This report assesses two management questions for the Hawai‘i deep-set longline fishery around Johnston Atoll: whether the closure period was associated with spillover into adjacent fishing grounds, and whether the brief 2025 reopening produced immediate catch-rate gains inside the monument area. The analysis uses species specific mixed-effects models applied to logbook data from January 2005 through August 2025, with permit-level random effects and standardized operational/environmental covariates. A key design feature is the use of four spatial distance definitions (100, 150, 200, and 250 nm), which allows direct evaluation of how sensitive conclusions are to the width of the analysis rings.
Robert Ahrens (Fri,) studied this question.