Distribution, abundance and biology of Group V humpback whales ...

6.1.2 Sloughed skin sampling
Sloughed skin sampling is a technique used for collecting
genetic material from samples such as skin, hair and faeces
from an individual at the surface (Palsbøll 1997). Sloughed
whale skin contains enough DNA for genetic analysis,
and offers a non-intrusive method for collecting tissue
(Valsecchi et al.1998). A study undertaken by Valsecchi
(1998) demonstrated that sloughed skin sampling is a viable
alternative to genetic sampling and is particularly effective
when applied to active groups. The sloughed skin sampling
technique offers a viable alternative to biopsy darting in
regions where darting is either not permitted or otherwise
undesirable.
Amos and Hoelzel (1992) described a method for preserving
skin tissue for DNA-based analysis. The collection of skin
tissue for genetic analysis is preferable because skin is
easily accessible and is rich in DNA. Skin from stranded
whales can remain usable for at least a week, and probably
longer depending upon ambient conditions (Amos and
Hoelzel 1992).
6.1.3 Acoustic tracking
Male humpbacks sing while migrating to and from their
wintering grounds and while they are present at the
wintering grounds. However, it is uncertain whether or
not song functions to maintain a space between pods or
to attract females (Tyack 1981). All males in a population
produce the same song, which changes over time and with
increasing distance (Cato 1991).
Noad et al.(1998) undertook an acoustic and visual tracking
study in south-east Queensland and concluded that acoustic
tracking may be especially useful for the study or survey
of whale movements beyond visual range of shore-based
observation points. The information gathered is dependent
upon the number of hydrophones used. Three hydrophones
provided positional information on singing humpbacks and
the paths they took. Three hydrophones are required to
make a direct comparison between visual and acoustic
tracking methods. The study has implications for the
interactions between singers and non-singing humpbacks;
interactions between individual singers; migratory behaviour
and travel rates; pod composition; habitat use; song function
and boat-whale interactions. Although acoustic tracking
gathers information from singing individuals, it cannot be
used as a technique to identify individuals for long-term
studies.
For other innovations in monitoring humpbacks out of visible
range of ships, acoustics have been used with other species
and may eventually prove feasible for monitoring humpback
occurrence at remote areas such as outer reef complexes
(Clark et al.1996 and 2002; Clark and Fristup 1997;
Clark and Ellison 2000; Frankel et al.1995).
6.2 Manipulative sampling techniques
A close approach to a whale is required for the attachment
of a conventional tag, the taking of samples for genetic
analysis and the taking of identifying photographs. The
attachment of tags and biopsy sampling are considered
as manipulative research (Queensland Department
of Environment 1997). However, the certainty with
which a sample is taken and the information provided
is considerable, especially when combined with photoidentifi
cation data.
In general biopsy samples have not been taken from calves
due to cultural sensitivities and the perceived impacts of
the technique. In 1992, a study undertaken by Valsecchi
et al.(2002) targeted mother and calves pairs for genetic
analysis;
biopsy samples were taken from the mothers and when
conditions were favourable sloughed skin samples were
taken from the accompanying calf. The study supports the
notion that mothers travel with their offspring for the fi rst
year of the calf’s life.
6.2.1 “Discovery tags”
Chittleborough (1959a) and Dawbin (1959) used “discovery
tags” to provide distributional information on the group IV
and V populations during the commercial whaling period.
Discovery tags were conventional metal tags inserted
sub-dermally into the humpback. The tags were retrieved
when the harvested whale carcass was processed. The
discovery tags were successfully used to reveal that some
intermingling was occurring on the feeding grounds between
the group IV and V populations; and the migratory routes,
either side of the Australian continent, to the wintering
grounds of the group IV and V populations
(Chittleborough 1965).
6.3 Biopsy sampling
Biopsy sampling is a technique that involves the taking
of a core of skin using a dart fi red from a crossbow. The
biopsy dart is a cylindrical punch measuring approximately
10mm in diameter and 30mm long. A metal fl ange at the
base controls the depth of penetration by the dart. The
dart has a collar of fl otation behind the tip, and may or
may not be tethered to assist retrieval (Brown et al.1994).
The combination of genetic and photo-identifi cation data
provides a powerful tool for identifying individual humpbacks
(Stevick et al.2001).
The reactions of several cetacean species to biopsy
sampling have been investigated (Patenaude and White
1995; Gauthier and Sears 1999; Weinrich et al.1992).
Clapham and Mattila 1993b and Brown et al.(1994)
undertook studies on humpbacks and concluded there
was no signifi cant change in behaviour to the biopsy
sampling. However, Weinrich et al.(1992) and other authors
have noted that there is a greater reaction to the human
disturbance caused by the boat and its occupants than to
the sampling technique itself.
Brown et al.(1994) investigated the behavioural responses
of east Australian humpbacks to biopsy sampling and
suggests that female humpback whales maybe particularly
responsive to human disturbances. They concluded that
biopsy sampling has minimal impact on humpbacks.
Hooker et al.(2001) compared the reactions of biopsy
sampling with tag attachment on northern bottlenose
whales Hyperoodon ampullatus. They found the reactions
of various species to biopsy darting is generally mild, the
most common response is a “startle” reaction, although
the level of reaction varies slightly between species, and
also between populations and individuals. In contrast, the
reaction of cetaceans to tagging with suction-cups-attached
tags has been found to vary dramatically.
Biopsy sampling is described as a manipulative research
technique. The technique is neither encouraged nor
excluded by the management approach adopted in
Queensland.
6.4 Telemetry
Telemetry tags methods include the use of satellite-linked
time-depth recorders, satellite-linked position beacons,
time-depth recorders and VHF radio tags. This technique is
a powerful took for investigating aspects of baleen whales’
ranging behaviour, and are likely to become a powerful tool
in the future. Mate et al.(1997, 1999 and 2000) illustrates
the use and application of the tagging techniques on other
baleen species.
12 • Distribution, abundance and biology of Group V humpback whales Megaptera novaeangliae: A review • August 2002