ECOLOGICAL STUDIES ON FRESHWATER GASTROPODS (SNAILS) OF INDUS RIVER AND ITS CANALS AT KOTRI BARRAGE SINDH, PAKISTAN

Abstract

Occurrence of freshwater gastropods in Indus River and its canals at Kuuri Barrage. near Jamshoro, Sindh were studied from (October 2005 to September 2006) Sampling area inchaled five stations namely, Pinyari Canal, Phuleli Canal, KB Feeder, Chakumber (Ring Dam) and River Indus (downstream). A total of seven genera including 10 species of gastropods were identified in which Bellamya bengalensis being most dominant Gastropod populations were fairly good and more or less same numbers of individuals were recorded at K.B. Feeder, Pinyati Canal Phuleli Canal and Chakumber The Indus River (downstream) was very poor in live gastropods, where only dead shells were found 1/4 The lowest temperature was in January (167 °C) while highest being in August (325 0 Lowest D.O was 5.0 mg/l at Chakumber in August and highest was 6 2 mg/l in January TDS and conductivity were higher at Chakumber in January. Water transparency was very low (20 cm) throughout all stations during flood season (July September) and higher (580 cm during dry season (January-March). The Chakumber was more transparent than other stations because of its shallow and stagnant water. The pll ranged in between 74 to 82 whereas hardness ranged between 70 mg/l to 1.30 mg/l. The gastropod population showed a direct relationship with the temperature and strong correlation was evident. On the other hand pll, hardness and secchi transparency showed a negative correlation with the population density.