fishery of estuary

1. HOOGHLY-MATLAH ESTUARINE FISHERY
Upama Das
M.Sc. IF, 2nd SEM
RO-18
SIF, CUSAT

2. INTRODUCTION
• The river Ganges has an extensive estuarine system covering the southern
part of west bengal, and bangladesh.
• The portion within the Indian territory in southern West Bengal comprises the
hooghly-matlah Estuarine complex.
• The principal component of it. Viz., The river Hooghly runs a winding course
from its point of divergence from the parent river till it merges with the sea.
On its way it receives river Rupnarayan, a major tributory alongwlth the
rivers Saptamukhi, Thakuran, Matlah, Gosaba, Bidya. Hartnbhanga,
Ichamati and Raimangal forming an estuarine Complex.
• The lower portion of this estuarine system, a network formed by the main
channel. Its distributaries creeks, is known as the Sunderban delta.
• The rivers Saptamukhi, Thakuran, Matlah are now just inlets of tidal water
with their upper connections lost due to siltation and neo-tectonic activities of
12th century.

3. GEOGRAPHICAL LOCATION
21⁰-23⁰ N LATITUDE
88-89⁰E LONGITUDE
WEST BENGAL
 Largest estuarine ecosystem in India, with an area 8029 km2
The Hooghly is a positive estuary in the mixo-haline range (pantutu,
1966). This estuarine system supports commercial fisheries of
considerable value.
It forms world’s largest delta (Sundarban), endowed with largest
mangrove vegetation (4,264 km2)

5. Hooghly estuary and its various fishing zones

6. DIFFERENT ZONES OF
HOOGHLY-MATLAH ESTUARY
For estimating fish landings, CIFRI divided this estuarine system
into the following zones:
Zone 1-Nabadwip to Konnagar (upper zone of the freshwater
zone). Salinity- 0.011 to 0.036 ppt.
Zone 2- Konnagar to Diamond Harbour (middle zone of the
hoogly estuary or the ‘gradient zone’). Salinity- 0.020 to 0.596 ppt.
Zone 3- Diamond Harbour to the mouth of the estuary including
entire lower Sunderbans (lower or marine zone of the system).
Salinity- 0.20 ppt to near neritic salinity.
Zone 4- Includes river Rupnarain. Salinity-0.043 to 1.025 ppt.
Zone 5- Includes river Matlah around port canning.

7. PHYSICO-CHEMICAL PARAMETERS OF
THE ESTUARY
Soil texture mostly clay silty loam
Temperature 16 0 C – 330 C
pH 7.8- 8.8
Salinity 0.5- 32.5
DO 4.8- 8.9
Temperature and salinity are the most significant factors that
determining the fishery.
The maximum and minimum temperatures recorded in the
pre-monsoon and post-monsoon respectively, in all zones
except Zone 4 ,where the maximum temperature prevails
during monsoon

8. Fish species 172
Molluscs 23
Crab 67
Prawn 15
Algae 150
Aquatic Biodiversity

10. TOTAL CATCH ( t ) from the HOOGHLY-
MATLAH ESTUARINE SYSTEM

11. CATCH
Month-wise catch structure
• Low catch during the summer months of March to June.
• The catch begins to increase from July with the onset of monsoon.
• Reaches peak during winter months of November to January.
• Maximum average catch (82%) was accounted during winter months
of November, December and January.
• Minimum average catch (3.5%) was during the summer months of
March to June, leaving the rest i.e.,14.5% average catch for the
monsoon months (July to October).

13. Average monthly landings (t) from the Hooghly-Matlah estuarine system

14. ..CATCH
zone-wise catch structure
• As usual, most of the total annual catch (92 to 95%)
comes from the lower estuarine zone (zone IIl), i.e.,
Diamond harbour to the mouth of the estuary including
entire lower sunderbans (lower or marine zone of the
system).
• The upper estuary i.e., Zone I, II and IV together
contribute 5 to 8% of total annual catch.

