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The purpose of this study was to investigate the relationships between the abundance and occurrence of juvenile Atlantic goliath grouper and physicochemical variables in a tropical mangrove ecosystem, employing a non-lethal methodology. Juvenile Atlantic goliath grouper individuals were captured biweekly, using blue crab traps, across three locations within the São Mateus estuary (18°36'S, 39°44'W), from August 2021 to July 2022. Simultaneously, the physicochemical water variables were assessed during each trap inspection. The physicochemical water variables influence on the abundance and occurrence of Atlantic goliath grouper juveniles were assessed using the Zero-Inflated Binomial (ZIB) and the Poisson (ZIP) generalized linear mixed-effects models (GLMMs). A total of 66 Atlantic goliath grouper juveniles were sampled (Pontal do Sul = 50, Lagoa Creek = 13, and Pitangueiras Creek = 3), ranging from 32 to 319 mm in total length. The best model fitted to presence-absence data (AIC = 278.6) consisted of location, depth, and salinity, with only location having a significant influence on the likelihood of species occurrence. Regarding abundance data, the best model (AIC = 336.4) included location, depth, and turbidity, with only location and depth showing a significant impact on abundance variation, with lower abundance at deeper areas. Although our results indicate a weak significant influence of physicochemical variables on juvenile Atlantic goliath grouper distribution, it is imperative to continue this monitoring effort, considering that additional data may be required to gain a deeper understanding of these patterns.

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The dusky grouper (Epinephelus marginatus) is an overfished and threatened fish species with coastal distribution. In the Southwestern Atlantic, it occurs across a broad region influenced by two major oceanographic features: the Cabo Frio (23°S) and the Cabo Santa Marta (28°S) upwelling systems. Along the Brazilian coast, the species may present continuous or discrete populations, depending on the methodological approach used. In this study we combined otolith chemistry and muscle stable isotope analyses to examine the population structure of dusky groupers and its association with the two upwelling systems. Fish were collected in shallow coastal waters of the Southwest Atlantic Ocean, covering the southeastern and southern Brazilian coasts, among Macaé (22°S), Santos (24°S), Florianópolis (27°S), and in Rio Grande (32°S). The results show three statistically well-separated population groups along the region. We named these population groups as North (north of Cabo Frio); Center (between upwelling regions); and South (south of the Cabo Santa Marta system). Our findings allow to suggest that the upwelling systems may influence the distribution of E. marginatus stocks along the Brazilian south-western coast, even though a causal effect may not be attributed at this point. Overall, this combined approach, leveraging information from distinct natural tags, and reflecting variability of water chemistry and food webs with latitude, allowed us to enhance our understanding on how major upwelling systems influence the structuring of fish populations along the southwestern Atlantic Ocean.

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The three most important grouper fishery species in southern Gulf of Mexico, Epinephelus morio, Mycteroperca bonaci and Mycteroperca microlepis, do not have life history parameters data reported such as growth, age and natural mortality essential to management. Individuals from the three species were captured in the Campeche Bank (CB) at different times from 1988 to 2001. Sagittae were thin-sectioned to count annuli: n = 1081 for E. morio, n = 920 for M. bonaci and n = 251 for M. microlepis. Otoliths from the three species exhibited successive opaque and translucent bands deposited with an annual frequency, occurring between January and April for E. morio and M. bonaci, and between January and March for M. microlepis. Estimated age in the three grouper species ranged from 0+ to 20 years. The most frequent ages were 7-10 years for E. morio and 8-12 years for M. bonaci and M. microlepis. The von Bertallanfy Growth Function model parameters (L∞ , K and t0 ) were consistent with reported growth patterns for Epinephelidae family species, as established by growth performance Ф' (near 3). The CB groupers appear to reach maximum ages over 13 years with K values between 0.09 and 0.12 year-1 , indicating all three studied species displayed relatively slow growth rate and medium longevity. Lifespan values ranged from 13 to 33 years for E. morio, from 18 to 30 years for M. bonaci and from 17 to 33 years for M. microlepis. A50 was 6.1 years for E. morio and 5.5 years for both M. bonaci and M. microlepis. Age at which all females were mature was 8 years for M. bonaci and 10 years for E. morio and M. microlepis. P50 was 9.3 years for E. morio, 13.6 years for M. bonaci and 11.6 years for M. microlepis. Age at which 100% of individuals were male was 13 years for E. morio, 19 years for M. bonaci and 15 years for M. microlepis. Values of M at age exhibited an exponential decrease with age for all three species, but overall values were 0.13 year-1 for E. morio, 0.14 year-1 for M. bonaci and 0.17 year-1 for M. microlepis. For the three species size at age varied by geographical distribution area, but particularly for E. morio the discrepancy in average size between published studies may be the consequence of the fishing effort exerted on the stock and/or the lack of regulation for the fishery prior to 2001; after this stock biomass fell below the reference limit point and was declared overexploited. Resource managers could use the information provided in this study as a reference, representing pre-overexploitation values, to evaluate the current status of these populations and ensure sustainable management actions for the CB grouper fisheries.

