UTTAR PRADESH JOURNAL OF ZOOLOGY

Invasive prey species pose significant ecological challenges by altering food web structures and predator-prey dynamics. For apex predators like the Marsh Mugger (Crocodylus palustris), dietary flexibility often facilitates adaptation, yet the long-term effects on growth, health, and conservation outcomes remain underexplored. This study investigates the influence of invasive prey species on the feeding ecology and growth rates of crocodiles at the Crocodile Breeding Centre (CBC), Bohr Saidan, Kurukshetra, Haryana, India. Data were collected through direct feeding observations, faecal and regurgitate analysis, and morphometric monitoring over a one-year period. Feeding observations (n = 120 sessions) were conducted between March 2024 and March 2025. Fecal and regurgitate samples (n = 85) were collected and examined under a dissecting microscope. Data were analyzed using one-way ANOVA and Tukey’s post-hoc tests in R software. Results showed that invasive prey species, particularly Oreochromis niloticus (Nile tilapia) and Clarias gariepinus (African catfish), have become prominent components of the diet. While invasive prey facilitated short-term increases in feeding efficiency and juvenile growth, long-term analyses revealed nutritional imbalances, stunted growth, and health trade-offs. Native Indian carps, primarily Labeo rohita and Catla catla, collectively represented only 29% of prey items (17% and 12% respectively). Amphibians, mainly local anurans such as Hoplobatrachus tigerinus, accounted for 9%, while other mixed fish species contributed another 9%. These findings highlight the need for management interventions at CBC to ensure dietary diversity and sustain robust crocodile populations for reintroduction programs. Incorporating native prey or nutritionally balanced supplemental feeding regimes could mitigate these impacts and ensure robust crocodile populations for reintroduction.