Marine Biological Invasions Research Articles

Non-native fish species in the North Aegean Sea: a review of their distributions integrating unpublished fisheries data

Fisheries-dependent data and information gathered through fisheries-related scientific surveys can significantly contribute to research on the patterns and processes underlying marine biological invasions and their interactions with fisheries. This study presents an overview of the presence of non-native fish species in the North Aegean Sea, offering insights into their distributions and impact on fisheries. The findings are based on a comprehensive compilation of commercial fisheries-dependent and scientific survey data collected in Greece from 2016 to 2023, along with a systematic review of the international scientific literature. The study resulted in the documentation of the presence of 37 non-native fish species, including several recorded for the first time in the area. The results suggest that non-native fish species invasions in the North Aegean Sea are dynamic. Although most species were classified as casual, and the frequencies of occurrence as well as the quantities in commercial fisheries catches of established species are smaller than in the South Aegean Sea, species introductions and the extent of occurrence and area of occupancy of several species have been increasing since the 2000s. The significance of non-native fish species is becoming increasingly relevant to commercial fisheries in the study area. This is particularly evident in the Northeastern Aegean Sea, where catches of non-native species are on the rise, and new species with potential commercial value have emerged in recent years.

Gaining a (tube) foothold – trends and status following two decades of the long-spined echinoid Diadema setosum (Leske, 1778) invasion to the Mediterranean Sea

The Eastern Mediterranean Sea is an exceptional habitat. Its relative isolation and distinct characteristics create a unique ecosystem recognized as a marine biodiversity hot spot, where one-fifth of the species are endemic. Yet, native Mediterranean biodiversity is under increasing threat, mainly due to massive alien species invasions of Indo-Pacific origin. To date, more than 800 non-indigenous species have been reported in the Eastern Mediterranean Sea, justifying its reputation as one of the most severely affected habitats in the world in terms of marine biological invasions. Here we summarized the Mediterranean invasion dynamics of the long-spined echinoid Diadema setosum (Leske, 1778), one of the most ubiquitous Indo-Pacific sea urchin species. We show an alarming exponential population growth of D. setosum throughout the Eastern Mediterranean since 2018, following more than a decade of ‘invasion lag’ since its first detection in 2006. Molecular analyses illustrate the presence of a single genetic D. setosum clade in the Mediterranean Sea – corresponding to the Arabian Peninsula clade of this species, reinforcing the notion of a Red Sea origin. Our data support the current working hypothesis that the initial introduction of D. setosum occurred in the Northern Levantine Basin from which it gradually expanded in both north-west and south-east trajectories – in contrast to a stepping-stone hypothesis of gradual advancement from the opening of the Suez Canal. Demographic data of D. setosum along the Israeli Mediterranean coastline reveals a well-established population of broad size distributions, from juveniles to adult individuals of remarkably large size. Additionally, we provide evidence of the reproductive capacity of D. setosum in its new environment. Due to the magnitude of Diadema’s ecological footprint, it poses a severe threat to the entire Eastern Mediterranean Sea, including the Levantine Basin and South Aegean Sea, calling for rapid and coordinated action at both national and regional scales.

Testing differences of marine non-indigenous species diversity across Macaronesia using a standardised approach

The introduction of non-indigenous species (NIS) induces severe impacts on marine biodiversity and ecosystems. Macaronesia is an ecologically relevant region where several NIS were detected recently. For the first time, a standard experimental approach was designed to examine biofouling assemblages and investigate NIS across the region. In this context, sessile biofouling assemblages were examined in four recreational marinas in all the Macaronesian archipelagos from 2018 to 2020: the Azores, Madeira, Canary Islands, and Cabo Verde. We hypothesised that NIS numbers, abundance, and recruitment differed in each location due to abiotic and biotic features. From the Azores (higher latitudes) to Cabo Verde (lower latitudes), NIS recruitment and percentage cover decreased following a partial latitude gradient. The present study unveiled 25 NIS, with new records for the Azores (two cryptogenic species), Canary Islands (one NIS and two cryptogenic species), and Cabo Verde (three NIS and three cryptogenic species). The present research represents a pioneer and relevant step in advancing our current understanding of marine biological invasions in Macaronesia, employing a standard and low-cost approach.

