2. Definition of estuary
☼ An estuary is defined as a semi-
enclosed coastal body of water, which
has a free connection with the open
sea and within which the seawater is
measurably diluted with the
freshwater of land drainage.
3. • Estuaries are important & distinct
component of coastal landscape with highly
complex ecosystems,varying
physicochemical properties & highly diverse
flora & fauna.
• Estuaries are of different shapes & sizes, &
are known by different names,such as ‘river
mouth’,’bays’,’lagoons’,’harbours’ or ‘inlets’.
4. ESTUARINE RESOURCES OF
INDIA
• Indian coastline is
more than 7500km
in length with an
EEZ of 2.015 X 106
km2 that accounts
for 61% of total land
area.
5. • The country commands a distinct position
with more than 55 estuaries,located on East
& west coasts
• The estuarine resource,including the
associated waters,of India has been
estimated approx. at 30,000,00 ha.
• Amoung the major rivers Ganga, Mahanadi,
Godavari,Krishna,Cauveri [east coast] &
Narmada,Tapti,Mandovi,Zuari [west coast]
forms highly productive esuarine systems
esp. in relation to fisheries.
6.
7. PRESENT STATUS OF FISH
PRODUCTION & PRODUCTIVITY
• The estuarine fisheries in India are
always above the subsistence
level,contributing sizably to the inland
fish basket in the country.
• The fish productivity of various
estuaries has been estimated in the
range of 45-75 kg/ha.
8.
9.
10. ECOLOGY AND FISHERIES OF SELECTED
ESTUARIES &
ASSOCIATED WATERS
• HOOGHLY ESTUARY
• Largest estuarine systems in India.
• width 2-12km.
• Salinity : 0.2-31.6 ppt
• live estuary supporting rich
biodiversity
• better known for its profitable winter
fishery,the famous sunderban
mangroves & Hilsa fishery.
11. TRENDS OF FISH CATCH
• The trend of fish catch in Hooghly indicated
significant increase during recent years
primarily due to increase in Hilsa catch.
• Between 1998-99 & 2002-2003,the average
per annum catch of Hilsa has been
estimated at 10,382.9t with an impressive
increase of 63.3% from previous 5 years
[6279.6t]
12.
13. KRlSHNA ESTUARY
• Salinity : 20-35ppt.
• fishery dependent on marine
migrants.
• Mullets are hallmark of Krishna
estuary.
• Other gps. found in catch include
clupeids,perches,catfish,penaid
prawns & crabs.
14. • Annual fish catch during 2004-06 has
been estimated at 496.1 – 540t with
productivity ranging from 83-
90kg/ha.
• Average catch per unit of effort - low &
depend on season – 13.6kg/boat
[post-monsoon] & 1.74kg/boat[pre-
monsoon].
16. • Godavari estuary as a whole supports
23 prawn sps. Of this Penaeus
indicus,P.monodon, P.japonicus etc are
impo. from fishery point of view.
• Palaemonid prawns like
Macrobrachium
rosenbergii,M.malcomsonii etc are
also impo..
17. MAHANADl
• Comprises 2 impo. estuaries of Odisha viz.
Mahanadi & Devi.
• Salinity : 0.6-18 ppt.
• Fishery include – mullets,prawn,thread
fins,perches & others contributed by 96
sps. of fin fish & 10 sps. of shell fish.
• Sps. diversity differs with depth & salinity.
• However,relatively higher fish catch
,coupled with higher diversity, has been
recorded towards seamouth as compared to
freshwater stretch
18. CHILKA
• Largest lagoon in the east coast of India.
• Lagoon has distinct marine,brackish &
fresh water strands but is primarily an
estuarine ecosystem.
• Ramsar site.
• Endangered sps. & migratory birds.
• Highly productive with rich fishery
resources.
• Potential source for high priced prawn &
mullet fisheries.
19.
20. PULICAT LAKE
• Second largest brackish water lake in
India.
• Run //l to Bay of Bengal.
• Opens into Bay of Bengal through a
narrow passage at its southern
end,near Pulicat town.
• Shallow lake – average water depth :
0.7m.
• Salinity : 7.79 – 28.91 ppt.
21. • Fishery – largely depend on
P.indicus,M.cephalus & Chanos
chanos.
• However dominant fishery of Chanos
chanos in 1980s become rare.
• Fisheries of Sardinella,Hilsa,tiger
prawn also declined significantly
[over fishing].
• Penaeid prawns of importance –
Metapeneaeus dobsonii,M.monoceros
& M.brevicornis.
22. • The crab fishery – very conspicuous.
• The use of destructive gears,esp.
small mesh bar nets,has lead to
indiscriminate fishing of mullets.
• The average catch per fisher per day
has been estimated to be poor at
300g-500g/day,mainly of P.indicus
23. KERALA BACKWATERS
• 44 rivers in Kerala,41 flows westwards
from W.G to Arabian sea through
backwater.
• Total area : 500 sq.km
• Comprises of vast system –
interconnected lagoons,bays &
swamps.
• Fish landing :14000-17000t
24. • Vembanad is largest backwater.
• Northern part of vembanad – cochin
backwater.
• River Periyar in north & Pampa in
south along with many small
channels,streams,irrigation canals etc
–freshwater source of cochin
backwater.
• Salinity : 9-11ppt
