Lutjanus Jocu Research Articles

Coastal fish assemblages reflect marine habitat connectivity and ontogenetic shifts in an estuary-bay-continental shelf gradient

The success of marine management initiatives and our capability for dealing with environmental change largely depend on our understanding regarding the distribution of species and their habitat preferences. In the present study, we deployed baited remote underwater video systems (BRUVs) in a portion of Brazilian central coast (i.e., Todos os Santos Bay) to describe fish species-habitat associations along an estuary-bay-continental shelf gradient. Significant variation in the fish assemblage was found among three ecosystems, four depth classes, and eight different types of habitat, confirming that the structure and composition of fish assemblages is mediated by a set of habitat characteristics forming an ecological mosaic. The highest species richness and relative abundance were found in the mangroves and reefs. The data demonstrated that some species, such as Lutjanus jocu, Lutjanus synagris, Carangoides bartholomaei, Eucinostomus argenteus and Eucinostomus melanopterus had clear ontogenetic shifts among habitats and across ecosystems. Some species (Sphoeroides greeley, L. synagris, and Eucinostomus gula) were widespread along the ecosystem-level gradient and were observed in a number of different habitats, reflecting more generalist habitat associations. By contrast, a large number of species (54; e.g., Ptereleotris randali, Decapterus macarellus and Mugil curema) were recorded in a single habitat type, indicating they were habitat specialists. Despite this apparent habitat-related pattern, the size-mediated relationships found in many species indicate cross-migration along the ecosystem gradient. Our findings have implications for the conservation and monitoring of fish assemblages highlighting the role of the connectivity of marine habitats as a conservation priority toward to an ecosystem-based management strategy.

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.

The fishes of St Helena Island, central Atlantic Ocean-new records and an annotated check-list.

A check-list of the fishes of St Helena Island is presented. The following species are recorded for the first time from St. Helena Island: Rhincodon typus, Mobula tarapacana, Muraena melanotis, Caranx latus, Seriola rivoliana, Balistes capriscus, Lutjanus jocu, Centropyge aurantonotus, Acanthurus coeruleus, Lepidocybium flavobrunneum, Tetrapturus pfluegeri, Coelorinchus geronimo, Pentaceros richardsoni, Gephyroberyx darwinii, Brotula cf multibarbata, Poromitra crassiceps, Echiostoma barbatum, Malacosteus niger, Pachystomias microdon. Including these nineteen new records there are 189 fish species currently known from St Helena. Three of them appear to be undescribed. Eight species and two subspecies are currently considered endemic to St. Helena Island.

Levamisole on the biochemical and hematological responses to parasitism by monogenoids in dog snapper

ABSTRACT: The response of biochemical and hematological parameters were analyzed in dog snapper (Lutjanus jocu) grown in net cages, as well as for the specimens kept in the laboratory during an infestation by Neobenedenia melleni, and after treatment with freshwater bath and injectable application of levamisole. Significant changes were observed in N. melleni parasitized individuals, characterized by increased glucose and lactate levels, as well as a significant fish hematocrit reduction and leukocyte increase. Treatment with freshwater baths, concomitant with injectable levamisole application, showed therapeutic efficacy in several parameters after 14 days of treatment.

Potential Response of Coral Reef’s Functional Structure and Snapper Abundance to Environmental Degradation in San Andres Island, Colombia

To determine the coral reef morpho-functional structure of San Andrés, regarding functional benthic diversity and fish (Lutjanidae), we evaluated the condition of the coral structure on the leeward side of the island, which is an area impacted by tourism, through diving and fishing. Three sampling sites were evaluated during two years recording the distribution of benthic organisms, environmental variables and Snappers density (Lutjanidae). A low density of Lutjanus jocu and Ocyurus chrysurus was found, with a high density of juveniles of L. apodus and L. mahogoni, which showed a preference for reefs with submassive and brain corals. Algae especially Macroalgae and octocorals were those with the greatest coverage in the reefs, followed by inert substrates, while corals were epresented by species with a wide distribution such as Agaricia agaricites and Porites astreoides. Octocorals correlated negatively with stony corals and that the most widespread fragile corals were the finger. We concluded that there is a higher density of mainly juvenile snappers where there is a greater variety of coral morpho-functional groups, and not necessarily in sites with greater coral coverage. Also, adult snappers were associated with octocoral zones. This shows that morpho-functional diversity is a crucial factor in the permanence of snappers.

Biometric relation between body size and otolith size of seven commercial fish species of the south-western Atlantic

Given the importance and applicability of these biometric relations, the present work aimed to verify the existence of correlations between the length of saggitae otoliths and the body size of seven south-western Atlantic marine fish species and to generate equations to estimate the body size of these species through otolith measurements. Fifty otoliths of Centropomus parallelus, Centropomus undecimalis, Lutjanus analis, Lutjanus jocu, Lutjanus synagris, Chaetodipterus faber and Mugil curema were collected for analysis. Significant relations between otolith length and total length and otolith width and total length were found for all the species. The highest coefficient of determination was observed for Centropomus undecimalis and Lutjanus synagris, for both relations, and the lowest was observed for Mugil curema. The results show that estimates of body size of the species through biometric analyses of otoliths are reliable. Based on this, the equations generated to obtain the total length of the fish using biometric otolith data can be used in dietary studies of top predators and in paleontological recostructions of modern fish.

