Research articles |
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Mads S. Thomsen, Peter A. Staehr,
Cecilia D. Nyberg, Steen Schwærter, Dorte Krause-Jensen and
Brian R. Silliman
Gracilaria vermiculophylla (Ohmi) Papenfuss, 1967
(Rhodophyta, Gracilariaceae) in northern Europe, with
emphasis on Danish conditions, and what to expect in the
future (pp 83-94)
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Gracilaria vermiculophylla, a red macroalga from the West
Pacific, was discovered in western Germany (the Wadden Sea) in
2002 and has since also been observed in Sweden (from about 70
km south to about 80 km north of Göteborg), Denmark (Wadden Sea,
Horsens Fjord, Limfjorden, Vejle Fjord, Holckenhavn Fjord, Øster
Hurup Harbor) and eastern Germany (Kiel Bay). Today, less than 5
years following its first observation in the Wadden Sea the
invader is common in many invaded regions, often being amongst
the most abundant macroalgal species. G. vermiculophylla
is successful in shallow protected soft-bottom estuaries and
bays, typically in association with ubiquitous native
invertebrates (lugworms, tube-building worms, mussels, cockles,
snails). The invertebrates provide substratum for holdfast
attachment and thalli incorporation, most likely increasing the
stability of local G. vermiculophylla populations. We
hypothesize that this substratum provision is highly important
for its general invasion success. We also confirm that G.
vermiculophylla can maintain growth at all salinities
experienced along Danish coastlines (8.5-34 psu). In addition,
laboratory experiments indicate that the ubiquitous grazer
Littorina littorea has the potential to control G.
vermiculophylla growth under specific environmental
conditions, but also that L. littorea may facilitate
small-scale dispersal within invaded locations, because grazing
increases thalli fragmentation rates. Given its widespread
distribution, rapid range expansion, and known ecological
traits, G. vermiculophylla is clearly a permanent
resident of northern European waters.
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Paraskevi Louizidou, Maria
Thessalou-Legaki and Argyro Zenetos
First record of the Red Sea immigrant Chrysallida
fischeri (Hornung and Mermod, 1925) (Gastropoda:
Pyramidellidae) from Greek waters
(pp 95-98)
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The Red Sea mollusc Chrysallida fischeri (Hornung and
Mermod, 1925) was collected in 2005 off Makri, Rhodes, Greece.
This is the first record of the species in the Aegean Sea. The
presence of both live specimens and shells suggest that C.
fischeri is well established in the area.
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Momir Paunović, Bela Csányi, Slobodan
Knežević, Vladica Simić, Draženko Nenadić, Dunja
Jakovčev-Todorović, Bojana Stojanović and Predrag Cakić
Distribution of Asian clams Corbicula fluminea (Müller,
1774) and C. fluminalis (Müller, 1774) in Serbia (pp 99-106)
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Among numerous recently introduced species in Serbian waters,
two new mussel taxa were detected. The aim of this paper is to
present the current distribution of two morphotypes of the
Asiatic clam - Corbicula fluminea (Müller, 1774) and
C. fluminalis (Müller, 1774), in order to discuss pathways
of dispersal and reasons for successful adaptation. According to
our results, the morphotype C. fluminea is better adapted
to local environmental conditions, while C. fluminalis
has rarely been found in Serbia. At present, Asiatic clams are
widespread within potamon-type rivers that are under the
influence of hydromorphological alterations and exposed to
intensive ship traffic. The distribution of Corbicula, as
well as some other alien aquatic invertebrate taxa (Branchiura
sowerbyi, Anodonta woodiana, Orconectes limosus),
indicate that heavily modified waterways are suitable recipient
areas for species introduction and adaptation. Corbicula
gen. sp. is a characteristic taxa for Pleistocene interglacial
deposits in the Pannonian Plain. The comparison between
Pleistocene and recent taxa is necessary in order to categorize
Corbicula as either introduced or reintroduced taxa.
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Gordon H. Copp, Keith J. Wesley, Hugo
Verreycken and Ian C. Russell
When an ‘invasive’ fish species fails to invade! Example
of the topmouth gudgeon Pseudorasbora parva (pp 107-112)
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A major problem in evaluating biological invasions is the lack
of information on failed non-native species introductions, with
invasiveness determined purely on establishment successes. This
is the case of topmouth gudgeon Pseudorasbora parva, an
Asiatic cyprinid fish that now occurs throughout most of Europe
and is said to be highly invasive. Although the species has
established itself in many locations, and often in high
densities, not all topmouth gudgeon invasions are successful. In
this brief communication, the appearance and disappearance
(following pond drain down and repeated electrofishing
depletion) of topmouth gudgeon Pseudorasbora parva from a
small pond in northeast London (England) is described, along
with two other cases elsewhere in Europe.
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Gordon H. Copp, Luke Moffatt and Keith
J. Wesley
Is European catfish Silurus glanis really becoming
more abundant in the River Thames?
(pp 113-116)
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An increased number of reports (by anglers, in the angling
press) of European (wels) catfish Silurus glanis
occurrences in the River Thames (England) has led to the
perception that the species has become more abundant in that
river. If proved true, then this would have ramifications for
non-native species policy and practice. To assess catfish
density, a total of 256 rod hours of specialized angling
(‘clonking’) was undertaken during both day and night between 17
and 21 July 2006 at numerous sites within six sectors of the
River Thames. No European catfish were captured, which suggests
that European catfish remains a rare species in the River
Thames, providing no corroboration of anecdotal reports of
increased abundance.
