Management of exogenous threats to Antarctica and the sub-Antarctic Islands: balancing risks from TBT and non-indigenous marine organisms

The discovery of high levels of tributyltin compounds in Antarctic marine sediments has prompted managers to consider the banning of such substances in this region. We propose that the banning of antifouling coatings may result in an increase in the risk of non-indigenous species invasions. Our studies show that un-treated vessels carry a more diverse community of fouling organisms than treated hulls on which fouling is restricted to specific untreated niches. Up to 40% of the species recruited to the hulls of Southern Ocean vessels are species with invasive histories. Viable fouling assemblages can survive prolonged voyages to high-latitude coastlines, yet passage through sea-ice may remove fouling communities due to mechanical abrasion reducing the hazard of introductions to ice-bound coastlines. The banning of antifouling compounds may be of particular concern for the ice-free sub-Antarctic islands which represent a common anchorage point for vessels on-route to Antarctica.     

Recommendations on methods for the detection and control of biological pollution in marine coastal waters

Adverse effects of invasive alien species (IAS), or biological pollution, is an increasing problem in marine coastal waters, which remains high on the environmental management agenda. All maritime countries need to assess the size of this problem and consider effective mechanisms to prevent introductions, and if necessary and where possible to monitor, contain, control or eradicate the introduced impacting organisms. Despite this, and in contrast to more enclosed water bodies, the openness of marine systems indicates that once species are in an area then eradication is usually impossible. Most institutions in countries are aware of the problem and have sufficient governance in place for management. However, there is still a general lack of commitment and concerted action plans are needed to address this problem. This paper provides recommendations resulting from an international workshop based upon a large amount of experience relating to the assessment and control of biopollution.     

Phytoplankton invasions: comments on the validity of categorizing the non-indigenous dinoflagellates and diatoms in European seas

The validity of categorizing the diatoms and dinoflagellates reported in the literature as non-indigenous phytoplankton in the European Seas was investigated. Species that are synonymous are often included as separate species (Gessnerium mochimaensis=Alexandrium monilatum, Gymnodinium nagasakiense=Karenia mikimotoi, Pleurosigma simonsenii=P. planctonicum), while other species names are synonyms of cosmopolitan taxa (Prorocentrum redfieldii=P. triestinum, Pseliodinium vaubanii=Gyrodinium falcatum, Gonyaulax grindleyi=Protoceratium reticulatum, Asterionella japonica=Asterionellopsis glacialis). Epithets of an exotic etymology (i.e. japonica, sinensis, indica) imply that a cosmopolitan species may be non-indigenous, and several taxa are even considered as non-indigenous in their type locality (Alexandrium tamarense and A. pseudogoniaulax). The records of Alexandrium monilatum, A. leei and Corethron criophilum are doubtful. Cold or warm-water species expand their geographical ranges or increase their abundances to detectable levels during cooling (Coscinodiscus wailesii) or warming periods (Chaetoceros coarctatus, Proboscia indica, Pyrodinium bahamense). These are a few examples of marginal dispersal associated with climatic events instead of species introductions from remote areas. The number of non-indigenous phytoplankton species in European Seas has thus been excessively inflated.     

Removing vessels from the water for biofouling treatment has the potential to introduce mobile non-indigenous marine species

Vessels found contaminated with biofouling non-indigenous marine species are predominantly removed from the water and treated in vessel maintenance facilities (i.e., slipways, travel lifts and dry-docks). Using pre-fouled settlement plates to simulate a vessel’s removal from the water for treatment, we demonstrate that a range of mobile organisms (including non-indigenous marine species) may be lost to the marine environment as a consequence of this process. We also determined that different levels of biofouling (primary, secondary and tertiary) and emersion durations (0.5, 5 and 15 min) affected the abundance and composition of mobile taxa lost to the marine environment. Primary biofouling plates lost 3.2% of total animals, secondary plates lost 19.8% and tertiary plates lost 8.2%, while hanging duration had only minor effects. The results suggest that removing vessels contaminated with biofouling non-indigenous marine species from the water for treatment may not be as biosecure as is currently recognised.     

