20
predators (Langridge et al. 2007) and are directed towards an approaching potential
predator (Mather 2010), though not to an imminent danger. Octopuses ( Octopus
cyanea) escaping from a scuba diver following them may use unpredictable pattern
changes (Hanlon et al. 1999b) and eventually escape. Similarly, young cuttlefish
(Hanlon and Messenger 1988), S� sepioidea (Mather et al. 2010b), and Euprymna
scolopes (Anderson and Mather 1996) use a combination of an unpredictable sequence of moves to different locations, pattern and posture change and ejection of
a squid-sized ‘dummy’ dark blob (see Hanlon and Messenger 1996 for discussion).
The primary response of octopuses is hiding (Mather 1994). The provision of
even a pair of bricks in the laboratory evokes this response, and an octopus not
given such material may cower arms outward in the corner of a tank. Such a shelter
can also be provided in the form of an open cube or a pot, which is very useful for
transport of a captive animal with the minimum amount of handling stress. Given
more material, however, octopuses will manipulate it to form a shape they prefer. In the wild, octopuses can hide in shells, human discards such as beer bottles
(Anderson et al. 1999), crevices, and under rocks. They do not find the ‘ideal’ home
in terms of characteristics such as volume and aperture area, but instead modify
shelter by clearing out sand and rubble, detaching algal fronds, and bringing rocks
to block the aperture (Mather 1994). Many octopus species are likely limited in
the wild by the availability of shelter (see Hartwick et al. 1978 for Enteroctopus
dofleini). Cuttlefish and other sepiolids (Mather 1986; Anderson et al. 2004) bury
themselves in sand if they are provided with small grain size and an adequate depth.
Squid primarily use jet-propelled escape responses (O’Dor and Webber 1986).
Most cephalopods have the ability to release ink during a major threat, and do
so in combination with escape and appearance change. This may deter predators by
either blocking their chemoreception (Wood et al. 2010) or impeding their vision.
Ink can be dispersed in the sea as a screen or held together as a ‘dummy’ (Anderson
and Mather 1996). Ink can also become an alarm cue to conspecifics (Wood et al.
2008). Given its efficacy, it is surprisingly rarely used, but a replacement must be
metabolized for future threats if ink is lost by ejection. Increased or maximal initial
threat eventually causes escape responses in most cephalopods. In the laboratory,
many of the display responses are harmless and seldom seen; eyespots seem to be
the exception. But jet escape responses can lead to posterior mantle skin damage
(Hanlon et al. 1983) and ink circulating in a restricted tank environment can damage
the health of cephalopods and any other animals in the same system.
2.3 Foods and Feeding Behaviours
All cephalopods are carnivores, and most exhibit a preference for live natural foods.
These factors have constrained the aquaculture of cephalopods and are part of the
current challenge of improving aquaculture methods, particularly for early life
stages where mortality is the highest (e.g. Vaz-Pires et al. 2004; Sykes et al. 2006;
Uriarte et al. 2011). In the wild, cephalopods may forage solitarily, as cuttlefish and
J. Mather and D. Scheel
predators (Langridge et al. 2007) and are directed towards an approaching potential
predator (Mather 2010), though not to an imminent danger. Octopuses ( Octopus
cyanea) escaping from a scuba diver following them may use unpredictable pattern
changes (Hanlon et al. 1999b) and eventually escape. Similarly, young cuttlefish
(Hanlon and Messenger 1988), S� sepioidea (Mather et al. 2010b), and Euprymna
scolopes (Anderson and Mather 1996) use a combination of an unpredictable sequence of moves to different locations, pattern and posture change and ejection of
a squid-sized ‘dummy’ dark blob (see Hanlon and Messenger 1996 for discussion).
The primary response of octopuses is hiding (Mather 1994). The provision of
even a pair of bricks in the laboratory evokes this response, and an octopus not
given such material may cower arms outward in the corner of a tank. Such a shelter
can also be provided in the form of an open cube or a pot, which is very useful for
transport of a captive animal with the minimum amount of handling stress. Given
more material, however, octopuses will manipulate it to form a shape they prefer. In the wild, octopuses can hide in shells, human discards such as beer bottles
(Anderson et al. 1999), crevices, and under rocks. They do not find the ‘ideal’ home
in terms of characteristics such as volume and aperture area, but instead modify
shelter by clearing out sand and rubble, detaching algal fronds, and bringing rocks
to block the aperture (Mather 1994). Many octopus species are likely limited in
the wild by the availability of shelter (see Hartwick et al. 1978 for Enteroctopus
dofleini). Cuttlefish and other sepiolids (Mather 1986; Anderson et al. 2004) bury
themselves in sand if they are provided with small grain size and an adequate depth.
Squid primarily use jet-propelled escape responses (O’Dor and Webber 1986).
Most cephalopods have the ability to release ink during a major threat, and do
so in combination with escape and appearance change. This may deter predators by
either blocking their chemoreception (Wood et al. 2010) or impeding their vision.
Ink can be dispersed in the sea as a screen or held together as a ‘dummy’ (Anderson
and Mather 1996). Ink can also become an alarm cue to conspecifics (Wood et al.
2008). Given its efficacy, it is surprisingly rarely used, but a replacement must be
metabolized for future threats if ink is lost by ejection. Increased or maximal initial
threat eventually causes escape responses in most cephalopods. In the laboratory,
many of the display responses are harmless and seldom seen; eyespots seem to be
the exception. But jet escape responses can lead to posterior mantle skin damage
(Hanlon et al. 1983) and ink circulating in a restricted tank environment can damage
the health of cephalopods and any other animals in the same system.
2.3 Foods and Feeding Behaviours
All cephalopods are carnivores, and most exhibit a preference for live natural foods.
These factors have constrained the aquaculture of cephalopods and are part of the
current challenge of improving aquaculture methods, particularly for early life
stages where mortality is the highest (e.g. Vaz-Pires et al. 2004; Sykes et al. 2006;
Uriarte et al. 2011). In the wild, cephalopods may forage solitarily, as cuttlefish and
J. Mather and D. Scheel