The presence and abundance of non-indigenous, and/or harmful or toxic dinoflagellate species in ballast sediments is examined for 65 cargo ships visiting ports on the East coast of Canada, as part of the Canadian Aquatic Invasive Species Network (CAISN). Ships visiting several ports in the provinces of Quebec, New Brunswick and Nova Scotia were sampled during three summers (2007, 2008, 2009). These ships included general cargo, bulk carriers and oil tankers, and they represented two major categories: ships undergoing continental and trans-oceanic voyages. Our results show that potentially viable dinoflagellate cysts are present in ballast sediments of all the categories of ships arriving to the East coast of Canada. The concentrations of all types of dinoflagellate cysts are higher in continental ships without ballast water exchange (BWE) than in ships with BWE, including trans-oceanic ships, which presented lower risk of introduction of non-indigenous species (NIS) of dinoflagellates. We identified 14 non-indigenous dinoflagellate cyst species not yet reported from Canadian coasts, including 4 potentially harmful/toxic species, representing a possibility of new introductions. These introductions of toxic NIS could represent a problem for marine Canadian ecosystems, with potentially disastrous effects on fish communities, aquaculture and human health. This potential risk may be facilitated with climate change.

Blooms of the stalked diatom Didymosphenia geminata (Lyngbye) M. Schmidt, 1819 have been increasingly reported worldwide since the 1990s. In 2004, the appearance of blooms in New Zealand, for the first time, highlighted the invasive nature of this organism. In the absence of previous reliable records for this species, D. geminata was assumed to be non-indigenous and a nationally coordinated biosecurity response was initiated in an attempt to contain it. We examined the spread of D. geminata over five years using presence/absence data from national and regional delimiting surveys, combined with information from local agencies on potential vectors and data from national recreational angling surveys. Use of a rigorous sampling method raised confidence in the accuracy of negative results. Survey results supported the 2004 assumption that D. geminata was a recent arrival. Incremental but rapid spread to many South Island rivers from two main foci (the Mararoa and Buller Rivers) suggested mass dispersal of an invasive organism via human vectors. The distribution of affected rivers relative to angler usage data for 2007-08 was consistent with angler-mediated dispersal from catchment to catchment. This conclusion was supported by local information about likely vectors of D. geminata to individual sites. Other potential vectors were considered important (e.g., kayaking and power boats) but no river usage datasets were available to verify the patterns. At the time of writing D. geminata had not been detected in the North Island. Although D. geminata has been detected in a high proportion of South Island rivers, blooms have a more restricted distribution. The extent, drivers and impacts of these blooms are the subject of ongoing studies.

The colonial tunicate, Didemnum vexillum Kott, 2002, has a history of invading and overgrowing marine communities in temperate waters worldwide. The species can colonize and dominate remarkably large areas of benthic habitat, including coastal bays and outer coastal areas, causing concerns about potential long-term effects on community structure, critical habitats, and fisheries resources. We report here the confirmed occurrence of D. vexillum in Alaska, representing a dramatic 1000 km northward extension of this non-native species along the western coast of North America. The species was detected as part of a “bioblitz”, engaging citizen scientists to survey local biota and detect non-native marine species incursions. Following detection, the identity of D. vexillum was confirmed with robust genetic methods, and morphological characters were also consistent with previous species descriptions. Although invasions have been relatively rare in Alaskan waters to date, it is now clear that D. vexillum is established in at least one site (Whiting Harbor) near Sitka, Alaska. Given the explosive growth and spread of this species in other global regions, and its potential for significant impacts across diverse habitats in Alaska, current efforts are underway to evaluate its distribution and options to eradicate or control the species.

The distinctive Mediterranean-Atlantic fanworm polychaete, Sabella spallanzanii (Gmelin, 1791), is recorded from New Zealand, in both North and South Island, consequent upon its discovery first in the port area of Lyttelton in Lyttelton Harbour and later 800 km further north in the port area of Auckland in Waitemata Harbour. Morphology distinguishing the species from other sabellids is highlighted. In the initial occurrence in March 2008 one large specimen was identified from samples taken by a surveillance team off subtidal wharf structures in Lyttelton port. In July and August 2008 further large specimens were found both nearby and dispersed across the inner port area, with reproductive maturity appearing imminent in some. The New Zealand Government funded repeated search and culling by divers, directed towards possible local elimination, with over 380 specimens removed from Lyttelton by December 2009. However, in August 2009 a single large specimen was found in an enclosed port area in Waitemata Harbour, then several more, and in October 2009 numerous specimens were found on a barge hull berthed there. Also it became apparent that a second generation of colonisers was present in both harbours. By early 2010 well-grown specimens had been found in disparate Waitemata Harbour locations over a large area. The decision to suspend culls was made in February 2010, and elimination efforts were abandoned in June 2010, two years after first detection. The arrival and apparent establishment of S. spallanzanii in New Zealand is ascribed to accidental international transfer probably in 2007, either via hull fouling or ballast water, but it is not known if the two ports were colonised via the same transiting vessel.

