Fishery reforms for the management of non-indigenous species

This study assessed the influence of summer seawater temperature and shipping on the introduction, establishment, and spread of nonindigenous fouling species on both local and regional scales in coastal regions of the USA. Using photographic surveys of 80 marinas on the east and west coasts of the USA, we defined thermal niches and ranges of summer sea surface temperature (SSST) for 27 abundant fouling species. We calculated percent cover of all abundant tunicates and bryozoans across sites and correlated species richness with water temperature and cargo shipping volume in each region. We quantified the relative importance of cargo shipping, seawater temperature, and distance between sites using Jaccard similarity between paired sites. Native species richness was positively correlated with SSST, while nonindigenous species (NIS) richness displayed a parabolic relationship with a peak at 20 °C. Temperature and cargo shipping traffic explained 53 % of variability in NIS richness, and only temperature was correlated with similarity between sites. We also found no link between similarity and distance between sites, and site–site comparisons showed no effect of NIS on native species richness on the scale of this study. It appears that cargo shipping may play a regional role in introduction of new species, but on local scales NIS distributions are more haphazard, possibly driven by local recreational boat traffic and associated larval dispersal or by other vectors affecting the local spread of these species. Our study demonstrates the importance of seawater temperature in allowing spread of NIS and influencing similarity between sites and regions.

ABSTRACTAnthropogenic disturbance is considered a risk factor in the establishment of non‐indigenous species (NIS); however, few studies have investigated the role of anthropogenic disturbance in facilitating the establishment and spread of NIS in marine environments. A baseline survey of native and NIS was undertaken in conjunction with a manipulative experiment to determine the effect that heavy metal pollution had on the diversity and invasibility of marine hard‐substrate assemblages. The study was repeated at two sites in each of two harbours in New South Wales, Australia. The survey sampled a total of 47 sessile invertebrate taxa, of which 15 (32%) were identified as native, 19 (40%) as NIS, and 13 (28%) as cryptogenic. Increasing pollution exposure decreased native species diversity at all study sites by between 33% and 50%. In contrast, there was no significant change in the numbers of NIS. Percentage cover was used as a measure of spatial dominance, with increased pollution exposure leading to increased NIS dominance across all sites. At three of the four study sites, assemblages that had previously been dominated by natives changed to become either extensively dominated by NIS or equally occupied by native and NIS alike. No single native or NIS was repeatedly responsible for the observed changes in native species diversity or NIS dominance at all sites. Rather, the observed effects of pollution were driven by a diverse range of taxa and species. These findings have important implications for both the way we assess pollution impacts, and for the management of NIS. When monitoring the response of assemblages to pollution, it is not sufficient to simply assess changes in community diversity. Rather, it is important to distinguish native from NIS components since both are expected to respond differently. In order to successfully manage current NIS, we first need to address levels of pollution within recipient systems in an effort to bolster the resilience of native communities to invasion.

Despite the Mediterranean being both a hotspot for recreational boating and for non‐indigenous species (NIS), no data currently exists on the recreational boating sector's contribution to the spread of NIS in this Sea.To improve the basis for management decisions, a wide‐scale sampling study on the biofouling communities of recreational vessels and marinas was undertaken. Specifically, we surveyed over 600 boat owners and sampled the same boat hulls for NIS in 25 marinas across the Mediterranean, from France to Cyprus, to determine which factors (i.e. boat characteristics, travel behaviour, home marina) are associated with higher NIS richness on boat hulls.Among the surveyed boats, we found recreational vessels to travel considerably, averaging 67 travel days and 7.5 visited marinas per annum. This results in a high potential for spreading NIS, especially as 71% of sampled vessels host at least one (and up to 11) NIS. Boats with high NIS richness strongly correlate with home marinas with high NIS richness. Over half of the vessels were carriers of NIS which were not yet present in the marinas they were visiting. The presence of biofouling in niche areas of the hull (i.e. in the cavities and metallic parts) emerges as the best predictor for NIS richness on boats, along with longer times since their last cleaning and antifouling applications. Interestingly, colonization of NIS occurred rapidly, even on boats that had recently had their hulls cleaned professionally.Synthesis and applications. We demonstrate that recreational boating has a very high capacity for the spread of non‐indigenous species (NIS) in the Mediterranean, due to both high NIS richness on boats and extensive travel. To counteract the spread of NIS, routine monitoring for new NIS needs to be established for both marinas and vessels, along with frequent pontoon cleaning. Additionally, policy should require preliminary screenings for incoming vessels from new countries, especially those emanating from high‐risk marinas. The niche areas of the boat hulls should be checked first for biofouling, which was the best predictor for NIS richness since they often go overlooked with in‐water cleanings are rarely have antifouling applied to them.

