Volume 7, Issue 4 (2012)
published November 2012
Contents | |
Research articles |
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François Lefebvre, Sébastien Wielgoss, Kazuya Nagasawa and František Moravec
On the origin of Anguillicoloides crassus, the invasive nematode of anguillid eels
(pp 443-453)
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The nematode Anguillicoloides crassus is one of the many threats hanging over anguillid eels, now known to infect six Anguilla species worldwide.
It was first described in Japan, in 1974, and is commonly thought to natively stem from East Asia. Here our primary objective was to critically evaluate
this long-held statement. We first retraced the factual history of this global invader, to later investigate the pros and cons for an East Asian origin.
After exploring the alternative scenarios for the joint origin of the two anguillicolid parasites occurring in this area, we concluded that the geographic
zone covering the natural range of the local eel A. japonica is still the most probable origin (in the absence of another identified candidate host and area).
However, we cannot exclude that A. crassus may have been previously introduced along with exotic eel species, at some early stages of aquaculture in Japan.
We call for caution when dealing with the native origin of this and other parasitic invaders in provenance of East Asia, a region to be regarded as a major crossroads
for fish and parasites of the world. We finally identified the need for a possible resolution of the question, which includes a deeper sampling effort in the
Indo-Pacific zone and the further development of molecular phylogeographic studies of all five anguillicolid species and their hosts.
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Lena Granhag, Sanna Majaneva and Lene Friis Møller
First recordings of the ctenophore Euplokamis sp. (Ctenophora, Cydippida) in Swedish coastal waters and molecular identification of this genus
(pp 455-463)
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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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Frances E. Lucy, Alexander Y. Karatayev and Lyubov E. Burlakova
Predictions for the spread, population density, and impacts of Corbicula fluminea in Ireland
(pp 465-474)
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In 2010, the Asian clam, Corbicula fluminea, was found for the first time in Ireland. The species is considered
to be one of the most aggressive freshwater invaders causing strong economic and ecological impacts. This paper provides
predictions for the spread, population density, and impacts of Corbicula fluminea in Ireland. Water chemistry datasets
from the Republic of Ireland and from Northern Ireland were analysed to determine suitable waters for colonisation. Only 3 rivers
and 6 lakes have pH levels considered too low (<5.6) for invasion of this species. Corbicula fluminea densities within a waterbody
will depend on suitable substrate and food availability, with greater populations in canals, rivers and lakes with a higher trophic level.
Boating and angling are likely to be the highest vectors of spread. Redevelopment of any canal sections will require risk assessment,
to minimise spread. Corbicula is likely to cause negative economic effects by creating blockages in drinking and industrial water
abstraction systems. The ecological impacts of C. fluminea are associated with their role as biofilters, and are therefore determined
by their filtration rate and the overall population density in a given waterbody.
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Barbara Lage Ignacio, María Soledad López and Julieta Salles Vianna da Silva
Colonization plasticity of the boring bivalve Lithophaga aristata (Dillwyn, 1817) on the Southeastern Brazilian coast:
considerations on its invasiveness potential
(pp 475-482)
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Lithophaga aristata is a boring bivalve native to the Caribbean Sea, first recorded in 2005 as an introduced species
on the Southeastern Brazilian coast. The geographic distribution and density of L. aristata and of its native congeneric
L. bisulcata were assessed in four areas of Brazil (24 sites), additionally considering their relationship with types
of substrate, depth and wave exposure. This study records the first occurrence of L. aristata in the Sepetiba Bay
and also reports the species at five new localities in the Arraial do Cabo Bay. Lithophaga aristata is established
in the four surveyed regions. At intertidal habitats, the exotic species only colonizes the infralittoral fringe but its
density was not related to wave action. At subtidal habitats, the species colonizes natural and artificial substrates,
from shallow (0.5m) to deep (5.0-7.0m) zones but no relationship between density and these evaluated factors was detected.
Broad geographical and ecological distributions and higher densities of this introduced species in relation to its native
congeneric are suggested as contrary to Darwin’s naturalization hypothesis and instead indicate a high invasiveness potential.
