The Sundarbans Biosphere Reserve, home to the world’s largest mangrove forest, is grappling with the global issue of microplastic pollution, according to a recent study. The research, conducted in the estuarine waters of the Indian Sundarbans, focuses on 13 fish species from the Saptamukhi River near Lothian Island, India.
The primary objective of the study is to identify the occurrence of microplastics (MPs) in the gastro-intestinal tract (GI tract) of these estuarine fish and understand the relationship between the presence of MPs and the morphological and feeding characteristics of the fish.
Various morphological parameters, including body size, mouth aperture length, eyeball diameter, and GI tract length, were measured for the 13 fish species. The study also analyzed the niche breadths and niche overlapping of these species using Levin niche breadth and Pianka niche-overlap indices.
Results revealed the pervasive presence of fiber-shaped microplastics in the GI tracts of all fish species, with films and fragments also commonly detected. The size of these microplastics ranged from 100µm to <5mm. Significantly, the study found a variation (p<0.0001) in the trophic morphology of the fish concerning the length of microplastics (p<0.05).
The research indicated a positive correlation between the length of microplastics and body size as well as mouth aperture, while the correlation was negative concerning GI tract length and eyeball diameter. Interestingly, despite the presence of microplastics in the GI tracts, the study noted that it did not significantly impact the niche breadth and niche overlap of the 13 estuarine fish species.
This study sheds light on the intricate relationship between microplastic pollution and the morphological characteristics of fish in the Sundarbans, emphasizing the need for continued research and conservation efforts to safeguard this vital mangrove ecosystem.
