Our primary focus is the collection of robust, independent data for use in conservation research and in describing the changing status of cetaceans and seabirds. This important work feeds into national and international reporting, education, public awareness raising and ultimately conservation advice and the advocacy work carried out by MARINElife.
The research coordinated and run by our science team fall into a number of survey programmes, all incorporating strict and scrutinised scientific methodologies, in order to produce high quality, useful data to meet reporting and conservation requirements.
We thank our sponsors and collaborating bodies for their support past and present without which we could not continue this vital work.
Survey methods
Line transect sampling for whales and dolphins
On each survey, effort-based cetacean and seabird monitoring is carried out by a team of trained and experienced volunteer observers using a standardised “Distance sampling” survey methodology, from a well-positioned viewing platform, usually the ship’s bridge. The methodology is adapted slightly (for pragmatic reasons) for use on platforms of opportunity such as commercial ferries and is reviewed on an annual basis to ensure it is in keeping with the most recent best practice methods and comparable with other research groups carrying out similar surveys.
Distance sampling is a widely-used method to estimate animal density or abundance in a study area. It uses the recorded distances to the animals sighted whilst surveying upon lines or points. A key assumption is that the probability of detecting an animal decreases as its distance from the surveyor increases. Analyses are carried out to calculate the probability of detecting an animal, given its distance from the survey transect.
There are a number of basic procedures which must be adhered to, to meet best practice methods:
- Use of a forward facing survey platform i.e. Bridge
- Scanning areas head of vessel (22.5 degrees ahead of the beam on either side to dead ahead)
- Scanning near and far afield
- Surveyors scan use both naked eye and binoculars to maximise their field of view
- Regular breaks to be taken by surveyors
- Effort/Environmental data is recorded every 15-30mins
- Any sightings are recorded at first point of observation
MARINElife Seabird Surveys
Bird box methodology is employed for recording birds at sea during MARINElife surveys. Researchers maintain a fixed position, this being towards the middle-right of the bridge, looking ahead. Seabirds and migrating land-birds are recorded throughout the survey within a 1km arc ahead of the ship. In order to determine relative abundance there is a 300 x 300 metre “box” offset, front right of the bow. Birds that pass through this box are recorded for the box and not for the wider area. Other birds within the arc are recorded as out of box. Behavioural data is also collected.
VSAS surveys (ESAS methods)
The European Seabirds at Sea (ESAS) method records seabirds and marine megafauna on the sea surface using line transect distance sampling and birds in flight using ‘snapshots’ (see below) (Camphuysen et al. 2004). Distance sampling allows for the correction of animals that may have been undetected during a survey, allowing a more accurate estimation of true density to be calculated. The ESAS method integrates four recording protocols; one for cetaceans and other marine megafauna, and three for birds. The observation type dictates how data are recorded. The protocols, which are run concurrently, record: (1) birds on the water (that can be divided according to whether they are ‘In transect’ or ‘Not in transect’); (2) birds in flight; (3) birds in flight in ‘snapshot’; and (4) marine mammals/large fish/marine reptiles.
The transect area consists of a 300 m wide 90° bow-to-beam strip which stretches ahead from the observer to the end of the transect line (Figure 1). It is subdivided into four distance bands (A: ≤50 m, B: 51–100 m, C: 101–200 m, D: 201–300 m) and all birds on the water are recorded within the band they are first observed in, using individually calibrated Heinemann-type rangefinder sticks to assess the distance (Heinemann 1981). Birds observed on the water outside of the 300 m wide transect area are recorded as in Band E.
‘Snapshot’ methods are used to record flying birds encountered within the transect area in consecutive 300 m by 300 m bow-to-beam quadrats. Birds are recorded as being in snapshot (i.e. in transect) when they are observed in the quadrat as the boat enters the beginning of each quadrat. All other birds in flight are recorded as being out of transect.
Photo Identification
Photo-ID is a cataloguing process for the distinctive features of individual whales and dolphins. Much like you and I can be told apart by our fingertips, so can individual dolphin and whales be identified by the unique occurrence, shape and size of nicks and scratches on their dorsal fins and bodies. By identifying and recording sightings of new and known individuals, we study dolphin populations and provide population size estimates based on re-sightings as well as population trends (increases or decreases in an area), group dynamics and social interactions, site preference and how they may use certain areas for important life stages such as feeding and calving. MARINElife currently have three main Photo-ID studies and catalogues. The South West Bottlenose dolphin catalogue and the Lyme Bay and North East White-beaked Dolphin catalogues.
Find a list of our research projects at Our Projects.