This document summarizes the life cycle of the squid species Uroteuthis duvaucelii. It describes the taxonomy, morphology, distribution, biology, and reproduction of squid. The life cycle lasts approximately one year. Squid spawn throughout the year but mainly in spring and autumn. Fertilized eggs hatch into planktonic larvae before developing into benthic adults. Males typically die after mating while females survive briefly to brood their eggs. The fishery production of squid in India has increased over 280% in recent decades.

1. SHELLFISH BEEDING AND HATCHEY MANAGEMENT
AQC-311,2(1+1)
A Presentation on
“Life cycle of Squid”
Presented By:
Joynal Abedin

2. SQUIDS
• The two main groups, Myopsid squids, “covered-eyed”, near-
shore (neritic) squids,and
• Oegopsid squids, “open-eyed” oceanic (pelagic) squids, occur
in the oceans and seas of the world and together form the basis of
major cephalopods production of the globe.
• Over 800 species known yet
• Exclusively Marine

3. TAXONOMICAL CLASSIFICATION
KINGDOM:Animalia
PHYLUM:Mollusca
CLASSS:Cephalopoda
ORDER:Teuthida
FAMILY:Loliginidae
GENUS:Uroteuthis
SPECIES:U.duvaucelii

4. Morphology
Bilaterally symmetrical.
Oval shaped body.
Body –divided into head
and trunk.
Internal shell (gladius) is
present.
8 sessile arms and 2
tentacular arms.
Fin lobes fused
posteriorly.
Locomotin – jet of water
produced by ventral
siphon.

5. DISTRIBUTION

6. BIOLOGY
• During brooding fertilized embryos hatch into a planktonic stage
migrating into the upper layers of the water column. As they grow
larger they take up a benthic existence as adults, with males being
slightly larger than females.
• Spawning occurs throughout the year but principally in spring and
autumn. It is initiated by males performing various displays to attract
potential females. During copulation, a male grasps the female and
inserts the hectocotylus into the female's mantle cavity where
fertilization usually occurs. Adult males usually then die shortly after
spawning, whilst females survive for a short while until after brooding.
• The life cycle of U. duvaucelii lasts around 1 year although this can
vary due to environmental factors.
• Breeds mainly in the spring and in the early summer.
• It can move fast both back and front by funnel
• It uses a black ink to escape from the predators.
• Has a great power of rapid colour change.

7. SEXUAL DIMORPHISM
Male
It includes a testis, a vas deferens,
a spermatophoric sac containing
sperm packets & a copulatory
organ or penis.
Female
It comprises of an ovary, an
oviductal gland, and a part of
nidamental glands, which produce
a jelly in which the eggs are
embedded.

8. Male
1.Gonoducts single
2.Suckers on buccal
lappets.
3.Hooks present
in tentacular
club.
Female
1.Gonoducts paired
2.Suckers absent
3.Hooks
absent.

9. REPRODUCTION
• Sexes are separate.
• Single testis.
• A single gland of the visceral mass opens directly into the coelom by
slit.
• Gonoduct runs on the left from the coelom to the mantle cavity &
opens near funnel.
• Hectocotylized arm – copulatory organ
• It is used for the transfer of sperm.

10. MATTING
• Attracting females begins in the morning
• Around dawn swims rapidly in very large circles
• After some time the squids they start swimming
in pairs.
• These are mating couples.
• Males start changing colours to attract female.
• Once the female shows interest mating takes
place.

11. • The females have an ink sac under a set of glands in gills.
• During mating ,sperms are stored inside sac where they
will fertilize her eggs.
• Male uses the shorter arm to place the sperm.
• Female uses the nidamental secretion to stick the eggs in the solid
object in the event.
• 7-8 weeks to hatch out.

12. Simalparity
 All cephalopods undergo only one breeding cycle(monocycly), except
nautiluses.
 All the modern cephalopods are single-season breeders
 Death is followed after that.

13. PRODUCTION TRENDS
• The present status of the fishery, biology and stock assessment of the India squid Loligo duvauceli
Orbigny was studied, based on the data collected at different centres on both the coasts of India for
1979-1989. The production had increased by over 280% in 3 states on the west coast, viz. Kerala,
Maharashtra and Gujarat. These states accounted for about 80% of the all-India squid production
(23,941 t in 1989). Trawl is the main gear, taking 86% of the total squid landings.

14. THANK YOU ALL
-“FOR YOUR PATIENCE LISTENING”