Lutjanus Analis Research Articles

Changes in artisanal fishing as a driver of the shifting baseline syndrome: from the perspective of local ecological knowledge

This study aims to analyze changes in artisanal fishing perceived by fishers based on their local ecological knowledge, highlighting changes in species availability over time on the coast of Paraíba, in Northeast Brazil. Through data collection from fishers, it was observed that 78.88 % of them noticed changes in fishing activity over time, with a greater perception of changes among groups of more experienced fishers, reaching 93.42 %. The regression analysis applied to the study revealed that the increase in fishing experience is related to the perception of changes that have occurred, suggesting an increase of 5.5 % in the perception of changes for each additional year of experience. The main factors cited for these changes include over-exploitation and environmental degradation. The following most affected species stand out: Mutton snapper (Lutjanus analis), Serra Spanish mackerel (Scomberomorus spp), Quenn triggerfish (Balistes spp) and groupers (Mycteroperca spp), indicating a significant reduction in their catches over the years. Therefore, this study highlights the importance of integrating local ecological knowledge into public policies, not only aiming at the management and conservation of fish fauna, but also at maintaining communities which depend on fishing for their subsistence. This would include more adaptive fishing regulations and fish stock recovery initiatives which are culturally acceptable and ecologically sustainable.

Daily age, growth rate, and pelagic larval duration of commercially important snapper species in Abrolhos National Marine Park.

The age and daily growth of fish are registered through the deposition of increments in their otoliths, which are concretions formed by the precipitation of substances present in the endolymphatic fluid, mainly calcium carbonate (CaCO3). Faced with the need to fill some of the gaps in the knowledge on the occurrence and duration of the initial stages of snapper species' life cycles in the Abrolhos Bank, this study aimed to describe the growth rates, age, and period of pelagic larval duration (PLD) of three snapper species during the larval pre-settlement phase, in the Abrolhos Bank region. The post-larvae were captured using light traps. Otoliths were removed from 117 samples of snapper species; however, only 69 were viable for age estimation, of which 15 were Lutjanus analis, 25 were Lutjanus jocu, and 29 were Lutjanus synagris. Together, the samples presented individuals with total lengths ranging from 16.14 to 24.76 mm and ages from 21 to 39 days. Settlement marks were found for all three species, and the average PLD was ~25 days. The somatic growth of the snapper species was positively correlated with otolith growth. L. jocu presented the greatest daily growth compared to the other species. The three species use the Abrolhos Bank as a larval settlement site, demonstrating plasticity by using different habitats throughout their lives.

Recruitment of Juvenile Snapper (Lutjanidae) in the Middle Florida Keys: Temporal Trends and Fine-Scale Habitat Associations

Juvenile recruitment is a major factor in the establishment and maintenance of local population structures of coral reef fishes. An understanding of the factors that affect juvenile recruitment and survival help explain spatial and temporal patterns in adult abundance, especially of commercially and recreationally fished species. Here, we examined the distribution and juvenile recruitment of 5 snapper species: Mutton Snapper (Lutjanus analis), Lane Snapper (L. synagris), Schoolmaster (L. apodus), Gray Snapper (L. griseus), and Yellowtail Snapper (Ocyurus chrysurus) collected in 1,314 seine samples conducted between 2007 and 2019 in the Middle Florida Keys. We use a generalized linear modeling routine to assess juvenile recruitment of each species as a function of temporal, environmental, and benthic habitat variables. Interannual variability in juvenile recruitment ranged between 2 and 15—fold differences in mean predicted abundance between the highest and lowest producing years by species. Predicted recruitment varied dramatically by species in 2010 following a historic cold spell in south Florida. Three of the 5 species (Lane Snapper, Yellowtail Snapper, and Schoolmaster) exhibited the lowest observed yearly recruitment in that year, while Gray Snapper recruitment peaked. For all species, recruitment indices exhibited strong seasonal trends with peak abundances observed in the fall. Aquatic vegetation type, aquatic vegetation cover, distance from shore, and water temperature were the most important predictors of abundance. Results of this study highlight species—specific preferences for settlement habitat, demonstrate the importance of local—scale recruitment processes, and provide updated, management—relevant juvenile abundance indices for shallow water snapper in the Middle Florida Keys.

