Project Summary and Results

Project Summary and Results

Contents Page 3 Page 4 Page 5 Page 7 Page 10 Page 14 Page 19 Page 23 Page 27 Page 31 Page 34 Page 39

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Foreword by Loughs Agency CEO, Sharon McMahon A Collaborative Research Project Like No Other The Consortium Meet the SeaMonitor Team Technology and Methodology Seals Basking Sharks Flapper Skate Cetaceans Salmon Looking to the Future Table of Figures

SeaMonitor

Foreword I am delighted to present this booklet which details and reflects on the findings from the SeaMonitor project, while simultaneously acting as a launchpad for its spiritual successor: STRAITS (Strategic Infrastructure for Improved Animal Tracking in European Seas).

Inside, you will find informative contributions and infographics from all the partner organisations involved in these projects, without whom this vital research would not have been possible.

Loughs Agency has been honoured to lead the project since its inception, while the support of eight leading marine research institutions from the UK, Ireland, Canada and the United States has allowed SeaMonitor to flourish. Funding provided by the EU’s INTERREG VA Programme (Environment Theme) as well as the governments of Ireland and Northern Ireland have been vital in the successful delivery of the project objectives, and we look forward to continuing these relationships in the future.

As I’m sure many of you are aware, SeaMonitor is a unique marine research programme studying the seas around Ireland and Western Scotland through the use of advanced acoustic telemetry equipment. The esteemed scientists involved in the project go into much more detail within this booklet, but the tracking and protection of vulnerable marine species during their early marine migration forms the foundation of the work that has been developed. Our team has successfully tracked the movements of a variety of aquatic life using these state-of-the-art tags and

receivers, including Atlantic salmon, harbour seals, cetaceans, flapper skate and basking sharks, and the results are truly fascinating.

We are also immensely excited to officially launch the STRAITS project, which will essentially work as a continuation of the research carried out through SeaMonitor. In partnership with our colleagues at the European Tracking Network (ETN) as well as other institutions, STRAITS will involve the redeployment of the receivers located at Malin off the coast of Donegal, as well as tagging initiatives in estuaries throughout both the Foyle and Carlingford catchments. Similar actions will also be carried out at various locations around Europe, including the Strait of Gibraltar, the Danish Straits and the Bosphorus Strait.

STRAITS would not be possible without funding made available from the EU’s Horizon Europe Programme (2021-2027), which provides crucial opportunities for research and innovation to excel. On behalf of every partner organisation involved in this project, I’d like to express a sincere thanks to all who played a part in securing this financial support.

Sharon McMahon Chief Executive Officer

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SeaMonitor

A Collaborative Research Project like no other STRAITS Conference 2023

SeaMonitor is an international consortium of nine expert organisations, delivering groundbreaking research on an unprecedented scale. Led by Loughs Agency, the project was developed and implemented jointly by all partners working together across a range of activities, using the latest technology to improve our understanding of some of our ocean’s most vulnerable species.

Applying the Learning Collecting data and advancing the science is key to research projects like SeaMonitor, but it is not the only aspect of the project. The SeaMonitor team has translated the learning into recommendations for policies, management plans and opportunities for future research to help better manage and protect our oceans.

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Over the life of the project, we have worked with local fishers, angling clubs and skippers. Although different groups have different relationships with the marine environment, they all share an interest in better protecting and managing it. In 2022, for example, Loughs Agency worked in partnership with the rivers Roe and Faughan angling clubs, with each contributing towards the purchase of additional tags for the tracking of sea trout. This led to generating more data and a better understanding of the movements and survival rates of the species so that the respective river systems can be better managed. The work represents a model of best practice for future research.

Agency staff with members of the rivers Roe and Faughan angling clubs.

Ultimately, what has made the SeaMonitor project successful is the people involved.

Behind every detection is a story of not only the animal but the scientists, administrators and crew that enabled the data to be generated. From planning and procuring equipment to deployments, tagging and retrieval, it is the dedication and professionalism of all the staff involved that has driven the work.

