Volume 10 No.3, 2004 The Eastern Ghats EPTRI - ENVIS Newsletter Estuarine Ecology of Eastern Ghats Foreword............................................. 1 Foreword Ecology and Biodiversity of Eastern We have pleasure in releasing our Newsletter : Ghats-Estuaries of India..................... 2 The Eastern Ghats Vol.10. No.3 2004. Faunal Diversity : Estuarine Ecosystem 8 It deals with Estuarine Ecology pertaining to Eastern Ghats. The articles cover floral & Abstracts:................................11-12 faunal diversity of Estuarine Ecosystem of • Icthyofauna of Ennore estuary • Behaviour of fluoride in Rushikulya Andhra Pradesh and Tamil Nadu. These Estuary, Bay of Bengal articles have been compiled, edited and coordinated • Distribution of recent benthic Ostracoda by the team. We hope that these articles in Adyar river Estuary, East Coast of ENVIS India will benefit and enrich scholars, scientists who have • Composition and abundance of been working in these ecosystems for improving meroplankton in Coringa mangrove ecosystem, Kakinada, the habitat, especially The Mangroves and the Andhra Pradesh with special Fishermen Community. As there was a good reference to aquaculture response on this important topic, the next issue also • A study on impact of hinterland farm practices on Coringa mangroves with covers the same subject. We invite articles and news k some eco-economic and sustainable clippings concerning Estuarine Ecosystem of solutions Orissa to fill this void. ANNOUNCEMENT ENVIS Coordinator Centre for Environment Education, India in partnership with Ministry of Environment & Readers are...... Forests and Ministry of Human Resources WELCOME to contribute articles to our Development, UNESCO and UNEP is Newsletter. The theme of our next issue is organizing an International Conference on again on “Estuarine Ecology of Eastern “Education for a Sustainable Future” (ESF) Ghats”. between 18th -20th January 2005. For further details please visit www.ceeindia.org/esf or e-mail: [email protected] Note The views expressed in the article/s are of the Authors. 1 ENVIRONMENT PROTECTION TRAINING & RESEARCH INSTITUTE (EPTRI), HYDERABAD EPTRI - ENVIS Newsletter Vol. 10 No.3, 2004 Ecology and Biodiversity of Eastern Ghats - Eastuaries of India N. Rajendran, S. Baskara Sanjeevi, S. Ajmal Khan and T. Balasubramanian Centre of Advanced Study in Marine Biology,Annamalai University, Parangipettai – 608 502,Tamil Nadu, India ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○ Introduction The Eastern Ghats are endowed with rich flora and fauna with various types of coastal ecosystem such as, estuaries, Estuary is an integral part of the coastal environment. mangroves, lagoons and coral reefs. The Eastern Ghats are It is the outfall region of the river, making the transitional located between 76° 56’ and 86° 30’ E longitudes and 11° zone between the fluvial and marine environs. Historically 30’ and 22° N latitudes, they extend in north East – South the term Estuary has been applied to the lower tidal reaches West strike in the Indian peninsula covering an area of about of a river. According to Pitchard, “An estuary is a semi-enclosed 70,0002 km with an average width of 200 km. in the North coastal body of water which has a free connection with the and 100 km. in the South. They extend over a length of open sea and within which the sea water is measurably diluted 1750 km. between the rivers Mahanadi and Vaigai along with the fresh water derived from land drainage”. East Eoast (Sudhakar Reddy et al., 2003). Eastern Ghats region mainly spreads through the state of Orissa, Andhra Estuaries have been the focal point of the maritime Pradesh and Tamil Nadu. studies and activities. As they are semi-enclosed water bodies they provide natural harbour for trade and commerce. They Throwing light on all these aspects, the are also effective nutrient traps and provide a vital source of Environmental Information System Centre in the Centre of natural resources to man and are used for commercial, Advanced Study in Marine Biology, Annamalai University industrial and recreational purposes. Biodiversity in this has prepared the State-of-the-art report on estuaries which ecosystem is very impressive. They are the best settling places enables one to know the present scenario and the recent for clams and oysters. They also act as nursery ground for a researches in the Indian estuarine ecosystems. variety of shrimps, finfishes and other marine organisms. This paper consolidates the findings of various India has a coastline of 7500 km with an exclusive research reports on the estuaries on the Eastern Ghats of India economic zone of 2.015 x 106 km2, which is 61% of the and their ecology, biodiversity and management. land area. The country has 14 major, 44 medium and 162 minor rivers with a total catchment area of 3.12 x 106 km2, Physico-chemical parameters discharging 1645 km2 of freshwater every year to the seas around the country. The important major rivers are Ganga, Physico-chemical parameters play the major role in Mahanadi, Godavari, Krishna and Kaveri on the East Coast the ecosystem to maintain the biodiversity. The level and and Narmada and Tapti on the west coast. These seven rivers their role in the estuarine ecosystem of the Eastern Ghats have a catchment area of 1.83 x 106 km2 and discharge 812 and given hereunder. 