-53)
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The recent invasion of water hyacinth Eichhornia crassipes (C. Mart.) Solms (1883)
in the Guadiana River Basin (Spain) is described and the distribution of this Amazonian
floating plant is analyzed from a geobotanical and chorological perspective. Georeferenced
locations of invasion in Spain and Portugal are presented and the relative growth rate (RGR)
and doubling time (DT) indexes defined by Gopal (1987) were calculated. The sexual reproductive
cycles were determined in order to evaluate the invasive capacity at these latitudes.
Predictive models of the plant's potential distribution in the Guadiana River were constructed
based on expert knowledge and using a Geographic Information System, on the basis of the water's
physico-chemical parameters. Given the size of the potential area of distribution, it seems
necessary to make provision for an important increase and subsequent maintenance in the level
of the means and logistics targeted at the prevention and control of this weed.
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Paul Elliott and Philine S.E. zu Ermgassen
The Asian clam (Corbicula fluminea) in the River Thames, London, England (pp 54-60)
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The Asian Clam, Corbicula fluminea (Müller, 1774) invaded British waters in 1998.
It remained confined to an isolated network or rivers in Eastern Britain until 2004,
when it was discovered in low densities in the River Thames, London. We report that
C. fluminea has now been discovered at three more sites on the tidal River Thames.
Surveys indicate that the clam has now established dense populations of up to 648±352 m^-2
at Ham on the River Thames, with evidence of annual recruitment. Given the substantial
connectedness of the Thames to many of Britain’s other rivers, it is likely that C. fluminea
will now continue to spread through Britain’s waterways.
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Scott Santagata, Zita R. Gasiūnaite, Emma Verling,
Jeffery R. Cordell, Karen Eason, Jill S. Cohen, Karolina Bacela,
Gemma Quilez-Badia, Thomas H. Johengen, David F. Reid and Gregory M. Ruiz
Effect of osmotic shock as a management strategy to reduce transfers of non-indigenous species among low-salinity ports by ships
(pp 61-76)
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Open-ocean ballast-water exchange (BWE) is currently the most common
treatment used to reduce the ballast transfer of organisms and the subsequent
risk of invasions among coastal ecosystems. Freshwater or estuarine organisms
remaining after BWE often experience high mortality, due to osmotic shock caused
by high-salinity exposure. We conducted 70 salinity tolerance experiments on
54 different taxa to measure mortality rates of freshwater and estuarine
organisms after exposure to oceanic seawater (34 psu), simulating both
flow-through (F-T) and empty-refill (E-R) BWE methods. We focused especially
on larval and adult crustaceans from freshwater and mesohaline habitats adjacent
to ports of the Baltic Sea, North Sea, Great Lakes, Chesapeake Bay, and San Francisco Bay.
Animals from oligohaline habitats (0-2 psu) experienced the highest mortality:
all individuals died in 82% of the F-T treatments and 88% of the E-R treatments.
The effectiveness of both treatment types decreased with animals from low-salinity
(2-5 psu, 100% mortality in 27% of F-T and 46% of E-R treatments) and mesohaline
habitats (5-18 psu, 100% mortality in 40% of F-T and 52% of E-R treatments).
In 43% of cases among all salinity categories, empty-refill treatments required
less exposure time to cause significant mortality than flow-through treatments.
Invertebrates that exhibited significant survivorship were most often peracarid
crustaceans including widely introduced species of mysid shrimps and amphipods.
Although salinity shock does not completely prevent the transfer of all low-salinity
biota, BWE provides a useful management tool to reduce species transfers,
especially considering the combined effects of removal and mortality.
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Short communications |
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Pietro Genoni and Andrea Fazzone
Barbronia weberi (R. Blanchard, 1897) (Hirudinea: Salifidae), an Asian leech species new to Italy (pp 77-79)
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Barbronia weberi (R. Blanchard, 1897), an Asian leech with records
of introductions to South and North America, Australia, New Zealand and Europe,
was found in two small-size pedemontane streams in North-West Italy (Regione
Lombardia) during macroinvertebrate bioassessment sampling. This is the first
record of the species in this country, where the family Salifidae is not represented.
The species can be distinguished from common native erpobdellids of similar general
habitus by the presence of two accessory ventral pores, three pairs of pharyngeal
stylets and the presence of minute papillae covering the body. Current distribution
and effects of B. weberi on Italian freshwater ecosystems should be determined
through further studies.
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Vitaliy Semenchenko and Tatiana Laenko
First record of the invasive North American gastropod Ferrissia fragilis (Tryon, 1863) from the Pripyat River basin, Belarus
(pp 80-82)
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The invasive North American gastropod Ferrissia fragilis (Tryon, 1863)
has been recorded for the first time in August 2007 at three sites on
the Pripyat River basin (the Belarusian part of the inland European
“central invasion corridor”). This species occurs in the onshore shallow
zone (depth 0.2-0.3 m) with dense aquatic vegetation and temperature from
21.8 to 23.7°C. Maximal abundances of this species have been observed
in Mykashevichy port bay. Most likely, this invasive gastropod entered
the River Pripyat basin from the Ukrainian territory where it was found
early in cooling reservoir of Chernobyl Nuclear Power Station however
invasion pathways though the western (Poland) and ornamental ways are also likely.