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Özcan Gaygusuz, Ali Serhan Tarkan and
Çiğdem Gürsoy Gaygusuz
Changes in the fish community of the Ömerli Reservoir
(Turkey) following the introduction of non-native gibel carp
Carassius gibelio (Bloch, 1782) and other human
impacts (pp 117-120)
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Changes in the relative density (catch per unit effort; CPUE) of
introduced gibel carp Carassius gibelio (Bloch, 1782) and
native fish species were monitored over four years in the Ömerli
Reservoir, a temperate drinking-water reservoir in northwestern
Turkey. Following the species’ introduction, the CPUE of gibel
carp increased significantly with the decrease in CPUE of
large-bodied native fish species.
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John M. Drake and David M. Lodge
Hull fouling is a risk factor for intercontinental
species exchange in aquatic ecosystems
(pp 121-131)
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Anthropogenic biological invasions are a leading threat to
aquatic biodiversity in marine, estuarine, and freshwater
ecosystems worldwide. Ballast water discharged from transoceanic
ships is commonly believed to be the dominant pathway for
species introduction and is therefore increasingly subject to
domestic and international regulation. However, compared to
species introductions from ballast, translocation by biofouling
of ships’ exposed surfaces has been poorly quantified. We report
translocation of species by a transoceanic bulk carrier
intercepted in the North American Great Lakes in fall 2001. We
collected 944 individuals of at least 74 distinct freshwater and
marine taxa. Eight of 29 taxa identified to species have never
been observed in the Great Lakes. Employing five different
statistical techniques, we estimated that the biofouling
community of this ship comprised from 100 to 200 species. These
findings adjust upward by an order of magnitude the number of
species collected from a single ship. Thus, overall invasion
risk from biofouling may be comparable or exceed that of ballast
water discharge.
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Mélanie Beguer, Michel Girardin and
Philippe Boët
First record of the invasive oriental shrimp Palaemon
macrodactylus Rathbun, 1902 in France (Gironde Estuary)
(pp 132-136)
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During summer 2006, the first specimens of the oriental shrimp
Palaemon macrodactylus Rathbun, 1902 were identified in
the Gironde Estuary (France). These specimens, which included
ovigerous females, are confirmed present throughout a large part
of the estuary, in large numbers compared to the local resident
shrimp Palaemon longirostris Milne Edwards, 1837. Native
to Asia, P. macrodactylus was first introduced in
California (USA) in the 1950s, before being detected recently
within several European estuaries, e.g. the Guadalquivir Estuary
(Spain) and the Orwell Estuary (England). According to these
records, P. macrodactylus appears to be a strong invader,
able to colonise a wide geographical range.
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Sandra Kube, Lutz Postel, Christopher
Honnef and Christina B. Augustin
Mnemiopsis leidyi in the Baltic Sea – distribution
and overwintering between autumn 2006 and spring 2007 (pp 137-145)
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In autumn 2006 the first observations of the West Atlantic comb
jelly Mnemiopsis leidyi in Northern Europe were reported
from the North Sea, the Skagerrak and the south-western Baltic
Sea. Here we report on the further spread of this invasive
ctenophore from the south-western towards the central Baltic Sea
up to the south eastern Gotland Basin during autumn/winter 2006
and spring 2007. The abundances were generally low (max. 4 ind.
m-3). While M. leidyi was located in the entire water
column in Kiel Bight, it was found exceptionally below the
halocline in the deep stratified central Baltic basins. Data of
a weekly sampling program at a near shore sampling location in
Mecklenburg Bight between January and May 2007 showed that up to
80 % of the individuals were juveniles, smaller than 1 mm total
body length and that M. leidyi survived the winter in the
Southern Baltic Sea, even if abundances dropped down to <1 ind.
m-3 in February. A first assessment of the
physiological demands of this species versus the environmental
conditions of the Baltic Sea showed that the successful
establishment of this ctenophore is probable in the
south-western and central Baltic Sea.
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Short communications |
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Gülnaz Özcan
Distribution of the non-native fish species, pumpkinseed
Lepomis gibbosus (Linnaeus, 1758), in Turkey (pp 146-148)
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The North American centrarchid species, Lepomis gibbosus
(Linnaeus, 1758), is a freshwater fish native to eastern and
central North America. The species is now established in at
least 28 countries of Europe and in Turkey the species’ spread
has been especially rapid between 2001 and 2006, with its
distribution including the following areas: Kemer Reservoir,
Akçay river catchment and inland waters of the Aegean and
Anatolian regions. This is the first report in a new locality of
the species in Asia Minor.
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Sergey E. Mastitsky
First report of parasites in Lithoglyphus naticoides
(Gastropoda: Hydrobiidae) from Lake Lukomskoe (Belarus) (pp 149-151)
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The Ponto-Caspian snail Lithoglyphus naticoides was
recorded for the first time in Lake Lukomskoe in 2003. During
parasitological examinations conducted in May and August 2006,
the snail was found to harbor cercariae of three trematode
species: Palaeorchis sp., Rossicotrema donicum and
Sphaerostomum bramae. The finding of R. donicum is
especially alarming because this highly specific parasite of
L. naticoides can cause severe epizootics among its second
intermediate hosts, i.e. perch and cyprinid fishes.
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Panagiotis Kasapidis, Panagiota
Peristeraki, Georgios Tserpes and Antonios Magoulas
A new record of the Lessepsian invasive fish Etrumeus
teres (Osteichthyes: Clupeidae) in the Mediterranean Sea
(Aegean, Greece) (pp 152-154)
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The Lessepsian invasive fish Etrumeus teres was recorded
for the first time off Crete, Greece in July 2005. Their
abundance suggests that the species may become of commercial
importance in the south Aegean Sea.
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