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The most important fisheries are recording catches below their historical averages despite increased effort. This level of overfishing is worrying and requires the establishment of feasible and precise measures to prevent a continuing decrease in biomass. Determining the factors that lead to changes in the abundance and distribution of overfished resources would allow us to identify the strengths and weaknesses of management schemes; this approach would also make it possible to estimate more accurate parameters for their evaluation. We hypothesize that environmental, temporal, spatial, and operational components contribute to the variation in the relative abundance. Thus, we analyzed the red grouper fishery, the most important demersal fishery in the southeastern Gulf of Mexico (SGM); it is locally known as escama. We employed the catch per unit effort (CPUE) as an index of relative abundance recorded by the semi-industrial fleet (kilogram per effective fishing day) and the small-scale fleet (kilogram per effective fishing hour) during the overexploitation phase (from 1996 to 2019). We fitted several variables of the components using generalized additive models (GAM) and used multi-model inference to determine the best GAM for each fleet. For both fleets, the operational and temporal components (fishing gear and year) have had a greater impact on the distribution and abundance of red grouper in the SGM than the spatial and environmental components (the place of origin and sea surface temperature). These findings encourage the exploration of métier schemes for more efficient fishery management. In addition, we have identified several strategies that would support the recovery of the resource, such as restricting fishing in the quadrants located to the northeast or regulating scuba diving. We recommend that in the future, researchers use the indices we have generated in the present study to evaluate the red grouper fishery.

To be as accurate as possible, stock assessments should account for discard mortality in fisheries if it occurs. Three common approaches to modeling discards in assessments are to lump dead discards with landings, treat dead discards as their own fleet, or link them conversely with landings through use of a retention function. The first approach (lumping) implicitly assumes that the selectivity of landings applies also to discards. In many cases, that assumption is false, for example, if discards comprise smaller fish than do landings. The latter two approaches avoid the assumption by modeling discards explicitly with their own selectivity pattern. Here, we examine these approaches to modeling discards. Using a simulation study, we demonstrate that the two approaches to modeling discards explicitly can provide identical results under both static and time-varying conditions. Then, using a stock assessment case study of red grouper Epinephelus morio in the U.S. Gulf of Mexico, we demonstrate that in practice the approaches to modeling discards can provide different outcomes, with implications for the resultant management advice. We conclude by comparing and contrasting the different approaches, calling for more research to elucidate which approach is most suitable under various sources of error typically encountered in discard data.

Ecosystem-based fisheries-management (EBFM) is increasingly used in the United States (U.S.), including in the Gulf of Mexico (GOM). Producing distribution maps for marine organisms is a critical step in the implementation of EBFM. In particular, distribution maps are important inputs for many spatially-explicit ecosystem models, such as OSMOSE models, as well as for biophysical models used to predict annual recruitment anomalies due to oceanographic factors. In this study, we applied a recently proposed statistical modelling framework to produce distribution maps for: (i) younger juveniles (ages 0-1) of red snapper (Lutjanus campechanus), red grouper (Epinephelus morio), and gag (Mycteroperca microlepis), so as to be able to define the potential larval settlement areas of the three species in a biophysical model; and (ii) the functional groups and life stages represented in the OSMOSE model of the West Florida Shelf ("OSMOSE-WFS"). This statistical modelling framework consists of: (i) compiling a large database blending all of the encounter/non-encounter data of the GOM collected by the fisheries-independent and fisheries-dependent surveys using random sampling schemes, referred to as the "comprehensive survey database;" (ii) employing the comprehensive survey database to fit spatio-temporal binomial generalized linear mixed models (GLMMs) that integrate the confounding effects of survey and year; and (iii) using the predictions of the fitted spatio-temporal binomial GLMMs to generate distribution maps. This large endeavour allowed us to produce distribution maps for younger juveniles of red snapper, red grouper and gag and nearly all of the other functional groups and life stages represented in OSMOSE-WFS, at different seasons. Using Pearson residuals, the probabilities of encounter predicted by all spatio-temporal binomial GLMMs were demonstrated to be reasonable. Moreover, the results obtained for younger juvenile fish concur with the literature, provide additional insights into the spatial distribution patterns of these life stages, and highlight important future research avenues. [ABSTRACT FROM AUTHOR]

