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Simple Summary: Ciguatera poisoning is a foodborne disease caused by the consumption of fish. Ciguatoxins are toxins produced by dinoflagellates. These microalgae attached to macroalgae are consumed by herbivorous fish, which are the prey of carnivorous fish that cause food outbreaks. The dusky grouper is a species capable of bioaccumulating ciguatoxins in its tissue and causing ciguatera in humans. This experiment consisted of studying the exposure of ciguatoxins in grouper through their diet, as occurs in the wild, through flesh naturally contaminated with ciguatoxins. This study of dietary exposure of ciguatoxins in grouper fish has allowed us to know the cytotoxic effects of the diet in this species and the fish's behavior against this toxic diet throughout the study time. Ciguatera is a foodborne disease caused by ciguatoxins (CTXs), produced by dinoflagellates (genera Gambierdiscus and Fukuyoa), which bioaccumulate in fish through the food web, causing poisoning in humans. Currently, the physiological mechanisms of the species with the highest amount of toxins in their adult stage of life that are capable of causing these poisonings are poorly understood. Dusky grouper (Epinephelus marginatus) is a relevant fishing species and is part of the CTX food chain in the Canary Islands. This study developed an experimental model of dietary exposure featuring adult dusky groupers with two diets of tissue naturally contaminated with CTXs (amberjack and moray eel flesh) with two different potential toxicities; both groups were studied at different stages of exposure (4, 6, 10, 12, and 18 weeks). The results showed that this species did not show changes in its behavior due to the provided feeding, but the changes were recorded in biochemical parameters (mainly lipid and hepatic metabolism) that may respond to liver damage and alterations in the homeostasis of the fish; more research is needed to understand histopathological and cytotoxic changes. [ABSTRACT FROM AUTHOR]

Despite the considerable research effort devoted to witnessing the reproduction of the emblematic dusky grouper, Epinephelus marginatus, the underwater spawning event has rarely been observed. In this study, we document for the first time the spawning event of the dusky grouper in the Marine Protected Area (MPA) of Cabo de Palos-Islas Hormigas (SE Iberian Peninsula, Spain), which represents the first direct spawning record of the species in the last 20 years. The reproductive event occurred on a seamount located within the buffer protection zone of the MPA. On the evening of July 27, 2021, the spawning of two individuals, displaying silverstreaked (male) and uniformly dark (female) colour patterns, was observed using SCUBA diving. The event was filmed and information on the environmental conditions in which reproduction occurred was collected. Successful spawning was documented at dusk, just one minute before sunset, three days after the full moon and with almost no current. In line with published data, our observation supports sea water temperature and photoperiod as primary potential triggers of dusky grouper reproduction in the Mediterranean. The confirmation of grouper reproduction within a well-enforced MPA established more than 25 years ago suggests that the survival and reproductive output of this large predatory fish may be favoured by protection measures, stressing the critical role of MPAs for maintaining a viable population of this valuable species. [ABSTRACT FROM AUTHOR]

Ciguatera is a foodborne disease caused by ciguatoxins (CTXs), produced by dinoflagellates (genera Gambierdiscus and Fukuyoa), which bioaccumulate in fish through the food web, causing poisoning in humans. Currently, the physiological mechanisms of the species with the highest amount of toxins in their adult stage of life that are capable of causing these poisonings are poorly understood. Dusky grouper (Epinephelus marginatus) is a relevant fishing species and is part of the CTX food chain in the Canary Islands. This study developed an experimental model of dietary exposure featuring adult dusky groupers with two diets of tissue naturally contaminated with CTXs (amberjack and moray eel flesh) with two different potential toxicities; both groups were studied at different stages of exposure (4, 6, 10, 12, and 18 weeks). The results showed that this species did not show changes in its behavior due to the provided feeding, but the changes were recorded in biochemical parameters (mainly lipid and hepatic metabolism) that may respond to liver damage and alterations in the homeostasis of the fish; more research is needed to understand histopathological and cytotoxic changes.

Despite the increased social and financial burden associated with autism spectrum disorder (ASD), no particular treatment for this illness has been identified. A detailed examination of prior trials conducted to treat autism revealed that nutrition intervention was commonly utilised as an additional method of therapy. Indeed, the early detection of nutritional deficiencies and metabolic problems, together with appropriate therapeutic measures, can be a cornerstone for enhancing the metabolic and behavioural abilities of individuals with autism. In this work, a propionic acid (PPA)-induced rodent model of ASD was fed Spangled emperor (Lethrinus nebuloses), Dusky grouper (Epinephelus marginatus), and Parrot Fish (Scaridae), which are locally named Hammour, Shour, and Hareed, respectively, in Saudi Arabia. The aim of this study was to investigate the effect of dietary intervention with three kinds of whole fish (Lethrinus nebuloses, Epinephelus marginatus, and Scaridae), as a rich source of ω-3 fatty acids, on selected biochemical markers (reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS), creatine kinase (CK), lactate dehydrogenase (LDH), dopamine) together with a histopathological examination of the cerebellum and hippocampus as neurotoxic features of propionic acid in a rodent model of autism. Briefly, our findings give preliminary evidence in favour of employing fish as a rich supply of omega-3 fatty acids to reduce the neurotoxic effect of a PPA-induced ASD in a rat model. It may be beneficial to provide an extra marine omega-3-rich diet for improving certain metabolic autistic features related to oxidative stress, energy metabolism, and brain neurotransmitters. [ABSTRACT FROM AUTHOR]

