A Preliminary inventory of alien and cryptogenic species in Monastir Bay, Tunisia: spatial distribution, introduction trends and pathways

The Mediterranean Sea is a marine biodiversity hotspot under threat. One of the major impacts on its biological resources and services comes from the invasiveness of non-indigenous species (NIS). Nevertheless, NIS monitoring programs in the south basin of the Mediterranean Sea are in an early implementation stage. This study aims to describe NIS and cryptogenic species distribution in Monastir Bay (Tunisia) and to identify risk areas for the introduction and spread of invasive species, providing a baseline for future monitoring programs. To this end, a series of Rapid Assessment Surveys were carried out to identify NIS and cryptogenic species in one marina, five fishing ports, two aquaculture farms and the Special Conservation Area of the Kuriat islands. 24 species were found, of which 11 constitute new records for Monastir Bay, which represent a 33.3% of the total NIS reported in this Bay. Assemblages differed between substrata types, being NIS more abundant in artificial than in natural substrata. Regarding locations, Cap Monastir Marina was the most invaded site, the most transited by vessels and the only one visited by international sailing. Hence, this marina constitutes the main risk area to be monitored, although the fishing ports and fishing farms in the semi-enclosed coastal lagoon of Monastir Bay can also be considered as risk areas. Nevertheless, more research effort is needed in Monastir Bay in order to update the records of NIS and cryptogenic species and increase insight on the ecological evolution of these species and their related impacts on natural communities and marine resources

Impacts of the non-indigenous seaweed Rugulopteryx okamurae on a Mediterranean coralligenous community (Strait of Gibraltar): The role of long-term monitoring

The Mediterranean is one of the most biodiverse and anthropogenically impacted seas and the coralligenous is one of its most diverse habitats. Its presence is indicative of well-preserved areas and its associated species are considered among the best bioindicators for monitoring nearshore rocky habitats. This study aims to report the temporal fluctuations of the coralligenous community in the marine protected area of Jbel Moussa (Strait of Gibraltar) in a period concomitant with the rapid expansion of the non-indigenous species Rugulopteryx okamurae (E.Y.Dawson) I.K.Hwang, W.J.Lee & H.S.Kim in the area. From year 2015 to 2019, an area covering 36 m2 of the coralligenous habitat was monitored across three sites, including temperature logs from 2017 to 2019. After its first record in the area in 2017, R. okamurae became the most abundant species in only one year, followed by a change in the coralligenous community structure and a regression of the bioindicator species Paramuricea clavata (Risso, 1826) and Mesophyllum expansum (Philippi) Cabioch & M.L.Mendoza. These species are sensitive to increases in water temperature and were already under a gradual regression due to anthropogenic disturbances and previous biological invasions, all of which could have reduced niche competition in the area and favoured the impacts caused by R. okamurae in the area. Results highlight the need of a rapid administrative response to increase mitigation efforts on this protected habitat. Due the potential expansion of this non-indigenous invasive species to the Mediterranean Sea, the present study could provide valuable information for future monitoring, conservation and management actions.SPA/RAC–UN Environment/MAP MoU n◦ 60_SPA/RAC_201

From plates to baits: using a remote video foraging system to study the impact of foraging on fouling non-indigenous species

Marinas are a gateway for the introduction and establishment of non-indigenous species (NIS). In these habitats, competition and predation are crucial determinants for NIS establishment and invasiveness. However, fish trophic preferences and biotic effects inside marinas are poorly known. This study proposes a novel method that combines the deployment of settlement plates to recruit different assemblages, followed by their use as bait in remote underwater video systems. This combined approach, addressed as a remote video foraging system (RVFS), can record fish foraging behaviour, including feeding choices and their impacts on fouling assemblage composition. An experimental RVFS trial carried out in a marina of Madeira Island, Portugal (NE Atlantic), identified the Mediterranean parrotfish, Sparisoma cretense, as the most important fouling grazer in the area. S. cretense behaved as a generalist and increased the heterogeneity of fouling assemblages, which can hamper NIS dominance of the fouling and reduce the pressure of propagules from the marina to the natural environment. The RVFS tool was useful to understand the trophic links between foragers and fouling and has the potential to provide relevant information for the management of NIS introductions, establishment and spread.info:eu-repo/semantics/publishedVersio

A worrying arrival: the first record of brown macroalga Rugulopteryx okamurae in Madeira Island and its invasive risk

