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128-130, October
& December 2000
FEEDING HABITS OF SQUTDS OF THOOTHUKKUDI,
SOUTH EAST COAST OF INDIA*
I
N. Neethiselvan and V.K. Venkataramanil
Departrnent of Fishing Technology and Fisheries Engineering
Fisheries College and Research lnstitute, Thoothukkudi - 628 008
ABSTRACT
The inaestigation on the feeding hnbits of squids of Thoothukkudi waters ra:ealed that they fed
mainly onihimps in tluir early phax of tlrc life and stuitched oaer to fsh in the later phase.
Cannibalism was; found to persist in all the three species of squids studied. Occurrenu of relatiaely
a highu praportion of shimps nnd other ctustaceans in the gut content of Sepioteuthis
lessoniana rersealed the oientation of this animal more toutards the sea bottom than Loligo
duvauceli and Doryteuthis sibogae.
Key words : Feeding habits, Squids
Squids are extremely effective predators,
preying predominantly on fish and pelagic
crustaceans (Caddy, 1983). The feeding
mechanisms of cephalopods, principally involve the
beaks (chitinous mandibles) and the radula
(Amaratunga, 1983). Holding the prey in the arms,
squid bite to get chunks of flesh. Cursory
information on the feeding habits of squids were
given by Rao (1954) for Sepioteuthis arctipinnies
(:S.lessoniana). Oommen (19'77) had studied the
digestive system and feeding habits of Loligo
duvauceli. Silas et a/. (1986) had reported that
Doryteuthis sibogae mainly feeds on fishes,
from a pealing shed which received squid catch from
mechanized vessels of Thoothukkudi. The study was
carried out for one year from June 1997 to May 1998.
Sampling was made once in a week and in a month l5
to 20 animals were collected and a total of 200 animals
cephalopods and crustaceans. However, a detailed
were studied for each species. The animals were
brought to the laboratory and preserved in I0%
formalin and cut open to study the food and feeding
habits. Generally, in squids, the food items were in a
well crushed and macerated condition due to the
action of powerful beaks at the time of ingestion,
rendering specific identity of food items difficult to
accomplish. Therefore, in the present study, the
various food items were categorized into groups,
study on feeding habits of squids have not been
based on the body components of food organisms such
far. Therefore the present study dealt
habits of Loligo duvauceli,
the
feeding
with
pigmented skin, appendages, lumps of flesh etc. They
attempted so
Sepioteuthis lessoniana and Doryteuthis sibogae in
Thoothukkudi waters.
MATERIALS AND METHODS
as scales, flesh, fin-rays, gill-rackers, eye balls,
were grouped into 'fishes', 'crabs' 'stomatopods',
other 'crustaceans' and 'digested matter'. As the
squids were carnivores, the volumetric method was
found to be most suitable. The entire content of each
To study the feeding biology of L.duvauceli,
S.lessoniana and D-sibogae samples were collected
a
stomach was considered as a unit and the various food
items present were expressed in items ofpercentages.
part of the ph.D. thesis submitted by the first author to the Tamil Nadu Veterinary and Animal Sciences University' Chennai
' 600 051
I Professor, Dept. ofFisheries Biology and Caplure Fisheries, Fisheries College and Research Institute, Thoothukkudi - 628 008
128
Neethiselvarr and Venkataranrani
RESULTS AND DISCUSSION
maturing individuals were found to feed mainly on
The analysis of gut contents of squids revealed
'that it consisted of partially digested food materials
and completely digested marter. The individual food
items were in semi-digested condition and hence it
fish(44.75%) and cephalopods (5.1 l%). Shrimps and
other curstaceans formed only lesser percentages of
2.31 and 2.14 respectively in the gut contents of
maturing individuals. In the case of matured and spent
specimens, fish contributed to a larger percentage
(63.65%). Cephalopods were also encountered in
good quantities in the gut contents of L.duvauceli.
Thus it could be observed that during mahrration,
decrease in shrimp and other crustaceans were evident
and fish was found to be more in the gut content. The
representation of small sepcimens of L.duvauceli in
serni-digested condition revealed the cannibalistic
narure of this species.
difficult to identify up to genus or species
level. However, they were segregated up to group
was very
level. The major groups identified in the present study
were fish, shrimp, stomatopods, crab, other
crustaceans and cephalopods. There was a clear cut
shift of feeding behaviour from one item to another
item on progress of growth. Among the semi-digested
food items, fish could be identified based or.] the
presence of scales and sntall spir.res. The existance
shrimp
in the gut content
vvas identitled
of
by
The feeding habit of Siessoniana
the
presence of rostrum and carapace. presence of arnr
and tentacular suckers of cepahlopods indicatecl the
cephalopods as one of the food items of the squid. The
details on the food conrposition of stonrach contcnts
of L.duvauceli, S.lessoniatta and D.sibogae in relation
to maturity stages are given in Table L
Fish was found to be the dominant food itenr
Though the feeding behaviour of D,sibogae
of
Lduvauceli. Immature individuals found to feed on
srustaceans (15.26%) and shrimps (5.18%) in addition
to fish (33.55%). As the animal gre.*, there was a
gradual increase in the quantiry of fish consumed. The
species
resernbled L.cluvauceli. Ilowever, shrimps and other
crustaceans were recorded in the gut contents in higher
propoftion in'espective of ntaturity stages. As in
L.duvauceli, cannibalism existed in S.lessonianq also
and occun'ence of cephalopod rentains were observed
in the gut content of rnaturing and rrratured animals.
resembled witir that of L.dut,auceli and S.lessoniana,
the crustaceans of the gut content was mainly
constiruted by shrimps rather than other crustaceans.