The production of fingerlings on a large scale is one of the biggest challenges for grouper aquaculture development. Groupers may be more susceptible to skeletal anomalies due to their complex skeleton formation ontogenesis. Such anomalies are normally associated with inadequate larviculture protocols for marine fish. The present study aimed to record the occurrence of skeletal anomalies in dusky grouper Epinephelus marginatus. Different degrees of kyphosis, lordosis, and scoliosis were identified. After the larviculture period (60 days), 42% of the dusky grouper presented skeletal anomalies. Therefore, we have concluded that the current protocol for the dusky grouper larviculture must be re-examined, especially to determine a more appropriate water flow in the tanks. [ABSTRACT FROM AUTHOR]

No-take areas are key instruments to promote the effectiveness of Marine Protected Areas (MPAs), particularly concerning the protection of endangered species such as the dusky grouper (Epinephelus marginatus). However, despite the establishment of no-take areas and the prohibition of catching this species in a southwestern Portuguese MPA (SACVMP—'Sudoeste Alentejano' and 'Costa Vicentina' Marine Park) since 2011, there is still no evidence of population recovery. By using acoustic biotelemetry, this work aimed to evaluate the feasibility of restocking hatchery-reared adult dusky groupers in two no-take areas within the SACVMP. In 2019 and 2021, thirty groupers were tagged with acoustic transmitters and the site attachment and movements of the groupers were assessed in the releasing sites (no-take areas). None of the tagged fish settled down in either of the areas, leaving the no-take areas mainly at dusk and night. Some individuals displayed extended movements of more than a hundred kilometers along the Portuguese coast which was rarely reported for this species. At least in some coastal stretches, those movements were performed close to the shore, which may evidence the importance of coastal MPAs to protect and promote the connectivity of species more associated with rocky reef habitats. Following studies should focus on the conditions that promote site attachment and fidelity by hatchery-reared dusky groupers so that future large-scale restocking programs can be successful in MPAs with appropriate habitats. [ABSTRACT FROM AUTHOR]

Despite the increased social and financial burden associated with autism spectrum disorder (ASD), no particular treatment for this illness has been identified. A detailed examination of prior trials conducted to treat autism revealed that nutrition intervention was commonly utilised as an additional method of therapy. Indeed, the early detection of nutritional deficiencies and metabolic problems, together with appropriate therapeutic measures, can be a cornerstone for enhancing the metabolic and behavioural abilities of individuals with autism. In this work, a propionic acid (PPA)-induced rodent model of ASD was fed Spangled emperor (Lethrinus nebuloses), Dusky grouper (Epinephelus marginatus), and Parrot Fish (Scaridae), which are locally named Hammour, Shour, and Hareed, respectively, in Saudi Arabia. The aim of this study was to investigate the effect of dietary intervention with three kinds of whole fish (Lethrinus nebuloses, Epinephelus marginatus, and Scaridae), as a rich source of ω-3 fatty acids, on selected biochemical markers (reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS), creatine kinase (CK), lactate dehydrogenase (LDH), dopamine) together with a histopathological examination of the cerebellum and hippocampus as neurotoxic features of propionic acid in a rodent model of autism. Briefly, our findings give preliminary evidence in favour of employing fish as a rich supply of omega-3 fatty acids to reduce the neurotoxic effect of a PPA-induced ASD in a rat model. It may be beneficial to provide an extra marine omega-3-rich diet for improving certain metabolic autistic features related to oxidative stress, energy metabolism, and brain neurotransmitters.

The current study has designed to investigate the morphological characteristics of the gills of the dusky grouper (Epinephelus marginatus) by gross morphology, scanning electron microscopy, and morphometric analysis. The study was carried out on 10 fresh fish. The fish has four‐gill arches on each side. The lengths of the first‐, second‐, third‐, and fourth‐gill arches were 5.27, 4.2, 3.2, and 2.8 cm. The gill arches carried a longitudinal band, the bases of the gill filaments, and gill rakers that varied from rectangular to circular shapes. Each gill arch had two main lateral and medial rows and two accessory rows of gill rakers in an alternative manner with each other. The dusky grouper fish had long rakers, whereas the longest one was the lateral rakers of the first arch, which were 467 and 1271.9 μm in width and length. Three types of spines appeared on the gill arches and rakers. The long spine had detected on the apex of the short rakers. Each gill arch carried on its ventral side two rows of gill filaments. The long filaments were at the middle of the gill arch, while the short ones were at the rostral end of the gill arch. The study has demonstrated the taste buds, mucous, chloride cells, and significant features of the epithelial covering of the gill arches and rakers. The morphology of the gills of the dusky grouper indicates the adaptation to their marine environment. [ABSTRACT FROM AUTHOR]