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Sergey E. Mastitsky, Frances Lucy and Vladimir G. Gagarin
First report of endosymbionts in Dreissena polymorpha from Sweden (pp
83-86)
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We report the first results of parasitological study of Dreissena polymorpha
(zebra mussels) from Sweden. The samples of Dreissena were collected from Lake Erken
in July 2007. The most common endosymbionts found in the mantle cavity of the mussels
were the commensal ciliate Conchophthirus acuminatus and free-living nematodes
Chromadorina bioculata and Laimydorus sp. Unidentified chironomid larvae
and aquatic mites were also occasionally observed in the mantle cavity. The finding
of host-specific ciliate C. acuminatus suggests that zebra mussels invaded
Lake Erken at the juvenile or adult stage.
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José Luís Pérez-Bote and Joaquín Fernández
First record of the Asian clam Corbicula fluminea (Müller, 1774)
in the Guadiana River Basin (southwestern Iberian Peninsula) (pp 87-90)
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The paper presents the first record of Corbicula fluminea (Müller, 1774)
in the Guadiana River Basin (Iberian Peninsula). This exotic bivalve was found
in June 2006 on the Lacarón and Guadiana rivers with mean density is between
3.3 and 16.9 individuals per squared meter. Population structure and the dates
of the first records suggest that the introductions may have occurred between
2003 and 2004. The potential impact of the invasion on native freshwater bivalves
is discussed along with the need for monitoring and prevention of further
introductions of non-indigenous bivalves in the Iberian Peninsula.
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Luboš Beran
Expansion of Sinanodonta woodiana (Lea, 1834) (Bivalvia: Unionidae) in the Czech Republic (pp 91-94)
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In this paper we have compiled all information on Chinese pond mussel
Sinanodonta woodiana (Lea, 1834) in the Czech Republic. This species
was found in the Czech Republic for the first time in 1996 and altogether
20 records about its occurrence had been obtained till the beginning of 2008.
The species was found in rivers, oxbow lakes and ponds. The expansion is
the most intensive in Southern and Central Moravia, which is likely due
to the fact that it is the warmest part of the country.
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Karolina Bącela, Michał Grabowski and Alicja Konopacka
Dikerogammarus villosus (Sowinsky, 1894) (Crustacea, Amphipoda) enters Vistula – the biggest river in the Baltic basin
(pp 95-98)
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Dikerogammarus villosus (Sowinsky, 1894) has been recorded
for the first time in the Vistula River, the biggest river in Poland
and in the whole Baltic drainage system. Until now the species has been
found in the Bug River that is a tributary of the Vistula. It has migrated
there from the Ponto-Caspian basin through the central invasion corridor
(namely Pripet-Bug canal). Another population of that species has been found
in the Oder River. It came there via the Mittelland Canal from the Rhine River
that had been colonised from the Black Sea basin through the southern invasion
corridor. In the Vistula River, D. villosus co-occurs only with other
Ponto-Caspian gammarids.
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Peter Borza
Recent establishment of the invasive Ponto-Caspian mysid (Hemimysis anomala G.O. Sars, 1907) in the Hungarian part of the Danube River
(pp 99-101)
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The mysid shrimp, Hemimysis anomala G.O. Sars, 1907,
has recently colonized the Hungarian reach of the Danube River.
It has formed self-sustaining populations. The species has been
found in samples collected in September 2004 almost one year
earlier than the first record published.
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Daniel Ahern, Judy England and Adam Ellis
The virile crayfish, Orconectes virilis (Hagen, 1870) (Crustacea: Decapoda: Cambaridae), identified in the UK
(pp 102-104)
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A population of the virile crayfish, Orconectes virilis (Hagen, 1870),
has been recorded within the River Lee system of North London in the United Kingdom.
First detected in 2004 and thought to be the spiny-cheek crayfish, Orconectes limosus
(Rafinesque, 1817), a recent re-examination of the specimens has confirmed that this is
the first recorded breeding population of O. virilis in the United Kingdom.
A monitoring programme is being established to assess the rate at which the species
colonises the catchment and its ecological impact.
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Christoph Chucholl and Thomas Daudey
First record of Orconectes juvenilis (Hagen, 1870) in eastern France:
update to the species identity of a recently introduced orconectid crayfish (Crustacea: Astacida)
(pp 105-107)
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In 2005 a new, non-indigenous crayfish species was discovered
in the Dessoubre River (eastern France). The species was initially
considered as Orconectes rusticus (Girard, 1852). However,
an examination of form I males caught in 2007 revealed that the species
is in fact Orconectes juvenilis (Hagen, 1870), a closely related
congener of O. rusticus. According to our knowledge, this is
the first record of O. juvenilis outside the North American
continent. The ecological implications as well as the possible impact
on the native European crayfish are discussed briefly.
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Javier Oscoz, Rafael Miranda and Pedro M. Leunda
Additional records of eastern mosquitofish Gambusia holbrooki (Girard, 1859) for the River Ebro basin (Spain)
(pp 108-112)
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Since the first authorised introductions to Spain in 1921 of the Eastern
mosquitofish Gambusia holbrooki (Girard, 1859), this North American
freshwater fish species has invaded large parts of several Iberian basins.
For the River Ebro basin, we report 24 new records of this exotic species
between 2005 and 2007 which represents a considerable expansion. Potential
negative implications for aquatic invertebrate and fish communities are discussed.
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