183
(Hanlon et al. 1999). This is probably due to the biology of the species, with males
maturing precociously (Forsythe et al. 1994). Males, before inserting their sperm
into this pouch, jet large amounts of seawater inside the seminal receptacles to flush
out the sperm from previous males and, in this way, assure that only its genetic
contribution will be used (Hanlon et al. 1999).
Females mate repeatedly (Hanlon et al. 1999), display intermittent or chronic
spawning (Boletzky 1987) depending on captive conditions and usually will die
shortly after laying the eggs. Nevertheless, we have observed an extension of this
intermittent spawning when using increased tank bottom areas (based on comparisons between data from Sykes et al. 2006a, 2013b). However, this does not happen
repeatedly and in all tanks tested. Therefore, we suspect that the optimal conditions
to obtain more and better eggs are related not only to bottom areas but also to other
variables, which are being investigated in current projects.
According to Boal (1997), females prefer males that have mated recently instead
of choosing males based on a dominance hierarchy, which is promoted by captive
conditions (Boal et al. 1999). If this is related to social recognition (Boal 2006),
chemoreception (Boal and Marsh 1998; Boal and Golden 1999) or specific pheromones (Zatylny et al. 2000, 2002) remains to be unveiled and are objectives of
future studies.
After the copula, it is not advisable to separate females from males since this will
not promote a reproduction resembling wild conditions and might have a negative
influence on egg quantity and quality. According to Boletzky (1983), bigger females will lay bigger eggs; which does not completely agree with more recent data
from Sykes et al. (2013b). By having extended intermittent spawning due to different culture conditions, the amount and quality of eggs should be better. However,
what is a quality egg in this species and how can we say that bigger eggs are better
eggs, since no results on this subject have been presented?
In the species, no parental care of eggs was ever observed, and senescent females
die after spawning. As a senescent species, reproduction will absolutely drain
females, which incorporate their little reserves in the eggs. The ability of cuttlefish
females to have more than one maturation cycle or continuous maturation during this
intermittent spawning is something that will need to be further investigated in the
near future, since not all the females or males will die after mating and eggs are laid.
11.4.2 Egg Capture and Handling
Eggs may be obtained from nature or from captive-bred populations, but the latter
is recommended. The use of eggs from a known source not only reduces the impact
on the environment but also assures that eggs will have a very low probability of
introducing contaminants and/or pathologies into the culture facilities. Within the
EU, these Animal Resource Centres are regulated by law and a wide network exists
(for details, check European Marine Biological Resource Centre—EMBRC—
http://www.embrc.eu/).
11 Sepia officinalis
(Hanlon et al. 1999). This is probably due to the biology of the species, with males
maturing precociously (Forsythe et al. 1994). Males, before inserting their sperm
into this pouch, jet large amounts of seawater inside the seminal receptacles to flush
out the sperm from previous males and, in this way, assure that only its genetic
contribution will be used (Hanlon et al. 1999).
Females mate repeatedly (Hanlon et al. 1999), display intermittent or chronic
spawning (Boletzky 1987) depending on captive conditions and usually will die
shortly after laying the eggs. Nevertheless, we have observed an extension of this
intermittent spawning when using increased tank bottom areas (based on comparisons between data from Sykes et al. 2006a, 2013b). However, this does not happen
repeatedly and in all tanks tested. Therefore, we suspect that the optimal conditions
to obtain more and better eggs are related not only to bottom areas but also to other
variables, which are being investigated in current projects.
According to Boal (1997), females prefer males that have mated recently instead
of choosing males based on a dominance hierarchy, which is promoted by captive
conditions (Boal et al. 1999). If this is related to social recognition (Boal 2006),
chemoreception (Boal and Marsh 1998; Boal and Golden 1999) or specific pheromones (Zatylny et al. 2000, 2002) remains to be unveiled and are objectives of
future studies.
After the copula, it is not advisable to separate females from males since this will
not promote a reproduction resembling wild conditions and might have a negative
influence on egg quantity and quality. According to Boletzky (1983), bigger females will lay bigger eggs; which does not completely agree with more recent data
from Sykes et al. (2013b). By having extended intermittent spawning due to different culture conditions, the amount and quality of eggs should be better. However,
what is a quality egg in this species and how can we say that bigger eggs are better
eggs, since no results on this subject have been presented?
In the species, no parental care of eggs was ever observed, and senescent females
die after spawning. As a senescent species, reproduction will absolutely drain
females, which incorporate their little reserves in the eggs. The ability of cuttlefish
females to have more than one maturation cycle or continuous maturation during this
intermittent spawning is something that will need to be further investigated in the
near future, since not all the females or males will die after mating and eggs are laid.
11.4.2 Egg Capture and Handling
Eggs may be obtained from nature or from captive-bred populations, but the latter
is recommended. The use of eggs from a known source not only reduces the impact
on the environment but also assures that eggs will have a very low probability of
introducing contaminants and/or pathologies into the culture facilities. Within the
EU, these Animal Resource Centres are regulated by law and a wide network exists
(for details, check European Marine Biological Resource Centre—EMBRC—
http://www.embrc.eu/).
11 Sepia officinalis