Organisms that either directly or indirectly modify the availability of resources can have profound effects on the structure and function of ecological communities. This holds true for organisms that enhance habitat complexity either as a function of their morphology or through mechanical activities, such as digging or burrowing. The net positive effects of engineers on local species diversity follows from activities that allow more species to live in modified habitats compared to unmodified ones. Here, we present the results of a multiyear observational study evaluating the effects of habitat modifications made by juvenile red grouper, Epinephelus morio (Valenciennes, 1828), on the fishes and motile macroinvertebrates associated with karst solution holes in Florida Bay, FL, USA. Because red grouper have multiple roles in these systems, acting as both habitat engineers and predators that consume a variety of benthic crustaceans and fishes, their influence on associated communities is complex. We found that the presence of red grouper resulted in deeper solution holes, increased abundance and richness of the associated fauna, especially among juvenile coral-reef fishes and motile invertebrates, and significant differences in the structure of faunal communities over time. These results suggest that red grouper shape unique communities, distinct from those of surrounding areas, and strongly influence the composition of communities associated with manipulated habitats. [ABSTRACT FROM AUTHOR]

Red and black groupers are large-bodied opportunistic ambush predators commonly found in Southwestern Atlantic tropical reefs. We investigated the diet of both species in order to detail ontogenetic, spatial and temporal trends, and to assess the extent of overlap in resource use between these two sympatric predators on the Abrolhos Bank, Brazil. Decapods and fishes were the main food items of Epinephelus morio while fishes were the main prey of Mycteroperca bonaci. Both diets were significantly influenced by body size and habitat, but only smaller individuals of E. morio feed almost exclusively on crustaceans. While the two groupers rely on many of the same prey types, coexistence may be facilitated by E. morio feeding more heavily on crustaceans, particularly the blackpoint sculling crab Cronius ruber, while black grouper take comparatively few crustaceans but lots of fish prey. Predators like red and black groupers could trigger indirect effects in the community and influence a large range of ecological processes, such as linkages between top and intermediate predators, and intermediate predators and their resources. [ABSTRACT FROM AUTHOR]

The spatial dynamics of the red grouper Epinephelus morio plays a fundamental role in the fishery management on the Campeche Bank, where it is overfished. The objective of this study was to characterize the spatial dynamics of this population. We used a dynamic model of spatial distribution to estimate population movement rates between adjacent areas. The model was applied using information on catch per unit effort and length-frequency distributions for the Mexican mid-sized fleet that operated in the area in the period 1973-1977. These data were chosen to ensure that the information would reflect the condition of the resource before overfishing. It was possible to quantify the spatial dynamics of the red grouper and the results were consistent with previously known movement patterns. The results showed different movement rates and temporal patterns of movement for different population sectors. The spawning aggregations and the seasonal upwelling occurring in the eastern part of the Bank were considered as key factors influencing the pattern of population movements.

End-to-end ecosystem modeling platforms, including OSMOSE, are key tools for informing ecosystem-based fisheries management (EBFM). End-to-end models ideally implement two-way interactions between model components, yet two-way interactions between high trophic level (HTL) functional groups and humans (fisheries managers and fishers) are currently missing in OSMOSE. We developed a management strategy evaluation (MSE) framework for OSMOSE, which allows for feedback between HTL functional groups and fisheries managers. This framework couples OSMOSE to a management procedure integrating decision rules and accounting for scientific uncertainty and the acceptable risk of overfishing. We applied the MSE framework to the OSMOSE model of the West Florida Shelf, so as to conduct an evaluation of total allowable catch (TAC) strategies for red grouper ( Epinephelus morio ) in a context of episodic events of natural mortality. Our simulations indicate that TAC strategies that assume higher scientific uncertainty and/or lower acceptable risk of overfishing result in higher biomass-related metrics for red grouper. However, the levels of scientific uncertainty and acceptable risk of overfishing impose a trade-off between biomass-related and catch-related metrics for red grouper. Our simulations also indicate that updating red grouper TAC more frequently in a context of episodic events of natural mortality does not have a large impact on biomass-related and catch-related metrics for red grouper and other functional groups. The MSE we conducted for red grouper is strategic, and its outcomes, which were obtained under a specific set of assumptions, must be considered preliminary. We discuss how future research could help enhance understanding of the possible impacts of TAC strategies for red grouper. The MSE framework designed for OSMOSE links the dynamics of HTL functional groups to that of fisheries managers, thereby allowing OSMOSE to be better suited for informing EBFM. This framework is an invaluable asset in assessing the performance of fisheries management strategies, but could also be used for other purposes, such as the evaluation of research monitoring programs. [ABSTRACT FROM AUTHOR]

