Influence of salinity on commercial Clams of Uttara Kannada Estuaries
Estuaries are ranked among the most productive ecosystems of the earth due to a variety of factors, the most prominent
being mixing up of freshwater from the rivers with the marine tides creating varying degrees of salinity in different
parts of the estuary. When these natural tidal rhythms are affected due to natural causes or anthropogenic activities,
estuarine organisms, especially sedentary ones, get affected. The sedentary organisms such as bivalves make ideal
cases for assessment of especially anthropogenic environmental impacts on estuaries. The rivers of Uttara Kannada
district, Karnataka particularly Sharavathi and Kali have been dammed for power production, which collapsed the
clam fishery. Hence, a survey was conducted in dammed river estuaries Sharavathi and Kali to know the impact of
dams constructed for the hydroelectric projects on the clams and compared with the studies from undammed river estuaries Aghanashini and Gangavali. The study revealed that the execution of hydroelectric projects in the Sharavathi and Kali rivers of Uttara Kannada district in Karnataka is the major cause for the elimination of most of the clam bivalves from the Sharavathi estuary, and habitat shifts and shrinkage for the bivalves in the Kali estuary due to
decreased salinity on account of continuous discharge of freshwater after power generation, a situation not favouring the bivalves. River valley projects are drastic interventions by humans with far reaching implications affecting even the estuarine regions, primarily due to fall in salinity creating adverse conditions. The bivalve situation in two more estuaries, of the rivers Aghanashini and Gangavali in Uttara Kannada, undammed and more natural, is compared with that of the dam affected ones to understand the situation better.
Keywords: Bivalve, Dam, Hydroelectric Project, Kali, Sharavathi, Salinity.
Citation: *, ( 2017), Influence of salinity on commercial Clams of Uttara Kannada Estuaries. Scientific Transactions in Environment and Technovation Journal(STET), 10(3): 117-121
Received: 2015-02-05 10:28:04; Accepted: 01/02/2017;