Backwater Ecosystems

The Kerala backwaters are a network of brackish lagoons and lakes lying parallel to the Arabian Sea coast (known as the Malabar Coast) of Kerala state in southern India, as well as interconnected canals, rivers, and inlets, a labyrinthine system formed by more than 900 kilometres (560 mi) of waterways, and sometimes compared to American bayous.[3] The network includes five large lakes linked by canals, both man made and natural, fed by 38 rivers, and extending virtually half the length of Kerala state. The backwaters were formed by the action of waves and shore currents creating low barrier islands across the mouths of the many rivers flowing down from the Western Ghats range. In the midst of this landscape, there are a number of towns and cities, which serve as the starting and endpoints of backwater cruises.

1. Backwater Ecosystems

2. contents Definition Important backwaters of World Ecotourism Important backwater ecosystems of Kerala Genesis of backwater systems Vembanad backwater ecosystem Physico chemical parameters Fauna and flora Astamudi backwater ecosystem and its fauna & flora Socio economic significance of backwaters Threats to ecosystem Major Threats to fisheries Measures taken for protection of Kerala backwaters References

3. What is a backwater ? A  backwater  is a part of a river in which there is little or no current. It can refer to a branch of a main river, which lies alongside it and then rejoins it a body of water in a main river, backed up by the tide or by an obstruction such as a dam It is a large network of natural lakes , inlets of oceans and natural/manmade canals connected each other and forms a large water body inside the land e.g. Kerala backwaters

4. Backwaters are a part of coastal wetlands system . Coastal wetlands include sand or pebble shores, estuarine lakes and lagoons, coastal floodplain forest, dune swamps, mudflats, coastal lakes, coastal floodplains, mangrove and saltmarsh swamps. Wetlands also called as Nature’s kidney . Wetland function and values Habitat for fish, wildlife and plants Habitat for fish, wildlife and plants Natural water quality improvement and biogeochemical cycling Flood protection Shoreline erosion Economic benefits of natural services and products at little or no cost Recreation ,education and research

5. BACKWATERS OF WORLD Backwaters of Kerala are a major tourist attraction over the world and it may be considered as one of the unique tourism products of the state Kerala. The state has 30 backwater areas in different districts spreading over 900kms. The important backwaters in India which constitute a sizeable fishery are Cochin backwaters , Vembanad backwaters, Kakinada backwaters and Killai backwaters The other backwater areas of the world are 1.Venice –Italy 2. Bay area, California- USA 3. Danube delta wetland – Romania

6. It’s a shallow body of brackish water situated in Tamil Nadu state between the Vellar and Colleroon ( Kolli dam) estuaries and extends to about 16 km in the north-south and 5 km in the east-west. It has a permanent connection with the Bay of Bengal. About 100 tonnes of prawns are landed annually. The prawn species in the order of abundance include F. indicus, Penaeus monodon and Metapenaeus dobsoni . Macrobrachium rosenbergi is found from October to December indicating that they migrate to estuary for breeding. Prawns are caught by stake nets, cast nets and drag nets. It extends from Kakinada in the north to the Gautami Godavari in the south They border the Kakinada bay on the east and covers an area of about 330 km2 The two rivers viz. the Coringa and the Gaderu rivers discharge their water in the Kakinada bay The entire backwater area is traversed by a network of tidal creeks which are directly or indirectly connected to the Kakinada bay Prawn fishery dominates the Kakinada backwaters. The important prawn species include Metapenaeus dobsoni , M. monoceros, M. affinis , M. brevicornis , F. indicus and P. monodon. KILLAI BACKWATERS KAKINADA BACKWATERS

7. ECOTOURISM Kerala was listed among “ 10 paradises on the world ’’ and " 50 must see destinations of a lifetime " by  National Geographic traveler magazine. The major component of back-water tourism is the houseboat cruising . It attracts a large number of international and domestic tourists. The “Venice of east” Alappuzha has become the hub of back water-based tourism activities. At present more than 2000 houseboats are operating in Vembanad Lake.

8. Kerala backwaters The Kerala Backwaters are a network of interconnected canals, rivers, lakes and inlets, a labyrinthine system formed by more than 900 km of waterways. Of the 44 rivers in Kerala, 41 flow westward from the Western Ghats to the Arabian sea through backwaters. Major rivers are Periyar (5400 km2, 244 km) and Chalakudy (1700 km2, 130 km) on the north and Pamba (2250 km2, 76 km), Achankovil (1500 km2, 128 km), Manimala (850 km2, 90 km), Meenachil (1250 km2, 78 km) and Moovattupuzha (1550km2, 121 km) in the southern region ( MaIlik and Suchindan , 1984) . The backwaters were formed by the action of waves and shore currents creating low barrier islands across the mouths of the many rivers flowing down from the Western Ghats range.