A single specimen of Dusky Grouper Epinephelus marginatus (Lowe, 1834) on 14 November 2021 at a depth of about 10 m from the southwestern Black Sea (Amasra, Turkey) was captured by a fisherman with fishnet. In this study, dusky grouper Epinephelus marginatus was recorded for the first time from the Black Sea as a new Mediterranean species for the Black Sea fish fauna. [ABSTRACT FROM AUTHOR]

5 × 2 = Five days of feeding and two days of fasting; 8 × 4 = Eight days of feeding and four days of fasting gl GLO:7ZE/01jun21:are15088-fig-0003.jpg PHOTO (COLOR): 3 Somatic indexes of dusky grouper Epinephelus marginatus under different periods of food deprivation. Keywords: Epinephelus marginatus; feed deprivation; haematological parameters; hyperfhagia; marine fish farming EN Epinephelus marginatus feed deprivation haematological parameters hyperfhagia marine fish farming 2891 2895 5 05/17/21 20210601 NES 210601 Aquaculture is an activity that has been growing in different countries given the potential for using the waters in food production (Herrera et al., 2019). 5 × 2 = Five days of feeding and two days of fasting; 8 × 4 = Eight days of feeding and four days of fasting gl The full compensatory growth should provide an improved efficiency of food use and, consequently, a lower food conversion rate and a higher SGR. [Extracted from the article]

No-take areas are key instruments to promote the effectiveness of Marine Protected Areas (MPAs), particularly concerning the protection of endangered species such as the dusky grouper (Epinephelus marginatus). However, despite the establishment of no-take areas and the prohibition of catching this species in a southwestern Portuguese MPA (SACVMP—‘Sudoeste Alentejano’ and ‘Costa Vicentina’ Marine Park) since 2011, there is still no evidence of population recovery. By using acoustic biotelemetry, this work aimed to evaluate the feasibility of restocking hatchery-reared adult dusky groupers in two no-take areas within the SACVMP. In 2019 and 2021, thirty groupers were tagged with acoustic transmitters and the site attachment and movements of the groupers were assessed in the releasing sites (no-take areas). None of the tagged fish settled down in either of the areas, leaving the no-take areas mainly at dusk and night. Some individuals displayed extended movements of more than a hundred kilometers along the Portuguese coast which was rarely reported for this species. At least in some coastal stretches, those movements were performed close to the shore, which may evidence the importance of coastal MPAs to protect and promote the connectivity of species more associated with rocky reef habitats. Following studies should focus on the conditions that promote site attachment and fidelity by hatchery-reared dusky groupers so that future large-scale restocking programs can be successful in MPAs with appropriate habitats.

This work describes betanodavirus infection in two species of groupers (family Serranidae) from the Algerian coast: the dusky grouper Epinephelus marginatus and the golden grouper Epinephelus costae. At necropsy, characteristic clinical signs, external injuries, clouded eyes and brain congestion, generally associated with viral encephalopathy and retinopathy (VER) infection were observed. The partial sequences of RNA1 and RNA2 from two viral strains were obtained, and the phylogenetic analysis revealed the presence of the red‐spotted grouper nervous necrosis virus (RGNNV) genotype closely related to strains previously detected in groupers in the same geographic area. Results obtained in this study support the hypothesis that VER disease is endemic in the Algerian grouper population. [ABSTRACT FROM AUTHOR]

Ceratomyxa mennani n. sp. is a new coelozoic Ceratomyxa species found in the gallbladder of Epinephelus marginatus from the Gulf of Tunis, Tunisia. Mature plasmodia were disporic, ovoid in shape measuring 9–12 μm in width and 11–14 μm in length. Mature myxospores were slightly crescent-shaped with almost straight posterior margin, measuring 5.8 ± 0.2 (5.4–6.1) μm in length and 12.7 ± 0.3 (11.9–13.0) μm in thickness. The two valves were unequal with rounded ends. Polar capsules were spherical, equal in size with 2.1 ± 0.2 (1.9–2.6) μm in diameter. The binucleated sporoplasm filled the entire cavity of the myxospore. Molecular analysis of SSU rDNA sequences indicated that C. mennani n. sp. was distinct from all other Ceratomyxa sequences in GenBank. Phylogenetic analysis revealed that C. mennani n. sp. clustered with Ceratomyxa species infecting Epinephelinae fishes. Seasonal prevalence of infection over one year was significantly higher in winter and the lowest in autumn. This is the third report of Ceratomyxa species infecting the gallbladder of Epinephelus marginatus from Tunisia and the first study to include molecular data. [ABSTRACT FROM AUTHOR]

Salt‐water recirculation systems using automatic feeders are a new frontier for marine aquaculture. The definition of the feed frequency is fundamental for the correct use of automatic feeders. Different feeding frequencies (1, 3, 6, 12 and 18 times a day) using automatic feeders were evaluated in two experiments on the performance of the dusky grouper (Epinephelus marginatus) in salt‐water recirculation system. In the first experiment, three feeding frequencies were evaluated: feeding once a day; three times a day and six times a day. In the second experiment, three feeding frequencies were evaluated: feeding six times a day; 12 times a day and 18 times a day. Waters parameters (temperature, salinity, oxygen level, total ammonia, pH and oxidation‐reduction potential) were maintained at specific ranges for the species. Among all the evaluated frequencies, 12 times a day provided the best productive performance, obtaining superior results for final weight, final biomass, specific growth rate and daily weight gain. For juveniles of the dusky grouper, the ideal feeding frequency is regular feedings every 2 hours, which is impractical to run without the use of automatic feeders. [ABSTRACT FROM AUTHOR]

