Small lagoon at Vembanad Lake in the Kumarakom region of Kottayam, Kerala, India
_th place in Biotope Aquarium Design Contest 2020
Volume: 54 L
Dimensions: 48x36x36 cm
List of fishes: Carinotetraodon travancoricus (Hora & Nair, 1941) (VU), Aplocheilus lineatus “Gold variety” (Valenciennes, 1846)
List of plants: Nymphoides hydrophylla, eleocharis acicularis
Description of decorations: Red Jasper stone, Orange quartz stone, Orange quartz gravel 3-5mm, gray fine sand, red Moor Wood, walnuts fruit and various leaves.
Description of equipment: Low tec aquarium with a spong filter running with Aquanova NA – 100, Aquanova heater NHA – 75w and a led flood light 20w cool white.
Water parameters: Tempeature 28c, pH 7.8, GH 12, KH 9, NH3 0 , NO2 0, NO3 0
Additional info: –
INFORMATION ABOUT BIOTOPE:
Description of the area surrounding the biotope: The small lagoon is at the East coast of Vembanad Lake (9.607484 76.429895) under the St. John Nepumseanos Church Shrine, near the Kumarakom Bird Sanctuary Observatory Tower. Half of the laggon (East side) is under palm and other trees and the other side has a small strip of grass that separates the lagoon from the Lake.
Description of the underwater landscape of the biotope: The small lagoon fills with water every time the level of the lake changes, not more than 50-60cm depth, lake water is cloudy and the bottom muddy from the uncontrolled mining of shells but at this small system the water stays transparent , eleocharis find the space to grow and the surface is almost full of nymphoides, many branches of the surrounding trees have dropped in to the lagoon, redish gravel have moved here from the rivers around.
Description of the parameters of the habitat: The average temperature was 29.0ºC, average salinity was 19.02% highest salinity was observed in the month of April, the average transparency was 71.60 cm and the lowest dissolved oxygen was observed during the month of March 3.8 mg/l, pH was observed maximum in the month of May (8.1) and minimum (6.2) in the month of October. The average alkalinity was 90.98 mg/l, Nitrate ranged between 16.3µg/l and 4.7µg/l and average of 9.56µg/l. Phosphate ranged between 1.01µg/l to 5.8µg/l
List of fishes and invertebrates occurring in the nature biotope: Anguilla bicolor(NT), Xenentodon cancila, Hyporhamphus xanthopterus(VU), Stolephorus indicus, Amblypharyngodon melettinus, Amblypharyngodon mola, Catla catla, Dawkinsia filamentosa, Laubuka dadiburjori, Labeo dussumieri, Labeo rohita, Puntius amphibius, Puntius vittatus, Rasbora daniconius. Systomus sarana, Aplocheilus blockii, Aplocheilus lineatus, Aplocheilus panchax, Chanos chanos, Chelon planiceps, Mugil cephalus,
Ambassis ambassis, Parambassis dayi, Parambassis ranga, Parambassis thomassi, Anabas testudineus, Channa diplogramma, Channa gachua, Channa marulius, Channa punctata, Channa striata, Etroplus maculatus, Etroplus suratensis, Oreochromis mossambicus, Oreochromis niloticus, Glossogobius giuris, Pseudosphromenus cupanus, Pseudosphromenus dayi (VU, Scatophagus argus, Nandus nandus, Brachirus orientalis, Arius subrostratus, Mystus gulio, Mystus vittatus, Clarias gariepinus, Heteropneustes fossilis, Ompok malabaricus, Wallago attu, Horabagrus brachysoma (VU), Mastacembelus armatus, Carinotetraodon travancoricus (VU), Fenneropenaeus indicus, Metapenaeus dobsoni, Penaeus monodon, Macrobrachium idella, Macrobrachium rosenbergii, Caridina naderjoni,
Scylla serrate, Villorita cyprinoides.