An exhaustive evaluation of modeling ecological niches above species level to predict marine biological invasions

Identifying the areas of the world with suitable environmental conditions for the establishment of invasive species represents a fundamental basis for preventing their impacts. One of the most widely used tools for this is ecological niche modeling. Nonetheless, this approach may underestimate the specie's physiological tolerances (it's potential niche) since wildlife populations of species usually do not occupy their entire environmental tolerance. Recently, it has been suggested that incorporating occurrences of phylogenetically related species improves the prediction of biological invasions. However, the reproducibility of this technique remains unclear. Here, we evaluated the generality of this protocol by assessing whether the construction of modeling units above species level improves the capacity of niche models to predict the distribution of 26 target marine invasive species. For each, we constructed supraspecific modeling units based on published phylogenies by grouping the native occurrence records of each invasive species with the records of its phylogenetically closest relative. We also considered units at species level, including only the presence of records in the native areas of the target species. We generated ecological niche models for each unit with three modeling methods (minimum volume ellipsoids – MVE, machine learning algorithms – Maxent and a presence-absence method – GLM). In addition, we grouped the 26 target species based on whether or not the species are in environmental pseudo-equilibrium (i.e., it occupies all habitats where it can disperse) and have any geographical or biological constraints. Our results suggest that the construction of supraspecific units improves the predictive capacity of correlative models to estimate the invasion area of our target species. This modeling approach consistently generated models with a higher predictive ability for species in non-environmental pseudo-equilibrium and with geographical constraints.

Public awareness of beach litter and alien invasions: Implications for early detection and management

Coastal areas are environments of high diversity and severely threatened by hazards as marine litter and biological invasions. Citizens’ knowledge and awareness are drivers of changes needed to improve environment conservation. Density both of litter and IAS Cortaderia selloana were measured from six beaches in southwest Bay of Biscay along with awareness of inhabitants of the zone using a social survey. Relationship between beach littering, alien invasion and perception and awareness of adults and students were assessed. Litter levels were associated with port presence and showed relationship between environmental degradation, IAS and litter accumulation. Adults were more aware about both issues and their perception of litter and plant invasion were positively correlated. Results suggest enhancing marine awareness, with more effort addressed specifically to students. There is a misperception of the real magnitude of IAS and litter impacts that should be approached improving awareness about this topics in the younger generations.

Diversity and patterns of marine non‐native species in the archipelagos of Macaronesia

AbstractAimsThe present study is the first attempt to grasp the scale and richness of marine biological invasions in Macaronesia. We pioneered a comprehensive non‐native species (NNS), inventory in the region to determine their diversity patterns and native distribution origins. NNS were defined here as the result of both introductions and range expansions. We also used statistical modelling to examine relationships among NNS richness, anthropogenic activities, demographic and geographical variables across Macaronesia.LocationMacaronesia.MethodsA comprehensive literature search was conducted for marine NNS records in Macaronesia, registering the first record's location and year from 1884 to 2020. We used univariate and multivariate analyses to evaluate differences and similarities in community composition. By applying a Generalized Linear Model (GLM), we tested hypotheses regarding NNS richness as a function of anthropogenic activities, demographic and geographical variables.ResultsA total of 144 marine non‐native species (NNS) were recorded for the whole of Macaronesia. The highest NNS richness was registered in the Canary Islands (76 NNS), followed by the Azores (66 NNS), Madeira (59 NNS) and finally Cabo Verde (18 NNS). Some differences amongst archipelagos were observed, such as the high number of non‐native macroalgae in the Azores, fishes in the Canary Islands and tunicates in Cabo Verde. Overall, macroalgae, tunicates and bryozoans were the predominant taxonomic groups in the Macaronesian archipelagos. Madeira and Canary Islands were the archipelagos with more similarity in marine NNS, and Cabo Verde the most divergent. Finally, GLM suggested that non‐native richness patterns across Macaronesia were dependent on the considered archipelago and strongly affected by (1) minimum distance to the mainland, (2) the total number of ports and marinas and (3) total marinas area (km2).ConclusionsThe model results and NNS listing in the present study will likely raise the awareness and response regarding marine NNS in the whole Macaronesia region, serving as a baseline for future research as well as implementing and enforcing regulations related to the introduction of marine NNS in oceanic islands.