The Consortium

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SeaMonitor at a Glance INTERREG VA

funding: Launch date: 10 April 2019 Finish date: 31 March 2023

Ocean Tracking Network

UG

UC Davis

LA QUB AFBI

seals, basking shark, skate, salmon and cetaceans

ATU MI

UCC

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Meet the SeaMonitor Team

Ross McGill Loughs Agency

Diego del Villar Loughs Agency

Ann McPherson Loughs Agency

Fredrick Whoriskey OTN

Joseph Pratt OTN

Cassandra Hartery OTN

Caitlin Bate OTN

Nathan Glenn OTN

Colin Adams UG

Hannele Honkanen UG

The financial administration has been a project in itself. A special mention and thanks goes out to all the financial staff that have worked on the project: Ann McPherson and Doreen Simpson (LA), Annette Matthys (UCC), Karen McLean (AFBI), Tara Hughes Fegan (QUB), Diana Mardare and Katie Wright (UG), Martha Bracken and Ruairí Cusack (MI) and Angela Mulgannon (ATU).

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Meet the SeaMonitor Team

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Jessie Lilly UG

Deirdre Cotter MI

Catherine Waters MI

Ross O’Neill MI

Niall Ó Maoiléidigh MI

Sam L. Cox UCC

Caroline Bradley QUB

Paulo A. Prodöhl QUB

Patrick Collins QUB

James Thorburn QUB

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Meet the SeaMonitor Team

Heather Vance QUB

Joanne O’Brien ATU

Robert Rosell AFBI

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Amy Garbett QUB

SeaMonitor

Jonathan Houghton QUB

Andrea Barkley AFBI

Morgane Pommier ATU

Richard Kennedy AFBI

Alexandra McInturf UC Davis

Using the Latest Technology to Track Aquatic Life in our Oceans What is acoustic telemetry? Telemetry means to measure from a distance and acoustic means using sounds. Scientists use acoustic telemetry to track animals from a distance using sounds. Acoustic telemetry consists of two main components: transmitters (tags) and receivers (data loggers). Tags come in a variety of sizes and battery life depending on the species studied and are either attached or implanted via a simple surgical procedure. Receivers are placed underwater at various locations to detect the signals from the tagged animals.

When multiple receivers are deployed at fixed locations of a study area, this is known as an array. Several inshore and offshore arrays around Scotland and Ireland were successfully deployed for multiple seasons as part of the SeaMonitor project.

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The SeaMonitor project has been an innovative study using new and improving technologies. Acoustic telemetry tags allow the location of a fish to be detected but there are also clever sensors that can detect water temperature, depth and even when a tagged fish has been eaten. Project partners from the Marine Institute, for example, used acoustic telemetry tags with and without predator sensors. The sensors allowed scientists to assess predation events on salmon smolts.

Deploying Europe’s largest fish counter Key to answering some of the questions about marine migration is the ability to deploy scientific equipment in the right places and at the right scale in the ocean. The area of the North Channel between Malin Head and Islay was identified as a strategically important “swimway” for a range of mobile species as well as an area of oceanographic interest as a frontal zone where the Irish Sea meets the North Atlantic. It was here that Loughs Agency and its partners deployed Europe’s largest and most ambitious array at over 60km and 100 receivers long (See Fig. 1 on p.13).

A Glider named Fionn

One of the objectives of SeaMonitor was to track the movements of tagged salmon smolts far beyond the listening range of the static estuarine and coastal arrays and monitor cetacean activity in offshore waters.

To accomplish this, an autonomous underwater vehicle (AUV), also known as a glider which the Marine Institute named Fionn after the legendary hero of Ireland, N. Ireland and Scotland, was used as a mobile platform. It carried external sensors to identify acoustically tagged salmon smolts and cetaceans in offshore locations, particularly along the Shelf Edge, an important area for fish and mammal migration. Along with the ability to track aquatic animals, Fionn’s onboard sensors also recorded a range of environmental data such as temperature, salinity, oxygen and chlorophyll levels giving scientists important data about the conditions during migration.

