Along the banks of the Pamba river, Kerala, India

71th place in Biotope Aquarium Design Contest 2019

Belgium. Xavier Bourdet

Volume: 75 L
Dimensions: 60х36х45 cm
List of fishes: Carinotetraodon travancoricus
List of plants: Cabomba caroliniana
Description of decorations: The substrate consists of a layer of sand covered with organic debris and plant debris, both produced by the aquariums ecosystem. Terminalia catappa leaves and branches litter the bottom to replicate fallen riparian vegetation, Cabomba caroliniana is forming a dense growth.
Description of equipment: Lighting: 21W integrated Superfish LED. Filtration: External 2-stage filter (Superfish X-Pro 400): Activated carbon, CrystalMax, BioBalls and filter foam. Water-flow is 400 l/h, filter has a volume of 5.8 l. Heating: JBL ProTemp S 100.
Water parameters: The aquarium is kept at a temperature of 30°C (based on the Pamba river average water temperature), pH has a value of 7, gH has a value of 4.
Additional info: –

INFORMATION ABOUT BIOTOPE

Description of the area surrounding the biotope: The Pamba river is the third longest in Kerala state with 176 km length. The river cuts across a diverse array of ecosystem settings from montane temperate grasslands, through moist deciduous and evergreen forests to a mangrove-lined estuary. Like all the river basins in Kerala, the Pamba basin also can be divided into three natural zones based on elevation, consisting of low land or seaboard, midland and high land. The coast for a short distance along the borders of lakes is flat, retreating from it the surface roughens up into slopes which gradually combine and swell into mountains on the east. The low land area along sea coast is generally swampy and liable to be flooded during monsoon inundation. The plains/midlands succeed low land in gentle ascents and valleys interspersed with isolated low hills. The high land on the eastern portion is broken by long spurs, dense forests, extensive ravines and tangled jungles. Towering above all their slopes are Western Ghats that form eastern boundary of the basins. The Pamba river basin has an area of 2082.80 km2, including 50.59 km2 Lowland, 238.711 km2 Midland, 902.74 km2 Highland and 568.25 km2 Highrange. The reservoirs and drainage network of the river basin consists of 268.509 km2. The longest river stretch was 90km of midland stretch followed by Highrange (41km), Highland (35km) and lowland (10km), the vegetation profile of the riparian forests of Pamba river basin correlated with this divergence and showed clustering of evergreen species in the highrange and highland stretches of the river. River Pamba, venerated as southern Ganga, originates at the Pulachimalai hill in the Peermedu plateau of the Western Ghats at an altitude of 1650 m and drains into the Vembanad Lake after nourishing many places. Pamba River nourishes hundreds of medicinal plants in the mountain ranges where it originates and carries its boons to everywhere it flows. Let us have a glimpse of some of the best known places and events on its banks. The sandy banks of river Pamba witnessed the emergence and growth of many cultural and religious centres. Sabarimala temple amid luxuriant forests and grasslands is the most popular religious center in Kerala for the Hindus and it is intimately connected to the river Pamba. Bathing in the river, believed to absolve one’s sins, is a requirement before commencing the trek to the shrine at Sabarimala. Cherukolpuzha Convention is an important religious convention of the Hindus held at Cherukole on the sand banks of a river Pamba, usually in February every year. Started in 1896, the Maramon Convention is also held on the banks of river Pamba at Maramon near Kozhencherry in Pathanamthitta District. It is the largest Christian convention in Asia. Aranmula is a unique cultural village on the banks of river Pamba. The ancient Parthasarathy temple, the annual regatta of snake boats during the festival of Onam and the magnificent Aranmula Kannadi are but to name a few attractions here. Noted for outstanding beauty and shrouded in secrecy, the Aranmula Kannadi is considered a medieval marvel in the annals of metallurgy. The technical know-how of this metal mirror is confined to a few households of master craftsmen in the village of Aranmula. The Pamba River is a veritable signature of a rich culture that continues to nourish the imagination, wisdom and happiness of many in its vicinity.

Description of the underwater landscape of the biotope: The Pamba river is mostly a clearwater river, turbidity in the water reduces the transparency due to the presence of particulate matter such as clay or silt, finely divided organic matter, plankton or other microscopic organisms. The river has different types of water flow such as stagnant water, slowflowing water, fast-flowing water and rapid water, with different grades of substrate such as silt, sand, clay, stones, boulders and bedrock. Observations on the habit of C.travancoricus in its natural habitat in river Pamba indicated its dominance in areas where Cabomba plants aggregated. Aquatic plants provide habitats containing food resources for both juvenile and adult fish. Their long stems and leaves support macro invertebrates in rivers and lakes and plant beds supply additional nutrients to support a diverse group of benthic macro organisms. Many juvenile fishes select structurally complex habitats, such as submerged vegetation, in response to predation risk. However, structurally complex habitats can reduce foraging return and growth rate of juvenile fishes. In the Pamba river, the major planktonic organisms collected from various stretches in the river were Anabena, Ankistrodesmus, Chlorella, Navicula, tintinnids, Pleurosigma and Microcystis. Benthic population consisted of Chironomus larvae, polychaetus(Dero sp. Nereis.sp), Tubifex sp, insect larvae, gastropods and bivalves. The algal and benthic biomass and diversity is generally low in most of the stretches.

