Short-term impact of cyclone Yass on the copepod community of Muriganga estuary of India

Tropical cyclones (TCs) are discrete events that affect ecology of estuaries. On 26 May 2021, TC Yass (category-1) disrupted the Muriganga estuary (ME), West Bengal coast, India. Authors assessed short-term cyclone-mediated changes of the copepod community by sampling three stations on the ME before and after TC Yass. Copepod and water samples collected on November 2020, and January and April 2021 were assumed as pre-Yass samples. Post-Yass samples were collected between 4 and 22 June 2021 once in every 6 days. It was hypothesized that diversity, total abundance and dominance of the copepods of the ME were impacted by TC Yass. Post-Yass the ME turned polyhaline from its meso-haline characteristic. Post-Yass species richness was higher than the pre-Yass period. Pre-Yass Bestiolina similis was the most abundant species, and species such as Paracalanus parvus and Acartiella tortaniformis co-dominated the copepod community. Post-Yass, Acartiella tortaniformis was the most abundant species of the copepod community followed by Oithona brevicornis and Paracalanus parvus. Post-Yass, total abundance of cyclopoid copepods was higher than the pre-Yass. Spatial heterogeneity of the copepods, which was observed during the pre-Yass was lost in the post-Yass period. Those changes in composition and abundances may have cascading consequences for the ecology of the copepods in the ME. Such changes could be traced through a high frequency sampling (e.g., daily to weekly) starting within the first week of a TC impact followed by a medium (e.g., monthly interval) frequency sampling based on the intensity of a TC, resident time of water in an estuary and the complexity of its copepod community.