3,200km

Fionn recorded

23 acoustic ‘pings’ environmental data points were recorded

from the SeaMonitor missions

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Passive Acoustic Monitoring Passive acoustic monitoring is similar to acoustic telemetry but doesn’t involve the use of transmitters implanted or attached to the animals. Passive acoustic monitors (PAMs) are used to record sounds (echolocation clicks, whistles and moans) emitted from elusive and highly mobile marine mammals such as cetaceans (porpoises, dolphins, and whales). Under the SeaMonitor project, five listening stations were deployed for two years across the North Channel, between Malin Head and Islay. Acoustic methods provide a significant advantage over visuals as they allow detections regardless of weather conditions, such as sea state and visibility. Sound recorders can be moored at the bottom of the ocean and collect data autonomously for months at a time, providing invaluable information on cetacean habitat use in specific locations across multiple timeframes (Static Acoustic Monitoring, SAM).

GPS Tags

In the SeaMonitor project, this technology was used as part of the seal research (p. 14-17). The tags are attached using a fast-acting glue to the back of the seal’s head, staying attached for several months until the seal moults and it drops off. (Example of juvenile seal with GPS tag attached).

Total number of tagged animals in project = over

,

Species detected on SeaMonitor arrays Basking Sharks

Salmon

Seal Greenland Halibut

Flapper Skate

Dolphins

Sea Bass Sea Trout

Bluefin Tuna

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Seals

Legend Acoustic array <10 listening stations

Over 100 acoustic listening stations to fully cover the North Channel

Complex acoustic array >10 listening stations Salmon tagging

Western Scotland

Seal tagging Basking shark tagging

Northern Ireland

Flapper skate tagging

FIG. 1

Map of study area (Ireland, Northern Ireland and Western Scotland) Main array, inshore arrays and tagging sites.

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Ireland

Rehabilitated Seals Monitoring Harbour Seals Overview

The Exploris Aquarium in Portaferry, Northern Ireland, has been running a seal sanctuary since 1989. Through the SeaMonitor project, scientists from University College Cork were able to use state-of-the-art GPS-GSM tracking technology to follow juvenile seals on their individual journeys after they were rehabilitated and released back into the wild.

Figure 2: Reason for seal rescue

Seal releases

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Exploris Aquarium

Seals are rescued by Exploris Seal Sanctuary from all over Northern Ireland. Of the 17 pups followed during the SeaMonitor project, over half were originally taken into care because of human disturbance at haul-out sites.

Most seals were under 4 weeks old when rescued. Information yielded from the SeaMonitor project allows us to better understand how these individuals adapt to life in the wild and if they survive.

Findings

Between 2019 and 2021, the post-release behaviours and movements of 17 rehabilitated juvenile harbour seals were tracked for periods ranging from 2 to 6 months. Tracked individuals adapted well to life in the wild, and were able to forage for themselves.

Some seals dived as deep as 150m

That’s around 1.5 times the height of the Statue of Liberty

Seven of the rehabilitated pups were either confirmed dead or needed re-rescuing, resulting in a tentative survival estimate of 59% which is within the range of first year survival estimates of wild juvenile harbour seals elsewhere.

Figure 3:

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Together, these results support the efforts of the rehabilitation team at Exploris Seal Sanctuary in their work to help maintain a local declining population of this protected species.

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Findings

Upon release, seals displayed a range of strategies in their movement patterns with over half the tracked individuals making large exploratory movements exceeding 150 km from the release site, which was much further than expected. Other seals remained locally. Released seal movements covered a geographical area of over 1250 km2, encompassing waters around the Republic of Ireland, Northern Ireland, Scotland, England, and Wales, highlighting the international range of the animals and a need for coordinated conservation management between countries.

Seal Tracks

High-use areas included Strangford Lough, Dundrum Bay, offshore of Carlingford Lough and Dundalk, and the waters around Skerries and Lambay Island, which correspond well with the known distributions of adult harbour seals, and may make good candidate areas for protection.

Based on information from fisheries Vessel Monitoring System (VMS), seals appeared to show little overlap with larger commercial fishing vessels suggesting rehabilitated seals do not become overly accustomed to human interaction.

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Ariel’s Story Ariel’s Rescue & Release

Ariel was found when she was around three days old, near a ferry crossing at Magilligan Point. A large crowd congregated around her, and the distress caused by this disturbance resulted in her rescue on 22nd June 2019.

Ariel was released on 17th November 2019 from Knockinelder Bay Beach, County Down, Northern Ireland.