Passive acoustic recorders were used to monitor sound production indicative of the use of spawning habitat by groupers (Serranidae) at Riley's Hump, which is located in the Tortugas South Ecological Reserve (TSER), part of the Florida Keys National Marine Sanctuary. Sound production by black grouper (Mycteroperca bonaci), red grouper (Epinephelus morio), and red hind (E. guttatus) was recorded yearround and at all times of day but occurred more often in the evening during the winter-spring spawning period than during other times of the day and year. This pattern for these species is consistent with results of previous studies that documented the association of sound production with reproductive behavior at spawning sites. Distinct diel and seasonal patterns of sound production by the longspine squirrelfish (Holocentrus rufus) and bicolor damselfish (Stegastes partitus) also were recorded. Riley's Hump is a documented spawning site for mutton snapper (Lutjanus analis), and recordings of black grouper, red grouper, and red hind indicate that it is used for reproductive purposes by these species as well. These results showed the importance of the TSER and the need for continued research to understand its role in the recovery and sustainability of managed fish populations. [ABSTRACT FROM AUTHOR]

Unsaturated fatty acids are of current interest for their potential to reduce cardiovascular disease, the first cause of death worldwide. By its content of essential fatty acids, fish is one of the food products most in demand among the population. One of the most popular processes for fish consumption in Yucatan Peninsula, Mexico is frying. However, studies show that frying food causes changes in the composition generating trans fatty acids. The objective of this study was to evaluate the fatty acid profile of Mero (Epinephelus morio) crude and processed with different types of commercial oil. The results showed a fat content in raw E. morio of 1.68%. The percentage of oil extracted and absorbed by the product to be fried with corn oil, sunflower/canola, soybean and safflower was found in a range of 2.3-3.93 and 26.95-57.25%, respectively. The lipid profile obtained by GC-MS suggested the formation of trans fatty acids by isomerization and effect of temperature frying. However essential fatty acids such as oleic and linoleic acids were absorbed by E. morio being fried in sunflower oil and safflower/ canola, respectively. [ABSTRACT FROM AUTHOR]

We evaluated eye lenses as potential recorders of stable isotope histories in fish because they consist of metabolically inert optical proteins that are deposited in successive, concentric circles (laminae) much like otolith circuli and tree rings. We conducted four different tests on lenses from red snapper, red grouper, gag, and white grunt. The first test was a low-resolution screening of multiple individuals (4–5 radial groups of laminae per lens, all species except white grunt). Along the radial axis, all individuals exhibited substantial isotopic variability. Red snapper individuals separated into two groups based on δ15N and gag separated into two groups based on δ13C. Two gag with the greatest variation were chosen for high-resolution temporal analysis using individual laminae from their second eye lenses. The first-order patterns from the high-resolution analysis generally mimicked patterns from the low-resolution screening of grouped laminae, yet the high-resolution plots revealed early-life details that were not apparent in the low-resolution screenings. For the third test, left- versus right-eye variation was compared using high-resolution methods. White grunt left- and right-eye radial isotopic patterns were almost identical for both δ13C and δ15N, suggesting the variations observed among individual fish were not artifacts. The final test evaluated intra-laminar variation; multiple samples were analyzed from different parts of the same lamina. Seven laminae from three individuals of two species were analyzed in this manner; variations among laminae were found to be much higher than variations within laminae. However, nominal intra-laminar variations were comparable to nominal differences between left and right lenses, suggesting intra-laminar variation established measurement precision. Eye lens isotopes appear to be useful for reconstructing the isotopic histories of individual fish; these histories can be compared with spatially-derived isoscapes to reconstruct individual histories for site fidelity, movement and trophic position. [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.