Distribution of Sargassum muticum on the North West coast of Spain: Relationships with urbanization and community diversity

Invasions are common in coastal marine environments where proximity to urban areas should influence the number of non-native organisms due to the likelihood of unintentional introductions from urban centers. Invasive species are widely recognised as important agents of global change, and can colonize new habitats and even cause local extinction of native species. This study was focused on the invasive marine macroalga Sargassum muticum, a problematic invasive species on the West coast of America and in European waters. An intensive survey was carried out along the Galician coast (North West of Spain) from March to August 2008 to determine the current distribution of this species, and its relationship with level of urbanization and native macroalgal diversity. We sampled the presence of S. muticum and native macroalgae in the mid and low intertidal zones of twenty rocky shores distributed along ten rias. Rias were grouped into high and scarcely urbanized based on their population density. Results indicated that S. muticum was present in nine out of the ten rias, confirming its presence in most of the intertidal rocky shores of Galicia twenty years after it was first observed. The presence of S. muticum was not related to the degree of urbanization of the rias, and its distribution and abundance did not seem to be influenced by diversity or functional groups of native algae. In addition, there was a great variability in the percentage cover, number and length of individuals amongst localities and rias suggesting that both large-scale and local processes may play a role in the distribution of this species. This study highlights the importance of future research into the distribution and impact of introduced algae and proves the urgent need for monitoring programmes and increasing efforts to prevent and control new introductions.     

International collaboration on marine bioinvasions--the ICES response

The International Council for the Exploration of the Sea (ICES) noted the risks associated with uncontrolled species introductions and transfers more than 40 years ago and launched two working groups to address the issue, i.e. the ICES Working Group on Introductions and Transfers of Marine Organisms (WGITMO) to deal with the movement of non-indigenous species for e.g. aquaculture purposes and the ICES/IOC/IMO Working Group on Ballast and Other Ship Vectors which focuses on species movements with ships. Both groups are actively working until today and the key achievements of the groups are outlined.     

Survey evaluations to assess marine bioinvasions

Countries need to know what species are present within their waters to effectively manage the issue of non-indigenous marine species. Five survey methods are currently employed to detect introduced marine species: the Hewitt and Martin protocols (66% of effort; 73 ports, 12 countries); Rapid Assessment Surveys (7% of effort; 8 regions, 4 countries); the Bishop Museum protocols (7% of effort; 8 ports, 3 countries); the Chilean aquaculture surveys (1% of effort; numerous regions; 1 country); and Passive Sampling protocols (18% of effort; 20 ports, 2 countries). These methods use either quantitative, qualitative, or a mixture of the two sampling techniques and tend to target locations that are potential inoculation sites (i.e., such as ports, marinas and aquaculture facilities). To date, introduced marine species surveys have been implemented in 19 countries and have detected more than 1185 non-indigenous, 735 cryptogenic and 15,315 native species.     

Managing invasive crayfish: is there a hope?

Given that the impact exerted by non-indigenous crayfish species (NICS) is most often severe, can occur across many levels of ecological organization, and results in the loss of native crayfish populations, the Convention on Biological Diversity approach, as complemented by the European Strategy, is viewed as an excellent framework to be followed to prevent the introduction of NICS and to alleviate or eliminate the damage they inflict. Much effort should be directed to minimize the risks of intentional introductions, as in part done by the Council Regulation No. 708/07 in force in the European Union since 2009. However, this and other regulations are not well harmonized, for instance, with those concerning both the aquarium trade and the harvest of crayfish for human consumption. To make prevention more difficult, there are many records of illegal release of NICS into the wild and of their accidental introduction as undetected contaminants in batches of regulated fish species. As a consequence, it seems necessary that post-introduction mitigation and remediation protocols and processes, such as contingency plans, are always in place to enable rapid detection and early response in order to minimize and, ideally, annul the threats posed by NICS. The aim of this review paper is to offer a synthetic view of the different methods (mechanical removal, physical methods, biological control, biocides, and autocidal methods) proposed and adopted until now to control NICS with a discussion of their pitfalls and potentialities. A glimpse to the ongoing research in the matter will be also given.     

