The Marinexus project brought together scientists and outreach experts from Plymouth, southwest England and Roscoff, France in an effort to improve our understanding of ecosystem functioning in the western Channel and to raise awareness of these ecosystems, particularly among schoolchildren and the public. Both the English and the French partners of this project have long traditions of ecosystem monitoring in the western Channel. The Marine Biological Association’s long-term monitoring programme dates back to the 19th century, and the Station Biologique de Roscoff also has a long history in this domain. Marinexus provided a long-overdue opportunity to integrate monitoring activities on the two sides of the Channel, and to trial innovative new observation methods, such as the installation of a ‘ferry box’ on the Brittany Ferries ship Armorique. The project also provided a forum for the exchange and comparative analysis of monitoring data. In addition to monitoring physical and chemical parameters, the project also implemented several approaches aimed at evaluating changes in biological diversity both in the open Channel and in different coastal environments.

A major aim of the Marinexus project was to investigate effects of modifications to the marine environment on Channel ecosystems, through, for example, identification and monitoring of invasive species on both sides of the Channel (see the section on non-indigenous species below).

Culturing algae. Image: © R. Lamoureux (photothèque CNRS).

The project also looked at how indigenous species are equipped to deal with changes to their environment. For example, seaweeds are an important component of coastal ecosystems but many have complex life cycles and it is not clear to what extent the complexity of their life cycles influences their susceptibility to changes in the environment. One of the aims of the project was to better understand how these complex life cycles function in order to address this question. Planktonic microalgae of Channel open water environments also fell under the scrutiny of this part of the project. Ocean acidification represents a significant challenge for several of these species because it affects their capacity to fabricate their protective calcium-based exoskeletons.

The outreach activities of the project used the results of these various research projects as raw material to construct attractive communication tools aimed at increasing knowledge about marine ecosystems and promoting citizen involvement in their protection and sustainable use. Activities aimed at schoolchildren and the public included workshops on Brittany Ferries ships during the crossings between Plymouth and Roscoff, and visits to schools on both sides of the Channel. On the French side, these and other activities were carried out using the ‘Marinexus Bus’, a dedicated outreach vehicle equipped with laboratory and demonstration apparatus. In Plymouth, a number of activities were organized, such as the ‘Marine biologist for a day’ programme and Bioblitzes, which involved the public and schoolchildren in describing biodiversity at seashore sites. As with the research projects, the outreach activities involved multiple interactions between the English and French partners, sharing of ideas and joint participation in several of the initiatives.

The Marinexus bus in action at a Bioblitz event

In addition to increasing general awareness about marine ecosystems in the Channel, Marinexus ran several activities aimed specifically at stakeholders. For example, a day dedicated to several round tables with themes such as ‘Citizen science as a means to involve the public in environmental issues’ and ‘The added value of international cooperation’ attracted participants from several sectors including local government and environmental protection agencies. This type of action proved to be a very effective means of transmitting key messages to local decision-makers.

Just over 100 scientists, outreach and technical staff worked on a range of projects under Marinexus. More information is available on the website but let us look at just two areas of research in a little more detail.

1. Monitoring the ecosystem of the Western English Channel – sharing resources

Moored buoys: Data from moored buoys maintained by the French and English labs provide a regional context for scientists on both sides of the Channel. The buoy data is integrated with measurements from the 'Ferry Box'. 

Phytoplankton: Researches on both sides of the Channel have collaborated to share phytoplankton time-series data and to ensure that their operating methods enable proper comparative studies of this valuable data.

 Benthic survey datasets: Scientists at Roscoff have built one of the longest detailed benthic datasets in the world. Sampling began prior to the Amoco Cadiz oil spill, providing an oportunity to assess the recovery of shores against a measured baseline. 

Continuous Plankton Recorder (CPR): The monthly CPR tow complements the moored bouys and Ferry box by collecting 'live' biological samples These are subsequently analysed using flow cytometry and molecular techniques.

Ferry box: The Ferry box aboard the croos-channel ferry Armorique allows real-time monitoring of parameters such as temperature and salinity during the crossing. It is providing an unprescedented perspective of climate variations across the channel. 

Dr Tim Smyth, a marine scientist who led this area of work said “The key has been bringing groups together who are working on similar things. For example, scientists on both sides of the Channel use flow cytometry, but the cross-border aspect, which is the key part of Interreg, has brought them closer, adopting the same methods and learning from each other”.

2. Non-indigenous species on the Channel coast

During the lifetime of the Marinexus project, substantial changes were documented in the marine nonindigenous fauna of the western English Channel.

Species deposited beyond their natural geographical range by human activities, either accidentally or deliberately, can modify ecosystems and pose major threats to both economic interests and native biodiversity. The Marinexus project included appraisal of these non-indigenous species (NIS) in the fouling communities of harbours and marinas artificial environments in which NIS are particularly prominent and which can act as stepping-stones for spread around the coast and thence into natural habitats. Marine biologists from the laboratories in Plymouth and Roscoff adopted joint protocols and undertook collaborative work to enable direct comparisons of localities on the two sides of the Channel, in north-west Brittany and south-west England (Devon and Cornwall).