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Justin I. McDonald
Detection of the tropical mussel species Perna viridis in temperate Western Australia: possible association between spawning and a marine heat pulse
(pp 483-490)
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In April 2011 a single individual of the invasive mussel Perna viridis was detected on a naval vessel while berthed in the temperate waters of Garden Island, Western Australia (WA).
Further examination of this and a nearby vessel revealed a small founder population that had recently established inside one of the vessel’s sea chests. Growth estimates indicated that
average size mussels in the sea chest were between 37.1 and 71 days old. Back calculating an ‘establishment date’ from these ages placed an average sized animal’s origins in the summer
months of January 2011 to March 2011. This time period corresponded with an unusual heat pulse that occurred along the WA coastline resulting in coastal waters >3 ºC above normal.
This evidence of a spawning event for a tropical species in temperate waters highlights the need to prepare for more incursions of this kind given predictions of climate change.
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Liam P. Gregory, Marnie L. Campbell, Carmen Primo and Chad L. Hewitt
Biotic and abiotic factors affecting the Tasmanian distribution and density of the introduced New Zealand porcelain crab Petrolisthes elongatus
(pp 491-501)
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Petrolisthes elongatus (Milne-Edwards, 1837) was first introduced into southern Tasmania in the late 19th century putatively
associated with live-oyster transfers from New Zealand. In the last century P. elongatus populations have expanded, inoculating
rocky intertidal zones around Tasmania. We initially identified the scope of P. elongatus introduced range around Tasmania by
visiting 57 sites to identify presence. Density of P. elongatus and populations of two native grapsid crab species was assessed
at 12 sites around Tasmania to identify any biotic resistance. Abiotic factors including substrate availability and preference, and wave
stress, were identified at each of the 57 sites. Our results indicate that P. elongatus has successfully invaded a large proportion
of the southern and northern coasts of Tasmania, with a small number of sites on the east and none on the west coast supporting P. elongatus
populations. Densities were found to be higher in southern Tasmania compared to the eastern and northern coastlines. Petrolisthes elongatus
presence was found to be positively correlated with native grapsid crab presence, however, no statistically significant relationship was found
between densities at scales of site or quadrat. Abiotic factors have been identified as the primary drivers of Petrolisthes distribution patterns.
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Anne Schrimpf, Lucian Pârvulescu, Denis Copilaș-Ciocianu, Adam Petrusek and Ralf Schulz
Crayfish plague pathogen detected in the Danube Delta – a potential threat to freshwater biodiversity in southeastern Europe
(pp 503-510)
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The crayfish plague, caused by the oomycete Aphanomyces astaci, is probably the most significant reason for declines in European freshwater crayfish species.
One of its hosts, the North American spiny-cheek crayfish Orconectes limosus, extends its range in the river Danube and recently reached the territory of Romania.
We used highly sensitive A. astaci-specific real-time PCR to test if the native narrow-clawed crayfish Astacus leptodactylus in the highly protected
Danube Delta about 970 km downstream of the current invasion front of American crayfish is a carrier of the crayfish plague. Thirteen out of 40 analysed native
A. leptodactylus tested positive for the crayfish plague pathogen, infected individuals were found at both sampled localities within the Danube Delta.
Therefore A. astaci has a much wider range in this river than assumed. The pathogen seems to persist in local populations, as neither crayfish mass mortalities
nor alien crayfish species have been reported from the region. Aphanomyces astaci may have reached the Delta by long-range passive dispersal of infected hosts
or pathogen spores, or by gradually infecting populations of native crayfish in upstream regions of the Danube in a stepping-stone manner. Alternatively, the crayfish
plague may have persisted in the Danube Delta as chronic infection from an old plague wave in the 19th century. In any case, the presence of this pathogen in the lower
Danube may become a threat to conservation of European crayfish and to freshwater biodiversity in many regions of southeastern Europe, at present considered
“crayfish plague-free”.
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Christoph Chucholl, Katharina Morawetz and Harald Groß
The clones are coming – strong increase in Marmorkrebs [Procambarus fallax (Hagen, 1870) f. virginalis] records from Europe
(pp 511-519)
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We describe a new occurrence of parthenogenetic Marmorkrebs in southwestern Germany and give a synopsis of recent records of this species in Europe.
