180
station but also if a digital solution is applied, a report on these abnormal situations
will be created by the system, and later used as experimental data and for reporting
animal welfare.
Tank cleaning should be avoided as much as possible to prevent stress, by enforcing
an ad libitum feeding scheme. Water and tanks should be kept clean from leftovers,
faeces and other debris and removed through water siphoning. Therefore, to avoid
problems with cleaning, sand substrates should not be used (Forsythe et al. 1994).
11.3.2 Sex Ratio and Stocking Densities
Reports on stocking densities and sex ratios are scattered in the literature, and experiments dealing primarily with this issue are scarce. Sex ratios and stocking densities are of particular importance since they are thought to have a high impact on
cuttlefish fecundity and fertility. This assumption is based on our experience of culturing the species and on previous studies which were not directly related to reproduction (Boal et al. 1999; Forsythe et al. 2002). However, researchers do not agree
on which are the best densities and sex ratios that will maximize egg quantity and
quality obtained in cuttlefish reproduction in captivity. In addition, most of them
do not consider the importance of tank bottom areas with regard to a species that
is benthic or the individual contribution of parents that may change depending on
available area, stocking densities and sex ratios. For instance, Forsythe et al. (1991)
mentions that sex ratios of one male for three females should be used to avoid male
aggression and aggressive mating behaviour, and Forsythe et al. (1994) suggests
densities of two cuttlefish m
−2
for breeders.
Table 11.1 summarizes the most relevant fecundity and fertility results obtained
in different tanks, stocking densities, sex ratios, temperature and food items (Correia
et al. 2005; Domingues et al. 2001b, 2002, 2003b; Sykes et al. 2006a, 2009, 2013b).
It is suggested that sex ratios should be maintained at two females for one male and
stocking densities kept relatively low when setting up a broodstock. For instance, a
9,000 L tank should have 21 animals, 14 of them females and 7 males, which will
correspond to a low stocking density of 4 cuttlefish m
−2
.
11.3.3 Food Supply
Despite Boletzky’s (1983) and Nixon’s (1985) descriptions that cuttlefish shifts its
food preferences from a predominant crustacean diet (crabs, prawns and shrimps)
to a mixture of crustaceans and fish while maturing and reproducing, recent
manuscripts report the successful culture of the species using only a frozen grass
shrimp ( Palaemonetes varians)-based diet (Sykes et al. 2006a, 2013b, Table 11.1)
during those periods.
The use of different kinds of food throughout the different stages of the life cycle
of cuttlefish was never studied, but examples of different feeding strategies are
A. V. Sykes et al.
station but also if a digital solution is applied, a report on these abnormal situations
will be created by the system, and later used as experimental data and for reporting
animal welfare.
Tank cleaning should be avoided as much as possible to prevent stress, by enforcing
an ad libitum feeding scheme. Water and tanks should be kept clean from leftovers,
faeces and other debris and removed through water siphoning. Therefore, to avoid
problems with cleaning, sand substrates should not be used (Forsythe et al. 1994).
11.3.2 Sex Ratio and Stocking Densities
Reports on stocking densities and sex ratios are scattered in the literature, and experiments dealing primarily with this issue are scarce. Sex ratios and stocking densities are of particular importance since they are thought to have a high impact on
cuttlefish fecundity and fertility. This assumption is based on our experience of culturing the species and on previous studies which were not directly related to reproduction (Boal et al. 1999; Forsythe et al. 2002). However, researchers do not agree
on which are the best densities and sex ratios that will maximize egg quantity and
quality obtained in cuttlefish reproduction in captivity. In addition, most of them
do not consider the importance of tank bottom areas with regard to a species that
is benthic or the individual contribution of parents that may change depending on
available area, stocking densities and sex ratios. For instance, Forsythe et al. (1991)
mentions that sex ratios of one male for three females should be used to avoid male
aggression and aggressive mating behaviour, and Forsythe et al. (1994) suggests
densities of two cuttlefish m
−2
for breeders.
Table 11.1 summarizes the most relevant fecundity and fertility results obtained
in different tanks, stocking densities, sex ratios, temperature and food items (Correia
et al. 2005; Domingues et al. 2001b, 2002, 2003b; Sykes et al. 2006a, 2009, 2013b).
It is suggested that sex ratios should be maintained at two females for one male and
stocking densities kept relatively low when setting up a broodstock. For instance, a
9,000 L tank should have 21 animals, 14 of them females and 7 males, which will
correspond to a low stocking density of 4 cuttlefish m
−2
.
11.3.3 Food Supply
Despite Boletzky’s (1983) and Nixon’s (1985) descriptions that cuttlefish shifts its
food preferences from a predominant crustacean diet (crabs, prawns and shrimps)
to a mixture of crustaceans and fish while maturing and reproducing, recent
manuscripts report the successful culture of the species using only a frozen grass
shrimp ( Palaemonetes varians)-based diet (Sykes et al. 2006a, 2013b, Table 11.1)
during those periods.
The use of different kinds of food throughout the different stages of the life cycle
of cuttlefish was never studied, but examples of different feeding strategies are
A. V. Sykes et al.