Developing a cost-effective monitoring strategy for coastal cetaceans

Abstract

The overarching aim of this PhD was to further our knowledge on the distribution of cetaceans around Northern Ireland and the surrounding region. These efforts were driven by a need to conserve and protect cetacean species in light of increasing pressures on the marine environment. Four discrete studies were devised to assess historical patterns in cetacean distribution and investigate areas of conservation importance through Passive Acoustic Monitoring (PAM).The harbour porpoise Phocoena phocoena was found to be the most commonly detected cetacean in Northern Irish waters exhibiting a persistent, but non-uniform distribution. The temporal distribution of this species, monitored in the western Irish Sea and off the north coast of County Donegal, varied across seasons consistently, peaking in winter, while fine scale variations across time of day and tide were found to be site-specific. Further fine-scale spatio-temporal trends (< 5 km) were identified within the Skerries and Causeway Special Area of Conservation (SAC). One deployment location in particular was suggestive of a foraging hotspot, potentially suitable for long-term monitoring through a Marine Protected Area (MPA) framework. It is anticipated that findings on the fine-scale temporal dynamics of harbour porpoise could facilitate local coastal management. While patterns in seasonality, suggestive of an interesting overwintering distribution, pose further questions on the location of these individuals during the summer months. This information places summer derived density estimates into a different perspective and provides another layer of information in which to assess the regional population status of this species.Throughout the project, a critical appraisal of the methods was carried out in the context of suitability for long-term monitoring. Specifically, the presence of fine-scale heterogeneity in distribution (< 5 km) and the association of reduced detection rates with increasing ambient noise were considered. To conclude the thesis, these findings were incorporated into a long-term cetacean monitoring strategy for Northern Ireland.

Date of Award	Jul 2021
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Jonathan Houghton (Supervisor), University Queensland (Supervisor), Adam Mellor (Supervisor) & Keith Farnsworth (Supervisor)