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4.1 Introduction
The attraction and curiosity of human beings to aquatic mammals dates prehistorical ages. Due to their grace and mystery, aquatic mammals have been
observed, described and portrayed in cave paintings, carved in rocks and bones,
drawn in vases, mosaics, totems. They were part of Greeks mythology, ancient and
autochthonous legends from all over the world. They have been seeing as gods and
beasts, have been hunted, kept in captivity, cared, protected and loved. While
humans would not venture out to explore the oceans, they would observe aquatic
mammals from land (Ellis 2009) and land-based lookouts were probably the first
platform used to observe live aquatic mammals.
Aquatic mammals inhabit almost every aquatic habitat on this planet. Study
these animals however, is not an easy task, since some have offshore distribution, or
pass by the coast only during a period of the year, while several never approach.
Some seasonally migrate long distances, inhabit inner regions in estuaries and rivers, many have crypt and/or inconspicuous surface behavior. Additionally, since
they spend most of the time diving, being out of view, aquatic mammals are observable for only a small proportion of time.
All research platforms and methods used to study aquatic mammals have advantages and disadvantages. The decision of which use will be mostly guided by the
objectives and goals of the research, within the available budget. Nowadays, new
technologies, allow animal monitoring for short and long periods, revealing details
about their behavior, dive and swimming patterns, distribution, among others.
However, with few exceptions, most research methods are in a certain manner invasive. In fact, just the observer’s presence may introduce subtle bias even when animals appear to be well habituated (Martin and Bateson 1993). It has been shown that
a simple boat approach may interfere in animal behavior (e.g., Corkeron 1995; Bejder
et al. 1999; Heckel et al. 2001; Failla et al. 2004; Scheidat et al. 2004; Morete et al.
2007a; Pavez et al. 2011; Lundquist et al. 2013; Vermeulen et al. 2012; Avila et al.
2015) and that most of the new technologies have the capacity to cause pain, injuries,
or modify the behavior of the animal being observed (Gales et al. 2003).
Behavioral studies are the key to understanding animals (Mann 2000) and to
build up the knowledge of their ecology, playing a role in investigating consequences
of anthropogenic activities (e.g., Bejder et al. 2006). However, link short- term
behavioral responses to long-term population-level consequences presents difficulties, a fact that can lead to the false, or at least premature conclusion that human
activities have no biologically significant effect on the targeted animals (Williams
et al. 2006). Behavior can be affected in many different manners but it will only be
perceived by the observer when the animal or a group of animal stop the activity
they were engaged in, or react in some way to respond to an external stimuli. A
punctual behavior change might be meaningless, but they usually have cumulative
effects. For example, if an animal stops its feeding activity, it will have to compensate extending its feeding period, which might reduce its socializing or resting time.
Thus, what seems to be a simple behavioral short-term change may affects life funcM.E. Morete et al.
4.1 Introduction
The attraction and curiosity of human beings to aquatic mammals dates prehistorical ages. Due to their grace and mystery, aquatic mammals have been
observed, described and portrayed in cave paintings, carved in rocks and bones,
drawn in vases, mosaics, totems. They were part of Greeks mythology, ancient and
autochthonous legends from all over the world. They have been seeing as gods and
beasts, have been hunted, kept in captivity, cared, protected and loved. While
humans would not venture out to explore the oceans, they would observe aquatic
mammals from land (Ellis 2009) and land-based lookouts were probably the first
platform used to observe live aquatic mammals.
Aquatic mammals inhabit almost every aquatic habitat on this planet. Study
these animals however, is not an easy task, since some have offshore distribution, or
pass by the coast only during a period of the year, while several never approach.
Some seasonally migrate long distances, inhabit inner regions in estuaries and rivers, many have crypt and/or inconspicuous surface behavior. Additionally, since
they spend most of the time diving, being out of view, aquatic mammals are observable for only a small proportion of time.
All research platforms and methods used to study aquatic mammals have advantages and disadvantages. The decision of which use will be mostly guided by the
objectives and goals of the research, within the available budget. Nowadays, new
technologies, allow animal monitoring for short and long periods, revealing details
about their behavior, dive and swimming patterns, distribution, among others.
However, with few exceptions, most research methods are in a certain manner invasive. In fact, just the observer’s presence may introduce subtle bias even when animals appear to be well habituated (Martin and Bateson 1993). It has been shown that
a simple boat approach may interfere in animal behavior (e.g., Corkeron 1995; Bejder
et al. 1999; Heckel et al. 2001; Failla et al. 2004; Scheidat et al. 2004; Morete et al.
2007a; Pavez et al. 2011; Lundquist et al. 2013; Vermeulen et al. 2012; Avila et al.
2015) and that most of the new technologies have the capacity to cause pain, injuries,
or modify the behavior of the animal being observed (Gales et al. 2003).
Behavioral studies are the key to understanding animals (Mann 2000) and to
build up the knowledge of their ecology, playing a role in investigating consequences
of anthropogenic activities (e.g., Bejder et al. 2006). However, link short- term
behavioral responses to long-term population-level consequences presents difficulties, a fact that can lead to the false, or at least premature conclusion that human
activities have no biologically significant effect on the targeted animals (Williams
et al. 2006). Behavior can be affected in many different manners but it will only be
perceived by the observer when the animal or a group of animal stop the activity
they were engaged in, or react in some way to respond to an external stimuli. A
punctual behavior change might be meaningless, but they usually have cumulative
effects. For example, if an animal stops its feeding activity, it will have to compensate extending its feeding period, which might reduce its socializing or resting time.
Thus, what seems to be a simple behavioral short-term change may affects life funcM.E. Morete et al.