Including the most recent records, 15 Marmorkrebs records are currently known, most of which are from Germany. At least six records represent established
populations, which is an alarming increase beyond the one Marmorkrebs population known prior to 2010. Most established populations occur in lentic habitats
near conurbations, typically in highly frequented secondary habitats, such as gravel pit lakes. In three instances, Marmorkrebs migrated over land, demonstrating
their potential for active spread, and two invasive populations endanger indigenous crayfish populations. Most Marmorkrebs populations are large and are most likely
several years old, suggesting a considerable lag between introduction and detection. Marmorkrebs populations in Europe are most likely the result of deliberate
releases from aquaria, although secondary introductions may have occurred in one instance. Because Marmorkrebs are still widespread in the European pet trade,
which most likely generates substantial propagule pressure, it is likely that the number of established populations will further increase over time. To mitigate
the risk of further harmful crayfish releases, we suggest the prohibition of trading live high-risk crayfish species, including Marmorkrebs.
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Fabian Herder, Ulrich K. Schliewen, Matthias F. Geiger, Renny K. Hadiaty, Suzanne M. Gray, Jeffrey S. McKinnon, Ryan P. Walter and Jobst Pfaender
Alien invasion in Wallace’s Dreamponds: records of the hybridogenic “flowerhorn” cichlid in Lake Matano, with an annotated checklist of fish species introduced to the Malili Lakes system in Sulawesi
(pp 521-535)
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Invasive fish species can have major impacts on freshwater faunas, particularly in isolated systems harbouring adaptive animal radiations.
Here, we report on the occurrence and recent rapid expansion of the hybridogenic “flowerhorn” cichlid in ancient Lake Matano, the hydrological head
of the Malili Lakes system in Central Sulawesi, Indonesia. We show that flowerhorns rapidly dispersed along the lake’s shoreline, inhabited most
of the southern inshore habitats in 2010, and were present all around the lake in mid-2012. In addition, we present stomach content and observational
data supporting the hypothesis that this cichlid threatens the local fauna through both predation and competition. We discuss 13 additional alien fish
species recorded in the Malili Lakes drainage since 2000, including the recent, first record of the invasive sailfin catfish Pterygoplichthys pardalis
for Sulawesi, highlighting the multitude of artificial introductions of foreign fish species into these unique and highly isolated freshwater systems.
We conclude that alien fish species pose both serious and diverse threats to the fauna of the Malili Lakes system – an ecosystem of high socio-economic
importance and an exceptional natural laboratory for study of evolution, referred to as “Wallace’s Dreamponds”. Finally, we provide recommendations
for minimizing future alien species introductions.
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Jacob W. Brownscombe, Laurence Masson, David V. Beresford and Michael G. Fox
Modeling round goby Neogobius melanostomus range expansion in a Canadian river system
(pp 537-545)
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We applied a gamma transit time model to predict the rate of range expansion of the round goby (Neogobius melanostomus Pallas, 1814) in the Trent-Severn Waterway (Ontario, Canada).
Gamma distributions were fit to actual transit times of the population front from 2009 to 2011. A lack of model fit in the second year is thought to be indicative of an upstream
bait bucket introduction, and this model may be useful for identifying such events. Range expansion predictions were highest in high quality habitats at 9.3 km/year, with a 5% probability
that highly mobile individuals may disperse 27 km/year. The model also predicts the arrival time of the population at any distance from the population front with a given confidence interval.
The estimation of a timeline for range expansion and determining underlying factors affecting the spread of invasive species could inform preventative strategies. This model is potentially
useful in predicting transit times of other invasive species expanding their range in linear space, and in separating natural population expansion from additional human-assisted movement
in the same system.
