Protecting top predators
Published: 15 October 2015
Understanding the factors determining the spatial and temporal distribution of marine top-predators (cetaceans and seabirds) remains a key research area, in particular with regard to predicting responses of these communities to both climate change and anthropogenic activities. However, the recent interest in marine protected area (MPA) initiatives and the anticipated growth of the marine renewable industries creates an immediate need to advance our understanding if MPAs are to successfully protect top-predators, and also to prevent negative impacts from extensive developments of renewables.
Our research at the School of Ocean Sciences (Bangor University) aims to better understand mechanistic links between physical conditions, prey characteristics and the foraging distributions of top-predators in the UK. This increased understanding can help to identify critical areas, quantify overlap with anthropogenic activities, and anticipate community responses to changes in oceanographic processes brought about by energy extraction and climate change.
Our core research involves the use of existing datasets to disentangle the various factors influencing when and where foraging top-predators are found. These datasets include vessel and aerial-based surveys of top-predator activities, prey characteristics from systematic fisheries surveys, and physical datasets from modern oceanographic modelling and mapping techniques. This research builds upon many previous studies seeking to explain the spatial and temporal distributions of top-predators by placing an much larger emphasis on establishing the dynamics of key prey species (fish and cephalopods) rather than using commonly used proxies of prey presence (sea surface temperature, surface chlorophyll), and also upon identifying the specific combination of physical conditions which may enhance the availability of key prey species to top-predators.
The knowledge gained will then be used to predict the foraging distributions of top-predators under a range of environmental scenarios. The collation of existing datasets has been supplemented by novel empirical datasets collected in dedicated research cruises. Our recent 4 week survey in the Celtic Sea and Western Approaches used hydroacoustic methods and visual observations to collect concurrent information on bathymetry, currents, prey characteristics and top-predator foraging activities. Initial analysis indicates higher abundances, biomass and diversity of foraging seabirds and cetaceans in shallow areas characterised by strong tidal currents and complex bathymetry, suggesting an importance of high energy habitats for these species.
Our subsequent analysis will seek to establish differences in prey characteristics between high and low energy habitats. For instance, is there simply more prey in high energy habitats, or is prey more accessible? By better understanding precisely how top-predators successfully exploit their environment, this research will provide the information needed to protect these charismatic species over a period of rapid environmental change and increased exploitation of marine resources.