Digital holography for real-time non-invasive monitoring of larval fish at power plant intakes

Delaney Sanborn, Alexis Base, Lysel Garavelli, Ranioy Barua, Jiarong Hong, Aditya R. Nayak

Research output: Contribution to journalArticlepeer-review


Effective evaluation of technological and operational approaches to reduce entrainment of marine organisms at cooling water intake structures (CWIS) requires accurate organism-sensing systems. Current detection methods lead to large temporal data gaps, require tedious manual analysis, and are fatal to organisms. Here, we describe integrating deep learning with a non-lethal, non-intrusive imaging method —digital holography —to rapidly detect fish larvae. Laboratory experiments demonstrated that the instrument could successfully image fish larvae at flow rates exceeding ranges seen in CWIS. Holograms of two fish larvae species, in the presence of bubbles and detritus, were collected to build a large database for training a lightweight convolutional neural network. The model achieves 97% extraction accuracy in quantifying larvae, and distinguishing them from other particles, including detritus and bubbles, when applied to a dataset of manually classified images, exceeding previous metrics for non-lethal, accurate, and real-time detection. These results demonstrate the potential of in situ holographic imaging for monitoring endangered larval fish species at power plant intake structures, and for high-fidelity, real-time applications in monitoring aquatic ichthyoplankton.

Original languageEnglish (US)
Pages (from-to)1470-1481
Number of pages12
JournalCanadian Journal of Fisheries and Aquatic Sciences
Issue number9
StatePublished - Sep 2023

Bibliographical note

Publisher Copyright:
© 2023, Canadian Science Publishing. All rights reserved.


  • deep learning
  • digital inline holography
  • endangered species
  • ichthyoplankton
  • real-time detection


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