SPECIAL ASPECTS OF SPERM WHALES AND THEIR RELEVANCE TO WHALE
WATCHING
7.6 Necessary Research
Effective management will require research to be conducted at many
different levels to provide information on a variety of subjects. This, and
appropriate techniques to use with this species, were discussed briefly by
the group. The operators should be obliged to keep detailed logs and to
furnish these and other data on a regular basis. Whale watching platforms
often offer opportunities for data to be collected inexpensively, by
researchers or naturalist guides. Independent platforms are more expensive,
but generally provide higher quality data and may be essential for collecting
some types of information. Often research using a combination of all three
will yield the best results. Wherever possible subsets of data provided by
methods likely to be less precise should be validated against higher quality,
independently collected, data. Passive acoustic techniques have often
proved to be efficient complementary or alternative research methods to
use with this species.
The main categories of management questions, the techniques which
could be used to address them from different types of platform and
the biological information which each would contribute (in brackets)
are outlined below.
7.6.1. Monitoring the Activity of the Industry
It is clearly important to know the extent and the operating practices of the
whale watching operators themselves. This can be achieved by:
Questionnaires and data-forms answered by operators.
Observers on whale-watching vessels.
Detailed vessel logs including instrumentation of whale-watching vessels.
e.g., to log movements and activities.
7.6.2 Establishing Baseline Information About the Whale
Population Being Subjected to Whale Watching
It should be noted that establishing information about migrations, biology
and threats faced by a population in other parts of its range should also be
an important part of this research.
7.6.2.1 Research from Whale-Watching Vessels
Photo ID (residence, minimum number, social organisation, movements)
Photographic length measurements (length, age)
Observations (indices of population abundance and distribution, length, age, sex,
behaviour)
7.6.2.2 Research from Independent Platforms
Photo ID (residence, mark recapture population estimates, social organisation,
movements, migrations, life history parameters)
Survey, visual and acoustic (distribution and abundance).
Pollutant loads, diet, life history parameters, population identity
7.6.3 Immediate Effects of Whale Watching
Observations of the same individual whale or group before, during and after
a whale watching encounter will often give the most sensitive measures of
disturbance. Telemetry is probably not an appropriate technique to use in
this case because it will provide data only from a few whales and introduces
its own disturbance.
7.6.3.1 Research from Whale-Watching Vessels.
Behavioural observations and video recordings from an elevated
platform will provide information on ranges and behaviour, and,
together with acoustic monitoring, can be used to compare the effects
of different types of approach and/or number of vessels on the
behaviour of whales.
7.6.3.2 Research from Independent Platforms (including the shore)
Behavioural observations and video recordings from elevated
platforms will give information on ranges and behaviour and, together
with acoustic monitoring, can be used to compare the effects that
different types of approach and/or number of vessels have on the
behaviour of whales. Acoustic tracking can give information on
underwater behaviour and dive times; photo-ID on individual variation
in behaviour and reaction to disturbance, Acoustic tracking using a
large 3D array might be practical in some areas but thorough feasibility
studies would be required.
7.6.4 Long-term and Population-level Effects of Whale Watching
7.6.4.1 Research from Whale-Watching Vessels
Long-term effects of whale watching may be indicated by changes in
areas or modes of operation of the whale watchers, 'catch per unit
effort,' or systematic long-term changes in the behaviour of the whales
being watched.
7.6.4.2 Research from Dedicated Platforms
Long-term changes in distribution or abundance can be shown by the
results of visual or acoustic surveys; long-term changes in behaviour,
including indices of feeding success can be investigated if standard
visual or acoustic records have been made; photo-ID studies may
indicate calving rates or mortality rates, especially of calves;
photographic or acoustic length measuring can be used to estimate
growth rates. There is a need to develop indices of condition, e.g.
measures of fatness from photogrammetry or ultrasound.
7.7 Incompatible Activities
Activities were discussed that would be incompatible with sperm whale
watching, and the following list was developed:
7.7.1. Loud Underwater Noises
Because of their dependence on acoustics for sensing their environment and
communicating, sperm whales are particularly vulnerable to loud
underwater noises (see 6.4). The following activities are especially likely to
have a deleterious effect:
Seismic surveys
In Kaikoura, New Zealand, sperm whales temporarily vacated areas
during and after the visit
of vessels conducting a seismic survey. Dramatic behavioural responses
and movements
of sperm whales out of areas have also been documented in response to
seismic surveys in
the Gulf of Mexico (Mate et al. 1994). The hearing of individual whales
close to seismic sources could also be damaged. Seismic surveys can be
particularly disturbing because they are conducted over extensive periods
and cover large areas.
Military sonar
The use of sonar near Dominica and in other parts of the Caribbean
caused sperm whales to cease social activity and leave the area. Use of
military sonar during the invasion of Grenada also disrupted sperm whale
acoustic behaviour (Watkins and Moore 1982).
Underwater explosions
These can cause actual physical damage. For example, Humpback whales
washed up in Newfoundland after underwater explosions in 1993, with
severe damage to their inner ears (Ketten et al. 1993).
7.7.2 Deep-water Gillnetting and Driftnet Fishing
Gillnetting, in particular driftnetting and deep-water gillnetting, is a potential
threat to sperm whales. This species seems to be particularly vulnerable,
perhaps because they swim slowly at the surface, and sperm whales have
been taken in large numbers by both oceanic and coastal driftnets.
Significant numbers of sperm whales continue to be taken in driftnets in the
Mediterranean where the activity may well be threatening the population (Di
Natale and Notarbartolo di Sciara 1994).
7.7.3 Pollution
Pollution was identified as a major hazard for sperm whales, in particular:
Refuse (especially plastic garbage bags, which have been found in the stomachs of stranded whales and
can cause blockage);
Persistent chemicals (e.g. PCBs);
Sewage (because of the potential harmful effects of human pathogens).
It was noted that many areas that are potential sperm whale habitat (e.g.
deep underwater canyons) are also favoured places for disposal of urban
refuse.
7.7.4 Whaling
Whaling directly removes live animals from the local population and is a
severe form of disturbance. In addition, whale watchers may be
philosophically opposed to whaling and, given the choice, may be unlikely
to favour whale-watching operations in whaling countries (or those that
support whaling) even if the whaling targets a different species than the
whale watching.
7.7.5 Large-scale Industrial Fishing
Prey depletion in whale feeding areas may result in animals leaving the area
and may lead to population declines. Recently industrial-scale fishing has
been targeting the deep sea ecosystem, often concentrating at the edge of
the continental shelf an area favoured by sperm whales. Virtually nothing is
known of the dynamics of this ecosystem or its ability to support a harvest.
However, the growth rates of many known deep-sea organisms are know
to be extremely low making them poor candidates to withstand a fishery.
7.7.6 Vessel Traffic
High-speed (and/or noisy) vessels, particularly ferries, may cause
disturbance to sperm whales. Sperm whales also seem to be susceptible to
being hit by vessels. For example, vessel strikes on sperm whales are a
particular problem in the Canaries.