SharkTrack: an accurate, generalisable software for streamlining shark and ray underwater video analysis

TL;DR

SharkTrack is a semi-automatic software that uses CNNs and multi-object tracking to efficiently analyze underwater videos for elasmobranch monitoring, significantly reducing manual effort and improving accuracy across diverse ecosystems.

Contribution

We developed SharkTrack, a novel semi-automatic underwater video analysis tool that generalizes across species and locations, enhancing efficiency and accuracy in elasmobranch population monitoring.

Findings

Achieved 89% accuracy in ssMaxN estimation on unseen data

Reduced manual analysis time by approximately 95%

Demonstrated effectiveness across diverse marine ecosystems

Abstract

Elasmobranchs (shark sand rays) represent a critical component of marine ecosystems. Yet, they are experiencing global population declines and effective monitoring of populations is essential to their protection. Underwater stationary videos, such as those from Baited Remote Underwater Video Stations (BRUVS), are critical for understanding elasmobranch spatial ecology and abundance. However, processing these videos requires time-consuming manual analysis that can delay conservation. To address this challenge, we developed SharkTrack, a semi-automatic underwater video analysis software. SharkTrack uses Convolutional Neural Networks (CNN) and Multi-Object Tracking to automatically detect and track elasmobranchs and provides an annotation pipeline to manually classify elasmobranch species and compute species-specific MaxN (ssMaxN), the standard metric of relative abundance. When tested on BRUVS footage from locations unseen by the CNN model during training, SharkTrack computed ssMaxN with 89% accuracy over 207 hours of footage. The semi-automatic SharkTrack pipeline required two minutes of manual classification per hour of video, an estimated 95% reduction of manual analysis time compared to traditional methods. Furthermore, we demonstrate SharkTrack accuracy across diverse marine ecosystems and elasmobranch species, an advancement compared to previous models, which were limited to specific species or locations. SharkTrack applications extend beyond BRUVS, facilitating the analysis of any underwater stationary video. By making video analysis faster and more accessible, SharkTrack enables research and conservation organisations to monitor elasmobranch populations more efficiently, thereby improving conservation efforts. To further support these goals, we provide public access to the SharkTrack software.