01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-07-0091 |
| Title of Abstract | An approach to scale net primary production to fish Biomass in Indian Marine waters using trophic transfer models |
| Authors | Dhanya M Lal*, Alakes Samanta, Bhagyashree Dash, Sanjiba Kumar Baliarsingh, Sudheer Joseph, T. M. Balakrishnan Nair |
| Organisation | Indian National Centre for Ocean Information Services |
| Address | ESSO Indian National Centre for Ocean Information Services Hyderabad, Telangana, India Pincode: 500090 E-mail: dhanya.ml@incois.gov.in |
| Country | India |
| Presentation | Oral |
| Abstract | Translating oceanic Net Primary Production (NPP) into fish biomass is essential for understanding marine productivity and guiding ecosystem-based fisheries management. This study proposes a framework for scaling NPP to higher trophic levels across the Indian Exclusive Economic Zone (EEZ), divided into Northeast (NE), Northwest (NW), Southeast (SE), and Southwest (SW) sectors over the period 2013⿿2024. Unlike conventional models that assume a fixed energy transfer between trophic levels, this approach provide due consideration to standing stock biomass, trophic diversity, and group-specific assimilation rates. The method uses mass-balanced Ecopath models from published studies representing each sector of the Indian EEZ. Key parameters such as production-to-consumption ratios (P/Q), ecotrophic efficiency (EE), and baseline biomass at the first trophic level were integrated with remote sensing-derived NPP estimates from MODIS-Aqua, calculated using the Vertically Generalized Production Model (VGPM). Considering phytoplankton biomass from the mass-balanced model as the baseline, this study estimates the additional biomass supported by the excess NPP at each trophic level (TL) on a monthly scale-from primary consumers (TL2) to apex predators (TL4). Results show strong regional variation in fish biomass potential. Small pelagic fish (TL2) biomass ranged from 3.96 to 14.56 million tonnes (MT), peaking in the SW and SE sectors, reflecting strong phytoplankton-mediated trophic pathways and balanced predation pressure in these sectors. Conversely, higher TL3 and TL4 biomass was recorded in the NW and NE sectors (NW: 19.02⿿29.17 MT; NE: 4.29⿿8.37 MT), indicating detritus-driven pathways and greater omnivory. This spatially explicit, ecologically grounded model offers a realistic tool for predicting fish biomass from primary production, supporting sustainable fisheries and ecosystem assessments in the Indian Ocean. The framework holds potential for future refinement by including more finer functional group compartmentalization and differential consideration of neritic and oceanic trophic dynamics. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Primary Production, Remote Sensing, Ecopath, Fishery, Fronts |
| For Awards | no |