Biologi pembiakan dan pembenihan sefalopoda, sepioteuthis lessoniana (lesson) dengan kaedah separa intensif
Loading...
Date
1998-01
Authors
Othman, Mohd.Fariduddin
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A study was conducted on big fin reef squid, Sepioteuthis lessoniana to
understand its reproductive biology in the wild, egg transportation methods to the
hatchery, incubation and hatching procedures, and breeding requirements. A
survey of the breeding population and breeding ground was conducted and
analyzed from squid trap operations ati.d catch. landings data. Semi-intensive
breeding trials and related experiments were conducted at the marine shrimp
hatchery of the National Prawn Fry Research and Production Centre (NAPFRE),
Fisheries Department, Kg. Pulau Sayak, Kedah.
In the wild, spawning activities were seasonal and localized. Breeding season
was between October-January. The breeding ground was about 2-10 nautical
miles offshore, at 5-10 m depth with salinity of 30-33 ppt, pH of 8.3-8.6, water
temperature of 26-31 °C, dissolved oxygen of 4.7-7.2 ppm, turbidity of2.5-7.5
m and water current of 0.0-0.2 tn!s. Matured males weighed 630 ± 330 g (body
weight - BW) and more than one individuals patticipated in mating and
copulation activities with a single female. Gravid females weighed 400 ± 170 g
(BW) with an average ovary size of 29.0 ± 16.6 g and fecundity of 123-14 70
. oocytes per female. The fecundity was directly related (R2 = 0.5609 ) to size
(mantle length - ML). The ovarian oocytes.(total length - TL 0.58 ± 0.08 em,
width- Wd 0.40 ± 0.06 em, weight- Wt 0.04 ± 0.05 g) and laid eggs were
physically and structurally different. The laid eggs were enclosed in a single,
finger-like elongated jelly capsule (TL 3.5 ± 0.5 em, Wd 0.9 .± 0.2 em, W 3.1 ±
0.3 g ,) whereby each was linked, forming a single egg mass of mop-like
structure of 300-450 capsules with an average weight of 900-1400 g. Individual
capsule carried 3-7 (mean 4.2) embryos. Transportation of egg mass at any
maturity stage from their natural habitat to the hatchery did not significantly
effect (P>0.05) hatching rate. Incubation was done best by hanging or free
floating method. After 18-21 days, egg capsules (TL 12.2 ± 0.3 em, W d 1.8 ± 0.2
em, W 12.7 ± 1.6 g,) hatched. The processlasted 6-8 days and peaked on day 3-5
with a hatching rate between 40-50 %. Incubation, hatching and larval rearing
were optimal when turbidity was near zero with salinity of 28-31 ppt, minimum
dissolved oxygen of3 ppm, pH of7.6-8.2 and water temperature of 28-30 °C.
The juveniles resembled the adults in many aspects e'xcept for size (ML 0.4-0.5
em) and began feeding strictly on live food 1-2 days later,. Shrimp larvae (TL
0.5-1.3 em) were preferred. Adult Artemia (TL 0.5-1.2 em), fish larvae (TL
0.7-1.5 em) or Acetes (TL 0.5-1.3 em) were not well accepted till day 7-IO.
After day 23-25 juveniles began to accept fresh fish flesh and gradually
switched to dead fish. Larval rearing is practiced best in two phases to optimize
feed distribution as well as to minimize cannibalism.
TI1e juveniles (BW 7-11 g, ML 3.5-4.5 em) packed at the rate of 2.5- 6.5
individuals/! for an 8-h journey survived 100% on arrival. Except for the posthatching
period, survival was consistent as growth proceeded. The marketable
size of 200-400g was achievable after 3-4 months of culture. After 4-5 months
female ovary was fully developed and ready to spawn again. To improve
breeding success, problem of live food supply has to be addressed beside
emphasizing on research to improve survival in the early phase and to determine
an optimum culture environment for the grow-out phase.
Description
Keywords
Sefalopoda, sepioteuthis lessoniana , Kaedah separa intensif