The brown macroalgae Rugulopteryx okamurae is described as one of the most severe and threatening invasive marine macroalgae in European waters. This study reports the first record of R. okamurae in the Madeira archipelago, which represents a new southern distribution limit of this species in NE Atlantic European waters. Morphological and molecular characters were used to confirm the species' identity, and its potential invasion risk in Madeiran waters was screened using the standard risk assessment tool AS-ISK. Results show that R. okamurae has a medium-high risk of becoming invasive in Madeira Island under present and future climate scenarios. The greater risk of impact involves suppressing local species growth and the modification and degradation of local habitats, including trophic cascade effects. However, environmental and commercial impacts could also occur in case of an explosion of the invasive populations. This new introduction in Madeira coastal waters emphasises the need for regular monitoring of R. okamurae, particularly to assess population dynamics to avoid establishing and further expansions. Finally, we recommend the evaluation of the possible derived impacts affecting rocky coastal communities and adopting the necessary mitigation measures and policies

Two new records and description of a new Perinereis (Annelida, Nereididae) species for the Saudi Arabian Red Sea region

Annelid biodiversity studies in the Red Sea are limited and integrative taxonomy is needed to accurately improve reference libraries in the region. As part of the bioblitz effort in Saudi Arabia to assess the invertebrate biodiversity in the northern Red Sea and Gulf of Aqaba, Perinereis specimens from intertidal marine and lagoon-like rocky environments were selected for an independent assessment, given the known taxonomic ambiguities in this genus. This study used an integrative approach, combining molecular with morphological and geographic data. Our results demonstrate that specimens found mainly in the Gulf of Aqaba are not only morphologically different from other five similar Perinereis Group I species reported in the region, but phylogenetic analysis using available COI sequences from GenBank revealed different molecular operational taxonomic units, suggesting an undescribed species, P. kaustiana sp. nov. The new species is genetically close and shares a similar paragnath pattern to the Indo-Pacific distributed P. helleri, in particular in Area III and Areas VII–VIII. Therefore, we suggest it may belong to the same species complex. However, P. kaustiana sp. nov. differs from the latter mainly in the shorter length of the postero-dorsal tentacular cirri, median parapodia with much longer dorsal Tentacular cirri, posteriormost parapodia with much wider and greatly expanded dorsal ligules. Additionally, two new records are reported for the Saudi Neom area belonging to P. damietta and P. suezensis, previously described only for the Egyptian coast (Suez Canal) and are distributed sympatrically with the new species, but apparently not sympatric with each other

‘Impossible’ re-introduction of the endangered limpet Patella ferruginea Gmelin, 1791? Progress in resolving translocation mortality

The Mediterranean ribbed limpet Patella ferruginea Gmelin, 1791 is the most endangered marine invertebrate listed in the EU Habitats Directive. A diversity of anthropic pressures have reduced its present-day distribution to a fraction of its former size. Perhaps surprisingly, this highly protected species has successfully established along man-made harbour breakwaters, resulting in serious complications when these structures have required modification or repair, often leading to costly impasses due to the legal status of the species. Attempts to move the limpets to other locations have resulted in unacceptably high mortality rates. This article describes the result of a field experiment where 97 P. ferruginea individuals were transported to a new site, using a technique which involved carefully moving the limpets whilst inactive (during low tide), still attached to their home scars on breakwater boulders. The results of this experiment were significantly positive, with 87% of all translocated limpets still alive 10 mo after the move, a mortality rate which compared favourably with that obtained for the existing control population at the receptor site. We propose that this method could be a practical solution to address the conflicts generated by this endangered species’ preference for harbour constructs. We further propose that this method can be used as a management tool to enhance the species’ survival prospects, by creating ‘stepping stones’ of pockets of reproducing individuals that can connect currently fragmented populations to effect a population recovery of this threatened organism

The Invasive Macroalga Rugulopteryx okamurae: Substrata Plasticity and Spatial Colonization Pressure on Resident Macroalgae

The present study constitutes the first evaluation of the space colonization strategies performed by Rugulopteryx okamurae when co-occurring with the resident macroalgal community in the introduced areas. Since the first apparition of the nonindigenous macroalga in the Strait of Gibraltar, its high propagation capacity together with its colonization ability has enhanced the establishment success of the species in detriment of the resident biota. In this study, we carried out observational surveys during 2017–2020 in order to assess the coverage levels of R. okamurae on different lighting conditions, surface orientations, and substrata types (artificial and natural). Results revealed that, beyond the high percent coverages already reported at illuminated and semi-illuminated natural rocky habitats, R. okamurae is able to settle on a wide variety of artificial substrata. The settlement performance of the species was also investigated and different mechanisms underlying the space colonization were proposed. Thus, R. okamurae was observed interacting with 43 resident macroalgal species at generally illuminated rocky habitats of the northern Strait coasts. Six colonization mechanisms were proposed for spatial growth scenarios. Overall, results pointed out that, in most of the cases where the invasive species co-occur with the resident community, R. okamurae would be favored as regards spatial growth success. Competitive interactions and environmental factors which influence results obtained must be addressed in order to fully predict impacts on resident communities. Moreover, together with previous scientific works, overall data provided in this study highlight the need to urgent implement management measures focused on habitats susceptible to be invaded, as well as studies on the ecology and dispersal vectors of R. okamurae in the Strait of Gibraltar and adjacent areas

