The epibenthic euryhaline hydromedusa Vallentinia gabriellae Vannucci Mendes, 1948 is an olindiid species native to tropical Atlantic waters. Here, we describe the cryptic introduction of this species in an estuary along the coast of Kerala, in southwestern India. This study records the existence of V. gabriellae outside of Atlantic waters for the first time and documents its geographical range expansion. Our identification was based on a combined morphological and DNA barcoding assessment using the COI and 28S markers. Although we noted some morphological differences between our specimens and those from their native range, our findings were conclusive. We suggest that phenotypic plasticity may result from differences such as prey availability between the native and introduced habitats. V. gabriellae medusae are epibenthic and cling to a variety of hard and soft substrates, including bivalves. Our specimens were associated with the invasive fouling mussel Mytella strigata, and we suggest that V. gabriellae could have been transported along with these mussels to the Kerala coast.

Mental health is fundamental to an individual’s health and well-being. Mental health disorders affect a substantial portion of the Australian population, with the most vulnerable time in adolescence and young adulthood. Indigenous Australians fare worse than other Australians on almost every measure of physical and mental health. Cross-sectional data from young adults (21–27 years) participating in the Life Course Program, Northern Territory, Australia, is presented. Rates of psychological distress were high in remote and urban residing Indigenous and urban non-Indigenous young adults. This rate was more pronounced in young women, particularly in Indigenous remote and urban residing women. Young adults with high psychological distress also had lower levels of positive well-being, higher perceived stress levels, experienced a higher number of major life events and were at an increased risk of suicidal ideation and/or self-harm. This study supports the need for a continued focus on early screening and treatment at this vulnerable age. The significant association seen between psychological distress and other markers of emotional well-being, particularly risk of suicidal ideation and/or self-harm, highlights the need for a holistic approach to mental health assessment and treatment. A concerted focus on improving the environs of young adults by lowering levels of stress, improving access to adequate housing, educational and employment opportunity, will assist in improving the emotional health of young adults.

Our study tracked three non-native, marine, sessile, invertebrate species which have recently colonized the south-eastern United States Atlantic coastlines and estuaries: Mytella charruana, the charru mussel; Perna viridis, the Asian green mussel; and Megabalanus coccopoma, the titan acorn barnacle. Along the eastern Floridian coast, Mytella charruana was discovered in the Indian River Lagoon, Florida (FL) in 2004. Perna viridis was found in Ponce de Leon Inlet, FL in 2002, after being introduced to Tampa Bay, FL in 1989. Megabalanus coccopoma was documented in St Augustine, FL and Brunswick, Georgia in 2006. From 2006 through to 2011, a biannual survey of the south-eastern Atlantic coastlines and estuaries was conducted from Jupiter, Florida to Charleston, South Carolina (894 km) to document the distribution and range expansion of M. charruana, P. viridis and M. coccopoma. Field surveys were conducted in June and December each year at 82 sites (e.g. docks, boat ramps, jetties and mangrove roots). The ranges of the three invertebrates have expanded and retracted along the Atlantic coast since the survey began. Mytella charruana had spread as far north as Savannah, Georgia in 2007, but the species was absent from northern Georgia in 2010 and 2011. Perna viridis and M. coccopoma were present in Georgia in 2007, but were absent in the 2010 and 2011 surveys. These range fluctuations may be explained by extreme cold temperatures, which occurred during the 2009/2010 and 2010/2011 winters. The patterns observed with these three sessile invertebrates provide information regarding how non-native species disperse and establish in new locations.

This is the first report about the arrival of the encrusting cheilostomatid bryozoan Watersipora subtorquata on floating seaweeds in German coastal waters of the North Sea. During summer 2012, drifting or stranded thalli of the non-indigenous brown macroalga Himanthalia elongata were investigated on the island of Helgoland showing numerous benthic species covering the holdfast of Himanthalia. Out of the 120 basal structures investigated, 8.3% had viable colonies of the invasive, non-native W. subtorquata attached to them. Himanthalia and W. subtorquata have both their nearest origin reported to be in the English Channel (La Manche), approximately 800 km away from Helgoland. Now we found W. subtorquata as a rafting species in the eastern part of the North Sea, showing its ability to distribute easily over very large distances using floating algae as a natural transport vector. This event might constitute the first step in the potential introduction of this alien species into German coastal waters.

