Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Fisheries Oceanography, 27 (2018): 246-258, doi:10.1111/fog.12249.
Description:
Swordfish Xiphias gladius (Linnaeus, 1758) are a circumglobal pelagic fish targeted by
multiple lucrative fisheries. Determining the distribution of swordfish larvae is important for
indicating reproductive activity and understanding the early life history of swordfish. We
identify and characterize larval swordfish distributions during peak swordfish spawning
throughout the Gulf of Mexico and western Caribbean Sea with generalized additive models
(GAMs) using catches of swordfish larvae during ichthyoplankton surveys in April and May of
2010, 2011, and 2012. The best fit GAM, as determined by stepwise, backward Akaike
Information Criterion selection, included both physiochemical (temperature at 5 m, sea surface
height anomaly (SSHA), eddy kinetic energy (EKE)), temporal (lunar illumination, hour of
sampling) and spatial (location) variables, while near-surface chlorophyll a concentration
residuals remained as a random effect. The highest probability of larval swordfish catch occurred
at sub-surface temperatures, SSHA, and EKE values indicative of boundary currents. Standard
lengths of larvae were larger further downstream in the boundary currents, despite high
variability in length with location due to multiple spawning locations of swordfish near these
currents. Probability of larval swordfish catch also peaked during the crescent and gibbous
moons, indicating a lunar periodicity to swordfish spawning. These results suggest that swordfish may spawn during select moon phases near boundary currents that transport their larvae to larval
and juvenile habitat including the northern Gulf of Mexico and coastal waters of the southeast
United States.
Description:
NASA Grant Numbers: NNX11AP76G, NNX08AL06G
Keywords:
Caribbean Sea
;
Generalized additive models
;
Gulf of Mexico
;
Larval habitat
;
Swordfish
;
Xiphiidae
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
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