Résumé
Mortality and predation of tagged fishes present a serious challenge to interpreting results of acoustic telemetry studies. There is a need for standardized methods to identify predated individuals and reduce the impacts of “predation bias” on results and conclusions. Here, we use emerging approaches in machine learning and acoustic tag technology to classify out-migrating Atlantic salmon (Salmo salar) smolts into different fate categories. We compared three methods of fate classification: predation tag pH sensors and detection data, unsupervised k-means clustering, and supervised random forest combined with tag pH sensor data. Random forest models increased predation estimates by 9–32% compared to relying solely on pH sensor data, while clustering reduced estimates by 3.5–30%. The greatest changes in fate class estimates were seen in years with large class imbalance (one or more fate classes underrepresented compared to the others) or low model accuracy. Both supervised and unsupervised approaches were able to classify smolt fate; however, in-sample model accuracy improved when using tag sensor data to train models, emphasizing the value of incorporating such sensors when studying small fish. Sensor data may not be sufficient to identify predation in isolation due to Type I and Type II error in predation sensor triggering. Combining sensor data with machine learning approaches should be standard practice to more accurately classify fate of tagged fish.
Langue d'origine | English |
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Pages (de-à) | 605-618 |
Nombre de pages | 14 |
Journal | Oecologia |
Volume | 198 |
Numéro de publication | 3 |
DOI | |
Statut de publication | Published - mars 2022 |
Note bibliographique
Funding Information:Funding provided by NSERC Strategic Partnership Grant No. 521256. R.J. Lennox was supported by the NFR project LaKES (#320726).
Funding Information:
We would like to acknowledge Cindy Hawthorne, Jeff Reader, Alana Ransome, George Nau, and other members of Fisheries and Oceans Canada and the Mi?kmaw Conservation Group for assistance in the field. As well as Darren and Erica Porter for receiver deployment and retrieval in the Minas Basin. We also thank Jake Brownscombe for answering questions about machine learning model tuning and members of the Ocean Tracking Network Data Centre for data acquisition and coding help.
Publisher Copyright:
© 2022, Crown.
ASJC Scopus Subject Areas
- Ecology, Evolution, Behavior and Systematics
PubMed: MeSH publication types
- Journal Article