Data from 'High population density limits predator access in Antarctic fur seal breeding colonies'

Description This repository contains the annotated image dataset and the pre-trained neural network weights developed for the research paper: "High population density limits predator access in Antarctic fur seal breeding colonies". The data was collected at Bird Island, South Georgia (54°00'24.8ʺ S, 38°03'04.1ʺ W) during the austral summer of 2020–2021. This is a comparative study between two breeding colonies differing four-fold in seal density, located approximately 300 meters apart: Freshwater Beach (FWB): An open beach intersected by a shallow stream that forms natural corridors and influences the spatial distribution of seals within the colony. Special Study Beach (SSB): A small cobblestone breeding beach separated from adjacent breeding sites by a cliff on the east side, open sea on the west, and rocky ridges to the north and south. A scaffold walkway provides safe access to the animals. Note: All information regarding the training, evaluation, and analysis of FWB can be found in our related paper (https://www.biorxiv.org/content/10.64898/2026.04.03.716266v1). The FWB dataset is available here: https://zenodo.org/records/18148442, and the associated code is on GitHub: https://github.com/fabrylab/AntarcticFurSealPredatorPrey Manuscript Abstract Population density can influence individual predation risk in colonial breeders through shared vigilance and predator deterrence. We investigated how predator-prey interactions are shaped by population density at two Antarctic fur seal (Arctocephalus gazella) breeding colonies at Bird Island, South Georgia, which differ four-fold in seal density. By deploying autonomous time-lapse cameras, we captured high-resolution images at one-minute intervals throughout the breeding season. Using a YOLOv8 neural network, we identified fur seal adult males, females and pups, as well as three predator-scavenger bird species: giant petrels (Macronectes spp.), brown skuas (Stercorarius antarcticus) and snowy sheathbills (Chionis alba). Abundance patterns corresponded to the known foraging and breeding behaviours of these species. Differences in seal density between the colonies were mainly driven by adult females and their pups, but not adult males. The ratios of predatory birds to pups were markedly lower at the high-density colony, while scavenger to pup ratios remained similar. Spatial analyses revealed that predators were largely excluded from areas of high seal density, whereas scavengers overlapped extensively with pups in both colonies. This study demonstrates the value of remote observation in resolving predator-prey interactions and illustrates how density can shape predation risk in a colonial breeder. Repository Contents 1. data.zip (Dataset) This archive contains the images and annotations used in the study. The dataset is organised as paired files: .jpg: High-resolution raw images from the autonomous camera system. .cdb: Corresponding annotation files created using ClickPoints. These databases contain the ground-truth labels for animals. (For information on opening .cdb files, please refer to the ClickPoints Documentation.) 2. model.pt (Model Weights) This file contains the final trained weights for the object detection network used to evaluate the SSB images. Architecture: Ultralytics YOLOv8l (Large) Purpose: To classify and locate species within the Special Study Beach colony. 3. Detected Animals (.csv) These files (FWB.csv and SSB.csv) contain the spatiotemporal data extracted from the images for both study sites. Columns: filename: Identifiers linking the detection to specific source images in the dataset. timestamp: Date and time the image was captured. class: The annotated species or demographic class male: Antarctic fur seal (adult male) — Arctocephalus gazella female: Antarctic fur seal (adult female) — Arctocephalus gazella pup: Antarctic fur seal (pup) — Arctocephalus gazella giant petrel: Giant petrel — Macronectes spp. skua: Brown skua — Stercorarius antarcticus sheathbill: Snowy sheathbill — Chionis alba x_px / y_px: The X and Y coordinates of the top-left corner of the bounding box in the image (in pixels). width_px / height_px: Dimensions of the bounding box (in pixels). lat / lon: Real-world geographic coordinates (latitude and longitude) of the detected animal. x_m / y_m: The position of the animal in metres relative to the camera. Associated Code The source code used to perform the comparative ecological analysis described in the paper is available on GitHub: https://github.com/fabrylab/AntarcticFurSealDensity