This study aimed to investigate parasite fauna of E. marginatus from the central Mediterranean Sea between Messina and Syracuse. In the present survey; parasite fauna of dusky grouper was investigated for two main reasons: the economic value of this species and the current lack of studies regarding the capture area. Seventy dusky groupers were caught from May 2018 to February 2020. Forty-seven out of the 70 specimens (67.2%) were infected with one or more parasite species. The most abundant species was Prosorhynchus caudovatus (42.9%), followed by Podocotyle temensis (28.6%), Didymodiclinus sp. (18.6%), Philometra jordanoi (5.7%), Anisakis Type II larvae (5.7%). Higher prevalence of infection of P. jordanoi and Contracaecum sp. was found in warm months (March to September), while P. caudovatus and P. temensis were mostly found during cold months. Weight and total length of E. marginatus were positively correlated with the parasitic load of P. jordanoi and Didymodiclinus sp. The different prevalence of parasite infection found between warm and cold months is probably related to the diet of the dusky grouper; which is characterized by mollusks that are intermediate hosts for parasite species found. None of the parasites found in the present survey is responsible for zoonosis

Trypanorhyncha are cestodes commonly infecting marine fish. Numerous studies have detailed the biology of Trypanorhyncha species, but information on the pathological changes produced by these parasites is limited. Dusky groupers are keystone species necessary for the preservation of several marine ecosystems. Considering their vulnerable state of conservation and the efforts being made to culture them, identification of the effects caused by Trypanorhyncha is vital. Here, we aimed to determine the prevalence and pathological changes produced by Trypanorhyncha in dusky groupers from the Canary Islands. The prevalence of trypanorhynch plerocerci was 96%. Grossly, in the abdominal cavity, there were numerous larvae-filled cysts and nodules. These were embedded in abundant fibrosis, producing visceral adhesions. Histologically, affecting the peritoneum, stomach, and intestine there were numerous degenerated encysted plerocerci and extensive deposition of mature connective tissue. These findings indicate that Trypanorhyncha is highly prevalent in adult dusky groupers from the Canary Islands, producing a progressive and chronic response. Furthermore, fish immune system appears to attempt to eliminate the parasites through fibrous encapsulation. Nonetheless, extensive fibrosis may have a detrimental impact on fish health when adjacent cells or tissues are compressed and their functions impaired.

Abstract: The dusky grouper Epinephelus marginatus (Lowe) is an ecologically and commercially important fish species of the Atlantic and Mediterranean coastal rocky habitats. Despite records of didymozoid infections in several grouper species, the identification and pathogenesis of these parasites in E. marginatus are lacking. The aim of this study is to characterize the didymozoids of E. marginatus, particularly their mechanisms of infection and histopathological features. Dusky groupers (n = 205) were caught off Majorca Island (western Mediterranean Sea) and examined for parasites. Of the fish sampled, 45% were infected with white and yellow didymozoid capsules and brown nodules, found on the gills and pseudobranchs. Parasite abundance had a strong positive relationship with the fish length; only fish larger than 20 cm were infected, suggesting infection via consumption of an intermediate host, for which E. marginatus size was a limiting factor. The capsules contained two convoluted viable adult trematodes, identified as Didymodiclinus sp., in close contact with host capillary vessels, with no evidence of the tissue inflammatory response. Conversely, nodules containing degraded parasites were surrounded by an intense inflammatory infiltrate. The findings suggest that Didymodiclinus sp. have the potential to evade the host's immune system by inhibiting the inflammatory response. [ABSTRACT FROM AUTHOR]

Two rearing conditions, tank light-dimensions and diet, were tested in dusky grouper—larvae and juveniles—in order to improve larval rearing techniques for this species. Larvae reared in high-volume and fluorescent tubes showed the highest survival rate at 18 dph (17.67%, 16%). This might be due to a higher depth and less trapping area during surface death in high-volume tanks than in low volume. Besides, a 500-lx evenly distributed light with fluorescent tubes might improve survival rate at early stages rather than illumination with energy-efficient light bulbs (4.68%, 9.64%). Light bulbs created shaded areas with less illumination inducing low larval activity. First feeding was performed with minimum rotifer lorica width of 102 ± 10.2 μm. No mixed diet was supplied. Throughout metamorphosis, stress shock syndrome appeared to be the main cause of mortality. Diet A showed best growth and survival (4.1-7.36%) during this period probably due to its high HUFA content (9.5%). Contrary to what was observed during first stages, groupers showed best performance with lower illumination. Cannibalism was observed during this period in all culture conditions. [ABSTRACT FROM AUTHOR]

