Journal of the Marine Biological Association of India

Evaluating environmental influence on Acromitus flagellatus Maas, 1903 (Cnidaria: Scyphozoa) blooms in the tropical estuaries and backwaters along southwest India

Volume 67 Issue 2

A. Riyas, K. Anoop Krishnan and A. Biju Kumar

doi:10.6024/jmbai.2025.67.2.2627-08

Abstract

Scyphozoan blooms, driven by complex interactions between biological and environmental factors, have garnered considerable attention due to their ecological, economic, and social consequences. In India, blooms of Acromitus flagellatus Maas, 1903 pose significant challenges for local fishers. Despite this, there is a notable gap in comprehensive research on the correlation between A. flagellatus blooms and hydrographic factors in the backwaters and estuaries of Kerala. This study aims to investigate the connection between A. flagellatus blooms and environmental parameters. Monthly data on the abundance of A. flagellatus were collected from 12 stations across Kerala during pre-monsoon and post-monsoon seasons through extensive field surveys and visual counts from 2016 to 2019. Principal Component Analysis (PCA) revealed relationships between A. flagellatus abundance and hydrographic parameters during pre- and post-monsoon seasons over the four years. Multiple regression analysis indicated a positive correlation between A. flagellatus abundance and factors such as temperature, chlorophyll-a, pH, and nitrate (NO 3 -) concentrations in the water. The seasonal abundance of A. flagellatus, along with the associated ecological changes and impacts on the local estuarine fishery, is discussed. Understanding the triggers of A. flagellatus blooms will enable stakeholders to better predict and mitigate their impacts on fisheries, tourism, and overall ecosystem health, thereby supporting more sustainable management of these ecosystems. 

Keywords

Jellyfish, Scyphozoa, bloom, estuary, hydrography, fishery

Date : 01-12-2025