Sixteen species of solitary ascidians were identified from subtidal marine fouling communities present on navigational buoys, jetty pilings, floating pontoons and nettings around the coastal waters of Singapore. Of these, twelve are new records: Ascidia gemmata, Phallusia arabica, Phallusia nigra, Rhodosoma turcicum, Rhopalaea crassa, Polycarpa argentata, Polycarpa aurita, Polycarpa captiosa, Polycarpa olitoria?, Styela canopus, Pyura curvigona and Herdmania pallida. The other four species include Ascidia sydneiensis, Phallusia philippinensis, Polycarpa papillata and Microcosmus exasperatus. A detailed morphological comparison of Phallusia nigra and P. philippinensis is included because these two species have been frequently confused, resulting in a significant under-reporting of the latter in the literature.

Dictyopteris prolifera, a marine algae (Phaeophyceae) native to Asian waters (Japan), has been collected recently on the western coast of the Baja California Peninsula, Mexico. Its finding represents the first record of this non-indigenous species on the Mexican Pacific coast, which also means a new record for American waters. Dictyopteris prolifera was found in June and September 2010, growing attached to rocks in the intertidal zone at Punta Morro Redondo, Cedros Island in Baja California, Mexico. Direct observations in the field about its abundance and size showed that D. prolifera has established as a permanent species. The mean length of specimens of this population is ~25 cm. Results of a monitoring programme show an increasing record of non-indigenous species on the coast of Baja California, mainly derived from ship traffic.

Globally, introductions of non-indigenous species have caused dramatic economic and ecological damage. Most research on marine invasions has occurred in locations easily accessible by researchers, but much less is known about introductions to remote islands. In the central Pacific, Palmyra Atoll represents one of the last remaining quasi-pristine reef systems left in the world. In the 1940s the Atoll underwent extensive military modifications, potentially making it susceptible to invasive species. Here we describe the presence of five non-indigenous invertebrate and algal introductions at Palmyra, including two sponges, Haliclona (Sigmadocia) caerulea and Gelliodes fibrosa; one bryozoan; Zoobotryon verticillatum; one hydroid, Pennaria disticha and one macroalga, Acanthophora spicifera. The Hawaiian Archipelago is the most likely source of the introductions via shipping or yachting activity to the Atoll. Currently, the impacts of these introductions remain unknown although future monitoring will assess the influence of these non-indigenous species on this remote reef system.

The introduction of invasive species is one of the greatest threats to Earth’s biodiversity, as they can reduce native biodiversity and alter ecosystem structure and function. Currently, the only two known non-native terrestrial invertebrates in Antarctica are the chironomid midge Eretmoptera murphyi and the enchytraeid worm Christensenidrilus blocki. These invertebrates were probably introduced to ground near Signy Research Station, South Orkney Islands, during transplantation experiments in the late 1960s. Between 2007 and 2009, this study surveyed the area around the introduction site for midge larvae and worms to assess any change over the last four decades in their spatial distribution, habitat preference and colonization status. Eretmoptera murphyi was found in concentrations up to 4.1 × 105 larvae m-2 (mean 2.1 × 104 larvae m-2) at distances of up to 220 m from the probable introduction site (c. 35 000 m2), while C. blocki was only found close to the introduction site in low numbers. Significantly more E. murphyi larvae were found in peat and dead organic material (3.34 × 104 m-2) than in stony soil and gravel (1.52 × 104 m-2) or living moss and other plant material (1.16 × 104 m-2). Eretmoptera murphyi can no longer be considered a persistent alien as it clearly expanding its distribution, while C. blocki remains a persistent alien species.

The first Mediterranean record of the African moonfish, Selene dorsalis, is reported, with the capture of a single female specimen by means of a trammel net from coastal waters off the Maltese Islands. The species is a non-indigenous one for the Mediterranean, being native of tropical and subtropical waters of the east Atlantic. The Mediterranean record of S. dorsalis could be indicative of a northward range expansion of the species, spurred in part by the recent warming trend observed in the Mediterranean Sea.