Development, ontogeny of the digestive system and the fatty‐acid (FA) profile, were analysed during development of Epinephelus marginatus. Larvae were analysed 7 and 17 days post fertilization (dpf) to evaluate fatty‐acid profile and morphological variables, respectively. Epinephelus marginatus larvae have relatively slow development of digestive structures, but were able to capture, ingest and digest prey by 5 dpf. Eggs were composed of high percentages of polyunsaturated fatty acids (PUFA) in phospholipids. The percentage of n3 PUFAs was higher than n6, especially docosahexaenoic acid (DHA), which exhibited higher levels compared with other marine species during the first 3 days of development, both in terms of phospholipids and triglycerides. The larvae present a high content of docosahexaenoic acid–eicosapentaenoic acid (DHA–EPA) and, during this phase, live food of small size was required (copepods or SS‐strain Brachionus rotundiformes), enriched with DHA–EPA. These results may guide future studies on the contribution of FAs required during this stage of the life cycle of E. marginatus, to advance knowledge of the use of these FAs throughout ontogeny and contribute to the culture of this species commercial production or restocking. [ABSTRACT FROM AUTHOR]

The ghost fishing effects of bottom trammel nets, which drift on rocks in the bad weather conditions were investigated in regards of mortality of commercially important and endangered species in this study. Underwater experiments were performed in Yumurtalik, Iskenderun Bay between June 2013 and October 2013. Two panel experimental nets were used and data were gathered by underwater observation. During the study, 26 different species, belonging to 17 families, were caught in experimental nets. Teleost and crustaceans formed 98% of the captured individuals. The 24-hour catch rate of the experimental nets showed a rapid decline in the first few weeks and, by the 60th day, the decline was 80%. Afterwards, the decline slowly continued. No individual was caught in experimental nets after the 105th day. For this reason, the fishing life of the lost nets was assumed to be day 105. In the region, the mortality numbers of teleosts and crustaceans caused by bottom trammel nets lost by the entire fishing fleet were identified as 1291 (100 kg) and 6102 (990 kg) individuals, respectively. This mortality rate (0.55% for fish) can be considered to be insignificant in all fisheries, but the mortality rates of threatened species, such as Epinephelus marginatus and Chelonia mydas, were found to be noteworthy. [ABSTRACT FROM AUTHOR]

Groupers are highly targeted and vulnerable reef fishes. The effects of fishing pressure on the density of three reef fishes were investigated in 21 islands outside (n=15) and inside (n=6) a Marine Protected Area (MPA) at the Paraty Bay, Brazilian southeastern coast. Two valued groupers (Epinephelus marginatus and Mycteroperca acutirostris) and a non-target grunt (Haemulon aurolineatum) were studied. The total biomass of fish caught in each island was considered as a measure of current fishing pressure, while the island distance from the villages was considered as a measure of past fishing pressure. Fish densities were recordedin number and biomass. The biomass of M. acutirostris was inversely related to current fishing pressure, which did not affect the other two fishes. The density of E. marginatus increased with the island distance from one of the fishing villages, which indicated that past fishing may have had decreased the abundance of E. marginatus. Densities of the three fishes and fishing pressure did not differ between islands inside and outside the MPA. Data on fishing pressure, densities of groupers and coral cover were combined here to assign conservation scores to islands. A redefinition of MPA boundaries to reconcile fish conservation, fishing activities and fishers' food security was proposed. [ABSTRACT FROM AUTHOR]

The dusky grouper (Mycteroperca marginata) is a marine species usually associated with rocky bottoms and reefs. The present work investigated the diet and feeding strategy of a dusky grouper population inhabiting a 4.5 km long pair of rocky jetties located in the mouth of Patos Lagoon estuary. No prior research has been conducted in such man-made habitat and the current study provides a basis for comparative studies on the diet of the dusky grouper populations inhabiting natural vs. man-made rocky habitats. Similarly with previous studies on natural substrates, crabs and fishes were the main food categories consumed (%IRI = 85.1 and %IRI = 12.6, respectively), whereas shrimps and mollusks had lower importance in the diet (%IRI = 1.9 and 0.4, respectively). As previously reported for dusky grouper populations inhabiting reefs and rocky bottoms, the present work revealed conspicuous size related dietary shifts. Blue crabs and fishes become increasingly important food items in the diet of larger individuals (> 500 mm, TL). Finally, it was found that the studied dusky population has a generalist feeding strategy with a high between-individual variation in prey consumption. Such strategy remained similar across the size increment of the species. Our findings suggest that man-made rocky substrates provide suitable feeding grounds for the dusky grouper in southern Brazil and could be used as an additional tool in the conservation efforts of this endangered species.A garoupa-verdadeira (Mycteroperca marginata) é uma espécie marinha geralmente associada a fundos rochosos e recifes. O presente trabalho investiga a dieta e estratégia alimentar de uma população da garoupa-verdadeira que habita um longo (4,5 km) par de molhes de pedra na desembocadura do estuário da laguna dos Patos, sul do Brasil. Não há trabalhos anteriores realizados nesse tipo de habitat construído pelo homem e este trabalho fornece uma base de comparação com estudos de dieta de outras populações da garoupa-verdadeira ocorrendo em habitats naturais. De modo similar ao encontrado em estudos prévios realizados em substratos naturais, caranguejos e peixes foram as principais categorias de alimento consumidas (%IRI = 85,1 e %IRI = 12,6, respectivamente), enquanto camarões e moluscos tiveram menor importância na dieta (%IRI = 1,9 e %IRI = 0,4, respectivamente). Como reportado anteriormente para populações de garoupa-verdadeira que habitam recifes e fundos rochosos, o presente trabalho revelou marcadas mudanças na dieta em função do tamanho da espécie. Siri-azul e peixes tornam-se gradativamente mais importantes na dieta de indivíduos maiores (> 500 mm de comprimento total, CT). Finalmente, foi observado que a população de garoupa-verdadeira teve uma estratégia alimentar generalista com uma elevada variação entre indivíduos no consumo de presas. Essa estratégia permaneceu similar ao longo do aumento em tamanho da espécie. Os resultados do presente trabalho sugerem que substratos rochosos estabelecidos pelo homem propiciam locais de alimentação adequados para a garoupa-verdadeira no sul do Brasil e que poderiam ser usados como ferramentas adicionais nos esforços de conservação dessa espécie ameaçada.

