Weddell seal dataset with identity, segmentation, visibility, and substrate annotations from Antarctica

This dataset provides 1,590 annotated instances of Weddell seals (Leptonychotes weddellii) from 1,568 photographs collected across five islands of the South Shetland archipelago, Antarctica, during austral summer field campaigns conducted in selected years between 2002–2014 and again in 2023–2024. Each instance is annotated with a bounding box, polygon segmentation mask, viewpoint classification, and binary body-part visibility indicators for seven anatomical regions in Common Objects in Context (COCO) format. A subset of 784 instances from 2002–2014 additionally includes individual identity labels (175 identified individuals). The remaining 806 instances from 2023–2024 are not individually identified. Per-instance metadata records date, geographic coordinates, island, substrate composition, and photographer. The dataset is structured to support individual re-identification, instance segmentation, viewpoint classification, substrate classification, and ecological monitoring research.