01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-08-0121 |
| Title of Abstract | Characterizing the meso-pelagic resources using underwater acoustic technique and in-situ sampling |
| Authors | Kranthikumar Chanda*, Dr K.M Meera, Dr Smitha BR, Dr Rasheed K, Dr Hashim Manjebrayakath |
| Organisation | Centre for Marine Living Resources and Ecology (CMLRE)-MoES Kochi |
| Address | Centre for Marine Living Resources & Ecology, (MOES) govt of India, Kochi. Kochi, Kerala, India Pincode: 682508 E-mail: kranthikumarocean@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | Acoustic studies were conducted to characterize mesopelagic resources in the North Arabian Sea. A split-beam acoustic survey (EK-80) was carried out on board the FORV Sagar Sampada from May 8-23, 2024. This was accompanied by in-situ midwater trawling of mesopelagic organisms, plankton, and other environmental parameters. The echosounder was operated at two frequencies (38 kHz and 120 kHz) to profile the water column from 10m to >1000m, with special thrust on the Deep Scattering Layer (DSL), which is a dominant feature of the Arabian Sea. The calibrated echosounder and the sampled volume backscatter profiles were used for the determination of the organisms' Target Strength (TS), as well as the spatial and temporal distribution of fish and plankton. During our study we employed a post-calibration technique to standardize the volume backscattering data. For unwanted voice removals we used background and impulse noise, based on the signal to noise ratio, using Echoview 14 software. Echo integration techniques were applied to characterize the mesopelagic organisms and their vertical migration patterns of the DSL. This clearly indicates the diel vertical migration of these organisms especially at depths of 250-450m. The TS was also estimated from selected myctophid fish based on the length-weight relationship. Additionally, the interlinkage between the DSL pattern and environmental variables such as dissolved oxygen and chlorophyll was estimated based on the observations. The study suggests that the acoustic method can serve as an effective monitoring tool to characterize mesopelagic resources and their vertical migration patterns. This research highlights the critical role of acoustic monitoring in advancing our understanding of the mesopelagic ecosystem and responsibly estimating its hidden resources. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Echo-integration, Mean volume backscattering, Myctophid Biomass |
| For Awards | no |