Follow my track!

sealandtrack

The mural shows a grey seal and the coloured dots surrounding the seal depict the recorded positions of a tagged seal (note the scale of the dots is in km while the seal is ~2m in length). The colours of the dots differentiate between the assumed behaviours of the animal at the respective locations. See our page on movement models and dive profile to find out more about how to follow these animals into their natural habitat.


This project focused on grey and harbour seals around the UK, and the use of spatial models to characterise their distribution and habitat use. Grey and harbour seal usage maps were developed so that their at-sea distributions could be characterised. We used movement data generated from locations collected by telemetry tags, which are temporarily attached to the seal's fur. These data were combined with counts from seal haul outs around the UK so that the maps could be scaled to the population size of grey and harbour seals. The primary paper associated with these maps is Patterns of space use in sympatric marine colonial predators reveals scales of spatial partitioning, published in Marine Ecology Progress Series.

seal maps

Grey seal (Halichoerus grypus) with telemetry tag attached. Photo credit: SMRU

The maps have been used in a number of conservation, commercial, and government projects including Marine Scotland, Department of Energy and Climate Change, Joint Nature Conservation Committee, EU MyFish, and offshore wind farm developments (FTOWDG, MORL/BOWL, Hornsea). We also developed finer scale maps with enhanced analytical methodology, which have been used when assessing potential impacts to seals of proposed tidal turbine developments. The report can be found here and a corresponding paper is under review.

Fine-scale harbour seal at-sea usage around Orkney.


Grey Seal Isoscapes

A project led by my colleague Dr Nora Hanson, has investigated how carbon and nitrogen stable isotopes recovered from grey seal (Halichoerus grypus) teeth have changed over time. Identifying and monitoring top predators' use of resources provides important information about both the ecology of the species and their response to changing conditions. However, direct observations of animal resource use in the wild are often difficult to obtain, particularly in the marine environment as they spend much of their time at sea. Derived information from sources such as analysis of stable isotopes can be used to infer long-term changes in resource use. We accounted for shifts in the isotopic baseline, investigated changes in adult and juvenile stable isotopic niche space (isoscapes) over time, and identified ontogenetic trophic shifts.

EJmap2

Example map of predicted mean grey seal (Halichoerus grypus) δ 15Nbase values for the North Sea.


Grey and harbour seals are coastal species resident around the UK. The UK also has some of busiest shipping lanes in the world, and vessel traffic is generally increasing in the Northern hemisphere. This project set out to build a framework to explicitly incorporate underwater noise from vessels into spatial planning. We used seal and ship usage maps to identify areas that may be acoustically sensitive around the UK. Identifying a study area where varying spatial overlap occurred, we then used contemporaneous seal and ship movements over several months and used an acoustic modelling approach to predict sound exposure levels that individuals received from underwater noise generated by vessels. A paper Seals and shipping: quantifying population risk and individual exposure to vessel noise is in press in Journal of Applied Ecology, and data associated with the paper is available to download here.

EJship
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University of St Andrews