Top Predator Interactions
With major declines in world fish stocks over the last few decades there has been increased interest in the extent of competition for resources between commercial fisheries and top marine predators such as marine mammals and seabirds. Early studies suggested that some seal and seabird populations consumed significant quantities of commercially important fish species and used to justify reductions in seal and seabird numbers. More recently efforts are made to manage fisheries under the principle of ecological sustainable development and the focus has shifted to examine how fisheries affect the conservation status of marine mammals and seabirds. There is a significant amount of research to suggest that commercial fisheries may be significant competitors with seabirds and marine mammals and in cases of over-fishing, cause major declines. Indeed intensive fishing may lead to large and long lasting ecosystem changes and an inability to support abundant healthy populations of apex predators. Some of these key species are protected under international conservation legislation and therefore the demands of resource management and conservation often come into conflict. Understanding the mechanisms and extent to which top marine predators are competing with fisheries through an ecosystems approach would facilitate management decisions regarding conservation measures for both fisheries and marine mammal and seabird populations.
This Work Package seeks to:
- assess the interactions between top marine predators and fisheries in Ireland;
- determine abundance estimates of seal and seabird populations in the study sites;
- determine food consumption of seal and seabird populations in the study sites;
- determine the at-sea distributions of seals and seabirds in Ireland;
- identify the determinants of habitat use by these top marine predators;
- quantify the spatial overlap between fisheries and top marine predators in the study sites.
Mark Jessopp is the Beaufort Research Fellow working on this Work Package.
Sea birds such as puffins are considered top predators in the marine ecosystem. Here one of our scientists is conducting field observations by tagging puffins on the Irish coast.
Fieldwork
- Deployed 25 geolocator loggers from Skellig Michael July 2012. Retrieval planned for June 2013 plus deployment of camera traps
- Retrieved loggers from gannets at Saltee islands for analysis of overwintering distribution July 2012
- Seal scat collection continues frequently to date at Blasket Islands Co Kerry and Slaney, Co. Wexford and at Moy Co Sligo until Dec 2012, to contribute to seal diet studies
- Seal ground and aerial counts at Slaney Co Wexford Feb 2013
- Seal tagging underway March 2013 in Wexford as part of Inland Fisheries Ireland seal/salmon project
CMRC (Top Predator) Collaborations:
- Zoological Society of London on puffin research
- QUB on seal/fishery model for SW Ireland
- CREEM/St Andrews on statistical modelling of fishery/seal data
- BIM on seal depredation study