Extraction of collagenolytic proteases from Aspergillus heteromorphus URM 0269 in an aqueous two-phase system for application in collagen hydrolysis

Collagenolytic proteases produced by Aspergillus heteromorphus URM0269 were extracted using a PEG/sulfate aqueous two-phase system (ATPS). A 23 factorial design was performed to analyze the independent variables: PEG molar mass (MPEG), PEG concentration (CPEG), and sulfate concentration (Csulf). The extracted proteases were also evaluated for their optimum pH and stability at different pH levels (4.0 − 11.0) after 20 h of incubation. Collagen was extracted from mutton snapper (Lutjanus analis) skin using acetic acid (0.5 mol L−1). The enzyme was preferentially partitioned to the PEG-rich phase (K > 1), whose highest purification factor and recovery (PF = 6.256 and Y = 404.432%) were obtained under specific conditions: MPEG 8000 g.mol−1, CPEG 30%, Csulf 10%. The ATPS extraction provided an enzymatic activity range of pH 7.0 − 11.0, exhibiting greater stability compared to the crude extract. Approximately 80% of protease activity was maintained after 20 hours of incubation at all analyzed pH levels, except pH 11.0. Collagen extraction from L. analis skin yielded 8.056%, and both crude extract samples and ATPS-derived samples successfully hydrolyzed the extracted collagen, reaching peak hydrolysis after 36 hours of treatment. These findings demonstrate the feasibility of extracting highly purified and active proteases capable of hydrolyzing L. analis collagen.

Microcotylidae (Monogena) parasites of snappers (Perciformes: Lutjanidae) collected from the northeast coast of Brazil.

Monogeneans are a diverse group of flatworms, being ectoparasites of marine and freshwater fish, with great morphological and ecological variety. Analyzes of monogenetics in fish with great habitat diversity such as snappers are scarce in the literature, which already emphasizes the need for an update in this regard. The presente study found, morphologically characterized and mapped the geographic distribution and in known hosts the species Microcotyloides incisa and Microcotyloides impudicus, describing the first occurrence of these monogeneans for South America and in new hosts. The survey of hosts in the literature shows that M. incisa seems to have a greater Affinity with congener species of Lutjanidae and fish from other families, which may indicate a preference or specificity for fish of this family because they are congeners of their host type. The introduction of these parasites into South American waters may have occurred due to the migratory behavior of snappers, which are well distributed along the Mexican coast, where the parasites are usually reported. Here, we also bring the first occurrence of M. incisa for Lutjanus analis and Lutjanus jocu and M. impudicus for Ocyurus chrysurus and Lutjanus synagris, helping in the mapping and distribution of these monogenetic species in the Americas.

Folk taxonomy and scientific nomenclature: Working together for conservation of fishery resources in Brazil

Folk taxonomies of fishers are important for understanding the dynamics and diversity of fishes throughout the world. This study analyzed the folk taxonomy of artisanal fishers of the coast of the state of Paraíba, Brazil. Data were collected through free lists, semi-structured interviews and participant observations. A total of 308 local names were recorded, corresponding to 127 scientific taxa. The broad folk categories ‘pescada’ (croakers) and ‘cação’ (shark) were the most common. The Cognitive Salience Index (CSI) was used to assess which fishes the fishers knew best; the mutton snapper (Lutjanus analis) had the highest CSI score. Four hierarchical levels of folk taxonomy (kingdom, life form, generic and specific) were recorded. The local ichthyofauna contained 16 species at risk at the national level and 34 at the global level. Our results suggest that fisher folk taxonomy can complement scientific knowledge, improve and update threatened species lists and in doing so benefit fisheries management and conservation actions.

