Abstract
The resident population of dugongs (Dugong dugon) in the Gulf of Kachchh (GoK) inhabits one of the most tidally dynamic habitats (3.4 m at Okha port and 6.2 m at Navlakhi) across their global distribution range. Semi-diurnal tidal frequency restricts marine herbivory and necessitates adaptive foraging strategies. Within this hydrodynamic framework, we investigated determinants of foraging area selectivity using fresh feeding trails (n = 1507) as a dugong presence tool and mapped foraging areas at intertidal reef-flats (reef-top meadows, n = 6), mid-intertidal mudflats (tidal creek meadows, n = 4), and subtidal meadows (n = 3) from 2018 to 2023. To understand macro-tidal habitat use patterns, we investigated tidally vigilant foraging strategies across habitat types by modelling the response of feeding trail counts, lengths, and distance travelled from tidal refugia (coves and tidal creeks), to water depth, seagrass abundance, and sediment texture using Generalized Additive Models (Negative Binomial and Gamma GAMs). We then estimated periodic tidal accessibility restrictions at each habitat by overlaying perimeters of dugong foraging areas on constructed regional bathymetric maps (30 m resolution) for average high tides (spring: 3.4 m and neap: 2.8 m) and daily low tide height (0.4 m). Traditional habitat selectivity variables such as seagrass quality, composition, and shoot abundance variations were relatively weak predictors of the overall habitat selectivity. An estimated 73.4% of the total foraging areas mapped are tidally influenced. At all habitats, dugongs remained tidally vigilant by preferentially foraging at habitat edges adjacent to deep-water refugia rather than utilizing the full seagrass expanse. At habitat level, tidally vigilant foraging dugongs regulated distance travelled from tidal refugia based on habitats depth and seagrass abundance. Feeding trail lengths varied according to the ease with which seagrass could be excavated across habitats. At reef-top meadows, which had a higher % crude protein advantage, dugongs travelled farther from the tidal refugia to forage. Dugongs utilized tidal creeks as movement corridors for inter- and intra-habitat travel during foraging. This replicable and cost-effective model, combined with robust spatio-temporal maps of dugong habitat use and corridor networks, provides critical insights to enhance conservation strategies and improve outcomes for the endangered dugong population in the Gulf of Kachchh and similar habitats.
Subjects
- Ecology
- Ocean sciences
Acknowledgements
We thank the Gujarat Forest Department for the arrangement of necessary provisions needed to conduct and supervise the surveys inside the Marine National Park and the funding agency; National CAMPA Advisory Council (NCAC), Ministry of Environment, Forests and Climate Change, Government of India. We are grateful to the Dean and Director of Wildlife Institute of India for their administrative support during the study. We thank the Dugong volunteer team of fishers, from Beyt-Dwarka’s islands Balapur village, Salaya, and Sikka township for supporting this study with their Traditional Ecological Knowledge and logistics. We are extremely thankful to our field assistants Junus Babbar, Bhargav Bhadreshwara, Musa Chana, Abulbhai Jeda, Mustufa Jeda, Abedbhai Jeda, Iliyas, Azizbhai, Fatema Hirkani, and for their constant support at data collection at all major foraging sites. For their contribution in data collection during the inception of the surveys, we are grateful to Diksha Dikshit, Prachi Hatkar, Shivani Patel, Pradhyuman Sindha, Sagar Rajpurkar, Himani Saini, Deven Mehta, and Sonalika Mamgain. We thank the SIMA laboratories, New Delhi, for fiber and % Nitrogen analysis and Dr. Sunil Jhadav, Indian Institute of Veterinary Research for his analytical support regarding the same. For their analytical support in sediment texture, we thank ICAR- Indian Soil and Water Conservation, Dehradun. We thank Mr. Vabesh Tripura for providing the illustrations of seagrass species used in the figures. Lastly, we thank Amir Lone for GIS-based technical advice and support.
Funding
This study was sponsored by the National CAMPA Advisory Council (NCAC), Ministry of Environment, Forest and Climate Change, Government of India (Grant/Award Number: 13–28(01)/2015-CAMPA).
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All seagrass samples and habitat surveys were conducted in accordance with institutional, national (Ministry of Environment, Forest and Climate Change, Government of India; Gujarat Forest Department), and international guidelines and regulations. Permissions were obtained from the Principal Chief Conservator of Forests (PCCF), Gujarat Forest Department, Gandhinagar for conducting the mentioned fieldwork at all habitats and seagrass sample collection for all analysis.
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Pathan, S., Christian, G., Sivakumar, K. et al. Investigation of tidally vigilant spatiotemporal foraging strategies of a Dugong (Dugong dugon) population in the macro-tidal Gulf of Kachchh, India.
Sci Rep (2026). https://doi.org/10.1038/s41598-026-60255-w
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DOI: https://doi.org/10.1038/s41598-026-60255-w
Keywords
- Sirenia
- Seagrass habitats
- Semi-diurnal tides
- Optimal foraging
- Habitat selectivity
- Tidal vigilance
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