451
16.4 Aerial Survey Methods
Aerial surveys for censuses and photographing individuals have been used for many
species, and can be done using aircraft or helicopters, depending on the survey area
and funding available.
Right whales have been surveyed along the southern coast of Brazil since 1987
by the Right Whale Project. The first aerial surveys were conducted from a
single- engine aircraft (Simões-Lopes et al. 1992). Since 1998 a helicopter has been
used (Groch et al. 2005). Despite the higher cost, the helicopter has proved to be a
better platform because of its safety, maneuverability and more panoramic view of
the whales. In regions where the water is turbid, the use of helicopter turns out to be
crucial for the efficiency of the survey, because you cannot see the animals under
water and the approach maneuver to register the sighting is facilitated.
Surveys have been concentrated along the central-southern coast of Santa
Catarina State, and the North of Rio Grande do Sul State (Fig. 16.1). In five opportunities, surveys were extended, covering a larger area between Chui-RS (33°40′ S,
53°28′ W) and Porto Seguro-BA (16.27.15.2 S, 39.03.40.9 W), with the aim of
gather information on occurrence and distribution of right whales along most of the
species´ historical range. Surveys have been conducted during or close to the time
of peak whale abundance, in September, however in Southern Brazil monthly
surveys were also conducted from 2002.
For optimal results, the requirement is to conduct surveys during days with
favorable sighting conditions, i.e. low wind, good visibility, sea state below 3 in
Beaufort scale and adequate lighting. This condition is necessary to easy whales´
detection. Because the survey area is extensive, usually this task became a challenge
for the time period programed for the survey. The challenge is to conciliate the best
weather forecast with the availability of the aircraft, and a similar time window
every year.
Surveys have been conducted at low altitude, about 300 m and a speed of 111–
167 km/h), depending on the aircraft, following a parallel trajectory at a distance of
approximately 500 m from shore. The search for individuals is usually restricted to
a stripe of up to 1500 m from shore, where mother-calf pairs concentrate. Up to
1997 a single engine aircraft was used. Since 1998 a helicopter has been used. In
most of the surveys (from 2002 to the present) a Bell Jet Ranger helicopter (Fig. 16.9)
with capacity for the pilot and up to four passengers has been used. Therefore two
to three observers can be involved in the search duty and data recording. The main
observer sits to the left of the pilot and searches for whales ahead of the aircraft. The
second observer sits behind the pilot and scan to the right of the aircraft and is
responsible for taking photographs of the sighted animals. The third observer sit
next to the photographer and monitor the area to the left of the aircraft. This side
was also observed by the main observer when only two observers are onboard.
Whenever a whale or group of whales is spotted they are approached at a minimum
height of (100 m) for determination of the number of whales and group composition. The helicopter hover over the group and as the callosity patterns of individuals
16 Conservation Advances for the Southern Right Whales in Brazil
16.4 Aerial Survey Methods
Aerial surveys for censuses and photographing individuals have been used for many
species, and can be done using aircraft or helicopters, depending on the survey area
and funding available.
Right whales have been surveyed along the southern coast of Brazil since 1987
by the Right Whale Project. The first aerial surveys were conducted from a
single- engine aircraft (Simões-Lopes et al. 1992). Since 1998 a helicopter has been
used (Groch et al. 2005). Despite the higher cost, the helicopter has proved to be a
better platform because of its safety, maneuverability and more panoramic view of
the whales. In regions where the water is turbid, the use of helicopter turns out to be
crucial for the efficiency of the survey, because you cannot see the animals under
water and the approach maneuver to register the sighting is facilitated.
Surveys have been concentrated along the central-southern coast of Santa
Catarina State, and the North of Rio Grande do Sul State (Fig. 16.1). In five opportunities, surveys were extended, covering a larger area between Chui-RS (33°40′ S,
53°28′ W) and Porto Seguro-BA (16.27.15.2 S, 39.03.40.9 W), with the aim of
gather information on occurrence and distribution of right whales along most of the
species´ historical range. Surveys have been conducted during or close to the time
of peak whale abundance, in September, however in Southern Brazil monthly
surveys were also conducted from 2002.
For optimal results, the requirement is to conduct surveys during days with
favorable sighting conditions, i.e. low wind, good visibility, sea state below 3 in
Beaufort scale and adequate lighting. This condition is necessary to easy whales´
detection. Because the survey area is extensive, usually this task became a challenge
for the time period programed for the survey. The challenge is to conciliate the best
weather forecast with the availability of the aircraft, and a similar time window
every year.
Surveys have been conducted at low altitude, about 300 m and a speed of 111–
167 km/h), depending on the aircraft, following a parallel trajectory at a distance of
approximately 500 m from shore. The search for individuals is usually restricted to
a stripe of up to 1500 m from shore, where mother-calf pairs concentrate. Up to
1997 a single engine aircraft was used. Since 1998 a helicopter has been used. In
most of the surveys (from 2002 to the present) a Bell Jet Ranger helicopter (Fig. 16.9)
with capacity for the pilot and up to four passengers has been used. Therefore two
to three observers can be involved in the search duty and data recording. The main
observer sits to the left of the pilot and searches for whales ahead of the aircraft. The
second observer sits behind the pilot and scan to the right of the aircraft and is
responsible for taking photographs of the sighted animals. The third observer sit
next to the photographer and monitor the area to the left of the aircraft. This side
was also observed by the main observer when only two observers are onboard.
Whenever a whale or group of whales is spotted they are approached at a minimum
height of (100 m) for determination of the number of whales and group composition. The helicopter hover over the group and as the callosity patterns of individuals
16 Conservation Advances for the Southern Right Whales in Brazil