Ontogeny drives allochthonous trophic support of snappers: Seascape connectivity along the mangrove-seagrass-coral reef continuum of a tropical marine protected area

Ecosystems are connected through the movement of organisms, nutrients, energy, and matter. The connection and dependence between aquatic habitats enhances our capacity to understand the functioning of the seascape. In this paper, we investigated the trophic ecology of two snapper species, Lutjanus analis and Lutjanus alexandrei, along a tropical coastal seascape (inner estuary, outer estuary, marine beach, and coastal reefs). To quantify and compare trophic (isotopic) niches, primary trophic support, and trophic connectivity along the ontogeny, δ13C and δ15N were used to construct isotopic metrics and mixing models for assessing consumers’ isotopic niches and the relative contributions of primary sources supporting them. The isotopic niche was wider for fishes from coastal reefs, but narrower for those from inner estuary, suggesting diversification on trophic support when these species move out from the estuary to the sea. Mixing models showed that smaller individuals generally showed their previous habitat support and as the fish start to feed locally and grow, they change tissues and reflect local sources. Inside the estuary, larger fish started to show marine support while smaller fish from coastal reefs still reflected sources from previous habitats. Specifically, the models revealed that smaller individuals of L. alexandrei retained their mangrove and estuarine particulate organic matter previous support, while the L. analis model was inconclusive but converged with stable isotope niche metrics, which indicated high variability that could be related to periphyton sources from seagrass beds. The allochthonous support seems to occur either by movement or recent migrations of organisms instead of organic matter flow promoted by abiotic vectors. These results suggest the importance of maintaining habitat connections for these valuable commercial species. Future studies should focus on other sites with seagrass beds to fully understand the habitat and resource use, as well as the movements among them, especially for L. analis.

Trophic resource partitioning among four sympatric lutjanid species in the southern Mexican Caribbean Sea

ABSTRACT Snappers are marine fishes that inhabit reef ecosystems and have a wide distribution throughout tropical and subtropical waters of the Atlantic, Indian and Pacific Oceans. These species are resources of economic importance, there is a lack of biological and ecological knowledge about these species in the studied area, and their meat is highly valued for human consumption. To contribute to the ecological knowledge, this work reports on the feeding habits of four species of snapper: Lutjanus synagris, Lutjanus griseus, Lutjanus analis and Lutjanus apodus, through the identification of stomach contents and a similarity analysis for the diets. Results showed that the most important prey items were crustaceans. Differences were found in the consumption of specific prey: Portunus were mainly consumed by L. griseus; Cronius was consumed by L. apodus; and Pitho was consumed by L. analis and L. synagris. Identification of prey species to genus and species levels allowed the characterization of the feeding habits of these sympatric species and highlighted the need for research programmes focused on crustaceans that guarantee their availability and abundance in the ecosystem.

Home range characteristics and diel patterns in space use of mutton snapper, Lutjanus analis, in St. Thomas, US Virgin Islands

BackgroundThe movement ecology of mutton snapper Lutjanus analis is poorly understood despite their ecological and economic importance in the Caribbean. Passive acoustic telemetry was used to determine home ranges of six adult L. analis, including diel patterns, in Brewers Bay, St. Thomas, US Virgin Islands. Understanding long-term space use, including site fidelity and habitat usage, is necessary to implement effective and appropriate management actions for a species with extensive space and resource needs.ResultsIndividual L. analis were tracked over an average period of 316 days (range 125–509 days) and showed high site fidelity to relatively small home ranges (mean ± SD: 0.103 ± 0.028 km2, range 0.019–0.190 km2) and core use areas with low overlap among individuals. Most home ranges had a habitat composition dominated by seagrass and to a lesser degree, coral reef and/or pavement. Nighttime activity spaces were distinct from but contained within daytime areas.ConclusionsMutton snapper showed strong site fidelity to home ranges in Brewers Bay. Two individuals that were absent from the array for more than a few hours were detected at separate arrays at spawning aggregation sites. This study expands upon knowledge of mutton snapper home range characteristics, highlights the importance of maintaining adjacent high-quality habitat types in any spatial management plan, and encourages the adoption of other types of management strategies, particularly for transient-aggregating species.