3 6 km of freshwater transporting 1194 x 10 t of silt to the ○○○○○○○○○○○○○○○○○○○○○○○○○○○○ marine waters every year (Zingde, 1989). The percentage of dissolved and particulate fractions of zinc showed significant variations in different seasons Estuaries are in a state of constant flux and dynamic because of their involvement in the biogeochemical cycles in in nature provides many ecological niches for diverse biota. the Rushikulya Estuary (Dash et al., 1997). In the Bahuda The health status and the biological diversity of the Indian Estuary all the physico-chemical parameters showed well estuarine ecosystem are deteriorating day by day through marked seasonal as well as spatial variations being influenced multivarious man-made activities including dumping of by monsoon cycle and tidal rhythm (Sujatha Mishra et al., enormous quantities of sewage into the Estuary, resulting 1993). drastic reduction of shallow water fish population. It has also caused considerable ecological imbalance and resulted in large- The pH and salinity increased during high tides scale disappearance of their flora and fauna. Further, while suspended solid during ebbs were high especially during introduction of untreated municipal waste-water and monsoon season. Concentrations of dissolved oxygen, industrial effluents into these water bodies leads to serious inorganic phosphate increased during ebb regime and a water pollution and majority of them with heavy metal decreasing trend was observed starting from monsoon to pre- pollution, which gets biomagnified and even reaches man monsoon, which indicates high productivity towards the through the food-chain. confluence with Bay. Higher values of ammonia during 2 EPTRI - ENVIS Newsletter Vol. 10 No.3, 2004 premonsoon, particularly during low tides may be attributed In Adyar Estuary, the temperature ranged between to the discharge of untreated domestic sewage and industrial 26.0°C and 32.6°C, the maximum during May (32.6°C) effluents intothe Mahanadi Estuary (Das et al., 1997). Nayak and minimum (26.0°C) during December. Salinity ranged et al. (2001) reported that the concentrations of dissolved from 4.24‰ to 36.56‰. Peak salinity (36.56‰) was Cu, Ni, Pb and Cd show an increasing trend towards the sea recorded during October and low salinity (4.24 ‰) during whereas that of Fe and Mn shows a decreasing trend in January. The dissolved oxygen content of the water ranged Dharma Estuary. from 0.91 ml l-1 to 4.78 ml l-1. Maximum DO content of 4.78 ml l-1 was observed during April and the minimum of Suspended matter concentration showed highest 0.91 ml l-1 during July. In general DO content of the water level during the southwest monsoon (Reddy et al., 1994). was higher during high tide period. The annual variation in Temperature variations are very small in vertical as well as pH ranged from 6.5 to 8.6. Maximum pH was 8.6 during longitudinal sections of the Estuary and the river discharge October and minimum (6.5) in November (Nammalwar et controls the salinity in the Godavari and Krishna Estuary al., 1991). The concentration of the heavy metals mercury, (Reddy and Rao, 1993). cadmium, copper, zinc, nickel, lead and iron in various tissues of Liza macrolepis inhabiting Adyar, Cooum and Ennore Sediment in the Godavari Basin is finer than in the ○○○○○○○○○○○○○○○○○○○○○ estuaries was found above the “permissible safe levels” Krishna. River channel bar, beach, dunes and paleo-beach (Nammalwar, 1992). ridges mostly consist of sand. Muddy sand is widespread in tidal reaches (Rao and Swamy, 1991). Somayajulu et al. In Uppanar Estuary, the range of variation in (1993) observed that the DOC and Fe concentrations in the temperature was 13° C and was found to be more important Godavari Estuary are below the average value reported for as a co-variate with other factors than as an individual factor. world rivers and estuaries. Silicon behaves non-conservatively; The range of variation in salinity was high at upstream its depletion, which is most likely due to biological activity (32.32‰). Dissolved oxygen content of the surface water during the non-monsoon periods of sampling, ranges from was higher than that of bottom water and this may be due to 25 to 37%. The U isotopes behave conservatively although the higher photosynthetic activity and higher solubility of there is some scatter in the low-chlorinity (£ 2 g Cl l-1) region. oxygen in lower salinity surface water. pH values did not The suspended matter concentrations, ranging from 4.2 to follow any definite seasonal pattern and the range of variation 7.9 mg l-1, are one to two orders of magnitude lower than was narrow (Murugan and Ayyakkannu, 1991a).