IRISH STUDY INTO MIGRATION MORTALITY OF SALMON
Irish study into migration mortality of salmon. Aisling Doogan is a PhD student at Galway-Mayo Institute of Technology (GMIT) and a Cullen Fellow at the Marine Institute. As part of her PhD she is investigating the causes of early migration mortality in Atlantic salmon (Salmon salar) from the Burrishoole Catchment in Newport, Co Mayo.
Atlantic Salmon are an important species to Ireland, and famed in Irish folklore and legend. They are also an ecologically important species and their presence is indicative of a healthy ecosystem. In recent decades salmon populations have declined, and Aisling’s research aims to increase our understanding of the early life stage of the salmon and areas where salmon may be most vulnerable to mortality.
Salmon hatch in fresh water where juveniles spend between two and three years before migrating to the ocean and returning to fresh water as adults to spawn.
“As salmon are widely dispersed across different habitat types, a number of factors at different life stages can affect their survival. One aspect of my research involves using acoustic telemetry to track salmon smolts – the juveniles migrating to sea. Salmon smolts are tagged at the Newport Research Facility and tracked through Lough Furnace, the Burrishoole Estuary and Clew Bay and as far as Clare Island,” Aisling said.
Aisling is based at the Marine Institute’s Newport Research Facility where hatchery reared salmon ranched from the hatchery and wild salmon, trout and eels are monitored for stock assessment purposes. She is carrying out this research on wild and hatchery ranched salmon of Burrishoole stock origin.
“Tagging the salmon enables us to follow the migration story of the Burrishoole salmon. We can see how long the salmon spend in the lake before continuing to migrate, how fast they swim and how tide and time of day impact migration behaviour. We can even see when a smolt has been predated on within the estuary – it stops behaving like a smolt and its movements began to resemble the behaviour of a seal.”
Aisling says the most challenging aspects of her Cullen Fellowship is researching, training and planning for the telemetry experiments. The most enjoyable part is undertaking fieldwork surrounded by sun, sea and salmon.
“During the summer, there were weekly boat trips to Lough Furnace, Clew Bay and Clare Island to download data from the receivers. Being surrounded by sea birds, seals, sunfish, bottlenose dolphins, whales and basking sharks is definitely a highlight for me.”
Aisling says one of the benefits of being a Cullen Fellow is the support she received from the Marine Institute and GMIT. “I have the opportunity to work alongside people with extensive knowledge and experience, and develop many skills by attending training courses and volunteering at open days and outreach events. From improving my communication and presentation skills to learning new software programmes and project planning, I have greatly progressed as an early-career researcher.”
Aisling’s research is entitled ‘Investigation into the causes of early migration mortality in Atlantic Salmon (Salmo salar) from the Burrishoole River using acoustic telemetry in freshwater and coastal areas.’ Her supervisors are Dr Deirdre Cotter of the Marine Institute and Dr Deirdre Brophy of GMIT.
The Cullen Fellowship Programme builds marine research capacity and capability by equipping graduates with the skills and expertise in raising awareness about our ocean, as well as Ireland’s rich marine biodiversity and ecosystems. The programme has provided grant aid to the value of €2.06 million supporting 24 PhD and three MSc students over the last five years. The research addresses a number of the 15 research themes identified in the National Marine Research & Innovation Strategy 2017-2021.
This project (Grant-Aid Agreement No. CF/15/07) is carried out with the support of the Marine Institute and funded under the Marine Research Programme by the Irish Government.