Exempted and Research Deep-Set Fishing Trials for Swordfish, Xiphias gladius, in the Southern California Bight, 2017–21

Abstract

—This work reports on ex-empted and research fshing trials using Deep-set Buoy Gear (DSBG) and Linked Buoy Gear (LBG), two commercial gear types designed to target swordfsh, Xi-phias gladius , off the coast of southern California. This study covers the period from 2017 to 2021 and supplements previous published data on the development and initial exempted fshing permit (EFP) trials of deep-set techniques for sword-fsh within the Southern California Bight (SCB; 2015–16). In this work, fve cooperative EFP participants deployed 12,015 pieces of DSBG on 1,225 sets during 299 individual trips (mean=4.1 d/trip). DSBG catch composition was found to be similar to previously published data obtained from the frst 2 years of exempted effort, with swordfsh comprising ~94 % of the total catch from 2017 to 2021. DSBG non-marketable catch (bycatch) primarily consisted of blue sharks and made up ~1% of the DSBG catch. Collective DSBG catch rates ranged from 1.2 to 2.1 swordfsh per standardized 8-h fsh-ing day (mean =1.7 swordfsh/std. 8-h day) over the course of this study. Commercial exempted testing of LBG resulted in similar swordfsh catch composition (~92%) and average daily catch rates (1.5–1.7 swordfsh/std. 8-h day), with fewer overall species caught. Research sets using LBG yielded similar catch composition to DSBG and included a wider range of species than the exempted trials. The fndings from this work align with previous exempted and research efforts using both DSBG and LBG and continue to suggest high selectivity in the developing California deep-set fshery for swordfsh