Crustacean assemblages in a polluted estuary from South-Western Spain

The spatial-temporal variation in crustacean assemblages of the Odiel-Tinto estuary, one of the most polluted areas in the world, was studied in 2000, 2002 and 2004. The crustacean assemblages were mainly established according to the natural gradient from estuarine to marine environment (based on water and sediment characteristics such as dissolved oxygen, salinity, granulometry or organic content). Pollutants such as copper, zinc or phosphates could also explain partially this pattern based on BIOENV and canonical correspondence analyses. However, there were clear symptoms of perturbation, mainly in the inner areas, such as a low number of species and a low abundance, especially in relation to the typical estuarine species (e.g. Cyathura carinata, Corophium spp.). This study provides baseline information which can be used as a reference point in a long-term perspective.     

Marine introductions in the Southern Ocean: an unrecognised hazard to biodiversity

This study investigated the potential for transport of organisms between Hobart, Macquarie Island and the Antarctic continent by ships used in support of Antarctic science and tourism. Northward transport of plankton in ballast water is more likely than southward transport because ballast is normally loaded in the Antarctic and unloaded at the home port. Culturing of ballast water samples revealed that high-latitude hitchhikers were able to reach greater diversities when cultured at temperate thermal conditions than at typical Southern Ocean temperatures, suggesting the potential for establishment in the Tasmanian coastal environment. Several known invasive species were identified among fouling communities on the hulls of vessels that travel between Hobart and the Southern Ocean. Southward transport of hull fouling species is more likely than northward transport due to the accumulation of assemblages during the winter period spent in the home port of Hobart. This study does not prove that non-indigenous marine species have, or will be, transported and established as a consequence of Antarctic shipping but illustrates that the potential exists. Awareness of the potential risk and simple changes to operating procedures may reduce the chance of introductions in the future.     

Comparative risk assessment of permethrin, chlorothalonil, and diuron to coastal aquatic species

The precise application of risk assessment can lead to different conclusions about risk depending on how species are grouped in the assessment. We compared the use of different risk assessment methods for three different classes of pesticide, the herbicide diuron, the fungicide chlorothalonil, and the insecticide permethrin for marine and estuarine species. Permethrin was the most toxic pesticide to marine and estuarine crustaceans. Diuron was the most toxic pesticide to algae, and chlorothalonil was most toxic to early life stages of molluscs and other invertebrates. Toxicity data (96 h LC50/EC50 values) were analyzed using a probability distribution on the ranked toxicity values and 10th centile values were calculated based on different groups of species and for all species combined. Our results indicate that an assessment of risk based on smaller taxonomic groups can be informative, especially for pesticides of less specific modes of action such as chlorothalonil.     

Evidence for the effects of metal contamination on the intertidal macrobenthic assemblages of the Fal Estuary

The intertidal invertebrate macrofauna of five creeks in the Fal estuarine system, Cornwall, UK, is compared with data from 40 locations in six other estuaries in south-west Britain. Multivariate analysis shows that the community composition in the Fal is distinct from all the other estuaries. The differences are principally due to the absence of two crustacean species, Corophium voluntator and Cyathura carinata, and the high abundance of small opportunistic annelid species. The Fal Estuary is heavily contaminated with heavy metals as a result of mining in the catchment, and the faunistic features are commensurate with what is known of the relative sensitivities of marine invertebrate taxa to pollution.     

Overview of integrative tools and methods in assessing ecological integrity in estuarine and coastal systems worldwide