9. The chain of brackish lagoons and lakes lie parallel to the Arabian Sea coast. The most potential area in the Kerala backwaters is the Kuttanad region , which is also known as the rice bowl of Kerala. It is also called by the name Holland of Kerala for the reason that like Holland, Kuttanad too is a region which is saucer shaped lying below sea level. It is probably the only place in the continent where farming is done below sea level(1.2-3m below MSL) , using a system of dykes and bunds. Continued.. National Waterway No. 3 from Kollam to Kottapuram , covers a distance of 205 km and runs almost parallel to the coast line of southern Kerala facilitating both cargo movement and backwater tourism .

10. Backwater Resources of Kerala Kozhikode has backwaters which are largely “unexplored” by tourist hordes. Elathur , the Canoly Canal and the Kallayi River are favourite haunts for boating and cruising. Other backwaters are Korapuzha , (the venue of the Korapuzha Jalotsavam ), Payyoli backwater, Beypore estuary and Kadalundi estuary. In Kannur there are 5 namely Kava backwater, Dharmapatanam backwater, Mannayed estuary, Mahe estuary and Kattampally backwaters. Kasargod known for rice cultivation, coir processing and lovely landscape has the sea to the west and the Western Ghats to the north and east. It has 2 backwaters named Karingote estuary and Nileswar backwater .

11. Genesis of Vembanad Backwater system According to geological records most of the worlds barrier-beach-lagoon systems had their origin during the post-glacial sea level rise, 5000-6000 years ago. However, the Vembanad Lake extending between Alleppey and Azhikode (between latitude 9°30' and 10°12' and longitude 76°10' and 76°29') now a typical estuarine system, which is the largest Westcoast estuarine system of India. It is believed to have attained its present configuration in the 4th century A.D., according to historians (Anon., 1973). Geomorphologically, all the sectors of the existing backwaters may not be of common origin

12. Vembanad lake

13. Aroor Arkooti

14. Cochin backwater Kumarakom backwater 12440 ha 8610 ha

15. Vembanad Backwater Ecosystem An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are linked together through nutrient cycles and energy flows. The backwaters have a unique ecosystem - freshwater from the rivers meets the seawater from the Arabian Sea.

16. Contd.. In certain areas, such as the Vembanad Kayal, where a barrage has been built near Kumarakom, salt water from the sea is prevented from entering the deep inside, keeping the fresh water intact. Such fresh water is extensively used for irrigation purposes in kuttanad region. Many unique species of aquatic life including crabs, frogs and mudskippers, water birds such as terns, kingfishers, darters and cormorants, and animals such as otters and turtles live in and alongside the backwaters. Palm trees, pandanus shrubs, various leafy plants and bushes grow alongside the backwaters, providing a green hue to the surrounding landscape. The backwaters contribute productive ecosystem and the total fish landings from Kerala backwaters vary from 14000-17000tonnes/year. 88000 tonnes of live clams and 0.17 million tonnes of dead molluscs shells are collected manually. Thannermukkom bundh

17. Climate Being situated in the humid tropical monsoon belt,there is high rainfall and humidity. 2 rainy season southwest and northeast monsoon Mean annual rainfall 2500-4000mm Soil Sandy to sandy loam with alluvial deposits in lowlands bordering arabian sea Alluvial and peaty soil dominate backwater These peaty soils are black and acidic, PH sometimes as low as 3.9 and become highly toxic to biota

18. Physico-chemical parameters influencing productivity

19. SPECIES DIVERSITY

20. Source: (Thomson et al 2001)

21. Finfish and Shellfish diversity Vembanad backwater was declared as a Ramsar site (Ramsar site no.1214), a wetland of international importance declared in august 2002 Fishes are mainly oligohaline. Marine penaeid prawns, clams like Villorita cyprinoides and Mertrix meretrix are exploited About 32.5% of the fisherman population of the state is concentrated on the banks of the lake 5000 tonnes of fish and almost same quantity of prawns, and 300-400 tonnes of giant freshwater prawn-production per year 214 species of crustaceans, either adults or larval forms, belonging to Copepoda , Ostracoda, Cladocera, Amphipoda, Isopoda and Decapoda have been recorded from Vembanad Lake Villorita cyprinoides (black clam) Mertrix meretrix

22. 39 of gastropods belonging to 24 families 45 species of bivalve belonging to 17 families including the doubtful occurrence of three bivalves, namely Tellina ( Angulus ) rhodon , Pandora flexosa and Nuculona mauritiana . There are also found a few species of freshwater snails viz., Bellamya bengalensis, Melanoides (= Thiara ) tuberculata , Thiara scabra and lndoplanorbis exustus from Kumarakom areas of the lake in Kottayam district of Kerala. Estimated finfish and shell fish production (tonnes) from Vembanad wetland during August 2012 to July 2013 period. (Asha et al., 2014)

23. Mangrove ecosystem of vembanad lake

24. The entire backwater area including Vembanad Lake earlier had mangrove vegetation Most of the mangroves have now been destroyed, and only a few isolated pockets of stunted Rhizophora and Sonneratia are still observed. ( 700sq.km 50 sq.km) Pathiramanal island is poor in mangrove vegetation due to human habitation . The extent of mangrove patches at Kumarakom includes 5 ha at KTDC area, 2.5 ha at Kari and 3 ha at Nalupanku areas dominated by Rhizophora, Avicennia and Acanthus species respectively. Patches of mangrove may be seen at Cherthala, Vayalar and Chanthirur along filtration ponds, canals and backwaters of Alapuzha district. Vaikom, Vechoor and Kulasekharamangalam areas of Kottayam district support some pockets of mangrove