The dusky grouper, Mycteroperca marginata, is an important commercial marine fish that is currently considered an endangered species worldwide and listed as overexploited in Brazil. Although its reproductive biology has been studied elsewhere, no information is available for populations in its southernmost distribution limit on the Brazilian coast. The present work investigates age structure, growth and reproduction of individuals inhabiting a pair of rocky jetties, about 4.5 km long each, located in the mouth of Patos Lagoon in the municipality of Rio Grande, in the southwestern Atlantic Ocean. A total of 130 individuals obtained between February 2007 and May 2009 were analyzed, with total length ranging from 260 to 800 mm. The growth coefficient found in the present study (K: 0.069) was lower than values reported for dusky grouper populations from the Mediterranean Sea (0.087) and southeast Africa (0.09). This difference could be related to higher average water temperatures in these regions compared to the current study site or due to poorer habitat quality in terms of the shelters available for dusky grouper individuals to establish their territories. Microscopic ovarian analyses of individuals during three years of sampling revealed only the occurrence of immature and resting females. The absence of ripe or post-spawning individuals, associated with low GSI values (A garoupa-verdadeira, Mycteroperca marginata, é uma espécie de importância comercial que atualmente é considerada como ameaçada mundialmente e sobre-explotada no Brasil. Embora sua biologia reprodutiva tenha sido estudada em outras regiões, nenhuma informação está disponível sobre populações que habitam o extremo sul da sua distribuição na costa brasileira. O presente trabalho investiga a estrutura de idade, crescimento e reprodução de indivíduos que habitam dois molhes de pedra, com cerca de 4,5 km de extensão cada, localizados na desembocadura da laguna dos Patos no município de Rio Grande, no Atlântico Sudoeste. Foram analisados 130 indivíduos obtidos entre fevereiro de 2007 e maio de 2009, com comprimento total entre 260 e 800 mm. O coeficiente de crescimento no presente estudo (K: 0,069) foi inferior aos valores reportados para oMediterrâneo (0,087) e sudeste da África (0,09). Essa diferença pode estar relacionada a temperaturas médias maiores nessas regiões comparadas ao presente local de estudo ou devido a menor qualidade de habitat em termo de abrigos para os indivíduos de garoupa-verdadeira estabelecerem seus territórios. Análises microscópicas dos ovários dos indivíduos durante esses três anos de amostragens revelaram somente a ocorrência de indivíduos imaturos e fêmeas em repouso. A ausência de indivíduos ovados ou em pós-desova, associada com baixos valores do IGS (

A garoupa-verdadeira (Epinephelus marginatus) é uma espécie de serranídeo com grande importância ecológica e boas perspectivas para o cultivo. A investigação da morfologia do trato digestório, associada à atividade alimentar, é fundamental para a compreensão da biologia dessa espécie e premissa básica para pesquisas sobrerequerimentos nutricionais, desenvolvimento de rações e práticas adequadas de manejo alimentar. O presente trabalho descreve a anatomia e, por meio da microscopia de luz, as variações histológicas ao longo do tubo digestório de juvenis de Epinephelus marginatus, correlacionando a histologia de cada seguimento com as respectivas funções e o hábito alimentar. Verificou-se que essa espécie possui elevado número de tipos celulares ao longo do tubo digestório que estão intimamente relacionados com a resposta imunológica inata e adaptativa, permitindo o hábito alimentar detritívoro.

The reproductive parameters of the dusky grouper, Epinephelus marginatus, in the Balearic Islands (western Mediterranean) were studied with a histological analysis of specimens caught by artisanal and recreational spear fisheries. The histological examination of the gonads showed that the dusky grouper spawning season extends from late spring to the end of summer with clear spawning peaks in July and August. The monthly variation of the hepatosomatic index (HSI) and the Le Cren condition index suggests that reserves for gonad development were obtained from the energy stored in the liver before spawning. Females reach maturation at 49 cm total length (TL) and 6 years, and transitional individuals start to occur before all females are matured. Males were the largest and oldest specimens but females were also present in the largest and oldest classes and there was a large sex, size and age overlap in the population. The fecundity data showed that the dusky grouper is a determinate spawner with asynchronous oocyte development. Potential fecundity ranged between 65 thousand and 8 million oocytes in females from 39 to 92 cm TL and from 6 to 42 years of age, with a mean relative fecundity of 334 x 103 oocytes kg-1. Females spawn an average of 10 batches during the spawning season, with a relative batch fecundity of 75 x 103 oocytes kg-1. Fecundity increased significantly with length, weight, age and HSI, while relative fecundity was only related to HSI. Based on the results obtained in the present study (long reproductive lifespan of females, influence of maternal attributes on fecundity and size at maturity) management measures for the species were evaluated.