Adding value to marine invaders by exploring the potential of Sargassum muticum (Yendo) Fensholt phlorotannin extract on targets underlying metabolic changes in diabetes

Marine biological invasions have considerable ecological and economic impact, and despite the attempts to control their spread, none has proved effective. Among seaweeds, Sargassum muticum (Yendo) Fensholt is recognized as one of the most successful invader species. If, on the one hand, S. muticum invasions are a potential threat to the marine environment, they can also arise as a valuable opportunity for obtaining unique bioactive compounds. While displaying a very mild inhibition towards α-amylase (IC50 > 5000 μg mL−1), phlorotannin-targeted S. muticum extract was particularly effective for α-glucosidase (IC50 = 27.06 μg mL−1), acting as a mixed-type inhibitor, and inhibited the activity of human aldose reductase (IC50 = 1345.85 μg mL−1), a key-enzyme in glucose metabolism. Moreover, the extract exhibited antiglycative effects and antioxidant properties, the latter being suggested as responsible for preventing macrophage-mediated injury. This work harnesses the biotechnological potential of S. muticum biomass, upholding the functionality of its polyphenolic constituents in the emergent interlink between diabetes, oxidative stress and inflammation.

The Case of Lionfish (Pterois miles) in the Mediterranean Sea Demonstrates Limitations in EU Legislation to Address Marine Biological Invasions

The European Regulation (EU) 1143/2014 on Invasive Alien Species entered into force in 2015, with the aim to fulfill regional and international biodiversity goals in a concerted manner. To date, the Regulation listed 66 Invasive Alien Species (IAS) that are subject to legal controls. Only one of these is marine. A recent lionfish (Pterois miles) invasion has been closely monitored in the Mediterranean and a detailed risk assessment was made about the profound impacts that this invasive fish is likely to have on the fisheries and biodiversity of the region. In 2016–21, lionfish rapidly became dominant predators along Eastern Mediterranean coasts, yet the process for their inclusion on the EU IAS list has been lengthy and is ongoing. There is an urgent need to learn from this experience. Here, we recommend improvements to the Regulation 1143/2014 and the risk assessment process to protect marine ecosystems and secure the jobs of people that rely on coastal resources.

Artificial Reef Monitoring Structures (ARMS) providing insights on hard substrate biodiversity and community structure of the Eastern Mediterranean Sea