List of plants found in the nature biotope: Ischaemum vembanadense (EN) Dimeria copei, Eleocharis acutangula, E. geniculata, E. retroflexa, eleocharis acicularis, Fimbristylis dichotoma ssp. glauca and
Fuirena umbellata, Eichhornia crassipes,Farmeria metzgerioides (VU), Willisia selaginoides, Rotala cookii, Limnopoa meeboldii, Nymphoides macrospermum (CR),Dimeria hohenackeri (EN), Fimbristylis hirsutifolia (CR)
Threats to the ecology: Vembanad Lake is the longest lake in India, fed by 10 rivers flowing into it including the six major rivers of central Kerala. The Vembanad Wetland system was included in the list of wetlands of international importance, as defined by the Ramsar Convention for the conservation and sustainable utilization of wetlands in 2002. Since it is a transitional ecotone lying parallel to the Arabian Sea and encompassing mangroves, mudflats, swamps and marshes, as an ecosystem, provides a harsh environment. Therefore many species of fish have found it to be an ideal place for spawning,
development and growth during their early life. Vembanad Lake is among the most productive life- supporting coastal wetlands in Kerala, having length of 96 km and surface area of 1512 km2 . Six riversbring freshwaters into Vembanad Lake and it has two permanent opening to the Arabian Sea, one at
Cochin and other at Azhikode . Fishes are living components of water bodies and are important food resource and bio indicators of the environmental health and wealth of the waters in which they inhabit. Globally aquatic ecosystems and fish diversity are adversely affected due to increase in unwise
anthropogenic activities such as untreated discharge of pollutants into a river from domestic sewage, storm water discharges, industrial waste waters, agricultural runoff and other sources all of which can have short term and long term effects on the water quality. Furthermore, decline in estuarine diversity as a result of overfishing, insufficient management practices and habitat degradation, reduces the chances of its sustainability. Fisherfolk are the primary stakeholders at Vembanad Lake and have always been actively involved in conservation efforts and the management of the resources they rely on every day. Today, tourism is a huge source of income at Lake Vembanad thanks to the idyllic backwaters. Houseboats are by the dozen, even causing traffic jams, and tourists have little or no ownership of the area to keep it clean. While people are willing to pay serious money to come to this part of Kerala and drift along the idyllic backwaters in the name of “ecotourism”, the relentless increase in the number of houseboats and the tourists that use them simply exacerbates the ecological threat to the lake. In addition, the sewage effluents and the heavy load of organic material released from the neighboring
areas including a medical college at Alappuzha are responsible for the decrease in dissolved oxygen content in the water in the water body. Another notable conflict of interest has arisen from the fact that vast areas of paddy fields have been reclaimed on Vembanad Lake. Since Vembanad flows into the
ocean, a narrow barrage has been constructed to regulate the flow of freshwater from the lake into the sea and vice versa. The authorities in the area seem to favour the paddy cultivators by keeping the shutters of the barrage closed so saline water doesn; it flow into the lake. This benefits the paddy farmers but does not benefit the fisherfolk, who are the original community that depended on the lake for their livelihoods. The more saline water that flows into Vembanad, the better it is for the diversity of fish in the lake; now there is an unfortunate conflict of interest between the two livelihoods. Other causes for the Vembanad ecosystem is declining health are the obstruction of river courses, sand mining and habitat destruction, loss of riparian canopy cover, encroachment, pollution and unethical fishing practices. Vembanad Lake is also facing ecological problems due to the rampant propagation of water hyacinth, an aggressive plant that spreads over the surface of the lake, covering large areas of water and thus depleting oxygen and sunlight. Other plants and vegetation die due to lack of sunlight, while fish and other aquatic life forms die due to lack of oxygen. Water hyacinth is considered by some to be nothing more than a pest plant; it has little or no known nutritional value to wildlife or aquatic ecosystems.
Sources of information:
- Bleher’s Biotopes by Heiko Bleher