 |
 |
| 8. ECOLOGY AND BEHAVIOUR OF SOME IMPORTANT FISHES Among 35 different ichthyofauna reported from Tinau River, some economically important fish species are described concerning their morphology, habitat, behaviour, fin formula etc. Tor tor (Hamilton) (Deep bodied Mahaseer) It is an important food and game fish which is called �Sahar� in Nepal. It inhabits in many snow-fed as well as other small hill streams of Bagmati, Bheri, Gandaki, Koshi, Lumbini, Narayani and Mechi zones (Shrestha, 1981). Generally body colour is silvery green or greyish green dorsally along upper half of the body, sides are slightly golden and the abdomen is silvery white with golden colour. It is a stoutly built fish with a deep body whose dorsal side is more convex and the head being shorter than the depth of the body. It has a fleshy mouth, the gape of which does not extend beyond the eye. It has two pairs of barbels, viz., maxillary and rostral among which former pair is longer. Lower fins are reddish orange in colour while that of the dorsal fin is slightly darker and the caudal fin is deeply forked. It attains a maximum size of about 1200 mm. This fish generally inhabits the deep pool-zone of Tinau river. It shows migratory behaviour in June/July towards upstream for breeding while the breeding season for this fish lies between August and September. It is omnivorous in habit feeding upon filamentous algae like Spirogyra, Oscillatoria, insects like mayfly (Ephimera) and small crabs (Cancer) etc. Fin formula: D. 3/9(12), P. 17, V. 9, A. 2/7(9), L.l. 25, L.tr. 41/2/41/2, B. 2 prs. Schizothorax plagiostomus Heckel (Spotted snow trout) It is commonly known as �Buche Asala� in Nepal. The body shape is elongated and slender. A suctorial disc or adhesive apparatus is present on the thorax. The body is extensively spotted with black dots on the background of greyish black on dorsal and silvery on belly and sides. It has four small barbels. The body is covered over by minute silvery scales. All the fins are with reddish tinge except dorsal and the caudal fin is deeply forked. It mostly occurs in Bagmati, Bheri, Dhaulagiri, Gandaki, Janakpur, Koshi, Lumbini, Mahakali and Seti zones (Shrestha, 1981). It attains a maximum size of 600 mm. It mostly prefers to live in clean water of Tinau River with swift flow, shallow and gravel riverbed which is the ideal spawning ground of this fish. It is herbivorous in nature feeding upon filamentous algae and small pieces of aquatic plants. The spawning period of this fish species begins in September. Fin Formula: D. 3/7(10), P. 16-17, V. 10, A. 2/5(7), C. 19-20, L.l. 105, L.tr. 24/23. B. 2 prs. Barilius bendelisis Var. Chedra (Hamilton) (Carp-minnow) It is commonly known as �Fageta� in Nepal. They are small sized fishes of which paired fins are enlarged, which, flesh and horizontally placed in males especially during breeding season. Colour if the body is silvery white with black spots on each scale except lateral line scales, where two spots are found. There are about 9 to 10 vertical dark bands on the body. Caudal fin is deeply forked, lower lobe being slightly longer. It is mostly distributed in the rivers of Bagmati, Bheri, Gandaki, Lumbini and Narayani zones. The maximum size recorded for this fish is 178 mm. This fish is very sluggish in habit (Hora, 1921 cited in Bhagat, 1985). Generally it inhabits in the low depth but the adult form occurs in rapids as well as pools of the streams. It is a resident fish species of Tinau river feeding upon insects, earthworm and green algae like Spirogyra, Oscillatoria etc. Breeding season of this fish starts from June to September. Fin Formula: D. 2/7(9), P. 14-15, V. 8, A. 3/8(11), C. 19, L.l. 43, L.tr. 3/31/2, B. 2prs. Barilius vagra (Hamilton) (Carp-minnow) It is commonly called �Fageta�. It is distinguished from other species by its mouth cleft extending up to middle of the eye and short vertical bands throughout the body. Upper jaw is slightly longer than lower jaw. Barbel two pairs one pair short maxillary, while other rostral extends up to half of the head length. Scales are of moderate size. Caudal fin is deeply forked. It is found in rapids and pools generally in groups. It attains a size up to 152 mm. It feeds upon large amount of algae and some insects and their larvae. The breeding season for this fish starts from June. Fin Formula: D. 2/7(9), P. 12-13, V. 9, A. 3/10(13), C. 19, L.l. 44-48, L.tr. 81/2/21/2, B. 2 prs. Noemacheilus beavani Gunther (Stone loach) It is commonly known as �Gadela�. It has tapering body with 9 to 10 brown vertical bands just behind head to the base of caudal. The general body colour