In marine sedimentary coastal environments such as the Wadden Sea (coastal south-eastern North Sea) shells of epibenthic molluscs are the only major available settlement substrate for an increasing number of alien sessile organisms. We investigated the effects of Pacific oyster Crassostrea gigas epibionts on body weight, mobility and fecundity of the native common periwinkle Littorina littorea. Body dry weight of snails without oyster overgrowth was twice as high compared to periwinkles covered with oysters. Also crawling speed of snails with oyster epigrowth was significantly slowed down and about ten times lower than in unfouled periwinkles. Additionally, oyster epibionts caused a strong decrease in reproductive output. In laboratory experiments, egg production of fouled L. littorea was about 100-fold lower than in periwinkles free of oysters. Field surveys in different years and habitats demonstrated that up to 10% of periwinkles occurring on epibenthic bivalve beds and up to 25% of snails living on sand flats may be fouled by C. gigas. However, oysters are not the only epibionts on L. littorea in the area. In previous studies it was shown that periwinkles can also be strongly overgrown by other alien epibionts such as Australian barnacles Austrominius modestus and American slipper limpets Crepidula fornicata. These epibiotic structures may cause similar effects as revealed for C. gigas. Thus, we conclude that an alien epibiont accumulation on L. littorea may have a significant impact on periwinkle population dynamics and its ecological functions in the Wadden Sea.

The Asian clam Corbicula fluminea was first discovered in Ireland in the Rivers Barrow and Nore in 2010. Scuba diving surveys were the primary sampling method used to determine the detailed distribution of this species in the two rivers. Sustainable populations of Asian clam were present in the tidal freshwater reaches of both rivers. No clams were present upstream of the tidal limit. A maximum density of 9,636 individuals m^-2 was recorded in the River Barrow. This paper presents some basic metrics in relation to the populations present in these two connected river systems.

Palaemon macrodactylus, an exotic shrimp native to the northwest Pacific Ocean, has been recorded in many estuaries along the Atlantic coast of Europe since the late 1990’s. In this study, a regular monthly survey, held since 1992 of the middle section of the Gironde estuary, revealed this species’ rapid and full colonization of the system since its appearance in samples during summer 1998. In the Gironde, the population of P. macrodactylus is self-sustaining and the species is now established there. Our study highlights two important elements that might explain its successful colonization: its ability to quickly invade a niche under-exploited by the similar native species and its greater reproductive output. The species’spatio-temporal distribution in relation to environmental variables was studied and compared with that of the native species P. longirostris. The exotic species was shown to mainly inhabit the polyhaline and mesohaline section of the estuary, which are sections generally under-exploited by females of the native species. Furthermore, fecundity analysis and larval abundance survey results revealed a higher potential fecundity and a greater proportion of larvae and juvenile stages for P. macrodactylus in the natural environment.

Introduction of Macrobrachium rosenbergii to Brazil for prawn farming has resulted in escapes to the local natural environment. In some areas risk of feral populations establishing in local environments is considered low due to a lack of suitable habitat for completing the life cycle. In contrast, introduction of this species along the mangrove coasts of northern Brazil can result in escape to highly suitable habitat for reproduction. We confirm colonization of these habitats by M. rosenbergii and define this species as a casual exotic in Brazil. We highlight that natural reproduction is now occurring, meaning that feral populations may soon become self-sustaining. Ecological niche models using the Maxent software were developed to assess potential areas at risk of invasion in Brazil and more widely across the world. These models indicate that there are large areas of suitable habitat available in northern Brazil where introduced populations of M. rosenbergii could expand. The effect of such introductions could extend to a very large area, from Maranhão in Brazil to the Orinoco delta in Venezuela.

The unintentional introduction of the Asian shore crab, Hemigrapsus sanguineus, along the French coast during the mid 1990s has revealed the problematic effects that invasive species can have on biodiversity, entering into competition with native crab species. This invasion along coastal ecosystems of northern France has become an ineluctable, irreversible phenomenon. The present study describes the distribution and abundance of H. sanguineus along the French side of the English Channel from the Cotentin to the Opal Coast on the Dover Strait in spring and summer 2010. The results were compared with those obtained previously in 2008 and 2009 for the same areas and now show that the crab has increased in numbers since its first sighting in 1999. In 2010, the maximal abundance reached 51 ind.m^-2 in Dunkirk harbour, and 69 ind.m^-2 at La Hougue in the eastern part of the Cotentin Peninsula. Hemigrapsus sanguineus has been sighted all along the southern coastline of the English Channel to the North Sea (approximately 1,500 km). Its high colonisation potential suggests that this brachyuran could continue its invasion in European waters. Therefore a European surveillance network might be necessary to monitor its progression in the north-eastern Atlantic Ocean.