Spatial and temporal patterns of spawning aggregations of fish from the Epinephelidae and Lutjanidae families: An analysis by the local ecological knowledge of fishermen in the Tropical Southwestern Atlantic

Local knowledge is a fundamental source of information for starting spawning aggregation studies in areas where this phenomenon is still unknown or little studied. Among the species that present this reproductive strategy, groupers and snapper represent two of the most relevant components of artisanal and commercial capture worldwide and are highly susceptible to overfishing. We conducted interview-based surveys to examine if local ecological knowledge can determine potential areas of spawning aggregations in southeast Brazil. Fifty-one local fishermen targeting groupers and snappers were asked about spawning aggregation areas and seasonality using charts and geographic information system (GIS) analysis. Information was obtained for 31 potential spawning aggregation sites, where black grouper (Mycteroperca bonaci) represented the most important resource for the fishermen interviewed, followed by yellowtail snapper (Ocyurus chrysurus). In addition, red grouper (Epinephelus morio), mutton snapper (Lutjanus analis) and dog snapper (Lutjanus jocu) were also mentioned as important resources that have spawning in aggregation as a reproductive strategy. The main possible spawning aggregation areas indicated occur within the Abrolhos Bank, the largest and richest reef complex in the South Atlantic. The lack of published records of spawning aggregations in Brazil, hinders the suitable implementation of measures that can protect this phenomenon and consequently the perpetuation of these and potentially other species. Therefore, additional studies and particularly in situ validation, are needed to determine the occurrence and status of the aforementioned aggregations.

Spatio‐temporal distribution of mutton snapper and dog snapper spawning aggregations in the South‐west Atlantic

Abstract Sites and periods of spawning aggregations of two important fishery resources, the mutton snapper, Lutjanus analis, and the dog snapper, Lutjanus jocu, were identified and validated along the Brazilian north‐east coast (latitude 8–15°S) using exploratory analysis of catch per unit effort (CPUE) data, gonadosomatic index analysis, and gonad histology. The CPUE analysis for both species allowed the identification of outliers and far outliers, representing fisheries with exceptional catches, which were used as proxies of possible aggregation. The presence of pre‐spawning and recent spawning signs (hydrated oocytes and post‐ovulatory follicles) in the ovary of females caught at sites with recurrent records of high CPUE allowed the validation of spawning activity at those specific sites for each species. All aggregation sites identified in this study were located on the outer shelf, close to the shelf break, a region that has been declared an Ecologically and Biologically Significant Marine Area. Comparison of two subregions showed significant differences in size structure of the fish sampled during landings, suggesting a fishing depletion effect in the north region. For both species, reproduction peaked twice in all regions studied, with a more marked peak during summer. However, spawning activity was observed in almost every month of the year, suggesting that seasonal closures could be more effective if combined with spatial measures. In the northern part of the study range, spawning grounds were found to lie just outside the boundaries of one of Brazil's largest marine protected areas. Inclusion of those grounds in the marine protected area would increase protection of these species and also mean increased protection of an Ecologically and Biologically Significant Marine Area, encompassing mesophotic reefs. The identification of these spawning aggregations sites on the north‐east coast of Brazil was conducted in collaboration with local fishers that traditionally use bottom handline. Co‐management approaches are suggested in view of the importance of these fishing sites for traditional fishing communities that may also face threats due to encroachment of mobile fleets.

Cambios en el perfil electroforético sérico de Lutjanus analis (Cuvier, 1828) en respuesta a la infección aguda por Listonella (sin. Vibrio) anguillarum

The results of electrophoresis of the blood serum of Lutjanus analis in agarose gel from two groups of fishes: (a) fish exposed to live Listonella anguillarum diluted in 0.9% NaCl solution (saline) by intramuscular injection and (b) control specimens injected with the saline solution are provided. Differences in the serum protein profiles of the two groups of specimens were observed. The method here employed, seems to be useful in detecting potential markers for monitoring infection or inflammatory reactions in L. analis after acute infection by L. anguillarum and has the advantage to allow easy analysis of several samples in a short time.