In recent years, several sets of legislation worldwide (Oceans Act in USA, Australia or Canada; Water Framework Directive or Marine Strategy in Europe, National Water Act in South Africa, etc.) have been developed in order to address ecological quality or integrity, within estuarine and coastal systems. Most such legislation seeks to define quality in an integrative way, by using several biological elements, together with physico-chemical and pollution elements. Such an approach allows assessment of ecological status at the ecosystem level ('ecosystem approach' or 'holistic approach' methodologies), rather than at species level (e.g. mussel biomonitoring or Mussel Watch) or just at chemical level (i.e. quality objectives) alone. Increasing attention has been paid to the development of tools for different physico-chemical or biological (phytoplankton, zooplankton, benthos, algae, phanerogams, fishes) elements of the ecosystems. However, few methodologies integrate all the elements into a single evaluation of a water body. The need for such integrative tools to assess ecosystem quality is very important, both from a scientific and stakeholder point of view. Politicians and managers need information from simple and pragmatic, but scientifically sound methodologies, in order to show to society the evolution of a zone (estuary, coastal area, etc.), taking into account human pressures or recovery processes. These approaches include: (i) multidisciplinarity, inherent in the teams involved in their implementation; (ii) integration of biotic and abiotic factors; (iii) accurate and validated methods in determining ecological integrity; and (iv) adequate indicators to follow the evolution of the monitored ecosystems. While some countries increasingly use the establishment of marine parks to conserve marine biodiversity and ecological integrity, there is awareness (e.g. in Australia) that conservation and management of marine ecosystems cannot be restricted to Marine Protected Areas but must include areas outside such reserves. This contribution reviews the current situation of integrative ecological assessment worldwide, by presenting several examples from each of the continents: Africa, Asia, Australia, Europe and North America.     

Marine biosecurity: The importance of awareness, support and cooperation in managing a successful incursion response

Shipping is almost certainly the most prevalent human-mediated transport vector for non-indigenous species (NIS) within the marine environment. The Royal Australian Navy (RAN) has long acknowledged the importance of sound environmental management and in recent years has taken a proactive approach to addressing risks associated with marine biosecurity. primarily as a result of biofouling on Navy vessel returning from overseas operations. This paper describes two case studies that highlight the effectiveness of the RAN marine biosecurity management framework in identifying an unwanted marine species on Navy vessels, and the successful biosecurity management program that ensued. In particular, the early detection and identification of a suspect NIS, the quick response to the discovery and the collaborative approach adopted between the RAN and the Government regulatory agency (Western Australian Department of Fisheries) charged with coordinating the incursion response serves as a model for how future incursion responses should be reported and managed.     

Introduced marine species: Management arrangements of consideration for the Torres Strait

Introduced marine species (IMS) can have significant impacts on economic, ecological, social and cultural aspects of coastal marine environments. There is, therefore, a need to minimise these impacts through the implementation of comprehensive and consistent management strategies and monitoring processes that work towards preventing introductions, detecting introductions if they were to occur and managing incursions should they be detected. There is also the need to ensure that approaches taken are comparable to provide consistency of IMS management effort, particularly across areas that are multi-jurisdictional (e.g. spanning State or Territory borders).     

Global change and marine communities: alien species and climate change

Anthropogenic influences on the biosphere since the advent of the industrial age are increasingly causing global changes. Climatic change and the rising concentration of greenhouse gases in the atmosphere are ranking high in scientific and public agendas, and other components of global change are also frequently addressed, among which are the introductions of non indigenous species (NIS) in biogeographic regions well separated from the donor region, often followed by spectacular invasions. In the marine environment, both climatic change and spread of alien species have been studied extensively; this review is aimed at examining the main responses of ecosystems to climatic change, taking into account the increasing importance of biological invasions. Some general principles on NIS introductions in the marine environment are recalled, such as the importance of propagule pressure and of development stages during the time course of an invasion. Climatic change is known to affect many ecological properties; it interacts also with NIS in many possible ways. Direct (proximate) effects on individuals and populations of altered physical-chemical conditions are distinguished from indirect effects on emergent properties (species distribution, diversity, and production). Climatically driven changes may affect both local dispersal mechanisms, due to the alteration of current patterns, and competitive interactions between NIS and native species, due to the onset of new thermal optima and/or different carbonate chemistry. As well as latitudinal range expansions of species correlated with changing temperature conditions, and effects on species richness and the correlated extinction of native species, some invasions may provoke multiple effects which involve overall ecosystem functioning (material flow between trophic groups, primary production, relative extent of organic material decomposition, extent of benthic-pelagic coupling). Some examples are given, including a special mention of the situation of the Mediterranean Sea, where so many species have been introduced recently, and where some have spread in very large quantities. An increasing effort by marine scientists is required, not only to monitor the state of the environment, but also to help predicting future changes and finding ways to mitigate or manage them.     

