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The ecosystem model OSMOSE-WFS was employed to evaluate natural mortality rates and fishing scenarios for Gulf of Mexico (GOM) red grouper ( Epinephelus morio ). OSMOSE-WFS represents major high trophic level (HTL) groups of species of the West Florida Shelf, is forced by the biomass of plankton and benthos groups, and has a monthly time step. The present application of the model uses a recently developed ‘stochastic mortality algorithm’ to resolve the mortality processes of HTL groups. OSMOSE-WFS predictions suggest that the natural mortality rate of juveniles of GOM red grouper is high and essentially due to predation, while the bulk of the natural mortality of adult red grouper results from causes not represented in OSMOSE-WFS such as, presumably, red tides. These results were communicated to GOM red grouper stock assessments. Moreover, OSMOSE-WFS indicate that altering the fishing mortality of GOM red grouper may have no global impact on the biomass of the major prey of red grouper, due to the high complexity and high redundancy of the modeled system. By contrast, altering the fishing mortality of GOM red grouper may have a large impact on the biomass of its major competitors. Increasing the fishing mortality of red grouper would increase the biomass of major competitors, due to reduced competition for food. Conversely, decreasing the fishing mortality of red grouper would diminish the biomass of major competitors, due to increased predation pressure on the juveniles of the major competitors by red grouper. The fishing scenarios that we evaluated may have slightly different impacts in the real world, due to some discrepancies between the diets of red grouper and its major competitors predicted by OSMOSE-WFS and the observed ones. Modifications in OSMOSE-WFS are suggested to reduce these discrepancies. [ABSTRACT FROM AUTHOR]

While conducting a standardized fisheries-independent longline survey in the northern Gulf of Mexico on August 20–21, 2014, dead and/or moribund fishes, estimated to number in the thousands, were observed within a well-defined area of the West Florida Shelf. Fishes from 15 families were identified; however, numerous individuals of relatively large-bodied serranid species were decomposed beyond a state that would allow for identification below the family level. Based on survey catch data from previous years and morphological characteristics associated with the decomposing fishes, it was determined that most of the large unidentified fishes were red grouper ( Epinephelus morio ). Water profiler cast data collected within the area demonstrated that when compared to previous years (1995–2013) bottom temperature and salinity were consistent with what would be expected; however, dissolved oxygen concentration was lower than normal, and in some cases, hypoxic and chlorophyll a and transmissivity values were anomalously high and low, respectively. Hypoxia, high chlorophyll a concentrations and low transmissivity are thought to have resulted from a bloom of Karenia brevis , which was documented to have occurred in close proximity to the sampling area. As necropsies were not performed, it was not possible to state a definitive cause of death as the effects of brevetoxins are species-specific. However, numerous individuals of most impacted species were observed floating incapacitated, yet alive, in normoxic surface waters suggesting that the impacts we observed were due to the neurotoxicological and/or hemolytic effects of a harmful algal bloom. [ABSTRACT FROM AUTHOR]

The article examines the survival of red grouper and red snapper caught on circle and J-hooks by recreational fisheries in Florida. It mentions the difference of delayed hook mortality of both species from blood loss of J-hook nicked internal organs. It notes that the survival rates of the fish correlate with feeding behavior, jaw morphology, and prey residence time. It also emphasizes the higher tag recapture rates for tagged red grouper caught on circle hooks than on J-hooks.

In this article, we consider the potential effects of anthropogenic disturbances on marine fish species known or suspected to be habitat engineers. The three species of interest inhabit different marine habitats at different life stages, and therefore can have significant influences across the sea floor at broad spatial scales. The primary species include the shallow-water Atlantic goliath grouper (Epinephelus itajara), which inhabits mangrove root systems as juveniles, and caves, shipwrecks, and rocky reefs as adults; red grouper (E. morio), which excavates habitat throughout its benthic life in Karst regions of the Gulf of Mexico and western Atlantic, from the coast to the shelf-edge; and tilefish (Lopholatilus chamaeleonticeps), a species that lives on the continental slope and constructs elaborate, pueblo-esque burrows. The anthropogenic disturbances of greatest interest in the Gulf of Mexico include fishing, hypoxia, red tide, oil and gas exploration, and climatic change. We suggest that to understand the broader effects of both natural and anthropogenic disturbances on biomass and productivity in these species requires that we first understand the strength of interactions between them and the other species residing within their communities (e.g., predators, prey, commensals, and mutualists). [ABSTRACT FROM AUTHOR]

Abstract: This study describes the historical evolution of the biomass, fishing mortality per age group, annual recruitment, and catchability of the Campeche Bank red grouper population. This fishery is based on three fleets (the Mexican Minor, the Mexican Major or Industrial, and the Cuban) with different capacities, areas of operation, and targeting of different age groups. During the last 10 years, the Minor fleet expanded, resulting in some overlapping with the other fleets areas. The biomass of the population of the red grouper in the Campeche Bank has decreased between 1986 and 2000. This decrease is evident from the commercial landings (from 14,410 to 9797t) and in CPUE from independent research surveys (from 3.8 to 1.5kg/100 hooks). The size of the spawning stock has decreased 25% since the beginning of the period, as well as the recruitment (from 24 to 11 million, 1–2 years old), while the catchability coefficient has increased (from 0.2 to 0.4). [Copyright &y& Elsevier]