Comparative Abundance, Species Composition, and Demographics of Continental Shelf Fish Assemblages throughout the Gulf of Mexico

Abstract

We analyzed the results of the first comprehensive, systematic, fishery-independent survey of Gulf of Mexico (GoM) continental shelves using data collected from demersal longline sampling off the United States, Mexico, and Cuba. In total, 166 species were sampled from 343 longline sets during 2011-2017, which deployed 153,146 baited hooks, catching 14,938 fish. Abundance, species richness, and Shannon-Wiener diversity indices by station were highest in mid-shelf depths (~100 m), declining by about half in deeper waters. Six spatial assemblages were identified by testing the results of cluster analysis using similarity profile analysis and then plotting the geographic location of identified station clusters. A high degree of depth-related and horizontal zonation was evident for demersal fish species. Multispecies CPUE (number per 1,000 hookhours) was highest off the north-central (NC) and northwestern (NW) GoM and lower on the West Florida Shelf (WFS), Cuba (CUB), Yucatan Peninsula (YP), and southwestern (SW) GoM. Snappers and groupers were most abundant in the WFS and CUB, while elasmobranchs were the dominant taxa in the NC and NW GoM. Pelagic species were relatively rare everywhere (owing to the use of demersal longline gear), but were most dense off CUB. Species richness was highest in the NC and WFS subareas and lowest in the NW and CUB. Slopes of multispecies size spectra, which integrated mortality, recruitment, growth, and species interactions among size-groups, were shallowest in the NW and NC GoM and steepest off the WFS and YP. These results provide a basis for evaluating the relative resiliency potential of species assemblages across the continental shelves of the GoM, and thus for identifying subareas that are most vulnerable to acute and chronic perturbations from cumulative effects of fishing, climate change, pollution (including oil spills), habitat loss, and invasive species.

DNA barcoding of fish eggs collected off northwestern Cuba and across the Florida Straits demonstrates egg transport by mesoscale eddies

“…(snappers), Makaira nigricans (Blue Marlin) , Scomberomorus cavalla (King Mackerel) , Ocyurus chrysurus (Yellowtail Snapper) , Trachinotus falcatus (Permit) , and Xiphias gladius (Swordfish). Several of the species that eggs were identified from were also captured as adults in a companion longline survey conducted on the same cruise and stations along the coast of Cuba, including Gymnothorax moringa (Spotted Moray), Thunnus atlanticus (Blackfin Tuna), Ocyurus chrysurus (Yellowtail Snapper), Lutjanus analis (Mutton Snapper), Epinephelus adscensionis (Rock Hind), and Haemulon plumierii (White Grunt) (Murawski, Peebles, Gracia, Tunnell, & Armenteros, 2018).…”

DNA barcoding reveals clear delineation between spawning sites for neritic versus oceanic fishes in the Gulf of Mexico

“…The second cruise focused on a smaller region of the northeastern GoM during spring 2016 (April 8–12), and the third cruise circumnavigated the GoM during late summer 2016 (August 4–September 10). Egg sampling was conducted on cruises where the primary activity was collecting adult fishes using demersal long lines (Murawski et al., ), and thus, plankton tows were only conducted at times when other shipboard research activities were not ongoing and long steaming periods were anticipated. As a result, potential transects were preselected during the cruise planning stage.…”

“…It can be equally effective at collecting small, cryptic species as it is for large, evasive species; most economically valuable species are at least moderately large and moderately evasive. The fourth objective provides linkages between biodiversity studies of fishes in continental shelf (Murawski, Peebles, Gracia, Tunnell, & Armenteros, 2018), deep benthic (Wei, Rowe, Haedrich, & Boland, 2012), mesopelagic (Sutton et al, 2017), and epipelagic (Habtes, Muller-Karger, Roffer, Lamkin, & Muhling, 2014) habitats of the GoM.…”

Associations Between Chronic Exposure to Polycyclic Aromatic Hydrocarbons and Health Indices in Gulf of Mexico Tilefish (Lopholatilus chamaeleonticeps) Post Deepwater Horizon

“…Tilefish were caught consistently at 9 stations in the northern Gulf of Mexico, which ranged from west of the Mississippi River, around the DeSoto Canyon, to the northern West Florida Shelf (Figure 1). Sampling occurred in the months of July (2017) and August (2012,2013,2014,2015) Murawski et al (2014), Snyder et al (2015, and Murawski et al (2018).…”