Monitoring marine biodiversity in hard-bottom habitats is challenging as it typically involves resource-intensive, non-standardized, and often destructive sampling methods that limit its scalability. Differences in monitoring approaches furthermore hinder inter-comparison among monitoring programs. Standardised collectors such as Artificial Reef Monitoring Structures (ARMS) can be used to monitor status and changes of hard substrate communities in coastal environments. In addition, ARMS constitute an early-warning system for marine biological invasions by identifying newly introduced Non-Indigenous Species (NIS) and track the migration patterns of already known NIS in European continental waters. In the framework of ASSEMBLE+ project and as part of the European ARMS programme (ARMS-MBON) (Obst et al. 2020), ARMS were deployed in two locations in Greece and, more specifically, in the marina of the Old Venetian Harbour of Heraklion (1HERP) and in the Underwater Biotechnological Park of the Hellenic Centre for Marine Research (2UBPC). The ARMS deployment and retrieval dates are shown in Table 1; deployment and retrieval were done according to the standards and protocols established by the Smithsonian Institution. Upon retrieval, the plates from the ARMS were disassembled, photographed (Fig. 1a) and samples of both the motile and sessile communities were collected for molecular analysis. Each sampling event produced three fractions (sessile, motile 90–500 μm and motile 500 μm−2 mm) as well as a stack of plate and specimen images. DNA was extracted from the sampled fractions and amplified by PCR, targeting different molecular markers (18S rRNA, COI and ITS). Resulting amplicons were sequenced using Illumina MiSeq Reagent Kit v3 (2 × 300 bp) and analyzed using PEMA (Zafeiropoulos et al. 2020). All raw sequence files of this study were submitted to the European Nucleotide Archive (ENA) (Harrison et al. 2021) with the study accession number PRJEB33796. Images were analyzed using photoQuad image processing software (Trygonis and Sini 2012), which is specialised for the analysis of sessile biodiversity on photoquadrats. Cover of sessile taxa was measured by superimposing on every image 100 randomly distributed points. Each point was manually assigned to the corresponding taxon or morpho-functional category based on external morphological characters. Repeatable workflow procedures for integrated processing of image and sequence data are currently under development as part of the LifeWatch-ERIC Internal Joint Initiative on NIS. In addition, all ARMS-related data are stored in the ASSEMBLE Plus data collection of the Marine Data Archive (MDA) using a Darwin Core Archive (DwC-A) format, including the linkages to the images and sequences (Exter et al. 2020). Comparison of traditional biodiversity assessment methods, such as image-based identifications, complemented by the eDNA metabarcoding results, will shed light on the investigation of marine biodiversity patterns in the Eastern Mediterranean Sea (Fig. 1b). Furthermore, the results will provide crucial information on the importance of ARMS for biodiversity assessment and as an efficient tool to monitor community shifts and invasion events in marine ecosystems undegoing fast change.

Participatory monitoring of marine biological invaders: a novel program to include citizen scientists

Voluntary participation of citizens scientists has become a valuable tool for scientific research, but rarely applied for detection of non-native species in marine environments. This study was conducted in the Rio de Janeiro state, southeastern Brazil, at sites used for the SCUBA diving. The awareness activity was directed at dive centres before dives, addressing themes such as marine biodiversity, rocky reefs, biological invasions and citizen science. After the briefing, divers were invited to record occurrences of the invasive Tubastraea spp. on a wet note slate that were left under the responsibility of the dive centers, usually visible on the boat. This study showed a high level (100%) of credibility for data provided by volunteers, new records (N = 39) for the invasive species that had not previously been mentioned in published articles, and that the approach used is efficient in its spatial and temporal aspects. The successful development of citizen-based monitoring programs depends on the approximation of the academic community and the commitment of dive operators. The diver plays a critical role within this process, providing valuable information, which can be used to confirm the engagement of common citizens and also to track the spread of non-native marine species.

Research on the detection and early warning technology of harmful marine organisms in the water intake of nuclear power plant by 3D image sonar

In view of the frequent water intake blockage caused by marine biological invasion in many nuclear power plants, which affects the safety of cold source in nuclear power plants, a defense system in depth including marine biological identification, detection, early warning and hierarchical response is established through investigation and analysis of the causes of the event. Underwater acoustic high-resolution multi beam detection method is used to detect jellyfish, hairy shrimp and other marine organisms, The echo characteristics are obtained, the distribution density in sensitive sea area is analyzed, and the effective early warning judgment is given. Among them, detection and early warning is the front-end disposal measure, which can provide accurate and timely marine biological information for the subsequent hierarchical response. At the same time, it can replace the underwater inspection work of divers, reduce the risk of divers, reduce the risk of industrial safety, and improve the reliability of cold source.