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Chelsea A. Harms and Ralph G. Turingan
Dietary flexibility despite behavioral stereotypy contributes to successful invasion of the pike killifish, Belonesox belizanus, in Florida, USA
(pp 547-553)
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It is well known that the establishment of invasive-fish populations depends on the ability of introduced individuals to adapt to environmental conditions in the invaded ecosystem,
including the ability to feed on diverse, locally available prey resources. Furthermore, the current invasive-biology paradigm postulates that having a generalist-food habit is key
to the successful invasion of a novel community by exotic species. This study investigated how the invasive pike killifish, Belonesox belizanus, has succeeded in establishing
exotic populations in Florida, USA despite having a feeding apparatus that is characteristic of a specialized piscivore (i.e., fish-eating fish). Pike killifish collected from their
point of introduction in south Florida were (1) filmed using high speed video while feeding on live fish- and shrimp-prey to determine whether prey type affects prey-capture kinematics
and then (2) subjected to a prey-selectivity experiment to determine which prey type (live fish or shrimp) the invasive pike killifish eats when both prey are available in the environment.
Results indicated that (1) prey-capture kinematics were not affected by prey type, indicating that consumption of fish and shrimp prey was accomplished using a stereotypical feeding repertoire,
and (2) pike killifish consumed fish and shrimp when both prey were available in the feeding environment. It is concluded that the invasive pike killifish has the ability to feed on alternative,
locally available prey using its piscivorous feeding functional morphology and prey-capture kinematics. This study contributes a new perspective to our understanding of the mechanisms that
underlie success of exotic fishes in invaded communities. That is, the ability of a functional-morphological specialist to utilize stereotypical prey-capture kinematics (= behavior)
in consuming alternative, locally available prey types (= dietary flexibility) contributes to the establishment of invasive populations. It is evident that these functional specialists
are not constrained in their diet, thus, enabling them dietary flexibility and enhancing their invasive potential.
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S. Christine Paetzold, Jonathan Hill and Jeff Davidson
Efficacy of high-pressure seawater spray against colonial tunicate fouling in mussel aquaculture: inter-annual variation
(pp 555-566)
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Invasive species such as ascidians have negative effects on aquaculture operations worldwide. Prince Edward Island, Canada,
in particular has seen high fouling levels of non-native tunicates including the colonials Botryllus schlosseri and Botrylloides violaceus.
Previous research indicated that high-pressure seawater spraying of mussel socks fouled with colonials is an effective mitigation strategy. Those results,
however, were based on a year (2009) with unseasonably low water temperatures at the beginning of the colonial tunicate growing season in June and July;
therefore, we repeated part of that study in the following year (2010) to determine whether typical (warm) early season water temperature affected tunicate
fouling levels and how both treatment efficacy and fouling effect on mussel productivity differed between the two years. In 2010, Botryllus schlosseri
fouling (in terms of biomass) was four-fold higher than in the colder year (2009), reaching an average biomass of 600-800 g per full-length mussel sock
(up to 2.4 m long), but it still did not affect mussel productivity. B. violaceus was also present on mussel socks, but only in very low amounts
(<50 g per mussel sock), so that results for this species were inconclusive. High-pressure water spraying was at least as effective in 2010 as in 2009
at removing B. schlosseri tunicate fouling from mussel socks, though in 2010, treatment also negatively affected mussel productivity by reducing mussel
biomass by 30% in the frequently (5×) treated group. Considering these results along with the potential risk of increased tunicate spread (through fragmentation)
and the cost of treatment, frequent application of high-pressure water spray is unnecessary.
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Alisha Dahlstrom, Marnie L. Campbell and Chad L. Hewitt
Mitigating uncertainty using alternative information sources and expert judgement in aquatic non-indigenous species risk assessment
(pp 567-575)
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Aquatic non-indigenous species (ANS) management employs risk assessment as a tool to prioritize prevention and control efforts, but timely and comprehensive risk estimates
are difficult due to various sources of uncertainty, particularly knowledge gaps. Several fields use or endorse the use of precaution, as well as group Delphic processes,
to mitigate this uncertainty. To test the application of these methods in ANS risk assessment, we surveyed the knowledge and attitudes held by ANS scientists and managers
regarding uncertainty and involved these experts in a modified Delphic process to determine consequence for a suite of 10 ANS. We found that participants supported
the application of precaution in risk assessments. We also found the Delphic process aided the risk assessment process by facilitating outcomes that are supported
by experts and stakeholders involved, account for uncertainty, and are therefore useful for policy and management purposes. Finally, we provide several recommendations
for mitigating uncertainty in consequence assessments. These outcomes and recommendations provide increased understanding of the presence and sources of uncertainty,
and the potential use of precaution and Delphic processes to facilitate the completion of comprehensive biosecurity risk assessments, despite the challenges posed
by existing knowledge gaps in ANS impact information.