Effective monitoring of non-indigenous seaweeds and combatting their effects relies on a solid confirmation of the non-indigenous status of the respective species. We critically analysed the status of presumed non-indigenous seaweed species reported from the Mediterranean Sea, the Northeast Atlantic Ocean and Macaronesia, resulting in a list of 140 species whose non-indigenous nature is undisputed. For an additional 87 species it is unclear if they are native or non-indigenous (cryptogenic species) or their identity requires confirmation (data deficient species). We discuss the factors underlying both taxonomic and biogeographic uncertainties and outline recommendations to reduce uncertainty about the non-indigenous status of seaweeds. Our dataset consisted of over 19,000 distribution records, half of which can be attributed to only five species (Sargassum muticum, Bonnemaisonia hamifera, Asparagopsis armata, Caulerpa cylindracea and Colpomenia peregrina), while 56 species (40%) are recorded no more than once or twice. In addition, our analyses revealed considerable variation in the diversity of non-indigenous species between the geographic regions. The Eastern Mediterranean Sea is home to the largest fraction of non-indigenous seaweed species, the majority of which have a Red Sea or Indo-Pacific origin and have entered the Mediterranean Sea mostly via the Suez Canal. Non-indigenous seaweeds with native ranges situated in the Northwest Pacific make up a large fraction of the total in the Western Mediterranean Sea, Lusitania and Northern Europe, followed by non-indigenous species with a presumed Australasian origin. Uncertainty remains, however, regarding the native range of a substantial fraction of non-indigenous seaweeds in the study area. In so far as analyses of first detections can serve as a proxy for the introduction rate of non-indigenous seaweeds, these do not reveal a decrease in the introduction rate, indicating that the current measures and policies are insufficient to battle the introduction and spread of non-indigenous species in the study area.

This paper evaluates the potential effects of future commercial shipping through the Northern Sea Route and Northwest Passage on the spread of nonindigenous species (NIS) between Europe, the United States, and the Asia-Pacific region. We modeled NIS spread risk as a function of two factors: NIS introduction and NIS establishment. The change in risk of NIS introduction from one region to another is based on the expected commodity trade flow between the two regions given Arctic shipping routes. The risk of NIS establishment is based on current marine climate similarities between regions and projected 2030 terrestrial climate similarities. Results indicate that the United States, China, and Japan are at greatest risk for increased terrestrial and marine NIS spread to and from one another given their relatively high levels of trading activity and terrestrial and marine climate similarities. While increased trade between European and Asia-Pacific countries is expected in the future, only Japan has terrestrial climate similar enough to that of European countries to be considered a substantial terrestrial NIS spread risk, while China has the potential to increase the risk of marine NIS species spread in Europe.

Non-indigenous Species (NIS) pose significant threats to marine biodiversity globally, especially in ecologically sensitive habitats such as Marine Protected Areas (MPAs). This study uses data collected in the Autonomous Region of Madeira (North Atlantic), Portugal, to create a spatial model aiming to (1) develop a spatially explicit index of NIS dispersal from known hotspots such as ports, harbours, marinas, and anchoring areas; (2) assess the relative vulnerability of Madeira's MPAs to local NIS dispersion and establishment; and (3) provide insights for a scalable NIS monitoring framework and evaluating invasion risks. The spatial model integrates maritime traffic intensity and proximity to NIS hotspots, using a straightforward approach that can be applied in data-limited contexts. While designed to address Madeira's regional challenges, the model is adaptable to other biogeographic contexts and can incorporate additional complexity, such as species-specific traits or ecological layers, to suit different settings. Our findings underscore the role of maritime infrastructure and vessel traffic in NIS spread, revealing the vulnerability of Madeira's MPAs due to insufficient ecological monitoring and the absence of NIS monitoring and early detection programs. This study provides practical recommendations for improving MPA management and mitigating NIS risks, contributing to regional conservation efforts. Additionally, it establishes a baseline risk assessment approach that can be customised and expanded to guide NIS management and biodiversity conservation in other regions, particularly those with similar challenges.