Research status of ship’s ballast water detection

Marine ballast water is the main way of marine biological invasion and poses a serious threat to marine ecological security. In order to effectively prevent biological invasion and protect marine ecological safety, the International Maritime Organization (IMO) has adopted the International Convention for The Control and Management of Ship’s Ballast Water and Sediments. In this paper, the progress of the implementation of the convention is briefly introduced, with emphasis on the detection methods of ballast water according to the requirements of regulation D-1 and regulation D-2, such as salinity analysis method, colored dissolved organic matter content analysis method, microscope detection method, chlorophyll A detection method, flow cytometry detection method and flow imaging detection method.

Experimental study of transgenerational effects, pH and predation risk on byssus production in a swiftly spreading invasive fouling Asian mussel, Musculista senhousia (Benson)

Marine biofouling by the highly invasive Asian date mussel, Musculista senhousia (Benson), has caused devastating ecological and economic consequences in most coastal seas. Acute and short-term exposure experiments have demonstrated the susceptibility of mussel byssus – a holdfast structure by which mussels strongly adhere to underwater substrates, to pH. Yet, the influence of long-term exposures, especially across multiple generations, is largely unknown. Here, we evaluated transgenerational effects of pH on byssal threads secreted by M. senhousia, and compared byssus performance in absence versus presence of predators. If no predation occurred, neither pH nor transgenerational exposure significantly affected the number, length and diameter of byssal threads. Under predation risk, mussels, even exposed to low pH, significantly enhanced byssus production. In particular, individuals originating from parents grown under low conditions produced significantly more, longer and stronger byssal threads compared with those spawn from parents exposed to high pH, demonstrating positive transgenerational effects which can confer mussel byssus resilience at low pH. Given the energetically expensive nature of byssus production, these observations can be in line with previously documented plasticity of energy metabolism arose following transgenerational exposure to low pH, which allows mussels to allocate more energy to fulfill the synthesis and secretion of byssal proteins. Our findings demonstrate the remarkable ability of highly invasive fouling mussel species to respond plastically and adapt behaviorally to low pH and hence provide important implications for linking marine biofouling, biological invasion, and coastal acidification.

Find invasive seaweed: An outdoor game to engage children in science activities that detect marine biological invasion

Invasive species threaten worldwide biodiversity. Success in facing this problem may be possible through the engagement of younger audiences. Here, a game was designed to teach children how to recognize invasive seaweed and to encourage them to participate in marine citizen science. The game was first tested in a pilot study, and then carried out in Salinas High School (Asturias, Spain). Game-based training consisted of an explanation of invasive species, followed by the ‘Find invasive seaweed’ game and was evaluated with tests before and after the activity. After training, students spent 3 months looking for invasive species. Four invasive species were detected in the study area. The results showed a positive impact on knowledge gains and significant differences in marine environmental awareness and conservation actions.

Keeping up with introduced marine species at a remote biodiversity hotspot: awareness, training and collaboration across different sectors is key

Despite being a well-recognized issue, the introduction of non-native marine species is an underestimated topic in highly biodiverse developing countries. The Indonesian archipelago sits at the center of the Coral Triangle, extending over several biogeographic regions with unique benthic communities, where the extent of non-native species presence is largely unknown. It is also at the center of maritime traffic between Australasia and Asia, and therefore at risk of introduction of species that are carried on the hulls and ballast water of vessels. In the present study, we aimed to raise awareness on marine biological invasions across the Indonesian archipelago by fostering discussions among scientists, educating science students, generating media articles for the public and actively involving island communities. We also aimed to test the suitability of a range of methods commonly used in bioinvasion research (settlement arrays, DNA barcoding and environmental DNA metabarcoding, vessel surveys) to establish a baseline for biofouling species and potential threats, while developing much needed capacity for monitoring and application to other areas. We recorded 66 different non-coral specimens in the fouling communities of a remote group of islands of the Indonesian archipelago, represented mainly by the taxa Porifera, Tunicata and Mollusca, which are known to include notorious invasive species. None of the identified species was known to be invasive in the region but several were cryptogenic and/or were considered to have a very broad global distribution range that can potentially include part, or all, of the Indonesian archipelago. One species, the ascidian Didemnum molle, was found to quickly settle and spread on available blank substrates. While settlement plates (monitored every 5 months) proved suitable for early detection of potential incursions of these organisms, benthic surveys, DNA barcoding and eDNA metabarcoding provide valuable complementary baseline biodiversity information. A combination of sampling methods is therefore recommended for similar studies in understudied high biodiversity areas. Results from vessel surveys highlights the importance of civil society education in helping prevent bioinvasions. This study represents the first marine biological invasions baseline, awareness and capacity development training carried in the Indonesian archipelago. The lessons taken from the variety of methods explored in a simultaneously scientific and educational setting should prove useful and motivate similar work in other areas of the world.

