Scottish Marine and Freshwater Science Volume 5 Number 8: EMEC Billia Croo Wave Test Site: Wildlife Observations Project Annual Report

3. Methodology

In September 2009, EMEC commissioned SMRU Ltd to develop a methodology for carrying out wildlife observations at its wave test site at Billia Croo. As well as documenting the methodology, SMRU Ltd provided initial training for the wildlife observers who carry out the observations. The methodology is available to download from the Marine Scotland Interactive website ^[2] .

Due to the featureless nature of the Billia Croo test site area, a grid-based recording system as used at the other sites within the EMEC wildlife observation programme was deemed unsuitable for this project. Instead the survey area is defined as a hemispherical shape extending offshore from the observation point. This area encompasses the whole of the Billia Croo test site and its surrounding area, extending to approximately 5km from shore (this is around the sighting limit for small cetaceans from a cliff-top at the height of the observation point).

The angle of declination and horizontal angle from the viewing tripod are used, together with information on tidal height, to estimate the geographical location of species sighted.

Following the establishment of the methodology and subsequent training of the wildlife observers, a boat based calibration was undertaken to validate the angle measurements.

3.1 Observations

Fully trained observers carry out observations from an ex-coastguard lookout station situated on a cliff-top approximately 90m above sea level overlooking the Billia Croo wave test site. Observations are made using a pair of 25x power binoculars ('Big Eyes') fix-mounted on a robust tripod with horizontal and declination angle boards to allow estimates of the geographical locations of wildlife to be made. The horizontal and declination angles are checked each day and realigned if necessary using pre-defined reference points.

Observing the area with the Big Eyes is carried out in a consistent manner from left to right at a series of distances from land ensuring the whole study area is covered. The study area is fully covered with two sweeps using the Big Eyes (a near sweep covering 800m - 1400m from shore and a far sweep covering 1400m - 5000m from shore) and a sweep of the near-shore area using hand-held binoculars. Figure 1 below shows the survey area with respect to the EMEC test berths and cables. Wildlife spotted is identified to species level using this method.

Figure 1: Survey area for EMEC's Billia Croo wave test site

3.2 Survey Effort

Data is collected for 20 hours per week, split over five 4 hour watch periods (based on five working days per week). The observers record wildlife sightings during daily watches by making regular scans of the study area as described above. Watches are carried out throughout the year during daylight hours, covering the period from 04:00hrs to 20:00hrs during summertime, and 09:00hrs to 15:00hrs in winter. It takes approximately 20 minutes to complete a single sweep of the survey area. This timing has been designed to maximise the probability of sighting wildlife whilst minimising observer fatigue. A rest period of 10 minutes is taken between scans in order to further reduce observer fatigue, making it possible to complete 2 sweeps per hour ( i.e. 8 sweeps per four hour watch).

A total of 886 hours of observations were completed for the period 01 April 2013 to 31 March 2014.

A watch rota, designed to ensure relatively uniform coverage across diurnal and tidal cycles, was created for each month. This rota is adhered to as far as possible, subject to weather conditions. If a watch is not carried out on a particular day, there is scope to transfer that particular watch to a day on the following weekend.

3.3 Data Recording

The observers record wildlife sightings during daily watches by making regular scans of the study area in a consistent manner. The details of any sightings made are recorded on paper field forms by the observer. This information is later transcribed into a bespoke Microsoft Access database. In addition to sighting data, the observer also records effort (date, start/end time), environmental conditions (tide state, meteorological conditions), and details of any shipping observed in the area during the watch. An updated database is submitted to EMEC each month.

Sightings are only recorded for any birds or marine mammals sighted in or on the surface of the sea. Details recorded include grid location, numbers, and behavioural details (e.g feeding, diving, swimming, stationary). Birds are recorded as sightings if they are on the water or hovering directly above the surface (within a few metres). Any birds flying higher than this or birds that are clearly transiting through the survey area are not recorded.