25. Ashtamudi Backwaters The Ashtamudi Lake has been designated as a Ramsar Site (No.1204) August 2002 and is also a major tourist place. Ashtamudi being the second largest estuarine system in Kerala covers an area of about 32 km2 It has eight major creeks known by different names. The Kallada River originating from the Western Ghats empties into the estuary at Arinalloor after traversing for about 120km. It has a permanent connection with the adjoining Arabian Sea at Neendakara which is an important fishing harbour . The salt penetration is evident up to Uppukootu , a place several km upstream.

26. The estuarine system is divided into 4 zones as shown in figure 91 species belonging to 39 families which comprises 68 species finfishes, 5 species of crabs and 9 species each of prawns and Molluscs Of the 68 species of fishes, 24 typically marine, 9 typically freshwater and four, typical estuarine. The rest were transient forms inhabiting estuarine-riverine (8 species), marine-estuarine (19 species) and marine-estuarine-riverine (4 species). Etroplus suratensis and Mugilidae support a good fishery in this estuary. Mullets Etroplus

27. Astamudi estuary, particularly the Kureepuzhakayal , supports a gobioid fishery based on the species Oxyurichthys tentacularis , (local name Koozhali ). A modified gill net, “ koozhalivala ”, is used for its fishing. Gill net is the major gear (used for different type of fishes: njanduvala , chemmeenvala , koozhalivala , choodavala , neetuvala , chalavala , vaisalivala andnandanvala ). Chinese and stake nets are the two main destructive methods of fishing employed in the lake. Stake nets are used in the estuarine area. The most dominant species in the Ashtamudi Lake clam fishery zone is Marcia recens which was misidentified as Paphia malabira (short neck clam) The latest in-depth taxonomic study points to the clam having been misidentified from the very beginning. According to the finding of the team from Department of Aquatic Biology and Fisheries, University of Kerala, and Graham Oliver of National Museum Wales, United Kingdom, the Ashtamudi short-neck clam belongs to a totally different genus, while its rightful scientific name actually is Marcia recens .

28. The fish caught from its waters, the paddy, coconut and other crops harvested along its banks, the boats they build and use to transport them across the labyrinthine backwaters, are all an integral part of their traditional way of backwater village life. Fishing, along with fish curing is an important industry. These particular processed product made is marketed in different places. Kerala backwaters have been used for centuries by the local people for transportation, fishing and agriculture Boat making has been a traditional craft, so has been the coir industry . Kuttanad is crisscrossed with waterways that run alongside extensive paddy fields, as well as fields of cassava, banana and yam. A unique feature of Kuttanad is that many of these fields are below sea level and are surrounded by earthen embankments. SOCIO ECONOMIC SIGNIFICANCE

29. Problems in Kerala backwaters

30. Impact of shrinkage on resources

31. Impact of Thannermukkom barrier

32. Reports on the Vembanad ecosystem had pointed out that electrocution, poisoning and use of explosives were common in the Vembanad Lake, which is home to 150 species of fishes. use of  adakkamkolli , which roughly translates into ‘kill-all’ nets and virtual bottom trawling using small mesh nets were destroying juveniles in sizeable quantities that the future of varieties such as pearlspots ( karimeen ) was seriously threatened. Ettamkettu  or trapping of fish in the landward side during high tides had been detected in some places close to Kochi, sources in the fisheries department said. laying of  padal   or secured artificial shelters that trap both adults and juveniles. This method was unique to Astamudi backwaters.

33. INITIATIVES TOWARDS THE PROTECTION OF KERALA BACKWATERS

34. References U. K. GOPALAN, DOYIL T. VENGAYIL, P. UDAYAVARMA AND M. KRISHNANKUTTY, THE SHRINKING BACKWATERS OF KERALA , J. mar. biol. Ass. India, 1983, 25 (1 & 2): 131 -141 Editor-Director. 2009. Faunal Diversity of Vembanad Lake - A Ramsar site in Kerala, India, Wetland Ecosystem Series,10 : 1-192. (Published by the Director, Zool. Surv . India, Kolkata) Thomson, K.T., 2002. Economic and social issues of biodiversity loss in Cochin backwaters. In Technical report (pp. 51-82). Cochin University of Science and Technology Cochin, India. Vijaya Krishna, A. and Ammini , P., 2018. Population characteristics of Villorita cyprinoides in Vembanad Lake, India.  Lake and reservoir management ,  34 (2), pp.130-140. Leena Grace, B., 2014. Biodiversity of Three Backwaters in the South West Coast of India. International Journal of Biodiversity , 2014 . www.Wikipedia.org envt.kerala.gov.in/state-wetland-authority- kerala - swak envt.kerala.gov.in https://www.keralatourism.org/responsible-tourism Newspaper Articles