Feature: beyond borders – the invasion of non-indigenous species

ICES Working Group on Introductions and Transfers of Marine Organisms (WGITMO) has been dealing with aquatic alien species since 1969. Here, we take a closer look at what the challenges the group faces today.
Published: 14 December 2015

​​​​​​​​​​In our final feature article of 2015, the chair of ICES Working Group on Introductions and Transfers of Marine Organisms, Henn Ojaveer, along with fellow group members James T. Carlton (Williams College​) and Bella Galil (Israel Oceanographic and Limnological Research Institute), expand on the group's work and the threats posed by invasive non-indigenous species.

Contributing to high priority areas in ICES

Shifting global trends and altered dispersal vectors (transporting agents such as vessels, aquaculture products, and other methods of transportation) have necessitated ICES marine bioinvasion studies to move into fresh areas of cutting edge biological research and tracking.

Two crucial developments are currently being addressed: warming coastal waters and the opening of the Arctic Corridor for shipping, a new cross-border economic region and transport passage connecting the Baltic Sea with deep-water ports around the Arctic Ocean. The former has been under the spotlight in terms of how the increase in temperature will influence future invasions from subtropical to polar waters, whilst the latter could prompt the appearance of novel species in the North Atlantic Ocean. In addition to temperature, coastal areas are also facing salinity change. A global review on how salinity change affects invasion potential and the success of non-indigenous species is currently underway  by WGITMO.

The main objective of recent international legislative measures and policies concerning marine ecosystems is to ensure sustainable environmental management that maintains  good environmental status, with the ultimate target of achieving an integrated ecosystem-based approach to management. Amongst others, the EU Marine Strategy Framework Directive (MSFD) and the EU Regulation on the prevention and management of the introduction and spread of[h1]  invasive alien species (IAS Regulation) require rapid reactions from the scientific community. Availability of taxonomic expertise, application of molecular tools, common guidelines for surveillance and monitoring of non-indigenous species (NIS), early detection and monitoring, standardization of data and information systems, investigation and assessment of propagule pressure (a composite measure of the number non-native species of individuals), careful choice of indicators, multi-vector management, cooperation with stakeholders, and adoption of the 'single authority' approach are the key requirements and principals for successful NIS management . While cost-efficient rapid assessments of target species may provide timely information for managers and policy advisers focused on particular NIS in particular areas, this cannot replace the need for long-term monitoring.

Alerts and advice

One of the hallmark WGITMO products is the ICES Code of Practice on the Introductions and Transfers of Marine Organisms which has garnered worldwide attention. It encompasses the risks associated with current commercial practices including trade in ornamental species and bait organisms, research, and the import of live species for immediate human consumption. It also includes species that are utilized to eradicate previously introduced harmful and native species, as well as genetically modified organisms and polyploids. It outlines a consistent, transparent process for the evaluation of a proposed new introduction, including the need for detailed biological background information and an evaluation of risks. While initially designed for the ICES Member Countries concerned with the North Atlantic and adjacent seas, all countries across the globe are encouraged to implement this code of practice.​

A series of up-to-date non-indigenous species alert reports, published as ICES Cooperative Research Reports, provide early warnings for both the scientific community and managers/policy-makers and are designed to guide scientific advice and inform management. The reports have considered such species as the as red king crab (Paralithodes camtschaticus) which was introduced from the Northern Pactific Ocean to the Russian Barents Sea in the 1960s, the Asian snail Rapaa, the North American razor clam Ensis directus​, and Japanese kelp which was carried unintentionally with oysters from its native northerwestern Pacific area to the French Mediterranean coast. (A report on the sea squirt Didemnum vexillum, which is native to Japan and first recorded outside in its native range in the late 1970s in the North Atlantic is due in 2016


International cooperation

The information system on aquatic non-indigenous and cryptogenic species AquaNIS  was developed by WGITMO and the EU FP7 project VECTORS.  It is an online database of marine NIS in Europe (from the Barents Sea to the Mediterranean Sea) and elsewhere (e.g. Canadian Arctic and the Black Sea). Scientifically validated invasion event data are freely available for several ecosystems and are regularly updated by WGITMO members. ​

The first comprehensive pan-European study based on AquaNIS highlights that​:

  • between 1970 and 2013 the number of recorded NIS has grown by 86%, 173%, and 204% in the Baltic Sea, Western European margin, and the Mediterranean Sea, respectively
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  • the Suez Canal, a corridor unique to the Mediterranean, is responsible for the increased species introductions into this warming sea.

ICES and the Mediterranean Science Commission (CIESM) hosted the first  Joint Workshop on Mnemiopsis Science, when they met in Coruña, Spain in September 2014. The workshop focused on the latest advances regarding the biogeography, ecology, impact, and economic aspects of this invasive ctenophore and its comb jelly Beroe predators.  Mnemiopsis leidyi has proven to be a highly invasive species with major ecological andeconomic impacts and severe invasion consequences.  Because of its broad environmental tolerance and phenotypic variability, it can establish in highly variable ecosystems. Food web pertubations from overfishing combined with eutrophication and the major influx of other non-natives have permitted the establishment of Mnemiopsis in some areas. ​​​

Keeping an eye on recent developments: increasing role of interoceanic canals as corridors for marine bioinvasions
The Suez Canal has recently undergone a major enlargement and the expansion of the Panama Canal, intended to double its capacity and transit vessels three times as big as it does today, will be concluded by April 2016. These two canals may be joined by a third, a canal across Nicaragua.

Literally cutting through natural barriers that prevent the dispersal of marine organisms, maritime canals serve as pathways for introduction by both natural means and shipping. Indeed, 450 of the 726 multicellular alien species recorded in the Mediterranean Sea are considered "Erythraean aliens" - species introduced through the Suez Canal. Though their number is substantially greater in the eastern than in the western Mediterranean, a few species have spread across the Mediterranean. Their number more than doubled (223%) between 1970 and 2015, commensurate with the increase in the size of the Suez Canal (from across sectional area of 1800 m² and depth of 15.5 m to 5200m² and 24 m, respectively). This is only a partial inventory though, as significant spatial, temporal, and taxonomic gaps lead to massive underreporting and thus an assumed underestimation of the true number of bioinvasions.

Introductions through the Panama Canal include at least 51 possible shipping-mediated species transferred from the Atlantic to the Pacific and 26 species from the Pacific to the Atlantic. A further increase in the frequency, magnitude, and spatial distribution of alien species along the American Atlantic coasts originating from the warm waters of the Eastern Pacific is likely, with marked potential for those species to then be carried by shipping to Europe and the Mediterranean. Unlike the Panama Canal Authority which published an Environmental Impact Study ahead of the expansion project, no environmental impact assessment has been made available for public view by the Suez Canal Authority.  While acknowledging the important role of the maritime canals in global trade, there is cause for concern as to their effect on environmental issues with long term consequences such as bioinvasions.​

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An aggregation of Plotosus lineatus (Thunberg, 1787), Israel . The venomous striped eel catfish, introduced through the Suez Canal, has spread from Israel to Turkey. Photo: B.S. Rothman​ 

ICES Working Group on Introductions and Transfers of Marine Organisms (WGITMO) has been dealing with aquatic alien species since 1969. WGITMO has been chaired successively by the late Henry A. Cole, England (1970–1973), Carl J. Sindermann, USA (1979–1990), James T. Carlton, USA (1991–2000), Stephan Gollasch, Germany (2001–2006), Judith Pederson, USA (2007–2010) and Henn Ojaveer, Estonia (2011–present). 
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Feature: beyond borders – the invasion of non-indigenous species

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