Indian J. Fish., 58(3) : 13-22, 2011 13 Exploited fisheries resources of the Pampa River, Kerala, India C. R. RENJITHKUMAR, M. HARIKRISHNAN AND B. MADHUSOODANA KURUP* School of Industrial Fisheries, Cochin University of Science and Technology, Fine Arts Avenue Kochi - 682 022, Kerala, India *Kerala University of Fisheries and Ocean Studies, Panangad P. O., Kochi - 682 506, Kerala, India e-mail: [email protected] ABSTRACT River Pampa is one of the longest river systems of Kerala. Out of the 60 species of fishes reported from the river, 26 species, belonging to 5 orders and 21 genera contributed to the exploited fishery. The landings were represented by one endangered (Gonoproktopterus curumca), two each vulnerable (Horabagrus branchysoma and Channa diplogramma) and near threatened (NT) fish species (Wallago attu and Ompok bimaculatus). The annual average landings from this river was estimated to be 394.22 t. Highest landings were recorded during pre-monsoon season (194.48 t) and lowest in monsoon (38.97 t). Labeo dussumieri (75.98 t), Puntius sarana subnasutus (39.61 t), W. attu (37.65 t), Channa striatus (36.34 t) and Amblypharyngodon microlepis (34.32 t) were the dominant fishes in the landings. Catla catla (17.28 t) and Clarias gariepinus were the exotic species observed in the landings. Macrobrachium rosenbergii was the most priced species used for export. Among the landing centers, Parumala accounted for 65.3% of total landings, followed by Edathua (14.5%). About 77% of exploited fishery was accounted from the gillnets followed by seines (19%), castnets (3%) and hooks and lines (1%). Highest catch per unit hours (CPU) was recorded in seines in respect of A. microlepis (2.40 kg unit-1). The major fishery resources, fishing methods, catch per unit hour and various biodiversity threats prevalent in the Pampa River system are discussed in this paper. Keywords: Biodiversity status, Exploited fishery, Pampa river, Quantification Introduction Randatinkara and Edathua (Fig. 1), where regular systematic surveys and sampling were conducted during Pampa River is one of the longest rivers in Kerala pre-monsoon, monsoon and post-monsoon seasons during (179 km) which spreads as an arterial network in Kuttanad, 2007-2009. Details of landings were collected from more the extensive low lying agricultural fields of the state. than 30% of the gears, giving emphasis to type of gear, Ichthyofaunal investigations in the rivers of Kerala had mesh size, species composition and weight, size groups drawn attention with the outstanding works of Jerdon represented in the catch, actual fishing hours and man (1849), followed by the classical work of Day power engaged. Selection of fishing units for detailed (1865;1878;1889), Pillai (1929), John (1936), Hora and observation was done following Alagaraja (1984) and Nair (1941), Chacko (1948), Silas (1951;1952), Menon Kurup et al. (1992). Catch Per Unit Effort (CPUE) was (1951), Thobias (1973), Antony (1977), Remadevi and Indra (1986), Kurup et al. (1994; 2000; 2006), Easa and Basha (1995), Easa and Shaji (1997), Ajith Kumar et al. (1999) and Gopi (2000). Among 174 fish species known from various rivers of the state, 55 are reported from the Pamba River (Radhakrishnan, 2006). Information on fish production from any water body is important for its judicious exploitation and management. This paper is a pioneer attempt in this direction and provides details of exploited fishery resources of Pampa River. Materials and methods The exploited fishery of Pampa River was estimated based on the data generated from major landing centres, Neeratupuram, Chakkulam kadavu, Parumala, Pavukkara, Fig. 1. Map of Pamapa River showing sampling locations C. R. Renjithkumar et al. 14 computed following Scaria et al. (1997). Fish samples Table 1. Inventory of fish species of Pampa River and their collected were preserved in 8% formalin and brought to biodiversity status the laboratory for species level identification following Species Cultivable/ Biodiversity Endemism Day (1878), Talwar and Jhingaran (1991), Jayaram (1999) Ornamental/ status and Radhakrishnan (2006). Daily landings from each type Food fish (IUCN) of gears and fishing methods were computed following Kurup et al. (1992). Anguilla bengalensis Cultivable LC - Cyprinus carpio Cultivable VU EX W = (w/n) X N Cirrhinus mrigala Cultivable LC TR where W = total weight of fish, w = total weight of Gonoproktopterus curumca Food fish EN EN-WG fish from gear sampled Labeo dussumieri Cultivable LC EN-K Labeo fimbriatus Cultivable LC EN-IS n = number of gear sampled, N = total number of Catla catla Cultivable LC similar gears operated. Osteobrama bakeri Ornamental LC EN-K Monthly catch was estimated by multiplying daily Puntius amphibius Ornamental DD - catch with total number of fishing days in a month. Puntius bimaculatus Ornamental LC EN-WG Season-wise landing was estimated by multiplying monthly Puntius chola Food fish LC - catch to number of months in the season. The annual Puntius denisonii Ornamental EN EN-K exploited