One of the major obstacles to propagating dusky grouper, Epinephelus marginatus, is the difficulty of rearing the early larvae. We have successfully raised dusky grouper larvae in mesocosms using a mixed diet of endogenous plankton grown in the rearing tank and an exogenous supply of Brachionus plicatilis and Artemia sp. Newly hatched larvae at an initial density of 1.3 ind.l-1 were stocked in partially shaded 3 m3 circular outdoor tanks during the summers of 2007 and 2008. Before introducing newly hatched larvae, the water was left for six days to promote plankton growth. Larval growth occurred at two different rates: i) a faster rate from first feeding to the beginning of metamorphosis, and ii) a slower rate at transformation. Survival at the beginning of metamorphosis was less than 10% (33 DPH) in 2007 and between 25 and 50% (25 DPH) in 2008. High mortalities were observed during larval transformation. The estimated minimum food requirement per grouper larvae increased more than 300% from the beginning of the notochord flexion to the beginning of metamorphosis. To meet such a high feeding requirement the number of larger prey organisms/copepods in the mesocosm should be eight times higher during this time period.

A pilot experiment of stock enhancement based on the release of hatchery-reared juveniles of dusky grouper, Epinephelus marginatus, was carried out at two artificial reefs located 0.9 km offshore the south-western Sicilian coast (Central Mediterranean). The fish assemblages inhabiting the reefs were characterized using underwater visual census (UVC) surveys. Despite some differences in fish species richness, diversity and abundance, both artificial reefs provide suitable feeding resources and shelter opportunities for the settlement of dusky grouper juveniles. A total of 95 dusky grouper juveniles, which were 3 and 4 years old, were released. No stress-related effects on fish swimming or behaviour were observed during the step by step transportation to the sea-bottom at 20 m depth. After release, several groupers showed very low reactivity; freezing and schooling were the most common behaviours. The sighting rate after one month of UVC surveys was 15.7% and 20% at the two artificial reefs. No effect of fish size at release on grouper survival was observed. Some groupers were not recorded on the pyramid of release but elsewhere in the same artificial reef, which demonstrated their ability to move around the reef. The extent of dispersal of the released juveniles largely exceeded the area encompassed by the reefs, which was shown by recaptures of tagged groupers by local fishermen up to 13 km from the release site. This result provides a first insight into the potential of stock enhancement of hatchery reared dusky grouper juveniles for marine ranching and conservation purposes.

O diagnóstico precoce de patologias no meio aquático constitui-se em uma necessidade vital para o sucesso dos cultivos. Considerados como parasitos oportunistas, surtos de infestação de monogenóides capsalídeos podem ocasionar mortalidades massivas gerando enormes prejuízos nos cultivos. Exemplares de garoupa-verdadeira Epinephelus marginatus (Lowe, 1834), com peso médio de 142,74 ± 38,65 g, apresentaram recusa da alimentação e sintomas como o escurecimento do corpo, natação errática, opacidade dos olhos, exoftalmia e hemorragias em diversas áreas do corpo. Alguns peixes apresentavam lesões no globo ocular e cegueira. Após análises dos peixes foi identificada a ocorrência do parasito Neobenedenia melleni. Este trabalho teve por objetivo testar o efeito de diferentes tratamentos por imersão em diferentes concentrações de formalina e água doce na erradicação de monogenoides capsalideos na garoupa-verdadeira. Foram testados três tratamentos em forma de banhos: T1 (água doce por 10 minutos); T2 (formalina: 1:2.000 por 10 minutos) e T3: (formalina: 1:4.000 por 10 minutos). Os tratamentos foram avaliados através de raspado de tecido epitelial, montados entre lâminas e lamínulas e observado ao microscópio de luz. Observou-se que nas condições testadas o T1 e o T2 foram eficientes na eliminação dos monogenóides capsalídeos na garoupa-verdadeira.The precocious diagnosis of pathologies in the aquatic way is constituted in a vital need for the success of the cultivations. Considered as parasites opportunists, infestations of monogeneans capsalides can cause missal mortalities resulting in enormous damages in the cultivations. Juveniles of dusky grouper Epinephelus marginatus (Lowe, 1834), with medium weight of 142.74 ± 38.65 g, presented refusal of the feeding and symptoms as the darkening of the body, erratic swimming, opacity of the eyes and hemorrhages in several areas of the body. Some fishes presented lesions in the eyeball and blindness. After analyses of the fish the occurrence of the parasite Neobenedenia melleni was identified. This work objective was to test therapeutic treatments seeking the monogenean capsalid eradication in juveniles of dusky grouper. Three treatments were tested in form of baths: T1 (fresh water for 10 minutes); T2 (formalin: 1:2,000 for 10 minutes) and T3: (formalin: 1:4,000 for 10 minutes). The treatments were evalueted by scraping epithelium tissue, mounted in slide glass and cover slip and observed by light microscope. It was observed that in the tested conditions T1 and T2 were efficient in the elimination of the monogeneans capsalids without presenting lethality in the dusky grouper.