Apparent digestibility in marine mutton snapper juveniles and digestive activity of enzymes

The marine species of snapper, Lutjanus analis, has carnivorous eating habits and with potential for cultivation. The aim of this study was to evaluate the apparent digestibility coefficient (CDA) of mutton snapper, and to evaluate its enzymatic profile after feeding with vegetable and animal protein sources. CDA was the indirect method of fecal collection, using chromic oxide as a biological marker. Eight hundred fish, with an average weight of 28.0 ± 2.58 g, were acclimated for 15 days in a net tank (2 m³), ​​and installed in the same collection environment. The acclimatization of 54 fish was carried out in digestibility aquariums (200 L), and the collection of feces started. For mutton snapper, the supply of octopus flour improves (P <0.05) the digestibility of dry matter (CDAMS, 67.17%), crude protein (CDAPB, 90.9%) and crude energy (CDAGE, 78, 8%). Regarding the digestibility of lipids (CDAL), anchovy flour has more (P <0.05) digestible lipids (78.1%), followed by the tested ingredients, fish meal (72.4%) and flour octopus (69.7%). Apparent digestibility of dry matter, crude protein and crude energy were low (P <0.05) for shrimp meal and soybean meal. Mutton snapper fed with octopus flour has higher digestibility coefficients, suggesting this ingredient for species. All diets caused low amylase activity in juveniles, and lipase and alkaline protease activities were higher with the inclusion of broadband anchovy flour and octopus flour, respectively.

Piscicultura marinha brasileira: desafios e perspectivas do seu desenvolvimento no estado do Ceará

A pesca ainda é a maior responsável pelo fornecimento de pescado marinho para consumo humano. Entretanto, visto a notória ameaça aos estoques pesqueiros e a crescente demanda pelo produto, este cenário precisa mudar e a piscicultura marinha continua sendo mundialmente apontada como medida viável para remediar esse quadro. Desta forma, o objetivo deste artigo é discutir sobre a piscicultura marinha no Brasil, com foco nos desafios e perspectiva de seu desenvolvimento no estado do Ceará. Durante o período de seis meses, a metodologia do trabalho constituiu-se de três ferramentas: levantamento bibliográfico, entrevistas e visitas técnicas. Os resultados obtidos retratam que, apesar de todas as inciativas públicas e privadas, a piscicultura marinha no Brasil continua incipiente e com obstáculos a serem superados. No que concerne ao Ceará, o estado, por intermédio de órgão de fomento, tem executado ações com o propósito de oportunizar o desenvolvimento da piscicultura marinha. Dentre as ações planejadas, incialmente está sendo executado a elaboração de projeto de laboratório para provimento de alevinos de espécies marinhas, simultaneamente a sua análise da viabilidade econômica financeira, e a prospecção de espécies profícuas para produção no estado, cuja conjectura preliminar tem apontado para Lutjanus synagris (ariacó) e, sobretudo, Lutjanus analis (cioba).

Anisakidae Skrjabin & Karokhin, 1945 and Raphidascarididae Hartwich, 1954 nematodes in lutjanidae (pisces: perciformes) from the Brazilian Northeast Coast.

