Dolphins, Whales and Porpoises: 2002-2010 Conservation - IUCN

Zealand, there is ongoing controversy among scientists and
conservationists as to whether pingers can be effective in
reducing the mortality of Hector’s dolphins in gillnets
(Dawson et al. 1998; Stone et al. 2000). Efforts to reduce
dolphin mortality in anti-shark nets through the use of pingers
have given disappointing results (Peddemors et al. 1991).
It is important to emphasize that approaches to bycatch
reduction used in well-regulated commercial fisheries may
not be appropriate or practical in the more diffuse, economically
marginal artisanal fisheries of Latin America,
Africa, and Asia. Unless the technique or device provides
fishermen with a compelling economic advantage of some
sort, there is little hope that they will incorporate it into their
standard fishing practices. Other strategies, such as restrictions
on the types of gear that can be used, or time/area
closures (see below), may be the only ways to address the
bycatch issue in those circumstances. Of course, in areas
such as Peru, Sri Lanka, the Philippines, and parts of West
Africa where there is a market for cetacean products, the
first step must be to establish an incentive for reducing the
bycatch. Technical fixes only work if people can afford
them, know how to use them, and are willing to operate
within a regulatory framework of some kind.
Reducing incidental mortality through
rescue and release efforts
In the previous Cetacean Action Plan, it was noted that
efforts were being made to rescue and release large whales
entangled in fishing gear along the east coast of North
America and in the Mediterranean Sea. Entanglements in
the Mediterranean have become very rare, probably because
of the declining abundance of sperm whales there. Programs
to detect and disentangle right whales in the United States
and Canada have been expanded, with government support
and funding (Silber and Payne 1998; Right Whale Recovery
Team 2000). It is important to acknowledge efforts outside
North America and Europe, of which few are more impressive
than the freeing of a humpback whale from a gillnet
in Oman, as described by Baldwin (1995). In Pakistan, a
program began in 2000 to rescue Indus dolphins that enter
irrigation canals and are unable to return to the main river
channel, or that become trapped in shallow pools downstream
of barrages where they are unlikely to survive until
the next flood season (Braulik 2000). In the first year, five of
ten dolphins (known to have become marooned in canals)
were rescued and in 2001 these numbers increased to ten of
15 (G. Braulik, pers. comm.). Rescuing animals that belong
to endangered populations, especially when the risk to their
lives is a direct result of human encroachment into their
habitat, has clear conservation value. However, rescue efforts
of all kinds are not equally justified. The often heroic
attempts to return stranded whales and dolphins to the sea
certainly reflect popular interest in the animals, and rehabilitation-and-release
programs can contribute to scientific
knowledge and heighten public awareness (Wells et al.
1999; Wilkinson and Worthy 1999). However, there are
also risks associated with returning to the wild gene pool
individuals that have been naturally “culled” and that may
be carrying new pathogens after spending extended periods
in captivity (St. Aubin et al. 1996). When decisions are
made to return cetaceans to the wild, it is important to weigh
the potential conservation, animal welfare, and scientific
benefits against possibly negative outcomes. In any event,
releasing cetaceans that have had prolonged exposure to
humans (or other species non-native to their environment)
should only be done after a thorough examination by a field
veterinarian. Inadvertent disease transmission could have
catastrophic effects on immunologically naive populations,
especially when their fitness may have already been compromised
by exposure to pollutants or by depleted prey
resources.
Managing cetacean-oriented tourism
to minimize biological impacts
Cetacean-oriented tourism has been promoted as a “nonconsumptive”
or “low-consumptive” use of cetaceans that
promises monetary rewards to people without requiring that
the animals be killed or removed from their natural environment.
Although the effects of tourism are probably of minor
relevance within the overall context of human-caused
threats to cetaceans, it is important to make sure that whaleand
dolphin-watching is conducted in a manner that is respectful
of the animals, local human communities, and
fellow tourists. Guidelines and codes of conduct are increasingly
available, and should be adopted and promoted by the
tourism industry and by government agencies (e.g., IWC
2002b). In general, long-established cetacean-watching enterprises
are closely monitored and conducted responsibly.
However, instances still occur in which numerous boats
surround a single whale or pod of whales, disturbing the
animals and at the same time detracting from the quality of
the experience for the tourists.
Greatest concern applies to start-up activities in new areas
or involving cetacean populations that have not been exposed
previously to this kind of boat traffic. In such cases, a
series of steps should be followed in advance of major
capital investments and commercial-scale promotions.
These might include: (a) obtaining a basic knowledge of the
biology and ecology of the species (e.g., behavior, seasonal
changes, and frequency of occurrence) and local ecological
conditions (e.g., local currents, weather, and distance from
shore); (b) completion of an impact study by an independent
assessor; and (c) establishment of an interim framework for
regulation and monitoring. One way of compensating for
disturbance is to use the cetacean-watching programs to
help accomplish research and monitoring objectives, especially
in developing countries where alternative funding
for dedicated surveys is unavailable (Leaper et al. 1997;
Smith et al. 1997b; Leatherwood et al. 2000; Smith and
Hobbs 2002).
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