We report on the distribution and abundance of the Iraqi crab Elamenopsis kempi in the Panama Canal and investigate possible interactions of this species with another invader, the North American mud crab, Rhithropanopeus harrisii. While more widespread than R. harrisii, E. kempi is currently limited to four locations within the Canal area: the Miraflores Lake, the Miraflores Spillway, the Southern Lagoon and the Northern Lagoon. Crabs reached peak abundances November through February. Where the two crab species overlap, the abundance of E. kempi was negatively associated with that of R. harrisii. Average E. kempi densities were significantly higher in cores with vegetation than those without vegetation. Laboratory experiments indicated that R. harrisii readily eats E. kempi, but that the presence of aquatic vegetation reduces predation rates. After four days, all E. kempi in treatments without vegetation were eaten, whereas only 53% of crabs were eaten in treatments with vegetation. Elamenopsis kempi is a small cryptic crab that can be easily overlooked even when abundant, suggesting that it may be more widespread than is currently reported.

The Indo-Pacific lionfish species [Pterois volitans (Linnaeus, 1758) and P. miles (Bennett, 1828): Family Scorpaenidae] are the first non-native marine fishes to establish in the Western North Atlantic and Caribbean Sea. Despite the continued documentation of its range expansion and highly publicized invasion (including public-driven removal efforts) there remains a paucity of basic information on lionfish ecology. This knowledge gap limits effective long-term management. In this study we conducted a multi-scale investigation of habitat occupancy of a newly established population of lionfish in Roatan, Honduras. Based on field surveys and citizen sightings in Roatan Marine Park we found that lionfish occurred more frequently on aggregate coral reef habitats (54% of sightings) compared to patch reef habitats (30%) and sea grass lagoons (16%). In general, these aggregate and patch reef habitats contained adults (mean total length =118.9 mm and 114.7mm, respectively) whereas sea grass habitats contained juveniles (mean total length=89.5 mm). At the micro-habitat scale lionfish occupied areas dominated by hard coral and overhanging structure; the same microhabitats containing native fishes of concern – grouper (Nassau grouper, Epinephelus striatus; yellow fin grouper, Mycteroperca venenosa) and snapper (dog snapper, Lutjanus jocu; mutton snapper, Lutjanus analis). Results from this study contribute information on basic habitat requirements of lionfish and inform current management removal efforts focused on containing spread and mitigating their impacts on native species.

The ctenophore Bolinopsis vitrea is first reported from the Turkish and Bulgarian regions of the Black Sea. In Turkish waters, a considerable aggregation was found in Sile on the Asian side and at Kilyos on the European side in 2007. This appears to be the first record of this species in the Black Sea, which is known in the Mediterranean Sea including the Aegean Sea. Bolinopsis vitrea most likely penetrated with currents from the Aegean Sea via the Sea of Marmara into the Black Sea. In 2010 individuals of this species were recorded at two locations in Bulgarian waters where it may have entered with currents or else was released with ballast water.

The rhizostome jellyfish Mastigias (Agassiz, 1862), native to the western and central Indo-Pacific, is recorded from the western Atlantic, in a marine lake in Puerto Rico (Laguna Joyuda) and a working quarry on No Name Key, Florida (USA) in the Florida Keys. The single individual from Laguna Joyuda, collected in 2002, was previously misidentified as Phyllorhiza (Agassiz, 1862) and Mastigias has not since been recorded there, while a large population of Mastigias was observed in No Name Key in 2009 and 2010 and may have been present for decades. Identification as Mastigias for both sampling sites was confirmed by molecular systematic analysis of mitochondrial cytochrome c oxidase I (COI) and ribosomal 16S (16S). Sequences from both molecular markers were identical for all individuals sampled from Puerto Rico and the Florida Keys. Phylogenetic analysis of COI indicated that the introduced Mastigias were most closely related to Mastigias sp. 1 (Dawson, 2005) from Kakaban, Indonesia (Kimura 2-parameter sequence divergence = 1.1%) and distantly related to Mastigias papua (Lesson, 1830) from Palau (6.4-7.2%) and Mastigias sp. 2 (Dawson, 2005) from Papua New Guinea (9.8%). Therefore, the source region may lie somewhere in the central Indo-Malayan region, though determining an exact source region is not possible at this time. While the invasion vector is unclear, possible mechanisms include commercial shipping, mobile oil platforms and live rock transport. These are the first two confirmed records of Mastigias in the Atlantic basin and the second confirmed identification of the genus occurring outside of the native range, after Hawaii.