mumbai

Updated: Jul 29, 2019 01:48 IST

Nineteen aquatic species use mangrove forests of Mumbai and the Konkan coast as breeding grounds, a first-of-its-kind study has revealed.

In the study, the Fish Genetics and Biotechnology division of the Indian Council of Agricultural Research (ICAR) - Central Institute of Fisheries Education (CIFE), Mumbai used deoxyribonucleic acid (DNA) sequences to identify species in mangrove areas. Six of the 19 species were identified as commercially and ecologically important for the mangrove biodiversity – Blue spotted Mudskipper (Boleophthalmus boddarti), two types of pomphret (Pampus argenteus and Pampus chinensis), Northern whiting (Sillago sihama), John’s Snapper or Golden snapper (Lutjanus johnii), and Giant tiger prawns or Asian tiger shrimps (Penaeus monodon).

“Due to developmental activities and anthropogenic changes, there is a lot of pressure on mangrove ecosystem, especially within the Mumbai Metropolitan Region (MMR), without knowing the value of these salt-tolerant trees. Apart from their importance in playing a critical role by acting as natural sponges and controlling flooding, there is a large biodiversity that thrives on this ecosystem,” said Annam Pavan Kumar, senior scientist, CIFE-Mumbai who carried out the study, along with Raju Ram, Ashok Kumar Jaiswar, Gireesh Babu Pathakota, Aparna Chaudhari, and Gopal Krishna, all CIFE scientists.

Apart from these, larvae of ornamental fishes such as Malabar glassy perchlet or Barehead glassfish (Ambassis dussumieri) and Indian glassy fish (Pseudambassis ranga) were also observed of which the Barehead glassfish is widely distributed throughout Indo-Western Pacific region while the Indian glassy fish is endemic to freshwaters of Asia.

“Till date the number of species using mangrove forests as breeding grounds was not available as larvae of aquatic species are very small and difficult to distinguish,” said Kumar. “This is the first report from India on utilizing DNA barcoding approach to identify indistinguishable fin and shellfish larvae from mangroves.”

A total of 80 larvae (fish and shellfish) were collected from selected mangrove zones from Maharashtra including Gorai, Mumbai, Shirgaon mangrove forests near Ratnagiri, and Karanja near Uran, Navi Mumbai from September, 2015 to February, 2016 using hand nets with a mesh size of 0.2-0.3mm. “In this study using molecular tools, we characterized the species diversity giving an indication of the aquatic life that calls mangrove forests their home. This will further enhance the need to protect these areas and also identifies the economic value they add,” said Kumar.

DNA barcoding relies on unique sequence of mitochondrial DNA specific to the species (using a single gene to identify a species through a series of sequences). The scientists first identified the adult specimen of each species and generated their barcodes based on their mitochondrial DNA. Using that as reference, the DNA sequence for fish and shrimp larvae collected from mangrove forests were compared and identified. “This is a standard global procedure, which we followed,” added Kumar. “More such studies are needed in mangrove areas along the entire Indian coastline to detect ecologically sensitive zones and declare those areas as reserved forest to avoid development. Currently, the data is lacking and it is a vital requirement to improve conservation.”

“The government is focusing on blue economy in terms of sustainable use of ocean resources for economic growth. The mission will help in leveraging the blue economy for the country’s overall economic growth,” said M Rajeevan, MoES secretary at an event in Delhi on Saturday. “Such studies using DNA barcoding is very useful for the identification of species in areas where research cannot be carried out very easily. If more such efforts are done, we will be able discover a wide variety of species within mangrove forests giving impetus to protect these areas better. Our aim should be use this research to ensure such species do not get wiped out,” said N Mohan Karnat, additional principal chief conservator of forests, Maharashtra forest department and director, Institute of Wood Science and Technology, Bengaluru.