BIOLOGY OF INDIAN OIL SARDINE.pptx

BIOLOGY OF INDIAN OIL
SARDINE
Vinod Kumar
FRM

Introduction Sardinella longiceps ( Valenciennes 1847 )
Classification
Kingdom : Animalia
Phyllum : Chordata
Class : Actinopterygii
Order : Clupeiformes
Family : Clupeidae
Genus : Sardinella
Species : S.longiceps

Characters
● Flat body which is covered with large,silvery, reflective scales
● They have set of specialized scales called scutes which are
jagged and pointed backward.
● Having very small teeth or no teeth at all.
● Caudal fin well forked and lobes are pointed.
● Body fusiform, elongate and subcylindrical.
● Midlateral line.

Distribution
● Indian Ocean: northern and western parts only, Gulf of Aden,
Gulf of Oman, eastward to southern part of India, on eastern
coast to Andhra; possibly to the Andaman Islands.
● Indian oil sardine is distributed on the entire west coast of India
from Gujarat to Kerala, and also on Tamil Nadu, Pondichery,
Andhra Pradesh and Orissa in the Indian east coast, but the
highest abundance is observed off Kerala and Karnataka coasts.

Marine; pelagic-neritic; oceanodromous
.
depth range ; 20 - 200 m Tropical;
25°N - 7°N, 57°E - 81°E .

Food and feeding habits
● It is predominantly a phytoplankton feeder, feeding mostly on
diatoms like Fragillaria oceanica, Coscinodiscus, Thallassiothrix and
Pleurosigma.
● However, F. oceanica is the most favourite food item.
● In addition to diatoms, they may also feed on copepods,
dinoflagellates, ostracods, larval prawn, larval bivalves, fish eggs
and some blue green algae.
● The presence of diatoms, Fragillaria oceanica in large numbers
indicates the abundance of oil sardine in coastal waters.

Food materials
1.Fragilaria oceanica 2.Cosinodiscus

Habitat
● Sardines are found in shallow coastal temperate and subtropical
oceans worldwide.
● This pelagic, marine species is a highly migratory species that
forms schools in tropical coastal regions along the continental
shelf between depths of 20 - 200 metres .
● It is known to move below surface water depths during the
daytime.

Growth and Age
● S. longiceps attains sexual maturity around 15 cm and 1 year of
age.
● The lifespan of this fish is about 2.5 - 3 years.
● Maximum length 23 cm and common length is of 20 cm.
● Maximum weight 200 gms.

Spawning
● Breeds once a year off western coasts of India when
temperatures and salinity are low during the southwest
monsoon months.
● Spawning peaks in August-September.
● Occurs at temperatures of 22.0-28.0 °C , spawning usually takes
place at night.

Contn….
● The movement of the fish dependent on water conditions
directly before and after the monsoon season.
● This affects the spawning season and means that it may vary
from any period between June and December.
● These fish only spawn once during the spawning season.
● The distribution of the fish throughout the spawning season is
determined by the size and age of the fish.
Many of the oldest, most mature adults between 17 and 19 cm .
Rarely S. longiceps survive a second spawn, but this is much more
common in females.

● Ovary development is classified in stages I-VI. Stages IV, V, and VI are able to
spawn.
● Fish at stage IV have ovaries that fill two-thirds of their available body cavity.
By stage VI, these ovaries fill the body cavity and are made up of large
transparent ripe eggs.
● These fish only spawn once in a spawning season and produce around 75,000
eggs.
● The development of the egg requires only 24 hours. These eggs are spherical
and range from 1 to 4 mm in diameter. These fish are called oil sardines
because an oil globule makes up a major part of the egg yolk.

Fishing season
The shoal starts appearing in the coastal waters in early June, but
commercial fishing start from July to March with maximum intensity
in October to January.

Craft and Gear used
● In south Kerala - one-boat boat seine ‘Thangu Vala’ and gill net 'Ayila Vala'
and some purse seines.
● In North Kerala, boat-seine 'Pattan Kolli' is the major gear,gill net 'Mathichala
vala' and the cast net.
● The chief crafts employed in Kerala are - dugout canoes, the bigger 'odam'
and the smaller 'vanchi'.

● Out rigger boats are common crafts in Karnataka coast.
● In Tamil Nadu, pair trawlers are also operated at 12 -16 m depths
in Pamban - Rameshwaram area while ring seines being used in
the Palk bay.

At present, purse seine fleet operates at 30 - 40 m depth almost throughout the
year. Motorized ring seines , Purse seine is the most important gear at present.
However, shore seine (Rampani and Vendi) and cast net are the gears commonly
used for catching .

1. Outrigger boat. 2. Pair trawler

IUCN RED LiST
Indian Oil Sardine Sardinella longiceps has most recently been
assessed for The IUCN Red List of Threatened Species in 2019.
Sardinella longiceps is listed as Least Concern.
Threats :
● Over exploitation
● Climate change

Conservation and Management
● Destructive fishing practices like -
● using small meshed seines should be effectively controlled by
enforcing mesh size regulation (minimum 18 mm).
● closed season and restricted fishing (June - Sep) besides strict
licensing and optimum deployment of fishing units especially
ring seines and purse seines.
● Present coastal fishery scenario demands responsible fishing
by all sectors to sustain the fishery as well as ensure the socio-
economic well being of the fishermen. Necessary steps should
be taken to exploit the offshore grounds to have better catch.

Reference
● http://ecoursesonline.iasri.res.in/mod/page/view.php?id=91743
● http://ecoursesonline.iasri.res.in/mod/page/view.php?id=85336
● https://www.fishsource.org/stock_page/1083#:~:text=Indian%20oil%20sardine
%20is%20distributed,off%20Kerala%20and%20Karnataka%20coasts.
● https://indiaagronet.com/indiaagronet/Fisheries/Contents/oil_sardine_fish.htm
● https://www.seapedia.net/sardines/
● https://www.fishbase.se/summary/sardinella-longiceps.html

BIOLOGY OF INDIAN OIL SARDINE.pptx

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BIOLOGY OF INDIAN OIL SARDINE.pptx