Ariels residence at Gwynt Y Mor wind-farm

Ariel’s Journey

After a large exploratory trip that lasted around six weeks and included time in the waters around Ireland, England, and Scotland, Ariel settled off the North Coast of Wales. Here she made repetitive trips out to a wind farm site known as Gwynt Y Mor, presumably due to an abundance of fish.

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Daisy’s Story

Daisy’s Movements

Daisy’s Rescue & Release

Northern Exploris Ireland

Daisy was rescued on 13th July 2020 along with Holby, when she was around two weeks old, following a dog attack on Kilkeel Beach during which they both suffered substantial injuries.

Exploris Daisy was released on 17th January 2021, near Ballyhenry Island, County Down, Northern Ireland.

Dublin

Weeks 1-4

Daisy’s Journey

Daisy initially spent four weeks around Strangford Lough, before wandering further afield. After two weeks of exploration, she eventually settled in the waters around the Skerries Islands, just north of Dublin.

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Ireland

Weeks 6+

Weeks 4-6

Basking Sharks The Basking Shark Growing to over 11 m in length, and weighing up to seven tonnes, the basking shark (Cetorhinus maximus) is the largest species of fish in the Northeast Atlantic and the second largest in the world. The species aggregates annually in Irish and British waters during the summer months, feeding extensively on rich zooplankton blooms.

Recent tracking studies have shown that individuals typically leave Irish shores in the autumn ranging widely across the Atlantic Ocean from Canada through to the west coast of Africa. Despite such important breakthroughs, aspects of their biology and ecology remain a mystery rendering the development of regional and international conservation policy difficult.

Overview

The SeaMonitor project gathered movement and diving data on basking sharks to inform potential management plans on a regional scale (Ireland, Northern Ireland, and Scotland). The project revealed under what environmental conditions basking sharks were most vulnerable to human interactions and developed an analytical framework to help provide real-time advice.

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Basking sharks

Satellite Tag

Figure 9: GPS shark tagging

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To complement the SeaMonitor acoustic arrays, satellite tags were deployed to 20 basking sharks. Two different tag types were used. Smart Positioning or Temperature tags (SPOT) reported the shark’s location every time it came to the surface. Six additional devices were donated kindly by the Manx Basking Shark Watch. The second type of device (Pop-up Satellite Archival Tags; PSATs) recorded sub-surface information on diving behaviour and environmental conditions (e.g., depth, temperature, light levels) that can be used to estimate location. After a period of 6 to 12 months, the tags detached from the sharks and floated to the surface, where they relayed location and environmental data via satellite.

Figure 10: One of our key goals was to produce a space-use model for basking sharks based on combined acoustic and satellite tracking data.

We combined acoustic data (A; > 2,500 detections) from 29 sharks with satellite data from 16 deployed PSAT and SPOT tags (B; examples from two individuals in the weeks following deployment) to produce a spatial use model for the INTERREG IVA area (C). This model does not show the full range of movements exhibited by basking sharks in the Northeast Atlantic (they can range as far as Canada and western Africa), but highlights where cross-border collaboration would be most effective.

Basking Shark Tracking

Through collaboration with the Marine Institute, Queen’s University Belfast attached state-of-the-art tracking devices to 35 sharks, including acoustic transmitters, satellite positioning tags, and archival data loggers.

The data from these tags revealed that within any given summer, basking sharks moved frequently through multiple jurisdictions, including Ireland, Northern Page 21

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Ireland, Scotland, and the Isle of Man. The data also showed how these areas were all connected to the Sea of the Hebrides Marine Protected Area (MPA), which is designated for the protection of basking sharks, among other species. Collectively, these findings highlighted the need for a regional approach to species management, with a close alignment in policy and conservation measures between the relevant nations.

Towards Real-Time Adaptive Management

Diving data from basking sharks was used to build predictive models that showed how changing environmental conditions (e.g., sunlight intensity and wind speed) underpinned when basking sharks were found at the surface or deeper in the water column.

This model will enable real-time advisory notifications on a localised scale for commercial and recreational marine users to minimise disturbance to the sharks.