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Jean-Michel Brylinski, Elvire Antajan, Thomas Raud and Dorothée Vincent
First record of the Asian copepod Pseudodiaptomus marinus Sato, 1913 (Copepoda: Calanoida: Pseudodiaptomidae) in the southern bight of the North Sea along the coast of France
(pp 577-584)
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The presence of the demersal Asian copepod Pseudodiaptomus marinus is reported for the first time in the southern bight of the North Sea,
in both Calais harbour and the coastal waters off Gravelines, France. This is the first record of P. marinus in the Atlantic Ocean sector
and the North Sea area. The species was collected in January and October 2010, and in January, February and April 2011. The very low number of
collected individuals (0.2 to 4.0 ind.m-3) and the capture of only two ovigerous females and of a few numbers of copepodid CV stages suggest
that the species survives and actually reproduces in both sites but does not manage to develop an abundant population. The presence of
P. marinus in Calais harbour and coastal waters of the southern North Sea supports recent observations of other Asian species
in the same area and suggests a passive transport via ship’s ballast waters.
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Ian C. Duggan, Karen V. Robinson, Carolyn W. Burns, Jonathan C. Banks and Ian D. Hogg
Identifying invertebrate invasions using morphological and molecular analyses: North American Daphnia ‘pulex’ in New Zealand fresh waters
(pp 585-590)
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We used a DNA barcoding approach to identify specimens of the Daphnia pulex complex occurring in New Zealand lakes,
documenting the establishment of non-indigenous North American Daphnia ‘pulex’. Morphological delineation of species
in this complex is problematic due to a lack of good morphological traits to distinguish the species, as there is a relatively
high degree of morphological stasis within the group through evolutionary time. Accordingly, genetic analyses were used to determine
the specific identity and likely geographic origin of this species. Morphologically, individuals most closely resembled
Daphnia pulicaria or Daphnia pulex sensu lato, which cannot be separated morphologically. Furthermore, each
of these taxa comprises separate species in North America and Europe, despite carrying the same names. We identified individuals
using a 658 bp nucleotide portion of the mitochondrial cytochrome c oxidase subunit 1 gene (COI) as North American Daphnia ‘pulex’,
being distinct from European Daphnia pulex sensu stricto and D. pulicaria from Europe or North America. Cellulose allozyme
electrophoresis was used to confirm that individuals were not hybrids with D. pulicaria. North American Daphnia ‘pulex’
in New Zealand were first recorded in New Zealand from South Island lakes that are popular for overseas recreational fishers, indicating
a possible source of introduction for this species (e.g. on/in fishing gear). Our study provides an additional example of how genetic
techniques can be used for the accurate identification of non-indigenous taxa, particularly when morphological species determination
is not possible. The growth of global databases such as GenBank and Barcode of Life Datasystems (BOLD) will further enhance this identification capacity.
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Marco A. Faasse and Adriana Giangrande
Description of Bispira polyomma n. sp. (Annelida: Sabellidae): a probable introduction to The Netherlands
(pp 591-598)
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Bispira polyomma sp. nov. is described. The taxon was recently found on the SW coast of The Netherlands (NE Atlantic),
and could not be referred to as any previously described species of the genus Bispira. The area has been thoroughly
investigated in the past, therefore we hypothesize the species is a new introduction to The Netherlands. The tubeworm is able
to settle massively on all kinds of hard substrates, is eurythermal and able to withstand slight pollution, and therefore wider
dispersal is a possibility to reckon with. For this reason we give a taxonomic species description even though the genus needs
further revision. Presently the taxon has been observed only near Yerseke, a centre of shellfish culture and trade with a marina.
The taxon was found in 2010. Subsequent surveys revealed a very dense population had developed in 2011, with the presence of small
individuals in summer 2011 suggesting successful reproduction.
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