Assessment of biopollution in aquatic ecosystems

The introduction of alien species (AS) in marine environments is a factor of disturbance that can be viewed as a pollution agent. Using basic information on abundance and distribution of alien species, we developed an index that classifies AS impacts on native species, communities, habitats and ecosystem functioning. This method can be used to evaluate impact at five different levels of biopollution, fitting within the existing schemes for water quality assessment. Both spatial and temporal comparisons are possible. The assessments may also be used to evaluate management performance where avoidance measures were necessary and assist in preventing further unwanted introductions. Such assessments made for the same areas over time provide opportunities for measuring change in biopollution. We have tested the method using four different well-studied areas within the Baltic Sea (brackish to freshwater environments) for two different times, 20 years apart. Further developments of the scheme may be needed to cover some specific cases and taxonomic groups according to their life history.     

Effects of the Black River (Cape,South Africa) on the distribution and survival of marine psammofauna

The physicochemistry of the Black River and adjacent marine beach, in terms of tidal, daily and seasonal fluctuations of temperature and salinity, presents a highly stressed environment exacerbated by canalization of the river mouth. Riverine pollution further stresses this environment, producing low densities and diversities of marine infauna adjacent to the river. No fauna were found in the river mouth where typical estuarine conditions exist only during high tide. Tolerance of the dominant marine species, Cerebratulus fuscus, to temperature, salinity and river water combinations showed that mortality was more rapid after exposure to river water dilutions than after exposure to distilled water dilutions. Computer-generated models suggested that this species should survive conditions closer to the river than were observed. This confirmed additional stress due to pollution carried in the river from urban and industrial drainage. Lower river water temperatures during winter appear to ameliorate pollution stress, enhancing survivability of the infauna.     

Using attached macroalgae to assess ecological status of British estuaries for the European Water Framework Directive

The EC Water Framework Directive requires that ecological quality be assessed in transitional waters using the abundance and species composition of macroalgae. In estuaries, which form the majority of transitional waters, species composition is not a suitable measure. This arises from two features: (i) there is a continuous, natural change in species composition along the gradient of estuarine conditions which makes it difficult to know where within an estuary the species composition should be assessed, (ii) the inner estuarine macroalgal community of mat-forming species is very tolerant to both natural and anthropogenic stress and species poor which makes it insensitive to environmental variations in terms of species composition. An alternative feature is proposed based on the extent of upstream penetration of perennial fucoid algae. This proposal is founded on a series of case studies of the changes in fucoid limits, within a number of estuaries in the British Isles, consequent upon changes in pollution status over the last three decades. This also has to take into account variations of fucoid penetration owing to natural factors such as range of salinity variation and turbidity. The abundance criterion is taken to mean the absence of macroalgal blooms or "green tides", because general abundance of species is hard to quantify meaningfully in the upper estuarine mat-forming species and in the lower estuary is subject to great variation owing to the physical variability of estuary types.     

Effects of heavy metal contamination on the macrobenthic fauna in estuaries: the case of the Seine estuary

Heavy metal contamination levels are generally higher in estuaries than in the open sea. Some estuaries, the Seine estuary for example, have particularly high pollution levels of metals, yet continue to support a very high benthic biomass and remain quite productive. Measurements of sediment contamination are highly variable due to diverse chemical analysis methods, sediments origin and sources of contaminants found in the estuaries. Salinity appears to be the principal factor controlling contaminant distribution in the sediment and the overlying and/or interstitial waters; it also affects the bioavailability of contaminants in estuarine sediments. Of course, the response to contaminants varies greatly among species and assemblages. Trace metals explain only a small part of the variation in benthic community structure. Some species, such as the shrimp Crangon crangon, appears vulnerable to metal pollution, while other species, such as Scrobicularia plana, are able to tolerate quite high levels of cadmium in their tissue. This paper demonstrates the wide variability of benthic responses to contamination, which is probably due to the high spatio-temporal heterogeneity of the estuary. To reduce the problems due the heterogeneity and variability observed to date in the available results, it will be necessary to encourage integrated estuarine studies, in which sedimentologists, chemists, and biologists work together on the same campaigns at the same sites.