484
R. Villanueva et al.
with vertebrates (Legall and Feral 1985), no induction or hormonal methods have
been used to obtain cephalopod maturation, and the role of olfaction and chemical
messaging and its effect on sexual behaviour have started to be recently understood.
The reproductive behaviour of S� officinalis and its relation to chemical cues have
been described (Boal and Marsh 1998; Boal and Golden 1999; Boal et al. 2010). In
addition, sex pheromones expressed from precursors in the oviducal gland during
egg laying have been identified, and induce hyperventilation as well as stimulate
mating (Enault et al. 2012). Despite the identification of these substances, studies that combine their effects at reproductive and behavioural levels in cultured
cephalopods are still needed. Research should also be focused on closing the life
cycle under controlled conditions, which will allow obtaining a sufficient number
of progenitors to avoid deleterious effects on the natural populations, renewing the
broodstock. Some experimental studies used broodstocks to obtain animals for the
multiple generations as for S� lessoniana (Lee et al. 1994; Walsh et al. 2002) and
S� officinalis (Forsythe et al. 1994; Sykes et al. 2006). Such closed-cycle practice
with captive breeders may have led to reproductive isolation from wild populations,
resulting in a loss of genetic variability due to the low effective breeding population size and inbreeding. This eventual inbreeding in consecutive generations needs
to be addressed by determining the effective number of breeders contributing for
reproduction by using behavioural analysis and paternity studies, and quantifying
the loss of genetic variation in consecutive cultured generations at given culture
conditions.
Reproduction in captivity needs interdisciplinary studies, integrating theoretical with experimental methods to understand the magnitude of different factors.
Studies should consider zootechnical factors (tank type, light type and intensity,
quantity and quality of food) as well as the chronobiology, sex ratios, inbreeding
increase, maternal effects and male contribution to offspring production, systematic
line crossing for the reduction of the rate of inbreeding accumulation, chemical
communication, mating behaviour and manipulation of reproduction using pheromones. Controlled production of sufficient quantities of quality offsprings remains
a major constraint for development of cephalopod culture. In fact, the viability of
eggs and hatchlings will, to a large extent, depend on the environmental influences
during egg development. Nonetheless, little progress has been made in elucidating the connections between the influence of environmental factors and how they
should be manipulated during embryonic development for the production of highquality and competent hatchlings for rearing. How air bubbles in oversaturated air
water affect the viability of O� vulgaris paralarvae may be an example of this (see
Chap. 23). In this respect, improvements of broodstock conditioning and determination of maternal effects and their impact on hatchling quality should, therefore, be
categorized as a high-priority research topic.
In addition to nutrition and reproduction, additional fields of research and zootechnical techniques need future studies and improvement. Cephalopods have delicate skin and the available knowledge on infections and general pathologies is still
very scarce and needs further research (see Chap. 6). In some countries, cephalopods are under the scope of animal welfare legislation. In any case, the performance
R. Villanueva et al.
with vertebrates (Legall and Feral 1985), no induction or hormonal methods have
been used to obtain cephalopod maturation, and the role of olfaction and chemical
messaging and its effect on sexual behaviour have started to be recently understood.
The reproductive behaviour of S� officinalis and its relation to chemical cues have
been described (Boal and Marsh 1998; Boal and Golden 1999; Boal et al. 2010). In
addition, sex pheromones expressed from precursors in the oviducal gland during
egg laying have been identified, and induce hyperventilation as well as stimulate
mating (Enault et al. 2012). Despite the identification of these substances, studies that combine their effects at reproductive and behavioural levels in cultured
cephalopods are still needed. Research should also be focused on closing the life
cycle under controlled conditions, which will allow obtaining a sufficient number
of progenitors to avoid deleterious effects on the natural populations, renewing the
broodstock. Some experimental studies used broodstocks to obtain animals for the
multiple generations as for S� lessoniana (Lee et al. 1994; Walsh et al. 2002) and
S� officinalis (Forsythe et al. 1994; Sykes et al. 2006). Such closed-cycle practice
with captive breeders may have led to reproductive isolation from wild populations,
resulting in a loss of genetic variability due to the low effective breeding population size and inbreeding. This eventual inbreeding in consecutive generations needs
to be addressed by determining the effective number of breeders contributing for
reproduction by using behavioural analysis and paternity studies, and quantifying
the loss of genetic variation in consecutive cultured generations at given culture
conditions.
Reproduction in captivity needs interdisciplinary studies, integrating theoretical with experimental methods to understand the magnitude of different factors.
Studies should consider zootechnical factors (tank type, light type and intensity,
quantity and quality of food) as well as the chronobiology, sex ratios, inbreeding
increase, maternal effects and male contribution to offspring production, systematic
line crossing for the reduction of the rate of inbreeding accumulation, chemical
communication, mating behaviour and manipulation of reproduction using pheromones. Controlled production of sufficient quantities of quality offsprings remains
a major constraint for development of cephalopod culture. In fact, the viability of
eggs and hatchlings will, to a large extent, depend on the environmental influences
during egg development. Nonetheless, little progress has been made in elucidating the connections between the influence of environmental factors and how they
should be manipulated during embryonic development for the production of highquality and competent hatchlings for rearing. How air bubbles in oversaturated air
water affect the viability of O� vulgaris paralarvae may be an example of this (see
Chap. 23). In this respect, improvements of broodstock conditioning and determination of maternal effects and their impact on hatchling quality should, therefore, be
categorized as a high-priority research topic.
In addition to nutrition and reproduction, additional fields of research and zootechnical techniques need future studies and improvement. Cephalopods have delicate skin and the available knowledge on infections and general pathologies is still
very scarce and needs further research (see Chap. 6). In some countries, cephalopods are under the scope of animal welfare legislation. In any case, the performance