The article highlights the activity of five exploited snapper-grouper species in the diverse coral reef habitat of Dry Tortugas, Florida. Among those included in the study conducted by the authors were red grouper Epinephelus morio, yellowtail snapper Ocyurus chrysurus and mutton snapper Lutjanus analis. The authors disclosed that movement of black groupers were small and infrequent while muttons like to make short and frequent movements. They also discovered that there were relatively small home ranges for red grouper, black grouper and yellowtail snapper.

The article explores the distribution and dynamics of holes red grouper Epinephelus morio in Steamboat Lumps Marine Reserve in the Gulf of Mexico. E. morio are known as ecosystem engineers for the depressions or holes they create in flat sandy bottom parts of the ocean. In the authors' study, they used high-resolution multibeam sonar data obtained in the reserve in 2006 and 2009. The authors found that from 2006-2009 there was an increase in hole density to 141 holes kilometer-squared and an increase in the number of holes from 181 in 2006 to 231 in 2009. They conclude that the use of active acoustic sonar is a effective way to observe red grouper spawning populations.

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]

Food poisoning due to ingestion of an unknown red grouper occurred in southern Taiwan. To identify the species of toxic red grouper implicated in food poisoning, a 475-bp sequence of the cytochrome b gene from six species of fresh red grouper meat was amplified by using a pair of primers (L14735/H15149). This fragment could be amplified when fish meat was treated with different heating processes. After sequencing, it was found that no variation in sequences was detected among individuals within each species. The species of toxic red grouper meat implicated in food poisoning was judged to be Lutjanus bohar based on sequence analysis. In addition, restriction enzyme analysis with HaeIII rapidly distinguished these six species of red grouper and the two samples implicated in food poisoning. No toxicity of viscera in 18 specimens of six red grouper species was detected, but two food poisoning samples were found to be toxic. This study indicated that DNA sequence and restriction enzyme analysis are powerful methods for identifying potentially toxic red grouper species as L. bohar. [ABSTRACT FROM AUTHOR]

The red grouper (Epinephelus morio) has historically been one of the most important fisheries of the Campeche Bank area in the Gulf of México, where two fleets from México and one from Cuba participate. Current stocks have been estimated to be a third or less as abundant as in the 1970s; hence, the fishery has been declared to be over-exploited. The federal government of México has expressed the need to investigate the potential use of protected areas as a management tool for recovery of this species. Based on artificial neural network (ANN) modelling, we analysed the spatial distribution of red grouper with respect substrate, considering the demographic structure of the stock. We found a significant relationship between the type of substrate and the three stages of development (juveniles, pre-adults and adults). Juveniles are distributed in shallow waters close to the coast on coral substrates; pre-adults are also associated with coral substrates, but at an intermediate depth; adults are found in deeper waters on sandy substrates. We also identified seasonal reproductive aggregation patterns, always in relation to substrate types. Reproductive aggregation during the winter and early spring in the north-eastern continental shelf and the almost permanent (exception in autumn) concentration of juveniles in coastal waters around the central and eastern coast of Yucatan are of particular importance for management. These patterns represent seasons and areas of high fish vulnerability, which is the basic criterion for further analysis of protected areas. [Copyright &y& Elsevier]

To be as accurate as possible, stock assessments should account for discard mortality in fisheries if it occurs. Three common approaches to modeling discards in assessments are to lump dead discards with landings, treat dead discards as their own fleet, or link them conversely with landings through use of a retention function. The first approach (lumping) implicitly assumes that the selectivity of landings applies also to discards. In many cases, that assumption is false, for example, if discards comprise smaller fish than do landings. The latter two approaches avoid the assumption by modeling discards explicitly with their own selectivity pattern. Here, we examine these approaches to modeling discards. Using a simulation study, we demonstrate that the two approaches to modeling discards explicitly can provide identical results under both static and time-varying conditions. Then, using a stock assessment case study of red grouper Epinephelus morio in the U.S. Gulf of Mexico, we demonstrate that in practice the approaches to modeling discards can provide different outcomes, with implications for the resultant management advice. We conclude by comparing and contrasting the different approaches, calling for more research to elucidate which approach is most suitable under various sources of error typically encountered in discard data. [ABSTRACT FROM AUTHOR]

