ECOPredS project investigates predator-prey interactions between killer whales and seals (including both grey and harbour) in Scotland, in order to better understand:
- mortality (consumption) of harbour seals by killer whales in coastal areas, and
- behaviour (non-consumptive) interactions, i.e., predator avoidance by seals, and the foraging behaviour of killer whales.
Our ultimate goal is to inform the conservation and management of both the predator and prey species.
As well as collecting new data, the project will bring together and analyze existing data from collaborators and citizen scientists. The project is currently focusing on three distinct research approaches:
- Analysis of seal behaviour and distribution in relation to killer whale presence
- Behavioural (focal follow) observations of killer whales found in coastal areas
- Passive acoustic monitoring (PAM) near coastal haulout sites
Approach 1 aims to investigate how seal behaviour might influence their risk of being detected and encountered by killer whales. For example, seals may have different haulout patterns in areas and times of frequent killer whale visitation. So far, the project can address this using existing data from collaborators, namely SMRU telemetry data and killer whale sightings from the public. We also conduct surveys of seal haulout sites to understand fine-scale variation in their distribution.
Approach 2 collects behaviour observations of killer whales to estimate their hunting effort and prey composition while foraging in nearshore areas. This involves both land-based and drone-based observations of behaviour, and estimating the proportion of predation events involving different prey types (species, age class). The observational data will also inform about killer whale hunting tactics and time allocation to different areas and behaviours.
Approach 3 aims to monitor the acoustic environment and predator-prey sound production in key areas where interactions are expected to occur. This will be achieved by using data from existing acoustic recorders, and deploying new hydrophones that can be left to record in a station for a couple of months at a time. Killer whales in Shetland have been recorded to produce pulsed calls, echolocation clicks and whistles, but they may be more quiet when hunting for seals. Harbour seal males produce breeding calls to attract mates, which may also attract killer whales.