They are here to stay: the biology and ecology of lionfish (Pterois miles) in the Mediterranean Sea.

The lionfish, Pterois miles, is one of the most recent Lessepsian immigrants into the Mediterranean Sea, and it poses a serious threat to marine ecosystems in the region. This study assesses the basic biology and ecology of lionfish in the Mediterranean, examining morphometrics, reproduction and diet as well as population structure and distribution. The population density of lionfish has increased dramatically in Cyprus since the first sighting in late 2012; by 2018 aggregations of up to 70 lionfish were found on rocky grounds with complex reefs and artificial reefs in depths of 0-50 m. Lionfish in Cyprus become mature within a year, and adults are capable of spawning year-round, with peak spawning in summer when the sea-surface temperature reaches 28.4°C. The Cypriot lionfish grow faster and bigger than in their native range, and females are more common than males. Lionfish are generalist predators in these waters, as also found in their native range, consuming a range of teleost and crustacean prey, some of which are of high economic value (e.g., Spicara smaris and Sparisoma cretense) or have an important role in local trophic webs (e.g., Chromis chromis). Overall, the reproductive patterns, the presence of juveniles and adults throughout the year, the rapid growth rates and the generalist diet indicate that lionfish are thriving and are now already well established in the region and could potentially become the serious nuisance that they are in their temperate and tropical western Atlantic-invasive range.

Recommendations for developing and applying genetic tools to assess and manage biological invasions in marine ecosystems.

The European Union's Marine Strategy Framework Directive (MSFD) aims to adopt integrated ecosystem management approaches to achieve or maintain "Good Environmental Status" for marine waters, habitats and resources, including mitigation of the negative effects of non-indigenous species (NIS). The Directive further seeks to promote broadly standardized monitoring efforts and assessment of temporal trends in marine ecosystem condition, incorporating metrics describing the distribution and impacts of NIS. Accomplishing these goals will require application of advanced tools for NIS surveillance and risk assessment, particularly given known challenges associated with surveying and monitoring with traditional methods. In the past decade, a host of methods based on nucleic acids (DNA and RNA) analysis have been developed or advanced that promise to dramatically enhance capacity in assessing and managing NIS. However, ensuring that these rapidly evolving approaches remain accessible and responsive to the needs of resource managers remains a challenge. This paper provides recommendations for future development of these genetic tools for assessment and management of NIS in marine systems, within the context of the explicit requirements of the MSFD. Issues considered include technological innovation, methodological standardization, data sharing and collaboration, and the critical importance of shared foundational resources, particularly integrated taxonomic expertise. Though the recommendations offered here are not exhaustive, they provide a basis for future intentional (and international) collaborative development of a genetic toolkit for NIS research, capable of fulfilling the immediate and long term goals of marine ecosystem and resource conservation.

Living with an enemy: Invasive sun-coral (Tubastraea spp.) competing against sponges Desmapsamma anchorata in southeastern Brazil.

The azooxanthellate corals Tubastraea coccinea and T. tagusensis invaded the Brazilian coast in the 1980s and is still in expansion, favored by lower predation and competition pressure in their new habitats. Interestingly, the native sponge Desmapsamma anchorata has been observed overgrowing these corals. Considering that competitive displacement is expected to play a major role in the successful outcome of an invasion, the present study tested the physical and chemical mechanisms possibly involved in the competition between D. anchorata and the Tubastraea corals through field and aquaria experiments as well as the Raman spectroscopy technique for chemical analysis. Our results showed that the sponge grew in all directions including over Tubastraea colonies and regardless of its presence. There was no evidence of a specific chemical response among sponges or corals. However, we observed the extrusion of mesenteric filaments and tentacles of corals and the projection of sponge tissue during interspecific interaction, which suggests that physical imposition plays a key role for space competition at micro scales. Given the interspersed nature of benthic species distributions and the fast expansion of Tubastraea, it is unlikely that D. anchorata or any other sponges could serve a biological control against these invasive corals at larger scales, but our results showed that at a microscale they can withstand the corals presence and even outgrow them locally.

Monthly eDNA Monitoring of an Invasive Bryozoan, Bugulina californica, in Seawater Using Species-Specific Markers.