Description of the parameters of the habitat: The average temperature ranges from 29.1°C to 31.7°C, with a minimum range of 29°C and a maximum range of 32.1°C. pH range is acidic, the average range in all seasons of pH ranges from 6 to 6.01. Transparency range showed variations in all the seasons, the average range of transparency is 16.3 to 21.1cm. In the pre-monsoon season the hardness ranges from 12 mg/l to 22 mg/l, in monsoon season the hardness is nearly 10 mg/l to 20 mg/l, in post monsoon season the hardness ranges from 14 mg/l to 18 mg/l. Salinity of the water in the pre monsoon season ranges from 3.22mg/l to 5.78mg/l, salinity of the water in the monsoon season ranges from 3.2mg/l to 5.7 mg/l, salinity of the water in the post monsoon season has a minimum range of 4.18mg/l and a maximum range of 6.4mg/l. Ammonia of the water in the pre monsoon season ranges from 42.5 mg/l to 59.5 mg/l, in monsoon season the minimum range is 38 mg/l and a maximum of 55.5 mg/l, ammonia of the water in the post monsoon season range from 34 mg/l to 51 mg/l. Carbon dioxide of the water in pre monsoon season has a minimum range of 4.4 mg/l and a maximum range of 7.9 mg/l, in monsoon season the carbon dioxide of the water has a minimum of 5.2 mg/l and a maximum of 7.9 mg/l, carbon dioxide of the water in post monsoon season ranges from 4.4 mg/l to 12.3 mg/l. Dissolved oxygen of the water in the pre monsoon season has a minimum range of 4 mg/l and a maximum range of 5 mg/l, dissolved oxygen of the water in monsoon season range from 7.3mg/l to 9.6 mg/l, dissolved oxygen of the water in the post monsoon season has a minimum range of 7.04 mg/l and a maximum range of 8.3 mg/l. (All the water parameters are based on the most recent data that was found)

List of fishes and invertebrates occurring in the nature biotope: Pamba river is one of the longest river systems of Kerala. There are 60 species of fish reported from the river, 26 species, belonging to 5 orders and 21 genera contributed to the exploited fishery. The fish are catogorised into 3 groups: Cultivable: Anguilla bengalensis, Cyprinus carpio, Cirrhinus mrigala, Labeo dussumieri, Labeo fimbriatus, Catla catla, Tor khudree, Horabagrus brachysoma, Heteropneustes fossilis, Etroplus suratensis, Channa marulius. Ornamental: Osteobrama bakeri, Puntius amphibius, Puntius bimaculatus, Puntius denisonii, Puntius vittatus, Puntius fasciatus, Puntius filamentosus, Puntius ticto, Amblypharyngodon microlepis, Barilius bakeri, Barilius gatensis, Danio malabaricus, Danio aequipinnatus, Rasbora daniconius, Garra mullya, Garra hughi, Garra surendranathanii, Bhavania auatralis, Mesonemacheilus triangularis, Mesonemacheilus guentheri, Lepidocephalus thermalis, Ompok bimaculatus, Wallago attu, Parambassis thomassi, Nandus nandus, Pristolepis marginatus, Etroplus maculatus, Carinotetraodon travancorius. Food fish: Gonoproktopterus curumca, Puntius chola, Puntius sarana subnasutus, Salmostoma acinaces, Salmostoma boopis, Garra ceylonensis, Bataso travancoria, Mystus gulio, Mystus armatus, Mystus menoda, Xenentodon cancila, Parambassis dayi, Glossogobius giuris, Anabas testudineus, Channa striatus, Channa orientalis, Channa diplogramma, Macrognathus aral, Clarias dussumieri, Mastacembelus armatus, Clarias gariepinus. Invertebrates: Paludomus annandalei, Caridina chauhani, Vanni deepta.

List of plants found in the nature biotope: The Pamba river has a vast amount of riparian flora, but only a few are true aquatic plants, these are divided into different statuses: Invasive: Salvinia adnata, Cabomba caroliniana, Pistia stratiotes, Eichhornia crassipes. Naturalised: Marsilea minuta, Ceratopteris thalictroides, Nymphaea nouchali, Nymphaea pubescens, Nymphoides cristata, Nymphoides indica. Naturalised or Invasive: Limnocharis flava. Endemic: Aponogeton appendiculatus.

Threats to the ecology: The habitat of Carinotetraodon travancoricus is severely modified by damming, indiscriminate de-forestation and subsequent conversion of forest area into agricultural plantations. This species is also a famous aquarium fish, and capturing the species for aquarium trade is a threat. The major disturbances along the riparian stretches of Pamba river basin include both long term (dams, bridges, road, channel diversion, settlements and plantation) and short term (sand mining, embankment, cultivation, vegetation clearing, bank erosion, weed infestation and waste deposition). It was observed that, sand mining has been prevalent in lowland stretches of the Pamba river, which drastically alters the floodplain structure causing bank erosion and destruction of natural riparian vegetation. Along the riparian zones in midland stretches, water-dispersed plants and rapidly spreading exotics colonized the depositional floodplains. The distribution of invasive exotics concentrated in midland and lowland stretches of the Pamba river basin. This is corroborated with the observation that exotic plant species generally associated with disturbed environments. On top of that on 16 August 2018, severe floods affected the south Indian state of Kerala, due to unusually high rainfall during the monsoon season. It was the worst flood in Kerala in nearly a century. Over 483 people died, and 14 are missing.

Sources of information:
Biotope information:
https://www.fishbase.se/summary/25293