Antarctica: The final frontier for marine biological invasions.

Antarctica is experiencing significant ecological and environmental change, which may facilitate the establishment of non‐native marine species. Non‐native marine species will interact with other anthropogenic stressors affecting Antarctic ecosystems, such as climate change (warming, ocean acidification) and pollution, with irreversible ramifications for biodiversity and ecosystem services. We review current knowledge of non‐native marine species in the Antarctic region, the physical and physiological factors that resist establishment of non‐native marine species, changes to resistance under climate change, the role of legislation in limiting marine introductions, and the effect of increasing human activity on vectors and pathways of introduction. Evidence of non‐native marine species is limited: just four marine non‐native and one cryptogenic species that were likely introduced anthropogenically have been reported freely living in Antarctic or sub‐Antarctic waters, but no established populations have been reported; an additional six species have been observed in pathways to Antarctica that are potentially at risk of becoming invasive. We present estimates of the intensity of ship activity across fishing, tourism and research sectors: there may be approximately 180 vessels and 500+ voyages in Antarctic waters annually. However, these estimates are necessarily speculative because relevant data are scarce. To facilitate well‐informed policy and management, we make recommendations for future research into the likelihood of marine biological invasions in the Antarctic region.

DNA barcodes of Antipode marine invertebrates in Bay of Biscay and Gulf of Lion ports suggest new biofouling challenges

Marine biological invasions threaten global biodiversity nowadays. In this article, we have studied fouling communities from 10 port areas of south Bay of Biscay (Atlantic Ocean) and Gulf of Lion (Mediterranean Sea). A total of 834 individuals were genetically barcoded and corresponded to 95 different species. A total of 76 native species 8 genera and 1 family were identified, 58 from the Bay of Biscay and 23 from the Gulf of Lion. Furthermore, 19 species were identified as non-indigenous or cryptogenic (18 from the Bay of Biscay and 4 from the Gulf of Lion). We found a high proportion of Antipode non-indigenous species (NIS) that represented the 19.3% of all sampled individuals and the 54.21% of NIS specimens of this study. A framework for inference of donor regions based on a phylogenetic screening of genetic sequences was proposed as a proof of concept and tested, as well as models for the relationship between NIS introductions, maritime imports and distance to NIS native range and inferred donor areas. Consistent generalized linear models (GLM) with positive association between NIS genetic diversity and distance, not with maritime growth weight imports, strongly suggest that distant NIS could pose higher invasion risk than closer species. Selection for wider tolerance ranges during the long travel –direct or stepwise, as well as environmental similarity between donor and receiving regions, may explain these results.