16. ZONE-WISE ANNUAL CATCH (t) FROM THE HOOGHLY-MATLAH
ESTUARINE SYSTEM

18. SPECIES 1994-1995 1995-96 1996-97 1997-98 1998-99 1999-2000AVERAGE(FROM1994-95TO1999-2000) AVERAGE(FROM1984-85TO1993-94
Tenualosailisha 6.95 10.01 14.69 18.99 17.75 10.52 13.15 8.14
Lizatade 0.01
Lizaparsia 0.03 0.05 0.05 0.12 0.03 0.03 0.05 0.06
Latescalcarifer 0.2 0.5 0.1 0.47 0.17 0.03 0.24 0.1
Sillaginopsispanijus 0.16 0.06 0.17 0.16 0.04 0.03 0.1 0.11
Polynemusparadiseus 0.4 0.63 0.59 0.61 0.65 0.58 0.58 0.56
Eleutheronematetradactylum 0.02 0.01 0.03 0.07 0.03 0.04 0.04 0.06
Polynemusindicus 0.07 0.21 0.14 0.28 0.17 0.16 0.17 0.33
Coiliaspp 3.95 2.45 2.82 2.73 4.16 3.38 3.25 2.39
Pamapama 12.92 10.99 12.02 8.36 10.04 12.3 11.11 11.99
Percentage composition of commercial species in the total catch from the
Hooghly-Matlah estuarine System.

19. FISHERY RESOURCES
 172 species recorded,73- freshwater and 99 occupy
the saline zone
Fish fauna classified into:
- Residents (mullets, threadfins, sciaenids, sea bass)
- migratory or transient (hilsa, pama pama, pangasius,
rosenbergii)
Dominated fish spp.
T. ilisha 51%
H. nehereus 11.3%
Pama pama 5.7%
Setipinna phasa 4.7%
Trichiurus spp. 4.2%
Penaeds prawn 4.35%

20. CONT…
 Other important fish species :
Polynemus paradiseus, P.Indicus, Eeutheronema tetradectylum,
Lates calcarifer, Pangasius pangasius, Liza parsia, L.Tade,
Rhinomugil corsula, Pampus argenteus ,Coilia dussumeiri, Mystus
spp. , Johnius dussumeiri , Clupisoma garua, Wallago attu, Sperata
seenghala, Ompok bimaculatus and Rita rita etc.
Prawns: Penaeus monodon, P. Indicus, Metapenaeus brevicornis, M.
monoceros ,Parapenaeopsis sculptilis, P. Stylifera, Macrobrachium
spp.
Crabs : Scylla Serrata, Portunus Pelagicus

21. HlLSA CATCH ( t ) from the HOOGHLY-MATLAH ESTUARINE SYSTEM

22. FISHERY OF HILSA
• The prime fish, hilsa forms commercially the most
important fishery of the estuary in view of its high market
value.
• Hilsa catch has increased from 1996-97 onwards which
may be ascribed to tremendous increase in effort in recent
years coupled with enormous improvement of
mechanization.

25. Season wise Hilsa catch (t) from Hooghly-Matlah estuary system

26. • Hilsa, winter migratory bagnet catch, forms the mainstay of the
estuarine.
• Fish catch contributing 15 to 29% to the total annual fish landing.
• The monsoon (July to October) hilsa catch contributes 68% of the
total annual landing of the species from the estuary.
• Dominance of large sized fishes in the length range of 23 to 53 cm
representing 3rd, 4th and 5th year age group, is the striking feature of
the monsoon hilsa fishery.
• The fishery in winter is of a smaller magnitude which contributes
26.5% of the total catch of the species.
• Hilsa juvenile (fry and fingerlings) constitute a major fishery during
their downward migration in upper zone.