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Mining activities are a current environmental issue due to heavy metal release and subsequent metal uptake by organisms. In this study, we quantified the concentrations of essential (Cu, Zn) and toxic (Cd, Pb) elements in the muscle of 248 leopard groupers, Mycteroperca rosacea, captured by spearfishing and free diving close to a mining district in the Gulf of California during 2014-2015. We analysed metals using high-resolution inductively coupled plasma source mass spectrometry (HR-ICP-MS). We analysed metal concentrations by fish size, sex, maturity, season, year and risk factor for human consumption. The results indicated common levels of essential elements (Cu: 11 ± 34.3 µg/g, Zn: 377 ± 1390 µg/g) in comparison with toxic elements (Cd: 0.06 ± 0.1 µg/g, Pb: 0.98 ± 1.5 µg/g). Cadmium was within the permissible limit of Mexican standards (0.5 µg/g), but lead content bordered its limit (1.0 µg/g). Heavy metal concentrations were comparable between males and females. Metal variations were not significantly correlated with sex, maturity, season or year (p > 0.05). The evaluation of benefits (daily mineral intake) and risks (target hazard quotients) to health indicated that these fish did not represent a risk of adverse effects to consumers within worldwide limits, while the nutritional benefits were high.

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The Atlantic Goliath Grouper (AGG), Epinephelus itajara, the largest Epinephelidae in the Atlantic Ocean, it is classified as critically endangered in Brazil. In the Brazilian northeast, studies focusing on the species are still incipient. Here we study the occurrence, habitat use, and spatial distribution of AGG in Alagoas (Brazil) by combining participatory methods, such as Citizen Science and Local Ecological Knowledge. Living individuals represented 64% (n = 85) of the records, while dead individuals were 36% (n = 47), with 14 records from illegal captures. Juveniles are common in estuaries and shallow natural coastal reefs, while adults are distributed in deeper areas on natural and artificial reefs. The occurrence was significantly higher on Alagoas' southern coast. The São Francisco River (SFR) estuary stood out with 52 occurrences. We mapped 37 occurrence sites for AGG distributed along the coast, emphasising an artificial reef near SFR that received 12 reports about aggregations. The influence area of the SFR was indicated as a priority for species conservation due to the identification of a nursery and possible aggregations close to its mouth. We highlight the urgency of implementing short and long-term management actions along Alagoas' coast.

