Irish research vessel Celtic Voyager. Image: Marine Institute

NUI Galway PhD student Ryan McGeady is a Cullen Fellow at the Marine Institute, working on oceanographic modelling of nephrops populations around Ireland.

Known variously as Dublin Bay prawn, Norway lobster or langoustine, nephrops are one of the most valuable fisheries in Ireland

‘Over the course of my PhD, I am examining the use of computer models to measure larval transport in Nephrops norvegicus populations around Ireland,’ explained Ryan, whose research supervisors are Dr Anne Marie Power (NUI Galway) and Dr Colm Lordan (Marine Institute).

‘Unlike the adults that inhabit burrows on the seabed, larvae are pelagic, meaning they live up in the water column. Oceanic currents play a very important role in how larvae are dispersed during this stage of their life cycle,’ he said.

‘When it comes to the end of the planktonic larval phase, there is a requirement for muddy seabed for settlement and subsequent development to the adult stage. If larvae are unable to settle on appropriate muddy habitat, they will not survive. Therefore, the importance of oceanography in larval dispersal is crucial.’

Through the use of computer models, Ryan measures the extent of larval transport and the amount of larvae being retained on important nephrops grounds around Ireland. By doing this, he hopes to improve understanding of how oceanography influences larval retention and settlement rates.

‘By modelling larval dispersal over the past few decades, I hope to identify the conditions that lead to high and low retention. Such information could be used to identify scenarios that lead to poor retention of larvae and therefore poor recruitment and ultimately help to ensure that the fishery is harvested at a sustainable rate,’ he explained.

Ryan’s research relates to the Fisheries Ecosystems Advisory Services (FEAS) section in the Marine Institute. With a greater understanding of the role of oceanography in larval retention, improvements in the stock assessment method can ensure sustainability of the fishery.

Ryan McGeady is a Cullen Fellow at Ireland’s Marine Institute. Image: Marine Institute

He commented that the main benefit of being part of the Cullen Fellowship Programme ‘has been the opportunity to carry out research in Ireland’s rich and diverse marine environment. With the support of the Marine Institute and NUI Galway, the programme has allowed me to develop my research skills and has also given me the opportunity to learn from skilled and experienced scientists. My time as a Cullen Fellow has provided me with many great learning experiences and I hope this continues as I continue my PhD research.’

He says one of the most memorable experiences during the Fellowship was being involved in planning and conducting a research cruise on board the RV Celtic Voyager in 2018.

‘The purpose of the survey was to examine the distribution of nephrops larvae in Irish waters and it was carried out off the west coast and in the Irish Sea. It was a great experience designing the survey to achieve particular goals and seeing it through to successful completion. The survey was a success due to the support provided by many in the Marine Institute and NUI Galway as well as crew and scientists on the RV Celtic Voyager. Many samples were collected and the acquired data will now be applied to my PhD research.’

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/16/04) is carried out with the support of the Marine Institute and funded under the Marine Research Programme by the Irish Government.