Incorporating slow-moving recorder data in a species distribution modeling framework

Team: Janelle Gardner, Yvonne Barkley, Devin Johnson, Kaitlin Palmer, Selene Fregosi, Megan Wood (PIFSC)

The SPACIOUS project (Spatial Population Assessment of Cetaceans Integrating acoustic Observations from Uncrewed Systems) aims to develop the analytical framework necessary to integrate PAM data from slow-moving passive acoustic recorders, including underwater gliders and drifting acoustic recorders, into quantitative assessments of population distribution and density. The PAM and UxS SIs are heavily investing in the testing and development of PAM-equipped gliders and this effort will ensure that those developments are more quickly leveraged to improve cetacean assessments. This project will focus on developing a statistical framework that integrates PAM data from underwater gliders and drifters with existing visual-based species distribution models (SDM) to achieve more accurate ensemble models with seasonal context.

Project goals

Identify aspects of spatial models and currenty density estimation methods that need modification/supplementation to incorporate slow-moving data
Conduct simulations and/or experiments to address missing model components
Develop analytical framework with an initial target species
Engage with the PAM glider and modelling communities to assess the state of the science and validate approaches

Project status

Last updated: June 2026

(Selene)

SPACIOUS draws on two glider datasets collected as part of a Pacific-wide effort to operationalize PAM gliders for NMFS cetacean surveys. Both datasets are named for concurrent ship-based visual and acoustic surveys, enabling direct comparisons across data collection methods.

CalCurCEAS (California Current Cetacean and Ecosystem Assessment Survey): Two gliders surveyed the shelfbreak from Newport, OR to Eureka, CA in Fall 2024, covering ~800 km each over 6 weeks (red and yellow lines, left).

WHICEAS (Winter Hawaiian Islands Cetacean and Ecosystem Assessment Survey): Five gliders were deployed around the Main Hawaiian Islands from February–April 2026 for 6–12 weeks, covering up to 1,400 km each. Three will be used in SPACIOUS; SG679 (purple) is excluded due to a memory issue and the Slocum glider (green) due to platform differences.

All gliders carried identical WISPR3 recording systems sampling at 200 kHz. Gliders dove repeatedly to 1,000 m on 5–7 hour cycles, recording at all depths below 10 m — yielding near-continuous acoustic records with only ~10-minute gaps at the surface.