Insult to Injury: Population Impacts of Sublethal Entanglement and Vessel Strikes of Common Bottlenose Dolphins ( Tursiops truncatus ) in Barataria Basin, Louisiana, 2011–2023

ABSTRACT Human interactions, specifically fishery entanglements (FI) and vessel strikes (VI), threaten marine mammals, including the Barataria Bay Estuarine System (BBE) Stock of common bottlenose dolphins ( Tursiops truncatus ). We reviewed whole‐body photographs to estimate the prevalence of sublethal entanglement and vessel strike scars for 227 dolphins sampled during catch‐and‐release health assessments, with 128 dolphins meeting analysis criteria. Two biologists independently classified scars, with good inter‐rater agreement for FI (𝜥 = 0.78; 95% CI [0.70, 0.86]) and excellent agreement for VI (𝜥= 0.91 [0.85, 0.97]). Fifty‐nine individuals (46.1% [37.5, 54.9]) had signs of entanglement; 19 (14.8% [9.6, 22.2]) dolphins had evidence of vessel strike. We fit generalized additive models to examine associations of FI or VI with sex and length. For FI, models were similar to the base model. For VI, the model that included only sex was selected, with males more likely to have strike scars ( p = 0.02). The prevalence of interactions in BBE dolphins is elevated compared to other populations and could impact the stock's recovery following the 2010 DWH oil spill. Reducing human impacts basin‐wide, but especially near Grand Isle, Louisiana could help restoration efforts.