TY - JOUR
T1 - Gag Grouper Larvae Pathways on the West Florida Shelf
AU - Weisberg, Robert H.
AU - Zheng, Lianyuan
AU - Peebles, Ernst B.
PY - 2014/10/1
Y1 - 2014/10/1
N2 - A numerical circulation model, quantitatively assessed against in situ observations, is used to describe the circulation on the West Florida Continental Shelf during spring 2007 when pre-settlement gag (Mycteroperca microlepis) were present in the surf zone near Tampa Bay, Florida. The pre-settlement fish were found to be isotopically distinct from settled juveniles in the area, which is consistent with recent arrival at near shore nursery habitats from offshore spawning grounds. Simulated particle trajectories are employed to test hypotheses relating to either a surface or a near-bottom route of across-shelf transport. The surface-route hypothesis is rejected, whereas the bottom-route hypothesis is found to be consistent with the location of pre-settlement fish and their co-occurrence with macroalgae of offshore, hard-bottom origin. We conclude that gag larvae are transported to the near shore via the bottom Ekman layer and that such transport is facilitated by remote forcing associated with Gulf of Mexico Loop Current interactions with the shelf slope near the Dry Tortugas. Being that such remote forcing occurs inter-annually and not always in phase with the preferred spawning months (late winter through early spring), gag recruitment success should similarly vary with year and location.
AB - A numerical circulation model, quantitatively assessed against in situ observations, is used to describe the circulation on the West Florida Continental Shelf during spring 2007 when pre-settlement gag (Mycteroperca microlepis) were present in the surf zone near Tampa Bay, Florida. The pre-settlement fish were found to be isotopically distinct from settled juveniles in the area, which is consistent with recent arrival at near shore nursery habitats from offshore spawning grounds. Simulated particle trajectories are employed to test hypotheses relating to either a surface or a near-bottom route of across-shelf transport. The surface-route hypothesis is rejected, whereas the bottom-route hypothesis is found to be consistent with the location of pre-settlement fish and their co-occurrence with macroalgae of offshore, hard-bottom origin. We conclude that gag larvae are transported to the near shore via the bottom Ekman layer and that such transport is facilitated by remote forcing associated with Gulf of Mexico Loop Current interactions with the shelf slope near the Dry Tortugas. Being that such remote forcing occurs inter-annually and not always in phase with the preferred spawning months (late winter through early spring), gag recruitment success should similarly vary with year and location.
KW - circulation
KW - gag grouper
KW - models and observations
KW - west florida shelf
UR - https://digitalcommons.usf.edu/msc_facpub/283
UR - https://doi.org/10.1016/j.csr.2014.06.003
U2 - 10.1016/j.csr.2014.06.003
DO - 10.1016/j.csr.2014.06.003
M3 - Article
VL - 88
JO - Continental Shelf Research
JF - Continental Shelf Research
ER -