Pleistocene marine fish invasions and paleoenvironmental reconstructions in the eastern Mediterranean

Marine bioinvasions affect ecosystems in irreversible ways, creating socio-economic problems worldwide. In particular, eastern Mediterranean marine fish faunas today are significantly disturbed due to overfishing, habitat deterioration, the Lessepsian invasion, and climate change. Isolating the impact of each parameter is difficult, because pre-anthropogenic activity data are lacking. In this study, we use the paleontological record to infer the causes and mechanisms behind marine fish invasions, focusing on the Mediterranean basin, which is a restricted basin and a biological hotspot, where the effects of climatic and oceanographic changes are amplified. Therefore, the Mediterranean Sea is an ideal area to study marine biological invasions in relation to abrupt climate changes. Furthermore, we focus on the Pleistocene, which was a period of intense glacial–interglacial changes. Thus, we investigate the effect of climate changes on the fish fauna of an eastern Mediterranean shelf, by identifying the fish otoliths in the Early–Middle Pleistocene marine sediments of Rhodes (Greece). We offer a synthesis of the Mediterranean marine fish from the Tortonian until today and hypothesize on the conditions that drove marine fish distribution range shifts during the Pleistocene. We reconstruct the paleobathymetric evolution of the study areas based on fish otoliths, and we consider taphonomy in our interpretations. The Pleistocene climatic variability induced periodic and gradual replacements of fish taxa. Episodic invasions of cold-water North Atlantic mesopelagic species are correlated with intervals of climatic deterioration, specifically during marine isotope stages 50, 44, 36, 20, and 18.

A Framework for Understanding Marine Cosmopolitanism in the Anthropocene.

Recent years have witnessed growing appreciation for the ways in which human-mediated species introductions have reshaped marine biogeography. Despite this we have yet to grapple fully with the scale and impact of anthropogenic dispersal in both creating and determining contemporary distributions of marine taxa. In particular, the past several decades of research on marine biological invasions have revealed that broad geographic distributions of coastal marine organisms—historically referred to simply as “cosmopolitanism”—may belie complex interplay of both natural and anthropogenic processes. Here we describe a framework for understanding contemporary cosmopolitanism, informed by a synthesis of the marine bioinvasion literature. Our framework defines several novel categories in an attempt to provide a unified terminology for discussing cosmopolitan distributions in the world’s oceans. We reserve the term eucosmopolitan to refer to those species for which data exist to support a true, natural, and prehistorically global (or extremely broad) distribution. While in the past this has been the default assumption for species observed to exhibit contemporary cosmopolitan distributions, we argue that given recent advances in marine invasion science this assignment should require positive evidence. In contrast, neocosmopolitan describes those species that have demonstrably achieved extensive geographic ranges only through historical anthropogenic dispersal, often facilitated over centuries of human maritime traffic. We discuss the history and human geography underpinning these neocosmopolitan distributions, and illustrate the extent to which these factors may have altered natural biogeographic patterns. We define the category pseudocosmopolitan to encompass taxa for which a broad distribution is determined (typically after molecular investigation) to reflect multiple, sometimes regionally endemic, lineages with uncertain taxonomic status; such species may remain cosmopolitan only so long as taxonomic uncertainty persists, after which they may splinter into multiple geographically restricted species. We discuss the methods employed to identify such species and to resolve both their taxonomic status and their biogeographic histories. We argue that recognizing these different types of cosmopolitanism, and the important role that invasion science has played in understanding them, is critically important for the future study of both historical and modern marine biogeography, ecology, and biodiversity.

Rate of biological invasions is lower in coastal marine protected areas.

Marine biological invasions threaten biodiversity worldwide. Here we explore how Marine Protected areas, by reducing human use of the coast, confer resilience against the introduction of non-indigenous species (NIS), using two very different Pacific islands as case studies for developing and testing mathematical models. We quantified NIS vectors and promoters on Vancouver (Canada) and Moorea (French Polynesia) islands, sampled and barcoded NIS, and tested models at different spatial scales with different types of interaction among vectors and between marine protection and NIS frequency. In our results NIS were negatively correlated with the dimension of the protected areas and the intensity of the protection. Small to medium geographical scale protection seemed to be efficient against NIS introductions. The likely benefit of MPAs was by exclusion of aquaculture, principally in Canada. These results emphasize the importance of marine protected areas for biodiversity conservation, and suggest that small or medium protected zones would confer efficient protection against NIS introduction.