quantity was calculated by summarising the Puntius vittatus Ornamental LC - landings of three seasons. The fish species inventory was Puntius fasciatus Ornamental LC EN-WG prepared based on data collected as part of a previous study Puntius filamentosus Ornamental LC EN-WG (Kurup et al., 2005) and present observations. The Puntius ticto Ornamental LC EN-WG biodiversity status of such fishes was assigned following Puntius sarana subnasutus Food fish LC - IUCN (2010). Tor khudree Cultivable EN - Results Salmostoma acinaces Food fish LC EN-WG Salmostoma boopis Food fish LC EN-I Inventory of fish species of the River Pampa Amblypharyngodon microlepis Ornamental LC EN-I Sixty species of fishes belonging to 17 families and Barilius bakeri Ornamental LC EN-WG 36 genera were identified from Pampa River (Table 1). Barilius gatensis Ornamental LC EN-WG It was noted that five species each belonged to endangered Danio malabaricus Ornamental LC EN-IS and vulnerable category (8% each), three belonged to near Danio aequipinnatus Ornamental DD EN-IS threatened (5%), 39 least concern category (65%) and Rasbora daniconius Ornamental LC - 8 species were assigned with data deficient status (14%). Garra ceylonensis Food fish DD - (Fig. 2). Among the 60 species, only 26 species contributed Garra mullya Ornamental LC EN-I to the exploited fishery. Family Cyprinidae ranked first Garra hughi Ornamental EN EN-K among different fish groups with a numerical strength of Garra surendranathanii Ornamental EN EN-K 30 species followed by Bagridae with five species. Bhavania auatralis Ornamental LC EN-WG Mesonemacheilus triangularis Ornamental LC EN-WG Mesonemacheilus guentheri Ornamental LC EN-WG Lepidocephalus thermalis Ornamental LC EN-IS Bataso travancoria Food fish VU EN-K Horabagrus brachysoma Cultivable VU EN-K Mystus gulio Food fish LC - Mystus armatus Food fish LC EN-IS Mystus menoda Food fish DD EN-IS Ompok bimaculatus Ornamental NT - Wallago attu Ornamental NT - Heteropneustes fossilis Cultivable LC EN-IS Xenentodon cancila Food fish LC EN-IS Parambassis dayi Food fish LC EN-K Fig. 2. Biodiversity assessment of fish species in the River Pampa. Parambassis thomassi Ornamental LC EN-WG LC : Least concern, NT : Near threatened, Nandus nandus Ornamental LC - VU : Vulnerable, EN : Endangered, DD : Data deficient Pristolepis marginatus Ornamental LC EN-K Exploited fisheries resources of the Pampa River 15 Etroplus suratensis Cultivable LC EN-IS Quantification of exploited fishery resources Etroplus maculatus Ornamental LC EN-IS The average annual exploited fishery of the Pampa Glossogobius giuris Food fish DD - River was estimated at 394.22 t. Highest landings were Anabas testudineus Food fish DD - recorded during pre-monsoon season (194.48 t) whereas, Channa striatus Food fish LC EN-WG it was lowest in monsoon (38.97 t). The species-wise Channa orientalis Food fish DD - landings are given in Table 2. Labeo dussumieri, commonly Channa marulius Cultivable LC - known as ‘Thooli’ recorded the highest landings (19.27%) Channa diplogramma Food fish VU En-K in the river. This species supported a lucrative fishery year Macrognathus aral Food fish LC - around and sustained as the major source of livelihood Clarias dussumieri Food fish NT EN-I source to the fishermen. The size group 110-159 mm Mastacembelus armatus Food fish LC - dominated the landing. W. attu formed 9.55% of total Clarias gariepinus Food fish DD EX landings and the dominant size group was 300-990 mm. Tetradon travancorius Ornamental VU EN-K Channa striatus (36.34 t), C. marulius (30.06 t) and LC - Least concern, NT - Near threatened, VU - Vulnerable, EN-Endangered, C. diplogramma (0.79 t) formed other major groups in the DD - Data deficient fishery, constituting 17% of total landings. Genus Puntius EX: Exotic, TR : Transplanted, EN-G:- Endemic to Western Ghats, EN-IS : Endemic to Indian sub-continent, EN-I : Endemic to India, represented by three species viz., P. sarana subnasutus EN-K: Endemic to Kerala. (39.61 t), P. filamentosus (20.64 t), and P. amphibius (0.07 t) constituted 15% of total landings. The annual Exploited fishery landings of M. rosenbergii in the river was estimated at Twenty six fish species belonging to five orders and 27.05 t. The small-sized fish A. microlepis, commonly 21 genera were identified in the exploited fishery of Pamba known as ‘Vayambu’, formed a major fishery in the river River. The commercially important species, their local accounting 34.32 t in the landings. P. thomassi and P. dayi, names, and size ranges are presented in Table 2. Percentage the two species of glassy perchlets, were represented by contribution of various fish families to the total riverine size ranges 60-179 mm. P. dayi was more abundant during fishery is depicted in Fig. 3. Among 26 fish species recorded post-monsoon season. in the landing centres, family Cyprinidae was the most Among the six landing centres, Parumala contributed dominant group with 8 species (31%) followed by 65.3% to the total fish landing, followed by Edathua Channidae (11%).