O mero, Epinephelus itajara, o maior Epinephelidae do Oceano Atlântico, está classificado como criticamente ameaçado no Brasil. No Nordeste brasileiro, os estudos voltados à esta espécie ainda são incipientes. Aqui estudamos a ocorrência, uso do habitat e distribuição espacial do mero em Alagoas (Brasil) combinando métodos participativos, como Ciência Cidadã e Conhecimento Ecológico Local. No total, os indivíduos vivos representaram 64% (n = 85) e os mortos 36% (n = 47), com 14 registros de capturas ilegais. Juvenis foram observados em estuários e em recifes naturais costeiros rasos, enquanto adultos grandes distribuíram-se em recifes naturais e artificiais em áreas mais profundas. A ocorrência foi significativamente maior no litoral sul de Alagoas. O estuário Rio São Francisco (RSF) se destacou com 52 ocorrências. Mapeamos 37 locais onde o mero ocorre, distribuídos ao longo do litoral, com destaque para um recife artificial localizado próximo ao RSF, que obteve 12 citações sobre agregações. Indicamos que a área de influência do RSF é prioritária para a conservação, em razão da identificação de um berçário e de possíveis agregações próximas a sua foz. Destacamos a urgência na aplicação de ações de gestão de curto e longo prazo em Alagoas.

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Our study incorporated a comprehensive suite of parameters (i.e., body size, age, diet and trophic position) to investigate mercury concentration in dusky groupers Epinephelus marginatus. This study was carried out in rocky bottoms in littoral and neritic habitats along the Southern Brazilian coast. We also determined spatial variation in mercury concentrations in individuals inhabiting both zones, which may provide insights into how dietary differences or potential pollution sources affect bioaccumulation. A total of 244 dusky groupers was analyzed to determine total mercury concentrations. Our study revealed that when considering similar body sizes, individuals inhabiting littoral rocky habitats had higher concentrations of mercury probably due to proximity to pollution sources associated with human activities in the estuary and its drainage basin. Furthermore, large individuals (>650mm and >8years old) showed mercury contamination levels that are potentially harmful for this endangered fish species and above the acceptable limits for human consumption.

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In this study, seasonal numerical abundance of the critically endangered Atlantic goliath grouper Epinephelus itajara was estimated by conducting scuba dive surveys and calculating sightings-per-unit-effort (SPUE) at three sites in southern Brazil. Seasonal differences in size and reproductive condition of captured or confiscated specimens were compared. The SPUE differed significantly with season, increasing in late spring and peaking during the austral summer months. A significant effect was observed in the number of fish relative to the lunar cycle. All females sampled during the summer were spawning capable, while all those sampled during other seasons were either regressing or regenerating. What these data strongly infer is that the E. itajara spawning aggregation sites have been located in the southern state of Paraná and the northern state of Santa Catarina and summer is the most likely spawning season. Size frequency distributions, abundance and reproductive state were estimated and correlated with environmental variables.

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This study provides direct and indirect evidence of temporally and spatially consistent spawning aggregations for the grouper Mycteroperca olfax. Recently reported declines in population numbers, probably related to the direct targeting of aggregations by artisanal fishermen, highlight the urgent need for species-specific management actions in the Galapagos Marine Reserve, such as minimum and maximum landing sizes, and the importance of protecting key aggregation sites with the declaration of no-take areas and the establishment of total fishing bans during the reproductive season.

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Spawning aggregations of red hind Epinephelus guttatus, tiger grouper Mycteroperca tigris and yellowfin grouper Mycteroperca venenosa were identified at two coral-reef systems: Arrecife Alacranes (emergent bank reef) and Bajos del Norte (submerged bank reef) on the continental shelf of the Yucatan Peninsula (Campeche Bank), Mexico. At both reefs, E. guttatus forms large spawning aggregations between February and March. At Bajos del Norte, M. tigris reproduces in a small, low-density aggregation in May, while M. venenosa aggregates at high densities for spawning between March and May. Multi-species use of an aggregation site by E. guttatus and M. venenosa was observed at Bajos del Norte. The identified spawning aggregations are apparently stable in location over time, and all three species were commonly observed to spawn within 1 week following the full moon. Development and survival of the larvae spawned in these aggregations are probably aided by a seasonal (spring-summer) upwelling in the north-east Campeche Bank. A permanent area closure at Bajos del Norte, currently outside any specific fisheries management area or regulations, would provide protection needed for the spawning aggregations of these three species.

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