equipment and methods
Standardized protocols and non-invasive research
In our surveys, we use standardised protocols common to most cetacean and marine turtle research institutions. This is an essential element for facilitating the international cooperation between different projects and for ensuring the coherence to management and conservation plans.
Animal welfare is important to us and respecting the marine environment is crucial. Our surveys include only non-invasive research methodologies. Since 2003, Alnitak has pioneered in the improvement of sea turtle capture and tagging techniques in order to reduce stress considerably.
The Toftevaag is great for conducting surveys, with its double observation platform. It has a visual range of 13.5 nautical miles in the crow’s nest and 3.5 nautical miles from the main deck.
Our main working platform is the Toftevaag, an 18 metre gaff rigged ketch, registered in the Netherlands (18584 ZR Rotterdam). Between 1910 and 1979, the Toftevaag was a fantastic working boat, fishing for herring in the North Atlantic. Today, she is a successful working platform for acoustic and visual marine science surveys. The boat is equipped with an old style diesel engine that gives us a cruising speed of 5-6 knots. Towed behind the Toftevaag, we have a 5.2 mere rigid hull inflatable boat (RHIB), Iruka. This small boat has a 90 Hosrsepower outboard engine. The Iruka is in close, cautious encounters for approaching whales, dolphins and sea turtles.
Basic visual and acoustic survey
For most of our work, we rely on a sea state ranging from absolute calm to small waves (Force 3 on the Douglas Sea state scale). When the conditions are right, the Toftevaag motors or motorsails at a constant speed of 5-6 knots. Depending on the swells, the main deck lookout is complemented with a crow’s nest lookout. Once in deep waters (over 200 meters), the towed hydrophone is deployed and we being to listen for whales or dolphins in the distance. Our basic survey data records observations of cetaceans, seabirds, marine turtles, fish, other fauna, marine litter, and human activities on the LOOGER software. Acoustic recordings are made separately on the PAMGUARD software. For analysis, the data is complemented with the SOCIB database (IOOS) on readings like maritime traffic (AIS), sea surface temperature, chlorophyll, currents, etc.
Depending on the species, different tracking methods are used. For sea turtles, we use satellite transmitters, acoustic tags or sometimes other devices, such as National Geographic Crittercams. We track sperm whales with our towed array hydrophone, in order to close in on them and take photographs of their flukes for identification purposes. This allows us to keep tabs on the populations. For other cetaceans, we look at the shapes and markings of each individual and their fins, as if it were a “fingerprint” for identification purposes.
In 2014, we developed an innovative methodology to study sea turtle habitat use and behavioural response. We film basking turtles on the surface, look at the ecosystem their shells have attracted and study their behavior in response to certain stimuli- such as different lights or sounds.
Data recording equipment
The Toftevaag is equipped with a series of hydrophones.
- We have a towed array with two Benthos AQ4© elements at the end of a 200 m cable. We use this to detect and record cetacean vocalizations.
- We also have an “echosounder”, used to give detailed information on the depth, slope and also on the presence and density of fish, underwater temperature gradients (thermoclines) and deep scattering layers, where sea animals gather to feed.
- We use an A.I.S. transponder which is needed to monitor shipping areas and used to send a signal of our location, heading and speed at all times.
We have two laptop computers with GPS units, used to record the acoustic and visual survey data respectively (programs used are Pamguard© and Logger©). Both software were developed and shared by the International Fund for Animal Welfare.
Other important instruments on-board are:
· a liquid Nitrogen flask for freezing samples
· a Five Gyre Manta trawl with microplastic filter
· a microscope for plankton and microplastics
· utensils for collecting, preparing and conserving samples
· professional photographic equipment, surface and underwater 4K video cameras