Several aspects of the reproductive biology of the dusky grouper Epinephelus marginatus were investigated using a collaborative methodology. 193 specimens of dusky groupers were obtained in collaboration with fish market personnel in the city of São Francisco do Sul, Santa Catarina State, Southern Brazil. Fish market staff were trained and encouraged to collect biological material required for reproductive studies, giving access to many specimens which otherwise would have been unavailable. E. marginatus was found to reproduce in early summer, spawning between November and December. Females reachedsexual maturity at approximately 460 mm total length. Sampled males ranged from 900-1000 mm and females from 300-960 mm in total length. No transitional (i.e. sex changing) males were observed. The regression equation for the relationship between total length (TL) (mm) and total weight (TW) (g) was TW = 4.4x10-5TL2.8. Suggestions to improve the performance of future collaborative sampling projects are discussed.Diversos aspectos da biologia reprodutiva da garoupa verdadeira Epinephelus marginatus foram abordados através de uma metodologia colaborativa. Ao todo, 193 exemplares da garoupa verdadeira foram obtidas em peixarias colaboradoras no município de São Francisco do Sul, Estado de Santa Catarina, Brasil. Os funcionários das peixarias foram treinados e incentivados a realizar a coleta de todo material biológico necessário para estudos reprodutivos, possibilitando o acesso a um grande número de vísceras que teriam de outra maneira sido dispensadas. Epinephelus marginatus esteve em atividade reprodutiva no inicio do verão, com desova provável entre novembro e dezembro. Fêmeas atingiram a maturidade sexual com aproximadamente 460 mm de comprimento total. Machos variaram de 900mm a 1000 mm e fêmeas de 300 mm a 960 mm. Não foram observados machos em transição sexual. A equação de regressão da relação entre o comprimento total (CT) (mm) e peso total (PT) (g) foi dada (PT = 4.4 x 10-5 CT2. 8). Sugestões são dadas ainda para o aumento da performance de futuras abordagens colaborativas de pesquisa.

Protection inside marine reserves and the desired ‘reserve effect’ depend directly on the home range and sedentary behaviour of fishes throughout their lives. Benthic territorial predators are typically seen as major candidates to beneficiaries, but empirical evidence of short-versus long term residency is still surprisingly rare. We studied the inter-annual patterns of site fidelity and finer scale movements in two of the most abundant benthic predators of the NE Atlantic coastal reefs, the dusky grouper ( Epinephelus marginatus ) and the blacktail comber ( Serranus atricauda ), using passive acoustic telemetry inside and around a small marine reserve in the Azores islands, central North Atlantic. Individuals of both species resided in the reserve year-round, occupying stable core activity areas within relatively small home ranges. Groupers were detected nearly every day ( n = 11, median = 5.0 years) while combers were still detected in 2/3 of the days ( n = 9, median = 2.0 years). Some dusky groupers underwent daily short-range forays during the summer, most probably related to spawning events, whereas combers appeared to foray for longer periods with no direct relation with reproductive activity. The two species also contrast in their diel pattern, strictly diurnal in the comber but crepuscular in the grouper. This study evidences that even small reserves within the size range of most coastal reserves can accommodate the multiple-scale patterns of space use of exploited benthic territorial species, and promote the recovery of their local exploited populations in the long-term via the ‘reserve effect’ and, potentially, via the ‘larval export’ effect. [ABSTRACT FROM AUTHOR]

The effects of halogen-light-irradiated and non-irradiated PAHs on the grouper Epinephelus marginatus were assessed through biomarkers including morphometric parameters, liver histopathology, biliary PAH concentration, genetic alterations, and enzyme activity modulation. E. marginatus juveniles were divided into three groups: control (C), non-irradiated PAHs (PAHs1), and irradiated PAHs (PAHs2). Test groups were exposed for 14 days to a 0.5 ppm PAH solution in the semi-static system. After this period, fish were anesthetized with benzocaine (2%) and peripheric blood was collected by caudal puncture. Blood smears were prepared and stained with propidium iodide. Fish livers were collected, fixed in McDowell's solution, embedded in paraplast, thin-sectioned, and stained with hematoxylin-eosin (H&E). For biochemical analyses including superoxide dismutase, catalase, and glutathione S-transferase activities, fish livers were collected and preserved in liquid nitrogen. Water samples were analyzed using gas chromatography-mass spectrometry (GC–MS) and bile synchronous fluorescence spectroscopy. Fish in the PAHs2 group had micronuclei (MN) in blood cells, as well as significant differences in nuclear morphology (NMA). Significant morphological alterations were observed in the livers from fish exposed to PAHs as well as inhibition of the catalase activity. Our results show that irradiation altered the bioavailability of PAHs, especially benzanthracene, which has great impact in aquatic ecosystems. Among the consequences of physical and chemical changes to PAHs, we observed a significant increase in NMA and MN incidence in E. marginatus erythrocytes, indicating the potential initiation of mutagenic and carcinogenic processes. [ABSTRACT FROM AUTHOR]