Epinephelus morio (Red Grouper) is an important component of commercial fisheries for the United States and Mexico. Fishery-independent long-line surveys that utilized standardized sampling designs were conducted along the west Florida shelf, Florida and Campeche Bank, Mexico (2001-2002). Detecting true differences in abundance and sizes are difficult, but by using standard collection and aging methodologies, the level of bias was kept at a minimum. Relative abundance was higher in the Campeche Bank compared to the west Florida shelf (1.74 and 0.63 Red Grouper/100 hook hr, respectively). Fish from the Campeche Bank were also significantly smaller at length and weight. Differences in length, weight, and relative abundance of Red Grouper may be because of historical fishing pressure and management regulations, or the available carrying capacity of each area for Red Grouper. These differences have a substantial impact on how an overfished population can recover and be sustained. [ABSTRACT FROM AUTHOR]

The article discusses the life history of the red grouper (Epinephelus morio) in North and South Carolina. The 2,146 sample specimens of red grouper have a total length range of 315 to 851 millimeter with the age range of 2 to 20 years. The von Bertalanffy growth equation was used to describe the length-at-age, while the sex type was assessed using histological analysis. It was determined that red groupers are protogynous hermaphrodite or their sex type changes as they mature.

The purpose of this study were to: (i) develop mitochondrial (mt)DNA probes for two species-groups of reef fishes, and (ii) assay mtDNA restriction fragment length polymorphism (RFLP) variation in two reef fish species from the Gulf of Mexico. MtDNA probes for groupers of the genera Epinephelus and Mycteroperca and for jacks of the family Carangidae were generated and mtDNA fragment patterns of 34 enzymes were assayed from samples of red grouper (Epinephelus morio) and greater amberjack (Seriola dumerilli). Ten polymorphic restriction enzymes (yielding 12 distinct mtDNA haplotypes) were identified in the red grouper, while 19 polymorphic enzymes (yielding 23 distinct mtDNA haplotypes) were identified in greater amberjack. Estimates of percentage nucleotide-sequence divergence among haplotypes ranged from 0.09–0.59 (mean ± S.E. = 0.29 ± 0.02) in red grouper and from 0.09–1.32 (mean ± S.E. = 0.49 ± 0.02) in greater amberjack. Estimated mtDNA nucleon diversity values were 0.418 and 0.900 for red grouper and greater amberjack, respectively. Estimated intrapopulational percentage nucleotide diversities were 0.078 ± 0.003 (mean ± S.E.) for red grouper and 0.336 ± 0.006 (mean ± S.E.) for greater amberjack. Estimates of the evolutionary effective female population size (Nflel) were generated for both species and compared to Nflel values for eight other marine fish species or subspecies. The Nflel value for greater amberjack was more or less intermediate, whereas the Nflel value for red grouper was low. The latter may indicate that red grouper warrant immediate management attention. Heterologous hybridizations to mtDNAs of two other species of Epinephelus (E. adscensionis and E. fulvus) and to Myeteroperca phenax (using the red grouper probe), and to mtDNA of the horse-eye jack, Curanx lutus (using the greater amberjack probe), were successful. MtDNA data generated from red grouper and greater amberjack, as well as the potential to obtain mtDNA data from other grouper and carangid species, should prove useful in future studies of genetic variation and population differentiation in these important reef fishes. [ABSTRACT FROM PUBLISHER]

Chlorine dioxide (CIO2) has been explored as a potential substitute for aqueous chlorine to clean seafood products. In an attempt to understand the interaction of CIO2 with organic compounds, duplicate fillets of Atlantic salmon ( Salmo salar) and red grouper ( Epinephelus morio) were treated for 5 min with freshly prepared aqueous CIO2 at 20, 40, 100, and 200 ppm total available CIO2 in 3.5% brine. Thiobarbituric acid (TBA) values and fatty acid composition were determined. CIO2-treated salmon and red grouper showed a dose-related increase in TBA; the 100 and 200 ppm groups had significantly ( P<0.05) greater TBA values than controls and the 20 ppm group. Treated red grouper and salmon did not differ in percentage monounsaturated and polyunsaturated fatty acids compared to controls, although differences occurred with some individual fatty acids. Thus, CIO2 treatment did not greatly affect fatty acid composition of treated fillets. [ABSTRACT FROM AUTHOR]

A correction to the article "Life history of red grouper (Epinephelus morio) off the coasts of North Carolina and South Carolina" that was published in the previous issue is presented.