Doctoral Programme on Marine Ecosystem Health and Conservation
 The MARES Researchers and their Research
Fate of pelagic fish production in the Celtic Sea, partitioning between marine megafauna, birds and fisheries; and the management implications
PhD Code: MARES_20_2010:
  • Host institute 1: P4 - Galway Mayo Institute of Technology (GMIT)
  • Host institute 2: P11 - Université Paris Marie Curie (UPMC)
  • Host institute 3: P19 - Irish Whale and Dolphin Group
Research fields:
  • T2 - Understanding biodiversity effects on the functioning of marine ecosystems
  • T4 - Natural resources : overexploitation, fisheries and aquaculture
  • Ian O'Connor
  • Jean-Marc Guarini
  • Simon Berrow
  • Coilin Minto
  • Pierre Petitgas
Contact Person and email: Ian O'Connor -

Subject description
All cetacean species occur on Annex IV of the Habitats Directive and are thus entitled to strict protection including prevention of deliberate capture or killing, prevention of deliberate disturbance, prevention of deterioration of breeding or resting sites, prevention of capture or sale and a requirement to monitor the incidental capture or killing or these species. The Celtic Sea, between the south coast of Ireland and France, is known to be the site of complex coastal fronts and upwelling of cold nutrient rich waters (Pingree & Le Cann 1989). The seasonal occurrence of cetaceans - including fin, humpback and minke whales and common dolphins in the Celtic Sea has been recorded in some detail by the Irish Whale and Dolphin Group (IWDG) and Galway Mayo Institute of Technology (GMIT) since 1999 (Berrow et al. 2002, Berrow et al. 2010, Whooley et al. 2010). Research into the presence of fin and humpback whales in the region strongly suggests that the whales utilize this habitat predominantly for feeding (Berrow et al. 2003, 2005, O’Donnell et al. 2004 - 2009). Fin whales and common dolphins also show a strong seasonal aspect to their use of this foraging habitat. Use of photo identification has yielded several inter-annual re-sightings of individual fin and humpback whales (Whooley et al. 2010) indicating that a level of site fidelity exists in fin and humpback whales using this foraging area. Recent research has shown that the ocurrence and abundance of baleen whales and the ocurrence of common dolphins is strongly linked to the abundance of herring and sprat. These fish species (along with pilchard and sardines) are also prey for coastal and pelagic seabirds foraging over wide area. The Celtic Sea herring stock is fished by vessels from Ireland, France, Holland, the Uk and Germany, these vessels currently land approximately 5900 tonnes. Estimates of natural mortality (M) do not partition the mortality among different consumsers and have not taken account of the recent increase in cetaceans in the area. There is potentially a serious conflict in the Celtic Sea between fisheries and predators of pelagic fish. Prudent management of the pelagic fish resource is needed to meet legislative demands for the protection of cetacean and birds, maximising the return to fishers whilst not adverselfy affecting predators competing for the same resource. In addition to fisheries, there is a developing ecotourism business in the Celtic Sea with several vessels offering whale watching services. The proposed research aims to :
1. estimate the population sizes of cetaceans and birds using the pelagic fish resource Celtic sea. This will be done using archived data and data gathered on dedicated surveys and using ferries, research vessels, ecotourism boats, naval vessels and air corps planes.
2. quantify pelagic fish production in the Celtic Sea in conjunction with Irish Marine Institute dedicated fisheries surveys and determine the seasonality of the pelagic fish predator guild
3. partition the consumption of pelagic fish into the different components of the predator guild to estimate an annual consumption rate. This will be done by estimating the energetic requirements of the components, stratified by body mass. This will create an estimate of annual pelagic fish consumption rates in the Celtic sea, using landings and observer data estimates.
4. the data will then be used to validate an ecosystem model of pelagic fish and their predators in the Celtic sea to permit analysis of the interactions between fisheries, predators and prey. The model will simulate the spatio-temporal variations of the interacting populations, including fisheries, which will be considered as a loss of biomass and a selective pressure for fish populations, when only a precise range of size is targeted. The applied objective of the model is both to calculate a maximum sustainable yield to the fishing industry, and to determine the size of the captures which will permit sufficient pelagic fish resources to sustain the predator guild.
To date, work has focussed on the spawning aggregations of pelagic fish and cetaceans in the Celtic Sea off the south coast of Ireland. This year the promoters are extending the study area further offshore to investigate the relationships between pelagic fish and their predators over a wider area and the current survey (Oct 2010) will see the introduction of dedicated aerial surveys for cetacean distribution data. This will be coupled with fisheries observer data to provide a wider view of the interactions between pelagic fish and their predators in the Celtic Sea. The forthcoming Marine Strategy Framework directive requires member states take a regional approach to management of trans-boundary species such as bird and cetaceans, this project will be an excellent example of co- operation between French and Irish researchers (the two countries that harvest the vast majority of Celtic sea herring). The dynamic nature of marine environments requires a flexible analysis to allow for a complex range of variables and model structures, (Redfern et al. 2006). The current proposal builds on recent work examining the aggregations of cetaceans, especially baleen whales (fin whale, humpback whale and minke whale) and common dolphins off the south coast of Ireland by using GIS and GLM to explore the ecosystem links that may be driving this activity.

