Testing conducted in July 2010.

At present, aerial survey is the most advanced method in the studies of marine mammal abundance and distribution. Comparing to boat surveys, it allows for wider area coverage within a shorter period of time, higher animal detection rate, using a method of platform (fixed) photography for abundance counts. The latter is especially important while counting the animals in dense aggregations, when visual counts lead to large errors.

Unfortunately, using the planes is very expensive; long flights lead to a heavy carbon footprint. In addition, study regions are often the remote wild areas impossible to be reached by plane. For the studies of cetaceans that aggregate near shore (for example, beluga whales, gray whales) and pinnipeds that haul out on land (sea lions, fur seals, walruses), i.e. for conducting work in a restricted coastal zone, it seems practical to use the means of ultra-light aviation (ULA).

We tested a motorized paraglider – paramotor – for beluga abundance count, age structure study, and photo-identification as a pilot-study within the project on Sakhalin-Amur beluga aggregation (the Okhotsk Sea). This apparatus consists of a paraglider wing, an engine with a fuel tank, a construction for carrying a pilot and a passenger (Fig. 1). It is relatively economical and portable: all our equipment – two complete paramotor sets – took less than 2 м3 and was delivered to the site by autotransport and further – by water, on a bayda, traditional fisherman boat with a wooden deck. Fuel consumption varied between 5 and 7 l/hr. depending on construction. Flying paramotor required operation by a professional pilot.

The work was conducted on Chkalova and Baydukova Islands in the southwestern part of Sakhalinsky Bay. We tested: 1) two constructions of seats – a trike vs. foot-launch double-seat; 2) flight stability (maintaining the course, altitude, and speed); 3) maneuverability on relatively low altitudes in order to shoot camera for photoidentification purpose; 4) dependence on weather conditions (wind, rain). We recorded animal reaction to paramotor while flying at different altitudes. The
results of abundance counts were compared to those of simultaneous opportunistic observations from the boat. On July 9-12, 2010, 9 flights, total duration of 8 hours, were conducted. The team consisted of a pilot and a photographer/observer. A motorboat with safety equipment and an independent observer followed within 500m of paramotor projection on the water. Either the grass-covered gravel surface of the island or a wet sandy coast could serve as a take-off/landing ground. The flight altitude varied between 30 and 300 m de-pending on observer‘s demands; technical potential of the apparatus allowed for maintaining the pre-set altitude fixed. Distance from the coast did not exceed 6 km, from the start point – 30 km. The flight speed varied from 20 to 70 km/hr. depending on wind di-rection. The flights were conducted when the wind was ≤7-8 m/sec, which is equivalent to Beaufort wind/sea state 4, i.e. to the wind strength close to maximum allowed for conducting the aerial surveys.

The work was suspended during the rain, but paramotor did not require an immediate emergency landing if moderate rain had started during the flight. For photography we used Nikon D700 and D90 camera models with Nikkor 80-200мм/f2.8 lens. The flight routes were both the line transects and circling the groups at different heights (under GPS control) for photography.

Whenever it was possible, belugas were counted not only from the paramotor, but also from the accompanying it boat. In these cases, the visual estimate from paramotor several times (up to 10) exceeded the boat-based count. Calf detection probability was even higher due to the fact that calves may be hidden behind mothers and masked with the waves of grayish murky water while searched for from the boat. Calf percentage (age 0-1 year, ≥13%) is close to similar data (16%, when dividing group into calves of 0-1 year and others) obtained during the aerial survey of the western Okhotsk Sea belugas in August 2010 from AN-38 plane (unpubl. rep.).

Paramotor speeds depended on the wind strength and direction, and could differ by 3 times. This factor must be taken into account in the abundance survey data analysis if survey design implies flying along multidirectional track-lines.

Beluga photo-identification from the air (from above), from one hand, underperforms comparing to the boat-based photography (from the side), because it has a limited resolution ability in identifying a whale by its dorsal ridge. From the other hand, in Sakhalinsky bay, where belugas usually don‘t let people closer than 200 m, photography from the air seems the only possible way to collect material for identification. We tested beluga reaction to paramotor and resolution ability of our photo-equipment at different flight altitudes. Minimal height that did not disturb the whales, and that is why may be rec-ommended for the survey, was 100 m when belugas were feeding, and 200m – when they travelled.

Photography suitable for photo-identification required lower flight altitudes – up to 50m. Crop-factor ×1.5 of Nikon D90 camera increasing max focus length of our lens from 200 to 300 mm appeared to be a more important factor for getting adequate images than a higher resolution power of Nikon D700. Thus, we found out that optimum flight altitude for the abundance count is 200m, while photo-identification requires separate effort and flying at lower heights; optimal ―resulting focus length of the photo-equipment used should be 300 mm.

Both tested paramotor constructions appeared to be adequate for work. The trike had an undeniable advantage in terms of the observer‘s comfort, especially during the long, over 1 hour, flights. The disadvantage of trike was a limited visibility look-down. Nevertheless, a technical decision to solve this problem and significantly narrow the ― blind zone has been found. A foot-launch double-seat construction is a priority option when it is neces-sary to minimize paramotor weight; for example, if the take-off site can be reached by foot only; also, the seat is less demanding in terms of surface coverage in the places of take-off and landing.

Our pilot project has demonstrated the effectiveness of using paramotor for beluga abundance counts, age structure and behaviour studies, as well as photo-identification. Paramotor-based aerial studies seem to be potentially productive for other cetacean and pinniped species research in the estuaries and coastal zones, provided all necessary safety measures are taken.

The study was supported by Ocean Park Corporation (Hong Kong); Georgia Aquarium Inc., Sea-World Parks and Entertainment, Mystic Aquarium and Institute for Exploration, (USA); Kamogawa Sea World (Japan). The author would like to express her sincere gratitude to the pilots Alexander Bogdanov and Vladimir Makurin for highly professional attitude and work enthusiasm, and to Vera Krasnova and Anton Chernetsky for scientific collaboration and providing our safety on the water.

Shpak O.

Marine Mammals of the Holarctic. 2012. Vol. 2.