Methods included deployment of settlement panels in marinas, standardized timed searches of a series of sites (Rapid Assessment Surveys RAS), both of these activities being repeated to monitor changes during the project, and the recording of species growing on yacht hulls and on the hull and in the ballast tanks of a cross-Channel ferry.

The lists of NIS on the two sides of the Channel were remarkably similar, the great majority of species being present on both sides. Nevertheless, the animal communities developing on panels during one year’s immersion in 13 marinas, scored in terms of the space occupied by each species, showed a consistently greater prominence of many of the NIS in Brittany (Figure 1).

RAS of 10 English and seven French marinas were undertaken in 2010 and repeated in 2013. In 2010 the marinas studied in Brittany had almost complete site occupancy by many of the sessile animal NIS present in the region most NIS were present in most marinas and the picture remained the same in 2013 (Figure 2). In Devon and Cornwall, occupancy was substantially lower in 2010 but had increased by 2013 largely because two species spread to several new marinas in Devon and Cornwall between the surveys: the compass sea squirt (Asterocarpa humilis) and red ripple bryozoan (Watersipora subtorquata). In Brittany, both these species were already present in 2010 at all of the marinas surveyed.

Parallel DNA-based population genetic studies suggested a common origin of the populations of NIS on the two sides of the Channel, i.e. a shared history of introduction with efficient spread across the Channel following initial establishment on one or other side. Based on the greater occupancy of habitat patches (marinas) and higher abundances seen in France, a general pattern over the past 3–4 decades of spread of marine NIS from France to England is inferred. The Marinexus studies and earlier records document a cluster of discoveries of new sessile animal NIS around the turn of the millennium. At least three of these are native to the north-west Pacific and are candidates for introduction to France via commercial movements of Pacific oyster (Crassostrea gigas).

We also inspected the hulls of over 120 yachts, documenting an average of four species of animal NIS per vessel in both Devon and Brittany, with similar lists of species on both sides of the Channel.

Fig. 1. Plot of faunal composition on settlement panels in marinas during three successive annual deployments, showing a consistent distinction between panels in Brittany (green symbols) and Devon & Cornwall (blue symbols).

Fig. 2. Frequency distribution of 13 non-indigenous species (NIS) based on the number of marina sites occupied by each species in surveys in Devon and Cornwall, and Brittany.

A picture therefore emerges of England and France sharing a common history of introductions of NIS on their Channel coasts, with a recent burst of new arrivals spreading across the Channel predominantly northwards, often after only a brief delay. Probable vectors of spread include leisure craft and cross-Channel commercial vessels, with initial introduction to north-west Europe often originating from aquaculture-related shipments of commercial species.

Confusingly similar species: DNA to the rescue

DNA-based identification (molecular ‘barcoding’) has been vital for resolving a group of polymorphic species that can closely resemble each other.

Colonial sea squirts of the genus Botrylloides (relatives of the better-known ‘star sea squirt’, Botryllus schlosseri) include at least two non-indigenous species in the Marinexus study region: orange cloak sea squirt (B. violaceus); and San Diego sea squirt (B. diegensis). Both occur in a variety of colour forms, and these species can resemble each other closely and are also difficult to distinguish from the putatively native species B. leachii. Molecular barcoding enabled colonies to be classified so that distributions could be clarified and subtle morphological distinctions looked for in well-chosen comparisons of specimens. A fourth group of DNA sequences brought to light an overlooked species within the samples, and distinguishing morphological characteristics in the corresponding specimens were then recognized.

Three species of Botrylloides, with the probable undescribed fourth species bottom-right. Images: John Bishop.


Over its four and a half year duration, the Marinexus project has significantly strengthened links between marine research institutions in Plymouth and Roscoff and many of the collaborative initiatives will be continued and expanded in the future. The strong outreach component of this project has also been very enriching for partners on both sides of the Channel, creating partnerships between academic and outreach organizations and allowing new skills to be developed by both types of partner. Discussions are currently underway to follow up on the success of this project with a similar collaborative initiative in the future.

Mark Cock1 (

Tim Smyth2 (

John Bishop3 (

Marinexus partners:

1. Station Biologique de Roscoff (Centre national de la recherche scientifique/Université Pierre et Marie Curie)

2. Plymouth Marine Laboratory

3. Marine Biological Association

4. Sir Alister Hardy Foundation for Ocean Science

5. National Marine Aquarium

6. Centre de Découverte des Algues (Algae Discovery Centre), Roscoff

7. Brittany Ferries Subcontractor: Association les Petits Débrouillards Bretagne (Young Investigators)

Marinexus was funded by the European Union Interreg program.