In the gut content of matured specimens of D. sibogae
remains of squids were observed.
Table
I
Composition of stomach contents of Loligo duvauceli, Sepioteuthis lessoniuna and Doryteuthis sibogae
at different maturity stages
Loligo duvauceli
Sepioleuth is I essonian a
Doryteuthis sibogae
Food items
Fishes
Immgture
(%)
I\Iaturing
(%)
l\latured /
nrnrature
lll atu ring
spent (7o)
(Y')
(r',)
I\latured /
spt'nt (7")
33.5
11.75
63.65
27.22
34.51
60.01
5.1 I
18.13
5. r8
2_lt
2.22
t5.26
2.t4
L09
t
45.69
14.91
Cephalopods
Shrimps
Other
I
46.0t
I
I
Maturing
I\Iatured /
(%)
("/")
spent (7o)
35.r8
47 68
62.01
9.'t
I4.8I
nratu re
I
t7.t4
5.12
4.24
15.09
10.i5
2.18
4.32
6.88
3.3 I
I"9t
2.32
t.l9
41.32
48.16
t6.69
47.82
30.t4
19.8 l
t29
rl
nr
5.3 3
-s.75
cruStaceans
Digested maner
I
I
Feeding habits of squids
Caddy (Ed.) Advances in Assessment of World
Cephalopod Resources. FAO Fish Technical
Paper,23l: 461-452.
The present study on food and feeding habits
revealed that all the squids studied were found to be
pisivorous. Shrimps contributed to the diet in the
juvenile stages in these squids. The maturing and
matured animals found to switch over to fish in their
later phase of life. Similar phenomenon had been
reported in L.opalescens by Fields ( 1965); in L.pealei
Fields, W.G. (1965). The structure development,
food relations, reproduction and life history of
the squid Loligo opalescens. Department of
Fish and Game Berry. State of California. -Eisfr
Bulletin, 131.
by Vinogradov and Noskov (1979); in L.vulgaris
reyanaudii by Lipinski (1987) and in L.forbesi and
L..vulgaris by Pierce et al. (1994). The behaviour of
feeding on other cephalopods and observation of
cannibalism in L.duvauceli, S. lessoniana and D.
sibogae tnthe present study are in accordance with the
report by Silas eral. (1986). Rao (1954) had observed
macerated parts of bony fish, crustacean appendages,
squids arm and squids body in the stomach content of
S.lessoniana. Occurrence
of relatively
higher
proportion of shrimps and other crustaceans in the gut
content of S./essoriana in the present study implies
their orientation with sea bottom where shrimps and
other crustaceans are abundant.
ACKNOWLEDGEMENT
The authors thank Dr.V. Ramaiyan, Professor,
Centre of Advanced Science in Marine Biology,
Paragipettai for critically going through the
manuscript and the Dean, Fisheries College and
Research lnstitute, Thoothukkdui - 628 008 for the
encouragement and facilities provided.
Lipinski, M.R. (1987). Food anci feeding of Loligo
vulgaris reynaudii from St. Francis bay, South
Africa. South African Journal of Marine
Science,5 :557-564.
Oommen, V.P. (1977). Studies on the food, feeding
and fishery of certain cephalopods from the
West Coast of India. Department of Marine
Science, University of Cochin, Bulletin, 8 :
73-152.
Pierce, G.J., Boyle, P.R., Hastie, L.C. and Santos,
M.B. (1994). Diets of squid Loligoforbesi and
Loligo vulgaris in the north east Atlantic.
Fisheries Research,
Silas, 8.G., Satyanarayana Rao,
marine ecosystem. In: J.F. Caddy (Ed.)
Advances in Assessment ofWorld Cephalopod
assessment and management of stocks
the
In : J.F.
Sarvesan, R.,
38-48.
Resources. FAO Fish Technical Papdr,231:
to their population dynamics and to
K.,
Prabhakaran Nair, K., VidYasagar, K.,
Meiyappan, M.M., Appanna Sastri, Y' and
Narayana Rao, B. (1986). Some aspects of the
biology of squids. In: Cephalopod Bionomics,
Fisheries and Resources of the exclusive
economic zone of India.Central Marine
Fisheries Research Instiute. Bulletin, 37:
Amaratunga, T. (1983), The role of cephalopods in
Caddy, J.F. (1983). The cephalopods: Factors relevant
149-163.
Rao, K.V. (1954). Biology and fishery of the
Palk-Bay squid, Sepioteuthis architipinnis
goutd. IndianJournal of Fisheries, 1 :37-66.
REFERENCES
379415.
2l:
Vinogradov, V.L and Noskov, S.S. (1979). Feeding
of short-finned squid, Illex illecebrosus and
long finned squid, Loligo pealei, off N.S. and
New England,1974-1975. ICNAF,5 : 3l-36.
130