Salmonid Management Round the Channel Project (SAMARCH) Explained
The Channel between England and France forms part of the migration route for juvenile and adult salmon from all salmon rivers in the area. It is also a key feeding habitat for sea trout from the rivers in the region and potentially further afield, where these migratory individuals feed and grow, increasing their reproductive potential much faster than their river resident counter parts before returning to their native rivers to breed. However, each day hundreds of kilometres of gill nets are set, which if set in the wrong place and time risk catching and killing salmon and sea trout. To better protect these fish, we need to gather evidence of how and when they use the Channel and its estuaries.
SAMARCH (2017 – 2023) is a seven-year project led by MSA member The Game and Wildlife Conservation Trust (GWCT) and part funded by the EU’s Interreg VA Channel programme, that will deliver practical tools for management to better protect salmon and sea trout in coastal waters.
Deploying Acoustic Receivers
SAMARCH is a cross-boarder project which has 10 partners, five in England and five in France who are a blend of research, NGO’s and regulatory organisations. In England the project is working on five rivers flowing into the Channel, which is one of the most heavily developed and commercially fished areas of our oceans targeting e.g. bass, mackerel, herring, and mullet especially with gill nets.
Various state of the art telemetry, genetic, scale reading and modelling approaches are being used to further our knowledge and understanding of salmonid use of coastal and transitional waters in order to better protect them.
Now that the data collection is almost complete, the project is focusing on ensuring the projects results are integrated into policy. To facilitate this work in England, the SAMARCH project has employed two dedicated SAMARCH policy officers to work alongside the Inshore Fisheries and Conservation Authorities (IFCA’s), Marine Management Organisation (MMO) and the Department for Environment, Food & Rural Affairs (Defra). In France round table discussions with policy makers and fisheries managers will be an integral part of the SAMARCH international forum "Salmon and sea trout : scientific tools for their protection" which will take place on May 17th – 18th 2022 in the Pléneuf Val André, France. The forum will be oriented towards improvements in management in estuary and at sea.
Conferences and stakeholder meetings will be held in France and England during 2022 and 2023 to share the results from the project.
SAMARCH partners from France and England at a project meeting in 2017.
The problems that SAMARCH will address:
By-catch of salmonids in commercial inshore fisheries: The Channel has the most intensive commercial gill net fishery in Europe. Each week an estimated 1.400 km of gill nets are set off the coast of Cornwall alone, this is equivalent to the straight line distance from London to Rome. There is a real risk that substantial numbers of salmon and sea trout are accidentally captured, damaged and killed.
Challenges to salmonids caused by estuarine and inshore coastal activity and developments: The Channel is a busy shipping channel with lots of anthropogenic activities that might impact both juvenile and adult salmonids. For example, dredging, flood and tidal defence work, estuary modifications. In addition, there are advanced plans for a number of tidal renewable energy schemes which could have significant impacts on these ecosystems and their inhabitants including salmonids.
Strengthening salmon stock assessment models: Working in conjunction with the network of salmon International Council for the Exploration of the Sea (ICES) index rivers in the Channel - the Tamar and Frome in England and the Scorff, Bresle and Oir in France - the project will implement a number of research activities to provide new evidence to update and improve salmon stock assessment tools. Including contemporary evidence on marine survival; marine growth rates over time; juvenile production; sex ratios of juveniles, grilse and multi sea winter adults; fecundity estimates and rod exploitation rates.
How is SAMARCH addressing these issues?
The project has implemented fish tracking and evidence gathering studies including: -
Gathering evidence of by-catch in commercial gill nets
Tagging and tracking of 480 salmon and 360 sea trout smolts in four estuaries to assess their migration timing, duration, survival and factors affecting these.
Tagging 315 sea trout kelts in three rivers using tracking equipment to assess the estuarine and marine migration timing, duration, survival, swimming depths and feeding areas.
Mapping the genetic signature of salmon and trout within 80 individual rivers across the Channel area. We will use this genetic database for salmon and trout to identify the natal river of fish caught at sea.
Tagging 120,000 salmon parr with unique identifiers to assess in-river and marine survival, and factors affecting them.
Reading 20,000 sets of salmon scales for age and growth collected over the last 30 years from five rivers in the Channel area.
Using non-destructive sampling to sex more than 15,000 individual salmon genetically.
Developing new salmon lifecycle models.
Delivering evidence to and engage with the key regulators – IFCA’s, MMO, ICES, NASCO, EA, Cefas COGEPOMI, DRIEE llde France and Defra.
Celine Artero, GWCT researcher, working on the SAMARCH project, downloading data from acoustic receivers
Key Achievements to date
Protection of salmonids from by-catch in inshore gill nets and marine management
· The 10 regional Inshore Fisheries Conservation Authorities (IFCA’s) are tasked with implementing bylaws to protect salmon and sea trout in England’s coastal waters. These include no fishing areas in estuaries where they will congregate and a “headline” rule where the top of gill nets must be fished at least 3 metres below the surface. This assumes that salmon and sea trout swim mostly in the top 3 metres. Our data from tagged adult sea trout shows that the headline rule is largely ineffective given that in parts of the year sea trout spend up to 80% of their time swimming deeper than 3 meters.