Berrow, S. (2001) Biological diversity of cetaceans (whales, dolphins and porpoises) in Irish waters. In Marine Biodiversity in Ireland and adjacent waters. Ed. Nunn, J. Pages, 115-119 
Berrow SD, Whooley P, Ferriss S (2002) Irish Whale and Dolphin Group Cetacean Sighting Review (1991-2001). Irish Whale and Dolphin Group. 34pp
Berrow SD, Oliver G, Roden C, Whooley P (2003)  Large whale survey off the south coast of Ireland.  Interim Report to the Heritage Council.  Project funded by the Heritage Council under the Wildlife Grant Scheme 2003.
Berrow S.D., Whooley P., O’Connell M. and Wall D. (2010) Irish Cetacean Review (2000-2009). Irish Whale and Dolphin Group, Kilrush, Co. Clare, Ireland. 60pp. ISBN 0-9540552-4-1
O’Donnell C, Saunders R, Lynch D, Lyons K, Wall D, (2004, 2005, 2006, 2007, 2008, 2009) FSS Survey Series, Celtic Sea Herring Acoustic Survey Cruise Report. Marine Institute Fisheries Science Service Ireland. 
Pingree RD, Le Cann B (1989) Celtic and Armorican Slope and Shelf Residual currents.  Prog Oceanogr 23: 303-338.
Redfern JV, Ferguson MC, Becker EA, Hyrenbach KD, Good C, Barlow J, Kaschner K, Baumgartner MF, Forney KA, Balance LT, Fauchald P, Halpin P, Hamazaki T, Pershing AJ, Qian SS, Read A, Reilly SB, Torres L, Werner F (2006)  Techniques for cetacean-habitat modelling.  Mar Ecol Proj Ser 310:  271-295.
Whooley, P, Berrow S, Barnes C, (2010) Photo-identification of fin and humpback whales off the south coast of Ireland.  Marine Biodiversity Notes 

Expected outcomes
This proposal will produce the following tangible outputs: Three peer reviewed papers:
1) Coastal and seabird predators of pelagic fish in the Celtic Sea: seasonality, scale and potential for conflict with fisheries
2) Cetacean predators of pelagic fish in the Celtic Sea: consumption, conflicts and implications for fisheries management
3) An ecosystem model for Celtic Sea resource management A tool to enhance the management of the Celtic Sea fisheries resources to take account of ecosystem requiremnents of these resources in addition to fisheries.
This project represents a collaboration between third level institutes: GMIT and UPMC; research organisations Irish Marine Institute and IFREMER; environmental non governmental organisations (IWDG, P19); whale watching ecotourism companies operating in the Celtic Sea (Colin Barnes Whale Watching Ltd);and fishing industry organisations.
This project will:
contribute to member states' requirements under the birds, habiats and marine strategy framework directives Explore the ecosystem links and trophic interactions in the Celtic Sea, which is consistent with current interest in developing an Ecosystem Approach to Fisheries Management (DGFISH and OSPAR). Provide data and interpretation to address OSPAR recommendations such as “Criteria for the Identification of Species and Habitats in need of Protection and their Method of Application” and “On the Protection and Conservation of the Ecosystems and Biological Diversity of the Maritime Area” Support the development of National Biodiversity Plans by obtaining data through the implementation of a programme of marine surveys and mapping. Provide information to support Strategic Environmental Assessments (especially Offshore SEA) Support the development of marine wildlife tourism in the Celtic Sea Bring added value to existing data collected in the Celtic Sea since 1999
The IWDG and GMIT have a strong track record in outreach and the dissemenation of research through scientific publications, and conferences; to government agencies through policy documents and advice, to the general public through awareness campaigns, public lectures, seminars , workshops and training courses. A selection of this material and other information is available online at As a measure of the popularity of the IWDG website it receives over 7000 differen page requests each month. This project will form part of the media output of the IWDG through its website, policy documents, lobbying of government and EU agencies and the general public through the IWDG/GMIT Whales Tales public lecture series.

Search website:
Last update on 04/12/2019 -
Management login
Site map