Northeast Pacific Coastal to Offshore Corridor is an important movement area for Bigeye Threshers.

Bigeye Threshers regularly move through this area, connecting seasonal nearshore feeding sites with offshore habitats (Sepulveda et al. 2019; Aalbers et al. 2021; SA Aalbers unpubl. data 2026). A study tagged 28 Bigeye Threshers in the Southern California Bight between 2016–2021 to assess post-release survival. Tags included six pop-up archival satellite tags (miniPATs) and 22 survivorship pop-up archival tags (sPATs), with a track duration of 16–41 days (average = 25 days). Tagged sharks comprised six males, four females, and 18 for which sex was not determined, and they ranged from 147–230 cm fork length (256–402 cm total length; Liu et al. 1998) including five juveniles and nine adults (SA Aalbers unpubl. data 2026). Sharks were tagged between July–December during a six-year period, with most tagged in August (55%; n = 15). The seasonality corresponds with the seasonal occurrence of the species in nearshore southern California in summer and autumn (Sepulveda et al. 2019). The Southern California Bight appears to be a feeding site for the species, with stomach content analysis suggesting they feed on a variety of epipelagic, mesopelagic, epi-benthic, and deep-scattering-layer species (Preti et al. 2008). Two tags did not report, leaving 26 sharks with a tag deployment and pop-up location. Tracks using light-level-based geolocation are not available because the species remains in the dark, staying deep during the day and shallow at night (Aalbers et al. 2021; SA Aalbers unpubl. data 2026).

Almost all tracked Bigeye Threshers (23 of 26; 88%) showed fast and directional movement from the Southern California Bight heading into offshore waters (Aalbers et al. 2021; SA Aalbers unpubl. data 2026). Four of these sharks moved directly south, outside of the area, while the remaining 19 individuals swam southeast through this movement corridor. The end point of the corridor corresponds to a seamount complex, with seamounts recognised as being hotspots of pelagic biodiversity (Morato et al. 2010). There were no clear differences between sexes or life-stages. The 19 individuals swimming through this corridor covered an average straight-line distance of 1,232 km (range 733–1,525 km) over their average 25-day track and had an average speed of 54 km day^-1. This fast horizontal movement is in addition to extensive diel vertical migration between surface waters and depths of ~400–500 m. While there are no intermediate positions between deployment and pop-up locations, the fast and directional movement, as well as the recurring movement pattern for most tracked individuals, highlight that this is an important movement corridor. It is possible that Bigeye Threshers move further into offshore waters, past the boundaries of this area, since track duration was short. However, available tracking data support this corridor as an important movement area that links seasonal nearshore feeding habitat with offshore waters (Aalbers et al. 2021; SA Aalbers unpubl. data 2026).