Spatial Distribution and Ecological Implications of Invasive Charru Mussel <i>Mytella strigata</i> in Ashtamudi Ramsar Lake, Kerala

Mytella strigata (Hanley, 1843), the Charru mussel, native to the eastern coast of South and Central America, has become an invasive species in various regions worldwide, including Asia, Europe, and North America. This research examines the spatial distribution of M. strigata within the brackish water Ashtamudi Lake, a Ramsar site in Kerala, focusing on its correlation with the water quality parameters and ecological implications of invasion. Field surveys were conducted across multiple sites, spanning from the barmouth to the freshwater zone of the lake, to meticulously document the distribution and abundance of M. strigata. The mean abundance of the mussel and salinity were high at the barmouth and low at the freshwater region. The mean abundance values at each site were in the order Neendakara barmouth > Dalavapuram > Ashtamudi > Pavumba > Koivila, varying from 2725.6 ± 611.4 ind. ft-2 to 588.4 ± 97.45 ind. ft-2. The correlation analysis revealed that the abundance of M. strigata has a positive correlation with salinity and total hardness (p ˂ 0.01). These invasive mussels pose a threat to the aquaculture infrastructure in the lake and disrupt the composition of native aquatic communities. Their sedentary lifestyle and capacity to form substantial biomass at the lake bottom contribute to these ecological alterations. The introduction of M. strigata has notably diminished the populations of coexisting commercially valuable native species such as Marcia recens, the edible oyster Magallana bilineata, and the green mussel Perna viridis. The implications of the invasive mussel’s distribution patterns are discussed in the context of ecological management and conservation efforts in Ashtamudi Lake.