256
with aeration and then, upon landing, are transported to the cephalopod hatchery.
The broodstocks are maintained in an open system of cylindrical concrete tanks of
2 m
3
with flow-through filtered seawater (for the seawater supply system in this
chapter, see also Chap. 7 “Aquaculture to Restocking”). Artificial substrates, made
from pieces of longitudinal-cut polyvinyl chloride (PVC) pipe (50-mm diameter,
150-mm length), are previously placed on the tank bottom as shelters or “dens”.
Broodstocks of southern dumpling squids, E� tasmanica, are collected by seine
net in shallow waters of Botany Bay, New South Wales, Australia. Adult animals
are transported to running open seawater facilities located at the Sydney Institute of Marine Sciences (SIMS) at Chowder Bay, NSW. Adults are acclimated to
the conditions in the tanks (34 psu, 18 °C) and transported to New Mexico State
University within 2–3 days. Transport of the squids takes approximately 36 h tank
to tank in aquaria bags with less than 1 L of seawater. Animals are then acclimated
to the contained recirculating artificial seawater tanks (100 L) at New Mexico State
University under the same culturing conditions. Each tank is divided into eight
cubic sectionals (each 0.3 m
2
), which holds three to four adult individuals. Sexes
are continuously kept separate, since the presence of males can stress female behaviour. The only time males are placed with females is when a planned mating is
scheduled. In this manner, we can document which particular male has mated with
which female (and therefore, track fecundity of each female). Males are placed in
the female cubical (usually at a 1:1 or 1:2 male to female ratio) and are removed
anytime between 4 and 10 h. PVC pipe cut longitudinally is placed in the female
cubical and used as artificial substrates for the females to lay their eggs after they
have been mated.
Squids will mate and spawn in the tanks. Mating occurs without prior pair
formation for E� hyllebergi, and controlled conditions (noting which pairs are mated,
and how many times) are maintained for E� tasmanica. Spawning behavioural pattern is similar for both species. The male responds to the presence of a swimming
female by initially approaching and then grasping her from below in a male to
female neck position. The female is pulled down to the bottom where copulation
takes place. Copulation takes 7–10 min and then the pair separate. Spawning is
observed at dawn, 2–3 days after mating. Prior to spawning, the female investigates
substrates for attaching her eggs by swimming around, and touching the substrata
with the tip of her arm cone. In the tanks, the female attaches her eggs in clusters to
the inner surface of the artificial substrates (Fig. 15.2). The time period for attaching
is 40–60 s for one egg. Intervals between each egg attachment lengthens as the
number of eggs increases, up to 2–3 min. Spawning is intermittent and irregular
and may be extended over several weeks. The total number of eggs per female
is about 100–470 with an average of 200 eggs. Females can spawn up to three to
four clutches in her lifetime, with the number of eggs decreasing as the female
becomes older (Steer et al. 2004; Nabhitabhata et al. 2005). For E� tasmanica, adults
reared in captivity (F1 generation) live longer (2–3 months) and produce larger
and more clutches per female. Wild-caught adult E� tasmanica at maturity produce
approximately 3 clutches while in captivity, ranging from 25 to 100 eggs per clutch
(with one exceptional female, which laid approximately 500 eggs in one clutch). F1
J. Nabhitabhata and M. K. Nishiguchi
with aeration and then, upon landing, are transported to the cephalopod hatchery.
The broodstocks are maintained in an open system of cylindrical concrete tanks of
2 m
3
with flow-through filtered seawater (for the seawater supply system in this
chapter, see also Chap. 7 “Aquaculture to Restocking”). Artificial substrates, made
from pieces of longitudinal-cut polyvinyl chloride (PVC) pipe (50-mm diameter,
150-mm length), are previously placed on the tank bottom as shelters or “dens”.
Broodstocks of southern dumpling squids, E� tasmanica, are collected by seine
net in shallow waters of Botany Bay, New South Wales, Australia. Adult animals
are transported to running open seawater facilities located at the Sydney Institute of Marine Sciences (SIMS) at Chowder Bay, NSW. Adults are acclimated to
the conditions in the tanks (34 psu, 18 °C) and transported to New Mexico State
University within 2–3 days. Transport of the squids takes approximately 36 h tank
to tank in aquaria bags with less than 1 L of seawater. Animals are then acclimated
to the contained recirculating artificial seawater tanks (100 L) at New Mexico State
University under the same culturing conditions. Each tank is divided into eight
cubic sectionals (each 0.3 m
2
), which holds three to four adult individuals. Sexes
are continuously kept separate, since the presence of males can stress female behaviour. The only time males are placed with females is when a planned mating is
scheduled. In this manner, we can document which particular male has mated with
which female (and therefore, track fecundity of each female). Males are placed in
the female cubical (usually at a 1:1 or 1:2 male to female ratio) and are removed
anytime between 4 and 10 h. PVC pipe cut longitudinally is placed in the female
cubical and used as artificial substrates for the females to lay their eggs after they
have been mated.
Squids will mate and spawn in the tanks. Mating occurs without prior pair
formation for E� hyllebergi, and controlled conditions (noting which pairs are mated,
and how many times) are maintained for E� tasmanica. Spawning behavioural pattern is similar for both species. The male responds to the presence of a swimming
female by initially approaching and then grasping her from below in a male to
female neck position. The female is pulled down to the bottom where copulation
takes place. Copulation takes 7–10 min and then the pair separate. Spawning is
observed at dawn, 2–3 days after mating. Prior to spawning, the female investigates
substrates for attaching her eggs by swimming around, and touching the substrata
with the tip of her arm cone. In the tanks, the female attaches her eggs in clusters to
the inner surface of the artificial substrates (Fig. 15.2). The time period for attaching
is 40–60 s for one egg. Intervals between each egg attachment lengthens as the
number of eggs increases, up to 2–3 min. Spawning is intermittent and irregular
and may be extended over several weeks. The total number of eggs per female
is about 100–470 with an average of 200 eggs. Females can spawn up to three to
four clutches in her lifetime, with the number of eggs decreasing as the female
becomes older (Steer et al. 2004; Nabhitabhata et al. 2005). For E� tasmanica, adults
reared in captivity (F1 generation) live longer (2–3 months) and produce larger
and more clutches per female. Wild-caught adult E� tasmanica at maturity produce
approximately 3 clutches while in captivity, ranging from 25 to 100 eggs per clutch
(with one exceptional female, which laid approximately 500 eggs in one clutch). F1
J. Nabhitabhata and M. K. Nishiguchi