Scyphozoan jellyfish blooms and their relationship with environmental factors along the South-eastern Arabian Sea

ABSTRACT

This study correlated the abundance of five jellyfish species in the south-west coast of India, South-eastern Arabian Sea, Crambionella orsini, Lychnorhiza malayensis, Chrysaora caliparea, Netrostoma coerulescens and Cyanea nozakii, with hydrographic parameters. Partial least square (PLS) analysis suggested strong correlations between jellyfish abundance and phosphate, silicate and chlorophyll-a content in water and showed a significant positive relationship with the first PLS component, while pH and sea surface temperature showed a significant negative correlation with the first PLS component, indicating that the abundance of four species, C. caliparea, C. nozakii, L. malayensis and N. coerulescens, increases with phosphate, silicate and chlorophyll-a content and decreases with pH and sea surface temperature. In contrast, the abundance of C. orsini increased with an increase in sea surface salinity and decreased with an increase in dissolved oxygen; except for this species, the abundance of jellyfish in the South-eastern Arabian Sea was positively affected by phosphate content of the water. The continuous decline in abundance of jellyfish from 2016 to 2019 in the south-west coast of India could be due to the influence of regional environmental changes or due to the specific ecological strategies of the jellyfish species in the upwelling zone subjected to high fishing pressure.

KEYWORDS:

• Bloom
• chlorophyll
• hydrography
• Kerala
• phosphate
• salinity
• Scyphozoa
• India

Acknowledgement

We are thankful to Kylie A. Pitt (Griffith University, Australia) for the inputs received on the early draft of this paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Availability of data and material

The datasets during and/or analysed during the current study are available from the corresponding author on reasonable request.

Authors’ contributions

Investigation, methodology, data collection and curation, writing first draft: AR; curation and analysis of data, review and editing: ND; Data Collection on water quality, Review and Editing: KAK; Funding Acquisition, Supervision, review and editing final draft: ABK.

Compliance with ethical standards

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. None of the jellyfish from India are endangered or protected, so they can be collected without any special permits.

Additional information

Funding

Authors also thank the financial support of Kerala State Council of Science Technology and Environment.