Technical Report Series

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The Hawai’i Cooperative Fishery Research Unit Technical Report Series was initiated in 2021 to enable the archiving and retrieval of research project data and reports resulting from work conducted by the students and scientists of affiliated with the U.S. Geological Survey Hawai’i Cooperative Fishery Research Unit. All contributions to this series with a U.S. Geological Survey author have been peer reviewed and approved for publication consistent with U.S. Geological Survey Fundamental Science Practices ( Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.


Recent Submissions

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    Estimating detection and occupancy coefficients for the Pacific Islands coral reef fish species
    ( 2021-01-27) Suarez, Bobbie ; Grabowski, Timothy
    The data-limited stock assessment models used to monitor the status of coral reef fish species in the Western Pacific region are dependent upon accurate estimates of standing stock biomass generated from underwater visual surveys of reefs. However, the imperfect detection of and variable occupancy of habitat by reef fishes are not currently accounted for in these estimates. Therefore, the objective of this project was to estimate detection and occupancy coefficients for the species listed in the Western Pacific Regional Fishery Management Council’s Fishery Ecosystem Plans by analyzing the Pacific Island Fishery Science Center-Coral Reef Ecosystem Program Reef Fish Dataset. These detection and occupancy coefficients would then be applied to refine standing stock biomass estimates. In general, species with higher detection probabilities and/or lower occupancy rates tended to exhibit the greatest differences in the estimates of standing stock biomass calculated with and without accounting for detection and occupancy. The standing stock biomass of most reef fish species seem to be underestimated when detection and occupancy are not accounted for. However, the standing stock biomass of larger-bodied targeted species, such as jacks, snappers, and groupers, seem to be over-estimated relative to the estimates generated when accounting for occupancy and detection. While there are still issues to resolve regarding how well the current data collection methods meet the underlying assumptions of the detection and occupancy modeling approach, the inclusion of detection and occupancy coefficients seems likely to improve estimates of standing stock biomass of coral reef fish species.