PCA-based denoising and automatic recognition of marine biological sounds to estimate Bio-voice Count Index for marine monitoring
Bibliographic record
Abstract
Passive acoustic monitoring faces methodological challenges when isolating biological signals from anthropogenically dominated marine soundscapes. To address this, we present two novel computational workflows: (1) a Principal Component Analysis (PCA)-driven noise reduction algorithm that selectively suppresses anthropogenic noise (e.g., vessel sounds) overlapping with biological frequency bands; and (2) an automatic Bio-voice Count Index (BCI) that quantifies target biological sounds through energy thresholding and adjustable frequency-weighting curve. We validated these methods using both synthetic soundscapes and 700 min of field recordings from coral reef ecosystems in Sanya, China. The PCA algorithm improved mean signal-to-noise ratios of field recordings by 5.3 dB (from 7.6 dB to 12.9 dB), effectively enhancing biological sound detectability. The BCI demonstrated strong correlations with biological metrics. When combined with the Acoustic Complexity Index, it improved the accuracy of fish abundance estimation compared to single-index approaches. Critically, our method reduces the analysis time by >90 % compared to manual methods. These tools provide ecologists with a reproducible framework for quantifying biodiversity in noisy environments, directly applicable to coral reef health monitoring and anthropogenic impact assessments.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".