189
growth and survival. Depending on the seawater system used during this stage,
different water parameters should be set and checked (see Sect. 11.3.1 for the list
and procedures). Normally, hatchlings’ rearing is performed at 20 ± 2 °C, in high
dissolved oxygen conditions (> 90 %) and high water-flow rates to avoid nitrogenous
waste-derived problems in low-volume seawater systems.
11.5.2.3 Light
There is no known minimal amount of light necessary for this stage but recent results
recommended 100 lx at the air–water interface of the tank (Sykes et al. 2013c), provided by daylight (450–650 nm) fluorescent bulbs. From published data, only Koueta
and Boucaud-Camou (2003) studied the effect of photoperiods in hatchlings and
suggested that cuttlefish hunts more during daylight. Photoperiodicity should match
habitat and lifestyle at given geographical locations (Sykes et al. 2006b), and daylight should be set with a 12–16 h light cycle. Nonetheless, little is known regarding
the daily activity and daily feeding rhythms at this life stage or even for the species
(Quintela and Andrade 2002) and this should be researched in the near future.
Up till now, the use of dusk-and-dawn light simulations in the photoperiod or
the use of polarization (light or filters) to enhance growth and survival was never
reported. Cuttlefish has polarized vision, which it uses to hunt in the natural environment (Shashar et al. 2000, 2002). This characteristic should be further explored
to determine if it could enhance conditions in captivity.
11.5.2.4 Diet
Cuttlefish may hatch prematurely, mature or ‘over-mature’, the differences being
characterized by the respective amount of inner yolk reserves remaining. These
reserves will determine how long the animal will endure without food and commonly last between 3 and 5 days (Sykes et al. 2004). During this period, the animal
must be given the opportunity to feed on an external diet or there will come a point
of no return and the cuttlefish will die.
Diets for hatchlings have been one of the most investigated themes in the
past 12 years and where research has attained some of the most relevant results.
It is known that in nature, cuttlefish hatchlings prey preferably on live crustacean species (Boletzky 1983), and a series of different alternative live diets were
tested (DeRusha et al. 1989). For several years, the rearing of cuttlefish during the
hatchling stage was obtained using a diet of live mysids followed by live shrimps,
when the animals grew bigger (Correia et al. 2005, 2008a; Domingues et al. 2001a,
b, 2002, 2003a; Koueta and Boucaud-Camou 1999). Domingues et al. (2004) proposed the use of live P� varians as an alternative prey for the rearing of cuttlefish at
this life stage, while Sykes et al. (2006a) extended this further by proposing the use
of grass shrimp for the culture throughout the life cycle of S� officinalis. Irrespective
of the prey used, its degree of availability and the use of freshly caught or starved
live food affect cuttlefish growth (Correia et al. 2008a, b).
11 Sepia officinalis
growth and survival. Depending on the seawater system used during this stage,
different water parameters should be set and checked (see Sect. 11.3.1 for the list
and procedures). Normally, hatchlings’ rearing is performed at 20 ± 2 °C, in high
dissolved oxygen conditions (> 90 %) and high water-flow rates to avoid nitrogenous
waste-derived problems in low-volume seawater systems.
11.5.2.3 Light
There is no known minimal amount of light necessary for this stage but recent results
recommended 100 lx at the air–water interface of the tank (Sykes et al. 2013c), provided by daylight (450–650 nm) fluorescent bulbs. From published data, only Koueta
and Boucaud-Camou (2003) studied the effect of photoperiods in hatchlings and
suggested that cuttlefish hunts more during daylight. Photoperiodicity should match
habitat and lifestyle at given geographical locations (Sykes et al. 2006b), and daylight should be set with a 12–16 h light cycle. Nonetheless, little is known regarding
the daily activity and daily feeding rhythms at this life stage or even for the species
(Quintela and Andrade 2002) and this should be researched in the near future.
Up till now, the use of dusk-and-dawn light simulations in the photoperiod or
the use of polarization (light or filters) to enhance growth and survival was never
reported. Cuttlefish has polarized vision, which it uses to hunt in the natural environment (Shashar et al. 2000, 2002). This characteristic should be further explored
to determine if it could enhance conditions in captivity.
11.5.2.4 Diet
Cuttlefish may hatch prematurely, mature or ‘over-mature’, the differences being
characterized by the respective amount of inner yolk reserves remaining. These
reserves will determine how long the animal will endure without food and commonly last between 3 and 5 days (Sykes et al. 2004). During this period, the animal
must be given the opportunity to feed on an external diet or there will come a point
of no return and the cuttlefish will die.
Diets for hatchlings have been one of the most investigated themes in the
past 12 years and where research has attained some of the most relevant results.
It is known that in nature, cuttlefish hatchlings prey preferably on live crustacean species (Boletzky 1983), and a series of different alternative live diets were
tested (DeRusha et al. 1989). For several years, the rearing of cuttlefish during the
hatchling stage was obtained using a diet of live mysids followed by live shrimps,
when the animals grew bigger (Correia et al. 2005, 2008a; Domingues et al. 2001a,
b, 2002, 2003a; Koueta and Boucaud-Camou 1999). Domingues et al. (2004) proposed the use of live P� varians as an alternative prey for the rearing of cuttlefish at
this life stage, while Sykes et al. (2006a) extended this further by proposing the use
of grass shrimp for the culture throughout the life cycle of S� officinalis. Irrespective
of the prey used, its degree of availability and the use of freshly caught or starved
live food affect cuttlefish growth (Correia et al. 2008a, b).
11 Sepia officinalis