Assessing Angler Honesty in Citizen Science, angler reported length data across North America from 2023-2025

This data release contains measurement‑accuracy information derived from angler‑reported fish lengths submitted through a smartphone mobile application. The dataset includes records from multiple fishing events across the United States and Canada in which participating anglers self‑reported total length (TL) for each catch. Lengths were subsequently reviewed and verified by app staff, generating paired original and final TL values. Discrepancies between reported and verified lengths were calculated and categorized as overestimates or underestimates, with additional annotation of error sources (for example, operator error, rounding, incorrect unit reporting, or order‑of‑magnitude errors). The dataset spans January–October 2024 and provides high‑resolution temporal metadata for each measurement event.

This release supports analyses evaluating the accuracy of citizen‑science length reporting and the reliability of mobile‑app‑based fisheries data collection. Preliminary analyses showed that discrepancies between original and verified TL values were generally small, with most errors falling within a few centimeters of the verified measurement. Operator error was the most commonly assigned error category, while rounding and unit‑conversion errors occurred less frequently. These data may be used to quantify reporting accuracy, assess sources of measurement bias, and support development of quality‑assurance procedures for mobile application–based fisheries monitoring programs.