km3 (409,000 ac·ft). Though it provides irrigation to 61630 ha for paddy and upland crops, it has aggravated the salinity ingress into the wetland and the river due to reduced outflows during summer months. Temperatures recorded in the area are a maximum of and a minimum of . The climate is hot and humid during April–May while cool during December–January. Flora Ashtamudi Estuary has mangroves Avicennia officinalis, Brugiera gymnorrhiza and Sonneratia caseolaris as also 43 species of marshy and mangrove associates including two endangered species Syzygium travancoricum (endangered species according to the Red Data Book of Indian Plants) and Calamus rotang in the Terrestrial system. These species offer excellent scope for development of marine bioreserve to promote eco-tourism in the estuarine of the lake. IUCN lists the two endangered species in IUCN 2008. The total number of Syzygium travancoricum is reported to be very small, not more than 200. The major threats to the endangered species are reportedly draining of the wet lands and conversion into paddy fields. Wildlife The lake supports 57 species of avifauna, of which 6 are migratory and 51 resident species. It is also reported that about 40 species of wetland-dependent birds are recorded in the lake, out of which 45% are long-distance migrants. Terns, plovers, cormorants, and herons are most abundant birds in the lake. A study report has identified 45 insect species, including 26 species of butterfly, 5 odonates, 9 hymenopteras, and 2 orthopterans, 1 hemipteran and 2 coleopterans. About 29 zooplankton species have also been identified. The water body is found to have 9 phytoplanktons such as Amphora, Borosigma, Cyclotella, Cymbella, Gyrozigma, Meloziva, Navicula and Nitzschi. World Wildlife Fund (WWF) reports 97 species of fish (42 are typically marine, 3 estuarine, 9 estuarine-riverine, 15 marine-estuarine) and unique copepod species. It is also a congenial habitat for all species of penaeid and palaemonid Prawns, edible crabs, paphia malabarica (short neck Clams) and a variety of fish. A comparative shell morphology study of short-neck clam Paphia malabarica, the main clam fishery resources in the Ashtamudi Lake re-assigned to the genus Marcia recens (Venus Clams) and this study found it was wrongly identified as short-neck clam in previous studies. Clams found in the estuary are exported. The estuary is the source of livelihood for thousands of fishermen and is stated to be the second biggest fish-landing centre after the Vembanad estuary. Islands in the lake Munroe