Who, why and how: stakeholder attitudes toward marine non-indigenous species management in Portuguese Atlantic Islands

Deforestation of rainforests requires active use of UN's Sustainable Development Goals

Rethinking marine resource governance for the United Nations Sustainable Development Goals

Defining the qualitative elements of Aichi Biodiversity Target 11 with regard to the marine and coastal environment in order to strengthen global efforts for marine biodiversity conservation outlined in the United Nations Sustainable Development Goal 14

Biological invasions are widely recognized as a major threat to native biodiversity, ecosystem functioning and services. Non-indigenous species (NIS) may in time become invasive (invasive alien species (IAS)), determining significant environmental, socioeconomic and human health impacts such as biodiversity loss and ecosystem service degradation. The Mediterranean islands, particularly Sicily and the circum-Sicilian islands (northwestern Mediterranean Sea), which are important hotspots of biodiversity, are notably vulnerable to anthropogenic pressures such as biological invasions. Therefore, monitoring NIS distribution as well as understanding their effects on native biodiversity is critical in these areas for planning effective conservation strategies. Here, we report four different case studies from Sicily that highlight how NIS may affect native biodiversity and habitats. The first three case studies were carried out within Marine Protected Areas (MPAs) and highlight (1) the ability of Caulerpa cylindracea to promote the establishment of other NIS, including biofouling worms belonging to the genus Branchiomma; (2) how the shift in habitat from the native Ericaria brachycarpa to the invasive Asparagopsis taxiformis may drastically erode the primary producer biomass and associated biodiversity; and (2) that the presence of Lophocladia lallemandii can affect the molluscan assemblage inhabiting the canopy-forming Gongolaria montagnei. The fourth case study, performed along the northwestern coast of Sicily, shows how Halophila stipulacea can affect the growth of the co-occurring native seagrass Cymodocea nodosa. Overall, these case studies demonstrate various ways in which NIS can interact with native biodiversity and habitats. Furthermore, they emphasize that MPAs are ineffective at preventing the introduction and spread of NIS.

The role of commercial harbours as sink and source habitats for non-indigenous species (NIS) and the role of recreational boating for their secondary spread were investigated by analysing the fouling community of five Italian harbours and five marinas in the western Mediterranean Sea. It was first hypothesised that NIS assemblages in the recreational marinas were subsets of those occurring in commercial harbours. However, the data did not consistently support this hypothesis: the NIS pools of some marinas significantly diverged from harbours even belonging to the same coastal stretches, including NIS occurring only in marinas. This study confirms harbours as hotspots for marine NIS, but also reveals that numbers of NIS in some marinas is higher than expected, suggesting that recreational vessels effectively facilitate NIS spread. It is recommended that this vector of NIS introduction is taken into account in the future planning of sustainable development of maritime tourism in Europe.

Many coastal regions are encountering issues with the spread of nonindigenous species (NIS). In this study, we conducted a regional risk assessment using a Bayesian network relative risk model (BN-RRM) to analyze multiple vectors of NIS introductions to Padilla Bay, Washington, a National Estuarine Research Reserve. We had 3 objectives in this study. The 1st objective was to determine whether the BN-RRM could be used to calculate risk from NIS introductions for Padilla Bay. Our 2nd objective was to determine which regions and endpoints were at greatest risk from NIS introductions. Our 3rd objective was to incorporate a management option into the model and predict endpoint risk if it were to be implemented. Eradication can occur at different stages of NIS invasions, such as the elimination of these species before being introduced to the habitat or removal of the species after settlement. We incorporated the ballast water treatment management scenario into the model, observed the risk to the endpoints, and compared this risk with the initial risk estimates. The model results indicated that the southern portion of the bay was at greatest risk because of NIS. Changes in community composition, Dungeness crab, and eelgrass were the endpoints most at risk from NIS introductions. The currents node, which controls the exposure of NIS to the bay from the surrounding marine environment, was the parameter that had the greatest influence on risk. The ballast water management scenario displayed an approximate 1% reduction in risk in this Padilla Bay case study. The models we developed provide an adaptable template for decision makers interested in managing NIS in other coastal regions and large bodies of water.

East is east and West is west? Management of marine bioinvasions in the Mediterranean Sea

The introduction and establishment of nonindigenous species (NIS) through global ship movements poses a significant threat to marine ecosystems and economies. While ballast-vectored invasions have been partly addressed by some national policies and an international agreement regulating the concentrations of organisms in ballast water, biofouling-vectored invasions remain largely unaddressed. Development of additional efficient and cost-effective ship-borne NIS policies requires an accurate estimation of NIS spread risk from both ballast water and biofouling. We demonstrate that the first-order Markovian assumption limits accurate modeling of NIS spread risks through the global shipping network. In contrast, we show that higher-order patterns provide more accurate NIS spread risk estimates by revealing indirect pathways of NIS transfer using Species Flow Higher-Order Networks (SF-HON). Using the largest available datasets of non-indigenous species for Europe and the United States, we then compare SF-HON model predictions against those from networks that consider only first-order connections and those that consider all possible indirect connections without consideration of their significance. We show that not only SF-HONs yield more accurate NIS spread risk predictions, but there are important differences in NIS spread via the ballast and biofouling vectors. Our work provides information that policymakers can use to develop more efficient and targeted prevention strategies for ship-borne NIS spread management, especially as management of biofouling is of increasing concern.