Future environmental data could be sourced beyond SeaMonitor from meteorological agencies, providing a cost-effective legacy tool.

Predictive Surface Model Predictions can update with realtime changes in weather and ocean conditions

Real-Time Advice for Key Stakeholders Alert recreational and commercial boat users about potential shark collisions, drawing their attention to relevant codes of conduct (e.g., appropriate speed and distances).

Provide information to the fishing industry about basking sharks vertical movements (e.g., likely to be at the surface or near the seabed).

Support ecotourism operations (e.g. identifying optimal times for shore-based sightings).

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Flapper Skate

Flapper Skate

Introduction to Skate The flapper skate (Dipturus intermedius) is the world’s largest skate. Unfortunately, overfishing over the last century has led to a catastrophic stock collapse of this long-lived and slow-reproducing fish. The species is now listed by the International Union for the Conservation of Nature as Critically Endangered, with flapper skate conservation given high priority throughout the INTERREG VA region.

Distribution

Queen’s University Belfast, through SeaMonitor, aimed to better understand flapper skate ecology across the NE Atlantic. The project compared the historical and contemporary distribution of the species and investigated regional connectivity using multidisciplinary approaches [Figure 11]. This data will inform the conservation management of the species throughout the INTERREG VA region. Furthermore, the SeaMonitor legacy is ensured through the establishment and continued activities of the Regional Flapper Skate Working Group.

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Figure 11: Verified distribution of Dipturus intermedius compared to the previous IUCN distribution of the ‘common skate’ complex and the current IUCN distribution for species. D. intermedius occurrences obtained from fishery trawling surveys, angling and genetic databases.

Flapper Skate Population Genetics Skate tissue samples were collected from a number of collaborative efforts, including academic partners, fisheries, and governmental-supported recreational angling. All samples were taken and stored in a standardised fashion with the sample collection held at Queen’s University Belfast. A large number of juvenile skates were sampled. However, these collections included the common blues, flapper, Norwegian and white skate.

To aid with the formal identification of species, all samples were molecularly barcoded. This highlighted the difficulty in separating juveniles between species based on morphology and supported geographic separation between the two species. Further, linking patterns of genetic connectivity with the movement ecology (tagging) provides a powerful tool to support the conservation of this species.

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Figure 12: Map showing all the sites for which we have genetic samples from skates.

Skate Ecology

Figure 13: Connectivity of flapper skate throughout the INTERREG IVA area.

The figure is based on acoustic detections (>400,000) from over 70 flapper skate. The straight lines are to aid visualisation and do not show actual movement.

Through collaboration with the University of St Andrews and the Marine Institute, Queen’s University Belfast has data from over 70 skate tagged with long-term acoustic transmitters throughout Northern Ireland, Scotland, and Ireland. The detections of these tags showed connectivity between Scotland and Northern Ireland, with high levels of residential behaviour and seasonal site associations observed [Figure 13]. The data also highlighted regional connectivity with the Loch Sunart to the Sound of Jura MPA, which is designated for the protection of the flapper skate, showing the wider impact of this site.

Skate Biology

The reproductive cycle of female skate was investigated Figure 14: An ultrasound image of an encapsulated using ultrasound imaging and levels of oestradiol, progesterone and testosterone in blood samples to show egg held in the uterus of a female flapper skate. The females lay pairs of eggs, and the initial evidence suggests large yolk can be clearly a winter egg-laying season [Figure 14]. seen surrounded by the Through a review of the impacts of catch-and-release angling on elasmobranchs, we developed a set of best practice guidelines for the rod and line capture of flapper skate. These guidelines can help reduce stress from capture, further supporting the species’ recovery.

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interior of the egg case which the young skate will grow into over 18 months once laid.

Regional Flapper Skate Working Group The SeaMonitor project hosted the first Regional Flapper Skate Working Group meeting in 2020. The initial workshop acted as a shopfront for research, conservation, policy and grant pump priming. Over 30 leaders in skate conservation, across academic, governmental and non-governmental sectors, worked

Figure 15: Photo of Regional Flapper Skate Working Group

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to focus future efforts and develop a consensusbased approach to species management. The workshop resulted in several key outputs, with the recommendations published in the scientific journal Marine Policy. A second meeting of the Working Group was held in Galway in March 2023.