The present study aimed at describing and evaluating the fauna of Anisakidae and Raphidacarididae nematodes of lutjanid fish (snappers) from the Brazilian northeastern coast unloaded at the city of Aracaju, capital of the State of Sergipe. A total of 186 lutjanids of 5 different species were analyzed including 69 Lutjanus analis, 51 L. vivanus , 29 Ocyurus chrysurus, 23 L. synagris, and 14 L. jocu. Nematode specimens found in the viscera of these fish were clarified with lactophenol. Illustrations of each of these specimens were prepared to help identify these samples and compose their taxonomic description and classification. At necropsy, 3,183 nematodes belonging to two families were collected from fish viscera which included the following: Anisakidae: Anisakis, Terranova , Contracaecum, and Goezia; Raphidascarididae: Raphidascaris (Ichthyascaris) and Hysterothylacium . A total of six genera of nematodes were found at postmortem examination of which adult worms of only three genera (Goezia, Raphidascaris and Hysterothylacium) were detected in the fish examined. Larvae of Terranova sp. were found only in the musculature of O. chrysurus . Most of the nematode larvae were present in the mesentery and organs of the fish necropsied. Therefore, the zoonotic potential of these nematodes cannot be ruled out. There was a significant negative correlation between the intensity of parasitism by anisakids and the total body length of O. chrysurus; the intensity of parasitism was greater in smaller and shortef fish. There was a significant positive correlation between the abundance of these parasites and the length of L. synagris; the presence of these parasites increased according to the fish's body length. To the authors' knowledge, these are the first records of Raphidascaris (Ichthyascaris ) sp. and Hysterothylacium sp. in L. vivanus , of Terranova sp. in O. chrysurus and L. jocu, and of Goezia sp. in L. analis. These novel findings add the Brazilian northeast coast and the State of Sergipe in the geographic distribution of these parasites in the country.

Phylogeography and Historical Demography of Two Sympatric Atlantic Snappers: Lutjanus analis and L. jocu

Lutjanus analis (mutton snapper) and L. jocu (dog snapper) are mesopredator species with extensive geographic distribution in the Atlantic Ocean. Although historically overfished, their genetic diversity, population structuring, and historical demography along the Brazilian coast are unknown. Here we present genetic data for the hypervariable region 1 (HVR1) of the mtDNA control region of both L. jocu and L. analis, and for cytB of L. analis from distinct geographic regions. Phylogeographic analyses based on HVR1 sequences revealed no geographic structuring of mtDNA lineages for either species. The bimodal mismatch distribution plots of mutton and dog snapper populations implied that they might have experienced secondary contact. Historical demographic parameters estimated that population expansions ranged from 13,631 to 61,171 years before present (ybp) for L. analis and 36,783-55,577 ybp for L. jocu, associated with events that occurred at the end of the last glaciation period. Estimates of the average effective population size for L. jocu were higher than those for L. analis, with the largest population occupying the Brazilian northeastern region coast. High migration rates are maintained among the three northernmost locations, with a substantial decrease to the further southern region. Our study suggests that a tripartite interaction of larval dispersion and interregional adult movement (aggregate spawning), allied to historical contingencies, contributed to contemporary population genetic patterns of these species, and adds relevant information for conservation management of such vulnerable - and valuable - marine resources.

Occurrence of Isopods in Two Species of Snappers (Lutjanidae) from Northeast Brazil.

Parasitic isopod species are poorly known in the northeastern coast of Brazil. In this sense, this study presents novel records of Isopoda of the families Aegidae, Cymothoidae, and Corallanidae. A total 69 specimens of Lutjanus analis and 19 of Lutjanus jocu, of which 46 isopods from 3 different species were collected, i.e. Rocinela signata, Cymothoa excisa, and Excorallana richardsoni. The species R. siganata and E. richardsoni are reported for the first time in L. jocu. A significant relationship between the parasite R. signata and the size of the fish L. jocu was also observed. The isopod C. excisa is considered an incidental finding in L. analis. To the authors' knowledge, this is the first report of this species in fish from Brazil. The three species of isopods are new occurrences in the State of Sergipe, northeast region of the country. An additional morphological characteristic observed in the dorsal setae of pleotelson in specimens of E. richardsoni was that one end of this structure wws bifid. This information contributes to the current body of knowledge of the morphology of this particular species.

