The completed life cycle of the octopus

mucktopus

Haliphron Atlanticus
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from Iglesias J., Otero J.J., Moxica C., Fuentes L. & Sanchez F.J. (2004) The completed life cycle of the octopus (Octopus vulgaris, Cuvier) under culture conditions: paralarval rearing using Artemia and zoeae, and first data on juvenile growth up to 8 months of age. Aquaculture International, 12, 481-487:

Abstract. This paper shows innovating results on Octopus vulgaris Cuvier 1797 growth under
culture conditions during the whole life cycle. Experiments were conducted at the Spanish
Institute of Oceanography of Vigo (Spain). Using mean water temperature of 22.5◦C (ddw: 72.5 F), salinity of 35 (ddw: 1.026 SG) and adult Artemia (1–4mm of total length) along with a diet complement of Maja squinado zoeae as living prey, it was possible to obtain a 31.5% paralarval survival at day
40 after hatching. At this age, paralarvae had reached a dry weight of 9.5mg, 23 suckers per
arm, and they began the settlement process. First results on juvenile growth showed that they
reached 0.5–0.6 kg at the age of 6 months after hatching, and 2 months later, they attained
weights ranging between 1.4 and 1.8 kg. Mean temperature of the ongrowing process was
18◦C.

Material and methods
Two thousand recently hatched (day 0) paralarvae were obtained from spontaneous
spawning of female octopuses kept in captivity using the technology
described by Moxica et al. (2001). They were transferred to a 1m3 PVC
tank provided with filtered seawater (1 μm) at a concentration of 2 ind l−1.
Tank was circular (130 cm of diameter) with black wall and white bottom.
Mean water temperature was 22.5◦C (19.6–22.9), salinity 35 (34.2–35.7)
and a 24 h light cycle was provided with two 36Wdaylight fluorescent tubes,
resulting in an intensity of 600–1000 lux on surface. Levels of dissolved oxygen,
nitrites and ammonium were measured daily. A close water circuit with
central aeration was maintained during the first week. Microalgae (Chlorella
sp., Isochrysis galbana and Chaetoceros sp.) were added daily in order to feed
the remaining preys in the culture tank, to keep them in the best nutritional
condition. From day 8 on, the water system was partially open (10 lmin−1) 4h
per day, with a central outlet provided with a 300 μm filter. The tank bottom
was cleaned by siphoning every 4 days.
Live diet consisted of adult Artemia (1–4mm TL) cultivated at 25◦C during
a week with a commercial cereal mix, Blevit Plus (from Ordesa Co.)
and enriched for 24 h with Chlorella sp. Artemia concentration was of 0.05–
0.1 indml−1. As a complementary diet, spider crab (Maja squinado Herbst
1788) zoeae, obtained from 16 ovigerous females, were added 4 days per
week at a concentration of 0.01–0.1 indml−1.
Dry weights of 10 paralarvae were recorded fortnightly after being washed
with distilled water, dried at 55◦C for 24 h and weighed individually. Survival
483
was recorded by counting the final number of survivors at day 40, and the
mean number of suckers per arm was also registered from 10 individuals at
this age.
In order to start the weaning process, two groups of 250 individuals (40
days-old) were transferred to 500 l square (1×1×0.5m3) grey tanks provided
with sand, gravel and macroalgae. An open water system of 2 lmin−1 was
used, with a surface inlet and a bottom central outlet of 1mm mesh size. The
rest of animals (n=130) were kept in the former larval tank. Mean temperature
during the weaning period was 22.5◦C. Diet consisted of sea urchin
(Paracentrotus lividus) and common crab (Carcinus maenas) gonads, live
small crustaceans (amphipods, mysidacea and shrimps) and thawed mussels
(Mitylus sp.). After the weaning period (2 weeks), subadults were fed with
frozen crabs and mussels; tank temperature was gradually decreased until
ambient values (17–19◦C). The same grey tanks were used in the ongrowing
period. Wet weight was recorded monthly throughout an 8-month period, in
order to obtain the first data on octopus cultivated from the paralarvae stage
up to final weights of 1.4–1.8 kg.

AND:
First feeding of Octopus vulgaris Cuvier, 1797 paralarvae using
Artemia: Effect of prey size, prey density and feeding frequency
J. Iglesias ⁎, L. Fuentes, J. Sánchez, J.J. Otero, C. Moxica, M.J. Lago:

Abstract
Different assays related to the first feeding of Octopus vulgaris Cuvier, 1797 are compiled in this paper. They include: age at
initial feeding age, prey size selection and optimal density, attack timing after feeding, and effect of dose number on the number of
captures. Prey capture and ingestion processes were also analysed. Food supplied was cultured Artemia sp. Each assay lasted
15 min.
Although paralarvae already start to feed on the hatching day (day 0), it is during day 2 when a greater number of attacks is recorded
(81.7±14.7% paralarvae attack). They mainly prefer (significance level α=0.05) large Artemia, 1.4±0.4 mm (77.0±5.6% of the total
attacks) than small Artemia, 0.8±0.1 mm (23.0±5.6%). There is also a slight predilection for the lowest Artemia concentration (33.3±
12.6% paralarvae attack in a 0.1 Artemia ml−1 density, opposite 16.7±7.6 and 18.3±7.6% in densities of 0.5 and 1 Artemia ml−1
respectively). The greatest predatory activity is recorded during the first 5 min after food is supplied (72.2±25.5%). An increase in the
predatory activity was also observed when food was distributed in several doses instead of a single dose (75.0±10.0%and 46.7±17.6%
respectively). It was proved for the first time that paralarvae completely ingest their preys (including their exoskeletons), in this case
Artemia. Time needed for their total ingestion ranges between 4 and 10 min.
© 2006 Elsevier B.V. All rights reserved.


VIA EMAIL: LET ME KNOW if you can't get a hold of this second paper, which has more detailed methods.
 

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