Cetaceans

Cetaceans

Passive Acoustic Monitoring of Cetaceans As part of the SeaMonitor project, scientists from Atlantic Technological University (ATU) in Galway used passive acoustic monitoring (PAM) to monitor a wide range of cetacean species in our waters. Using PAM allowed the scientists to target specific signals such as echolocation clicks, whistles and moans so they could listen for them instead of looking for them.

Collaboration with Sister Projects Close collaboration with other EU INTERREG VA funded sister projects COMPASS and MarPAMM allowed the standardisation of data collection protocols across projects. All acoustic datasets were pooled and analysed jointly to address new research questions, inform marine spatial planning, conservation, and management. These

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projects aimed to build and strengthen cross-border research and monitoring capacity. An important legacy of the projects will be the establishment of a network of partner institutions for future collaborations on cetacean ecology and ocean noise.

The harbour porpoise (Phocoena phocoena) is a protected species listed under Annex II of the Habitat Directive. Studies relying on visual observations are often restricted to data gathered in good weather and visibility conditions. As a result, knowledge of animal presence and overall data availability is often biased towards summer. Initial results from SeaMonitor (and other long-term acoustic projects) conversely indicate a peak in harbour porpoises occurrence from late autumn and throughout winter, demonstrating the importance of year-round monitoring and the value of acoustic approaches. In the second year of data collection, occurrence rates in the centre of the North Channel (stations 40, 55, 76) seem higher than in more coastal locations (stations 27 and 100). Such information can, for instance, be used as baseline data to inform future impact assessments in an area of interest for the development of marine renewable energies. In an applied conservation

Photo credit: Joanne O’Brien

context, data on cetacean spatio-temporal occurrence can contribute to the designation of MPAs or highlight the need for temporal management. Long-term monitoring initiated under SeaMonitor will be continued under followup projects and enable exploration of inter-annual trends in cetacean habitat use. This will allow the detection, recording, and possible anticipation of animal responses to the rapid modification of their environment due to anthropogenic pressures and climate change.

Feasibility of using New Technologies to Monitor Cetaceans in Coastal Shelf Seas PAM is well suited for long-term monitoring at specific sites, but more limited in terms of spatial coverage. Cetacean research also often relies on survey data, collected by visual observers or towed hydrophones to address questions related to continuous spatial distribution. One of the major biases associated with boat-based research is that vessel approach and/or noise disturbance may trigger behavioural responses from the animals, influencing detections and observation and so ultimately affecting data reliability. When PAM cannot be conducted from an “acoustically-silent” boat, noise can contaminate recordings and interfere with cetacean detections.

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Underwater gliders function without a propeller, moving vertically and horizontally using variable buoyancy and foils. Free from propeller cavitation sounds, they are very promising tools for conducting ambient measurement, marine soundscape research and cetacean monitoring.

The SeaMonitor project assessed the feasibility of using a commercially available, self-contained recorder (SoundTrap HF300), to conduct PAM. During two experimental missions, dolphins and harbour porpoises were detected in coastal waters of the Malin Shelf. These successful trials open future opportunities for the systematic addition of PAM in glider deployments, the development of multi-disciplinary missions and the transition towards more integrated ecosystem monitoring approaches.

Soundscape Monitoring and assessment of Noise Exposure Long-term monitoring of ambient noise and soundscape across space and time is also a useful way to identify trends in geophony, biophony and anthrophony.

Measures of sound exposure can highlight potential pressures from human activities.

Figure 16: Realised static acoustic monitoring effort under SeaMonitor. Temporal coverage achieved at 5 stations within the main array equipped with broadband recorders and/or click loggers (from west to east, stations 27, 40, 55, 76 and 100).

Example Case Study: the Harbour Porpoise (Phocoena Phocoena) Daily porpoise positive hours: SeaMonitor station 76

Figure 17: Daily number of porpoise positive hours (i.e at least one encounter) at station 76 (Main array).

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Figure 18: passive acoustic monitoring from SeaMonitor glider.