Environmental DNA (eDNA) method used by many ecologists as effective investigation tool can detect endangered species, rare species, and invasive species. In case of invasive species, eDNA method help to monitor the target species when the species was hard to detect through the traditional survey such as the early stage of invasion, low abundance, and larva or juvenile stage. The bryozoan, Bugulina californica, was known as a marine fouling invasive species in Korea since its first reported in 1978. This species expanded nationwide, and damages to ascidian aquaculture through attached on the ship hulls and artificial facilities. To monitor the distribution and biomass of invasive bryozoan, B. californica, the qPCR analysis of environmental DNA was performed on seawater samples from 12 harbors. In this study, we designed species-specific markers which can calculate the detected DNA copies of B. californica, and the presence and monitoring of this species can be more accurately estimated by environmental DNA analysis than by traditional survey, in which it is difficult to identify the species. Real-time PCR analysis using environmental DNA is an effective monitoring method that can determine both the distribution and the monthly change in biomass of B. californica in Korea.

Warming may increase the vulnerability of calcareous algae to bioinvasions.

Understanding the interactions between various stressors, and the resulting cumulative impacts they exert, is essential in order to predict the potential resilience of marine habitats to climate change. Crustose coralline algae (CCA) are a major calcifying component of marine habitats, from tropical to polar oceans, and play a central role as ecosystem engineers in many rocky reefs. These species are increasingly threatened by the stress of climate change. However, the effects of other stressors linked to global change, such as invasive species, have scarcely been addressed. We have studied the interactive effects of invasive algae and global warming on CCA, combining observational and experimental approaches. CCA sensitivity to invasive algae is heightened when they are concurrently exposed to elevated seawater temperature, and the interaction between these two stressors triggers drastic synergistic effects on CCA. The reduction and eventual disappearance of these "ecosystem foundation species" may undermine ecological functioning, leading to the disappearance and/or fragmentation of the communities associated with them.

Management priorities for marine invasive species.

Managing invasive alien species is particularly challenging in the ocean mainly because marine ecosystems are highly connected across broad spatial scales. Eradication of marine invasive species has only been achieved when species were detected early, and management responded rapidly. Generalized approaches, transferable across marine regions, for prioritizing actions to control invasive populations are currently lacking. Here, expert knowledge was elicited to prioritize 11 management actions for controlling 12 model species, distinguished by differences in dispersion capacity, distribution in the area to be managed, and taxonomic identity. Each action was assessed using five criteria (effectiveness, feasibility, acceptability, impacts on native communities, and cost), which were combined in an 'applicability' metric. Raising public awareness and encouraging the commercial use of invasive species were highly prioritized, whereas biological control actions were considered the least applicable. Our findings can guide rapid decision-making on prioritizing management options for the control of invasive species especially at early stages of invasion, when reducing managers' response time is critical.

Analyzing trends in ballasting behavior of vessels arriving to the United States from 2004 to 2017.

Maritime shipping transports over 90% of global goods. Ballast water, used to provide vessel stability, has been associated with the introduction of marine invasive species. Thus, understanding ballasting trends is imperative to protecting human and environmental health. This paper examines data from the National Ballast Information Clearinghouse to assess ballasting behavior and shipping trends in the United States. From 2005 to 2017, vessel arrivals have remained relatively constant (annual growth rate of 1.2% per year) while total ballast discharge per vessel has grown at an annual rate of 7.6%. Furthermore, from 2014 to 2016, alternative ballast water management methods have been on the rise, and these treatment options are likely to continue increasing in response to the International Maritime Organization Ballast Water Management Convention that entered into force in September 2017. It is critical that the shipping industry monitors potential cascading impacts on other ballasting behaviors stemming from this shift.

Research on the fundamental principles of China's marine invasive species prevention legislation.

China's coastal area is severely damaged by marine invasive species. Traditional tort theory resolves issues relevant to property damage or personal injuries, through which plaintiffs cannot cope with the ecological damage caused by marine invasive species. Several defects exist within the current legal regimes, such as imperfect management systems, insufficient unified technical standards, and unsound legal responsibility systems. It is necessary to pass legislation to prevent the ecological damage caused by marine invasive species. This investigation probes the fundamental principles needed for the administration and legislation of an improved legal framework to combat the problem of invasive species within China's coastal waters.