27. GEAR WISE COMPOSITION OF
CATCH
• Most of the gear are for multi species exploitation, but
some are selective for particular species.
• Bagnets and drift gill nets constituted the most
dominant gears in the estuary accounting for 62 to
82% (average 73%) and 16 to 31%b(average 24%)
respectively of the total catch with the rest contributing
only 3% on the average.

29. WINTER BAGNET MIGRATORY
FISHERY
• The total estimated winter bagnet fish landing fluctuated within
20820.6 to 35844.6 t per season with an average CPUE of 53.12
to 93.72 kg during the period 1994-95 to 1999-2000.
• Though the total catch of WMBF shows a rising trend upto the
year 1996-97, the downward trend of overall average CPUE from
1995-96 is a warning signal indicative of over exploitation.

38. THREATS
 Deteriorating ecological characters due to anthropogenic
pressure
 Overexploitation of faunal resources
 Destruction of mangroves
 Siltation and formation of sand bar
 Flood and shortage of fresh water discharge
 Hydraulic structure (dams, barrages, weirs)
 Wanton destruction of juvenile hilsa

39. SUNDARBAN FISHERY

42. FISH AND SHELL-FISH DIVERSITY
• A total of 156 fish species belonging to 53 families and 16 orders,
were recorded;
• Gobiidae was the most common family with 20 species,
• followed by engraulidae (13 Species),
• sciaenidae (11 species) and ariidae (8 species).
• Preliminary estimate of fish catch from winter bag net fishing,
along the lower sundarban revealed a major shift in catch
composition in comparison to landings during 2009-10.

43. ..FISH AND SHELL-FISH DIVERSITY
• Drastic reduction in landings of harpadon nehereus was recorded in current year,
which constituted 27.25% (9927 t) of total catch during 2009-10.
• High landing of pony fish was recorded, which curently forms the most dominant
component of winter bag net fishery. During january 2016 it constituted 92% of the
total catch.
• Non-penaeid prawns (mainly acetes spp.) Have emerged as one of the most
dominant fishery resource.
• There is overall reduction in the catch of fin-fishes.
• The fishery is presently dominated by prawns (58.5% as compared to 10.23% in
2009-10).
• The bag net catches were dominated by invertebrates (73.5 %), comprising prawns
(58.5%), crabs (11.65%), stomatopods (2.10%) and cephalopods
• (1.26%).
• Atypopeneus stenodactylus, which was a rare component in prawn catches, is now
one of the major prawn species with relative abundance of 3% among the prawn
landings.

51. Crab diversity and fisheries in Sundarban
Crab fishery resources of Sundarban are supported
by marine, estuarine, brackish water
and freshwater species.
During November 2015 to March 2016, 9 species of
marine and estuarine crabs, belonging to seven
genera and five families were recorded from
selected stretches of Sundarban viz. Nischintapur,
Patharpratima, Frazerganz, Jharkhali, Bally,
Jatirampur and Pakhirala.

52. Scylla serrata represented the largest known edible and highly valued
economic species of the Indo-Pacific region, both in domestic and
international markets; marketed live.
The professional crab fishers employ mainly four types of gears, viz., Sik or
hook, don (suti) or baited line, Chakjaal (a trap) and monofilament nets with
baits exclusively for capturing Scylla serrata in the deltaic Sundarban.
Hence, Scylla serrata was found dominant in commercial catch in all the
stretches of Sundarban.
However, various types of nets are mainly used to catch fishes in
the estuary by the local fishermen, also to trap crabs as supplementary or
by-catch. Such nets include bag nets, cast nets, Charpatajaal or set barrier
net.
Charybidis orientalis was most dominant (~79% of the total catch
composition of crab) in the catch of bag net with size ranging from 0.5 cm to
2.5 cm followed by Matuta planipes (10%), Varuna
litterata (7%), Scylla serrata (2%) and Philyra sps. (1%) as by-catch and
these species do not have any commercial importance.

55. Reference
• CIFRI bulletins
• CIFRI annual reports