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Photo credit: Joanne O’Brien

Salmon

Towards a Better Understanding of an Iconic Species

Over the years, Atlantic salmon (Salmo salar) have been the subject of numerous regional studies. Historically salmon are of both cultural and economic significance to Scotland and the island of Ireland and are a key indicator of healthy freshwater and marine ecosystems.

As an anadromous species, however, the marine phase of their life cycle remains a mystery. The SeaMonitor project aimed to address this directly through the use of acoustic telemetry in four key catchments: Burrishoole (Ireland-MI), Bush (NI-AFBI), Foyle (NI/Ireland-LA) and Clyde (Scotland-UG). Across the life of the project hundreds of salmon smolts were tagged and released to generate empirical evidence about their early marine migration. The results have been used to produce Ireland’s and Scotland’s first marine management plans for the species in the Clyde and Foyle catchments.

Between 2020 and 2022, collaboration with other projects and organisations in the region meant that the study could incorporate data from over 3,000 salmon smolts from 21 rivers across four countries. Led by the Page 31

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University of Glasgow, the study demonstrated that salmon utilise multiple pathways during the early phase of their migration, travelling in a north-westerly direction and that mortality is highest in the early marine phase of migration (see Fig. 20).

Figures 19 and 20: Atlantic salmon marine migration pathway model and SeaMonitor glider tracks.

3,000+ The number of salmon smolts tagged and released over the life of the project.

As previously mentioned, the use of the glider, Fionn, was also key to understanding where salmon smolts migrate once they enter the marine environment.

Fig. 19 highlights the survey area which was chosen based on previous results of the SALSEA-Merge (20082011). This research identified different migration locations and densities of Atlantic salmon smolts on the shelf edge. The success of the glider missions in identifying the presence of acoustically tagged Atlantic salmon smolts at the shelf edge shows the importance of the shelf edge current as a major driver in salmon migration. It also thighlights the level of interconnectivity of smolts from different rivers and jurisdictions in the open ocean.

An exciting additional research benefit from SeaMonitor was the collaborative tracking of sea trout on the Northern Irish coastline. Sea trout smolts were tagged in a number of river systems in 2021-22, including the Roe, Faughan, Ballycastle and Glenarm rivers. Initial results have indicated significant fish movements between rivers and fishery jurisdictions and have highlighted potentially important habitats for the species. As the data develops, fishery scientists in the Loughs Agency and AFBI will be able to estimate important Page 32

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biological metrics such as migration phenology, initial marine survival and finnock return rates. This additional research could only have happened with the collaboration and support of the Faughan and Roe anglers and the Northern Ireland Department of Agriculture, Environment and Rural Affairs.

Translating research into action Through analysis of new and existing data, Loughs Agency and the University of Glasgow were able to develop marine management plans for salmon in the Foyle and Clyde catchments. These documents represent the first known attempt in Ireland and Scotland to develop frameworks for the management of Atlantic salmon in the marine environment. To date, the efforts of the various statutory bodies, river trusts and angling groups have focused primarily on freshwater catchments. Along with the accountable departments, the plans were developed through working groups and in consultation with local stakeholders. The plans will be available in 2023 for wider public consultation and input.

The Incredible Journey of Salmon Sally began her journey in the River Gryffe in Glasgow, weighing 48.4g and measuring 174mm. She was tagged on the 20th of April 2021 and then travelled 8.4km downstream to the Clyde estuary. From the exit of the Clyde estuary, she spent 24 days travelling north towards Fionn the glider, where she was detected on the 23rd of May. She travelled at an average speed of 22.52 km/day, covering a total distance of 556km.

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Total dista nce of

556km

24

days travelling

Looking to the Future SeaMonitor has proven that a large-scale acoustic telemetry is a viable tool for monitoring a variety of mobile marine fauna.

The arrays serve as regional assets for academic, government and commercial sectors. As SeaMonitor comes to an end, the consortium is keen to continue the research and apply the knowledge to inform policy and decision-making.

In 2022, Loughs Agency and a consortium of partners from the European Tracking Network (ETN) were awarded funding from the European Research Executive Agency under the Horizon Europe Framework Programme for the STRAITS project (Strategic Infrastructure for Improved Animal Tracking in European Seas).

ETN members have recorded over

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since 2018.

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