is yellowish. A dark band is also present on the caudal base. Barbels are three pairs, viz., two pairs rostrals and one pair maxillary. Scales are minute and embedded in the skin. Generally dark bands are present on dorsal and caudal fins. Caudal fin is slightly forked. It is distributed in the hill streams of Bagmati, Gandaki, Koshi, Lumbini and Narayani zones (Shrestha, 1981). Generally it inhabits in the cold water of torrential streams while the fingerlings of this fish species prefer the shoreline of the stream. It feeds on crustaceans like Cyclopes, worm like Pheretima and algal materials like Oscillatoria. It is the resident species in the Tinau river, the breeding season of which starts from April to May. Fin Formula: D. 2/8(10), P. 10, V. 8, A. 2/5(7), C. 9, B. 3 prs. Noemacheilus botia (Hamilton) (Stone loach) It is commonly known as �Gadela�. It can be distinguished from other species by long barbels and 10 vertically molted bands from dorsal side towards lateral line. The maxillary pair of the barbels reaches up to the posterior boarder of the eye. The colour pattern slightly differs in adult specimens where these vertical bands become thin and broken into numerous small patches. Caudal and dorsal fins are tinged with black dots forming a distinct clear straight line in dorsal, and become wavy in caudal in shape. It attains a maximum size of 100 mm. Generally it inhabits in the cold water of torrential streams at bottom. It feeds upon large amount of Pheretima and algal filaments like Spirogyra and Oscillatoria etc. Mostly it breeds in April to June in Tinau river. Fin Formula: D. 2/10-12(12-14), P. 11, V. 8, A. 2/5(7), C. 18, B. 3 prs. Garra gotyla (Gray) (Sucker head) It is commonly known as �Buduna� in Nepal. The body is elongated and sub-cylindrical in shape. Mouth is inferior and semicircular in shape with upper lip fringed. A suctorial disc is present on chin which is large and rounded. Snout is covered with spiny conical tubercles and a deep groove is present across it. Two pairs of barbels are present, viz., rostral and maxillary. General body colour is black with greenish tinge and a black spot is present just behind the gill opening. It attains a maximum size up to 150 mm. It feeds on large amount of algal materials like Spirogyra and Oscillatoria etc. It is distributed in the rivers of Bagmati, Bheri, Lumbini and Narayani zones. The breeding season for this fish starts in the month of June. Fin Formula: D. 2/8(10), P. 15, V. 9, A. 2/5(7), C.17, L.l. 32-34, L.tr. 51/2/31/2, B.2 prs. Channa gachua (Hamilton) (Murrel head) It is commonly known as �Hile� or �Bhoti�. Body is elongated and sub-cylindrical with depressed head which is dorsally covered with plate like scales. Gill openings are wider. Caudal fin is round in shape. Lateral line is broker in 12 to 15 scales and slightly curve. Body colour is dark on dorsal and the sides and belly is dirty white. Pectoral fins are with three reddish orange bands alternating with blue. A blue block is present on the base of pectoral fin while the tip is black. Ventral fin has orange tinge while other fins are dark. Dorsal and anal fins are long. About 12 vertical bands or stripes are present on the lateral sides of body. It can attain a maximum size of 180 mm. It is widely distributed on the rivers of hills and plains. It is carnivorous in nature. Breeding season of this species ranges from June to August. Fin Formula: D. 34-37, P. 13-15, V. 6, A. 21, L.l. 42-45, L.tr. 4/7 Heteropneustes fossilis (Bloch) (Spiny catfish) It is commonly known as �Singhi�. It is found occurring in ponds, pools, ditches and rivers of plains and mountains of Nepal. The body colour is dark brown. It has a short dorsal fin originating opposite to the ventral fin, and long anal fin. The anal fin is separated from caudal by a deep notch. It bears 4 pairs of long barbels among which maxillary pair reaches beyond pectoral fin. The pectoral fins are slightly long with a strong spine serrated internally which is capable of inflicting wound acting as a horn hence the name �Singhi�. It is provided with a long air sac, accessory respiratory organ, therefore, can able to live in muddy water. Caudal is rounded. It is a resident fish species. It can attain a maximum size of 175 mm. It is predatory fish feeding on insects, worms, algae etc. The breeding season rages in between April to June. Fin Formula: D. 6, P. 1/(8), V. 6, A. 66, C. 19, B. 4 prs. |
| Home | Family | Curriculum | Thesis TU | Thesis NLH | Publications | Term Papers | Recent Paper | Proposal | Nepali Poems |
 |
| You are here: Home>>>MSc Thesis TU>>>Ecology and behaviour .......... |