The invasive ascidian Ciona intestinalis is irregularly and narrowly distributed in a few areas on the Brazilian coast. It was recorded in the States of Paraná, São Paulo, and Rio de Janeiro. In the State of Rio de Janeiro, all records refer to the Guanabara Bay, a polluted environment that probably hosts other introduced species. Ciona intestinalis was last recorded in this bay in 1991. Given the absence of records since then, researchers concluded that it had been extinct there, and even from the Brazilian coast. During our experiment, conducted with predator exclusion and light attenuation, we collected some samples of C. intestinalis, which suggests that it has either been reintroduced in the Guanabara Bay or that its presence there is a consequence of predator exclusion. Ciona intestinalis was found inside boxes with low luminosity, whose openings were turned to the bottom and protected with a net for predator exclusion. This method was successfully used 17 years ago, when numerous species samples were detected. Our conclusion is that the irregular recording of C. intestinalis on the Brazilian coast, in both time and space, probably derives from inappropriate techniques and methods to sample or observe it on natural substrate. Replicating this methodology in other regions of Brazil and in other South American countries, especially in port areas, would show that the distribution of C. intestinalis is possibly broader than previously reported.

The first record of the non-indigenous Corella eumyota on the Galicia coast (north-west Spain) is reported. One hundred and forty-one specimens of this solitary ascidian were found on soft bottoms at 12 m depth in the inner part of the Ría de Vigo. This is a species from cooler waters of the southern hemisphere and was recorded for the first time in the northern hemisphere in 2002, in France. The specimens have been compared with Antarctic and South American museum samples. Some intraspecific variability was noted.

The first record of the non-indigenous ascidian Microcosmus squamiger in the Salerno harbour (central Tyrrhenian Sea) is reported. Forty-eight specimens of this solitary ascidian were found (September, 2000) on hard bottoms of the internal piers and on the breakwater rocks along the harbour at 2 and 4 m depth respectively.

Biological invasions by non-indigenous species (NIS) are widely recognized as a significant component of human-caused global environmental change. However, the standard programme of mapping distributions, predicting future ranges, modelling species spread, assessing impacts, developing management guidelines and screening species suffers from a number of serious limitations. NIS distribution maps can often be as misleading as they are instructive. Perceptions of the intensity, scale and rate of invasion are a function of mapping resolution, and the lack of common mapping standards prevents accurate comparative assessments. Coarse resolution data may overestimate the role of climate in the invasion process relative to other variables such as land use or human population density. Climate envelopes have therefore been widely used to predict species future ranges, but often overestimate potential distributions. Without an appropriate mechanistic understanding of the invasion process, correlative approaches may misinterpret the relative risks posed by different NIS. In addition, statistical models of invasion fail to encapsulate the complexity of human-mediated dispersal, which includes such diverse processes as transatlantic timber trade, horticultural fashion and the continuing expansion of road networks. Screening tools based on species traits, taxonomy and/or invasion history can sometimes result in high discrimination rates. Yet where the cost of false positives outweighs the risks from false negatives, a higher discriminatory power is required. Certain research outputs have perhaps been counterproductive in the war against invasive species. Studies have highlighted that only a tiny proportion of NIS are invasive, that most invasions occur in human dominated rather than pristine ecosystems, that indigenous and non-indigenous species are sufficiently similar that their impacts may not necessarily be different, and that there is evidence that introduced species augment rather than reduce species diversity. It is crucial to address these wider perceptions of the problem in order to mobilize the resources necessary for a global invasive species management programme.

The introduction of bamboo to montane rain forests of the Luquillo Mountains, Puerto Rico in the 1930s and 1940s has led to present-day bamboo monocultures in numerous riparian areas. When a non-native species invades a riparian ecosystem, in-stream detritivores can be affected. Bamboo dynamics expected to influence stream communities in the Luquillo Experimental Forest (LEF) were examined. Based on current distributions, bamboo has spread downstream at a rate of 8 m y−1. Mean growth rate of bamboo culms was 15.3 cm d−1. Leaf fall from bamboo stands exceeded that of native mixed-species forest by c. 30% over a 10-mo study. Bamboo leaves (k = −0.021), and leaves from another abundant riparian exotic, Syzygium jambos (Myrtaceae) (k = −0.018), decayed at relatively slow rates when submerged in streams in fine-mesh bags which excluded macro-invertebrate leaf processors. In a second study, with leaf processors present, bamboo decay rates remained unchanged (k = −0.021), while decay rates of S. jambos increased (k = −0.037). Elemental losses from bamboo leaves in streams were rapid, further suggesting a change in riparian zone / stream dynamics following bamboo invasion. As non-indigenous bamboos spread along Puerto Rico streams, they are likely to alter aquatic communities dependent on leaf input.