· We have shown by setting gill nets in areas open to commercial gill net fisheries that salmon and sea trout are being caught in these nets.
Challenges to salmonids caused by estuarine and inshore coastal activity and developments:
· The project is using the geolocation of adult sea trout in the Channel to highlight key areas for sea trout at sea. These areas are currently being overlaid with information on a wide range of marine activities that can impact salmon and sea trout to target stronger protection measures.
· Swimming depth data recorded by our tags in adult sea trout highlighted an intense diving behaviour in the Channel that vary temporally (daily and monthly). These findings are shared with the Environment Agency to work on recommendations of the netting activities at sea.
· Our smolt tracking work showed that survival of salmon and sea trout smolts differ during their out-migration through estuarine environments with some variation through our four study estuaries
· The SAMARCH project is working closely with it’s project partners in England and France to ensure that information is going in front of the key regulators and marine spatial planners.
Strengthening salmon stock assessment models
Data from our juvenile salmon PIT tagging programme tells us that:
· Larger smolts are three times more likely to return from their sea journey than their smaller counterparts.
· Marine survival is low and largely independent of environmental conditions at the time of arrival at the near-coast.
· Smolt seaward migration is happening earlier and there is a real risk that this results in a mismatch with the timing of favourable conditions at sea.
· Returning adults are getting smaller for the same sea age. Analysis of scales from returning adults going back 30 years tells us that the growth of salmon during their first summer at sea has decreased in recent decades and which in turn negatively impacts their probability of returning after one year at sea. These findings have implications for population dynamics and stock assessment through reduced egg deposition in rivers.
Sea trout from River Frome
List of scientific publications produced by the SAMARCH project
Marsh, J. E., Lauridsen, R. B., Riley, W. D., [8 authors], Gregory, S. D. (2021). Warm winters and cool springs negatively influence recruitment of Atlantic salmon (Salmo salar L.) in southern England. Journal of Fish Biology, 99:1125-1129. DOI 10.1111/jfb.14760
Simmons, O. M., Gregory, S. D., Gillingham, P. K., Riley, W. D., Scott, L. J. & Britton, J. R. (2021). Biological and environmental influences on the migration phenology of Atlantic salmon Salmo salar smolts in a chalk stream in southern England. Freshwater Biology, 66:1581-1594. DOI 10.1111/fwb.13776
Tréhin, C., Rivot, E., Lamireau, L., Meslier, L., Besnard, A.-L., Gregory, S. D. & Nevoux, M. (2021) Growth during the first summer at sea modulates sex-specific maturation schedule in Atlantic salmon. Canadian Journal of Fisheries and Aquatic Sciences, 78:659-669. DOI 10.1139/cjfas-2020-0236
Simmons, O. M., Britton, J. R., Gillingham, P. K. & Gregory, S. D. (2020). Influence of environmental and biological factors on the over-winter growth rate of Atlantic salmon Salmo salar parr in a UK chalk stream. Ecology of Freshwater Fish, 29:665-678. DOI 10.1111/eff.12542
Marsh, J. E., Lauridsen, R. L., Gregory, S. D., Beaumont, W. R. C., Scott, L. J., Kratina, P. & Jones, J. I. (2020). Above parr: lowland river habitat characteristics associated with higher juvenile Atlantic salmon (Salmo salar) and brown trout (S. trutta) densities. Ecology of Freshwater Fish, 29:542- 556. DOI 10.1111/eff.12529
Gregory, S. D., Ibbotson, A. T., Riley, W. D., Nevoux, M., et al. (2019) Atlantic salmon return rate increases with smolt length. ICES Journal of Marine Science, 76:1702-1712. DOI 10.1093/icesjms/fsz066.
Riley, W. D., Ibbotson, A. T., Gregory, S. D., Russell, I. C., et al. (2018) Under what circumstances does the capture and tagging of wild Atlantic salmon Salmo salar smolts affect probability of return as adults? Journal of Fish Biology, 93:477-489. DOI 10.1111/jfb.13655.
As an Alliance of six organisations, we will build on the existing work of our partners and maximise our impact by taking a coordinated approach and vital action in order to halt and reverse the decline of wild Atlantic salmon.
The goal of the Missing Salmon Alliance is to build an evidence-base to influence national and international decision-makers to regulate activities that adversely impact wild Atlantic salmon.
The Missing Salmon Alliance
The MSA is comprised of the following members:
Game & Wildlife Conservation Trust, Atlantic Salmon Trust, the Angling Trust with Fish Legal, The Rivers Trust and Fisheries Management Scotland.
https://www.missingsalmonalliance.org