Artificial marine micro-reserves as a new ecosystem-based management tool for marine conservation: The case of Patella ferruginea (Gastropoda, Patellidae), one of the most endangered marine invertebrates of the Mediterranean

During the Anthropocene, species are becoming extinct at unprecedented rates, a trend that will be difficult to reverse, even if we ignore the possibility of a considerable extinction debt. Among the different factors that affect the natural environment, fragmentation of ecosystems by urbanization processes can cause a reduction in species population sizes, thus enhancing their risk of extinction. Nevertheless, some species can maintain stable populations in these urbanized ecosystems. This is the case of the intertidal mollusc Patella ferruginea (Gmelin, 1791), a broadcast spawner, and a sequential protandrous hermaphrodite limpet, whose populations have been historically decimated due to human harvesting. In this study, we analyse the benefits of a new marine conservation tool called ¨Artificial Marine Micro-Reserves¨ (AMMR) in P. ferruginea, one of the most endangered marine invertebrates of the Mediterranean Sea. The results showed that accessibility is the main factor concerning the conservation status of this species, with no-entry areas where populations achieve balanced sex-ratios and high reproductive outputs. The present study was conducted in Ceuta (North Africa, Gibraltar Area), and among its varying results, it shows that in the same body of water inside the port, the proportion of females of P. ferruginea in the area without accessibility (high protection) was 4.68 and 43.54 times higher than in the medium and low accessibility (non-protected areas), respectively. Therefore, the effective protection of these artificial areas has a positive effect on population size structures, as the female's percentage in the population is crucial for fostering the creation of genetic bridges for the recolonization of natural habitats. Furthermore, a potential ‘umbrella effect’ can be derived from the implementation of the proposed AMMR in other protected species, bioindicators, or commercially exploited species detected in artificial structures. In this sense, the creation of artificial marine microreserve networks (AMMRNs) in coastal defense structures is in line with the interdisciplinary approach of Ecosystem-Based Management (EMB), given that this methodology balances ecological, social and governmental principles for achieving humane sustainable development

A worrying arrival: the first record of brown macroalga Rugulopteryx okamurae in Madeira Island and its invasive risk

The brown macroalgae Rugulopteryx okamurae is described as one of the most severe and threatening invasive marine macroalgae in European waters. This study reports the first record of R. okamurae in the Madeira archipelago, which represents a new southern distribution limit of this species in NE Atlantic European waters. Morphological and molecular characters were used to confirm the species' identity, and its potential invasion risk in Madeiran waters was screened using the standard risk assessment tool AS-ISK. Results show that R. okamurae has a medium-high risk of becoming invasive in Madeira Island under present and future climate scenarios. The greater risk of impact involves suppressing local species growth and the modification and degradation of local habitats, including trophic cascade effects. However, environmental and commercial impacts could also occur in case of an explosion of the invasive populations. This new introduction in Madeira coastal waters emphasises the need for regular monitoring of R. okamurae, particularly to assess population dynamics to avoid establishing and further expansions. Finally, we recommend the evaluation of the possible derived impacts affecting rocky coastal communities and adopting the necessary mitigation measures and policies.MIMAR+ MAC2/4.6.d/249Fundo Azul FA_06_2017_067Madeira 14-20 M1420-09-5369-FSE-000002Ministerio de Ciencia e Innovación CGL 2017-82739-PFundação para a Ciência e a Tecnologia UIDB/04292/2020, CEECINST/00098/201

Predation Facilitates the Abundance of Biofouling Non-indigenous Species in Estuarine Marinas in NE Atlantic Portugal

Harbours are highly modified habitats that differ from natural areas. They are hotspots of non-indigenous species (NIS) and act as stepping-stones in invasive processes. However, local communities can exert biotic resistance against biological invasions through trophic interactions and competition. This study assesses the biotic effects of predation on the recruitment of fouling assemblages in three marinas of NE Atlantic Portugal (Cascais, Setúbal and Sines), with particular emphasis on NIS, using predator exclusion experiments. Predation increased the relative abundance of NIS, mainly Watersipora subatra, in the estuarine marinas of Cascais and Setúbal, while no predation effects were registered in the coastal marina of Sines. Therefore, predation can increase the risk of NIS invasion (biotic facilitation). Furthermore, local ecosystems may have different effects and differ in vulnerability against NIS invasions. Finally, a better understanding of coastal invasive ecology and biotic effects in coastal artificial habitats will improve our capacity for NIS management.Agência Regional para o Desenvolvimento da Investigação, Tecnologia e Inovação M1420-09-5369-FSE-000002Ministerio de Ciencia, Innovación y Universidades PRE2018-086266, CGL 2017-82739-PFundação para a Ciência e a Tecnologia UIDB/04292/2020, LA/P/0069/2020, CEECINST/00098/2018, 2020.01797.CEECIN