Potential connectivity between marine protected areas in the Mesoamerican Reef for two species of virtual fish larvae: Lutjanus analis and Epinephelus striatus

The potential connectivity network of marine protected areas (MPAs) with spawning aggregations sites in the Mesoamerican Barrier Reef system (MBRS) was examined through simulated dispersal of two study cases, Lutjanus analis and Epinephelus striatus larvae. The analysis was based on a particle tracking model incorporating four years of daily horizontal surface currents from the global scale HYCOM 1/12°. We carried out two approaches, the first one used the period of larval duration (PLD) and the second the time of flexion of the notochord as the limit time of dispersion of the particles. Additionally, peak spawning seasons (December-Febraury for E. striatus and March-July for L. analis), lunar phases and georeferenced spawning aggregations sites were considered for releasing the virtual larvae. Our findings suggest that in general, the network of MPAs of the MBRS are well connected, however, the connectivity network structure presented variations in the relative role of each MPA, and their played role will depend on the specie reproductive period, the oceanographic conditions and the assumed biological approximation (such as PLD or flexion). Our analysis suggested a regionalization of the MBRS. A southern region (Bacalar Chico, Roatan and Sapodilla) with low degree of connectivity, moderate self-recruitment rate, and low values of betweenness centrality. A second southern region (Turneff Island, Lighthouse Atoll, Glover Reef Atoll and Gladen Spit) with high rate of self-recruitment (up to 20%) that could be related to self-recruitment due to retention mechanism of the Honduras Gyre, with high values of source of larvae, function as bridges that connect the south zone with the north of the system. A third region (Mahahual and Xcalak) showing sink of larvae, low larval arrival rate but self-recruitment, low values of betweenness centrality area influenced by slow and variable currents and the presence of a southward flow. And a fourth region (Chinchorro, Sian Ka’an, Puerto Morelos and Cozumel) with moderate fast current speed (Yucatan Current), low self-recruitment, larval sink, bridge with the Gulf of Mexico and Florida.

First record of Dichelyne (Dichelyne) bonacii (Nematoda, Cucullanidae) parasitizing the intestine of two species of lutjanid fish (Perciformes, Lutjanidae) on the northeast Brazilian coast

Lutjanids are marine fish and commonly inhabit coral reefs, which have migratory habits and feed in a general way, due to these characteristics, are susceptible to infections by parasites, such as cuculanid nematodes. This work aimed to report for the first time, the occurrence of Dichelyne (Dichelyne) bonacii in Brazil, in two new hosts, Lutjanus analis and Rhomboplites aurorubens, acquired from local artisanal fishermen at the Aracaju city public fishing terminal (10 ° 54'17 "S37 ° 2'56" W), northeast coast of Brazil. Adult nematodes were collected from the intestinal tract of the hosts, clarified in Aman's Lactophenol and were briefly described here. Three adult males and five gravid females were found, indicating that the two species of fish acted as definitive hosts. Currently, this species of parasite has been reported only from fish collected in the coast of Mexico, which makes this work the first record of this parasite in Brazilian coastal waters. The results show that probably the range of hosts and the distribution of D. (Dichelyne) bonacii is not as restricted as data pointed in the literature, being a little wider, extending also to waters that bathe the Brazilian coast.

Length-based risk analysis for assessing sustainability of data-limited tropical reef fisheries

AbstractThis study extended a “data-limited” length-based stock assessment approach to a risk analysis context. The estimation-simulation method used length frequencies as the principal data in lieu of catch and effort. Key developments were to: (i) incorporate probabilistic mortality and growth dynamics into a numerical cohort model; (ii) employ a precautionary approach for setting sustainability reference points for fishing mortality (FREF) and stock reproductive biomass (BREF); (iii) define sustainability risks in terms of probability distributions; and, (iv) evaluate exploitation status in terms of expected length frequencies, the main “observable” population metric. This refined length-based approach was applied to six principal exploited reef fish species in the Florida Keys region, consisting of three groupers (black grouper, red grouper, and coney), two snappers (mutton snapper and yellowtail snapper), and one wrasse (hogfish). The estimated sustainability risks for coney were low (<35%) in terms of benchmarks for fishing mortality rate and stock reproductive biomass. The other five species had estimated sustainability risks of greater than 95% for both benchmarks. The data-limited risk analysis methodology allowed for a fairly comprehensive probabilistic evaluation of sustainability status from species and community perspectives, and also a frame of reference for exploring management options balancing sustainability risks and fishery production.