Hematological and biochemical characteristics during the transport of dog snapper Lutjanus jocu (Perciformes: Lutjanidae)

ABSTRACT The objective of this study was to evaluate stress responses in dog snapper (Lutjanus jocu) during transport by evaluating their hematological and biochemical responses. Twenty-five wild dog snapper specimens were used in the experiment (220 ± 68 g and 24.5 ± 2.5 cm total length). Blood samples were collected prior to transport (control), and fish were placed in two transport boxes, one with anesthetic and one without anesthetic. Immediately after transport and after 24 h, blood was collected from the fish that underwent each treatment (with anesthetic and without anesthetic). Biochemical and hematological results demonstrated the inefficiency of benzocaine as a stress reliever during handling and transport. Biochemical parameters revealed the effects of stress during transport, and after 24 h, glucose levels and hematological parameters (hemoglobin, erythrocytes, leukocytes, neutrophils and MCH) showed a tendency to return to control levels. This study is the first to report stress response measurements of hematological and biochemical indicators in dog snapper, representing an important basis for the planning of future experiments involving the transport and handling of this fish species.

Mapping fishing grounds, resource and fleet patterns to enhance management units in data-poor fisheries: The case of snappers and groupers in the Abrolhos Bank coral-reefs (South Atlantic)

In most small-scale fisheries, especially in developing countries, the collection of reliable fishing statistics is not regular, hampering traditional stock assessments. In those data-poor fisheries, a precise knowledge of resources co-occurrence at the ecosystem level, as well as the spatial mapping of fishing activities seem key to support management in a complex fishers-environment context. In the largest South Atlantic coralline reef, the Abrolhos Bank, fisheries are extremely diverse in terms of exploitation capacity, fishing gears, target stocks and operating areas, but any regional fisheries management is currently in place. The aim of this study was to assess, organize, and analyze fisheries of three snappers (Lutjanus jocu, L. synagris and Ocyurus chrysurus), and three groupers (Cephalopholis fulva, Epinephelus morio and Mycteroperca bonaci) along the Abrolhos Bank, with an ultimate goal of proposing useful management units. Surveys were conducted in the main fishing ports, including fishers' interviews and fish size measures in landings. Data analysis allowed a precise fishing characterization, a grouping of stocks co-occurrence, and the mapping of fishing spots and grounds. Three stocks and seven fishing areas clusters were obtained and defined statistically, suggesting useful management units. Specific fishers' groups per fleet were identified as the main stakeholders to be consulted in fisheries plans. Spatial units based on the occurrence of snappers and groupers stocks were defined, having the “Parcel das Paredes” the greatest number of fishing spots and the lower fish sizes. Overall, findings contain unprecedented fine scale resolution units that clarifies and simplifies the connections among species, fleets, fishing areas and fishers. They should also strength the call for action to implement fisheries management in a broader ecosystem-scale context.

Preliminary observations on the age and growth of dog snapper (Lutjanus jocu) and mahogany snapper (Lutjanus mahogoni) from the Southeastern U.S.

Dog snapper (Lutjanus jocu Bloch and Schneider 1801) and mahogany snapper (Lutjanus mahogoni Cuvier 1828) are infrequently caught snappers in the southeastern U.S. primarily occurring off of southern Florida. The species were opportunistically sampled from commercial and recreational fisheries in the southeastern U.S. from 1979 to 2015. Fish were aged (56 dog snapper and 54 mahogany snapper) by counting opaque zones on sectioned sagittal otoliths. Otoliths of both species were easily interpretable and agreement between readers was acceptable. Analysis of otolith edge-type revealed that annuli formed between May and July on both species. Dog snapper ranged from 200–837 mm total length (TL) and ages 2–33, while mahogany snapper ranged from 270–416 mm TL and ages 2–18. The Von Bertalanffy growth equations were Lt = 746(1–e(−0.20(t−0.32))) and Lt = 334(1–e(0.31(t+1.19))) for dog snapper and mahogany snapper, respectively. The weight-length relations were W = 1.31 × 10−5L3.03(n = 78, r2 = 0.99) and W = 5.40 × 10−6L3.15(n = 79, r2 = 0.79) for dog snapper and mahogany snapper, respectively, where W = whole weight in grams.

Kudoa spp. (Myxozoa, Multivalvulida) parasitizing fish caught in Aracaju, Sergipe, Brazil.

This study reports on Kudoa spp. (Myxozoa, Multivalvulida) from the fish species Lutjanus analis, Bagre marinus, Aspistor luniscutis and Lutjanus jocu, which were caught in Aracaju, state of Sergipe, Brazil. The parasites formed oval plasmodia around the esophagus of L. analis, and elongated plasmodia inside the skeletal muscle of B. marinus, A. luniscutis and L. jocu. Host myoliquefaction was not observed in all the cases studied. The current study provides a morphological and morphometric description of each parasite as well as a comparison with all the species described worldwide. Lack of molecular data impaired specific identification of the parasites. The importance of these parasites is discussed and the need for further studies on infections in Brazilian fish is emphasized because of the high economic impact of some Kudoa species which cause liquefaction in hosts' muscles and render these fish unsuitable for consumption.

Spatial variation in density and size structure indicate habitat selection throughout life stages of two Southwestern Atlantic snappers

The early life history of Lutjanus alexandrei and Lutjanus jocu in Southwestern Atlantic is still largely unknown. Habitat use of different life stages (i.e. size categories and densities) of the Brazilian snapper (L. alexandrei) and dog snapper (L. jocu) was examined in a tropical portion of NE coast of Brazil. Visual surveys were conducted in different shallow habitats (mangroves and reefs). Both snapper species showed higher densities in early life stages in mangrove habitat, with a clear increase in fish size from mangrove to adjacent reefs. Post-settler individuals were exclusively found in mangroves for both species. Juveniles of L. alexandrei were also registered only in mangroves, while sub-adult individuals were associated with both mangrove and reef habitats. Mature individuals of L. alexandrei were only observed in reef habitats. Juvenile and sub-adult individuals of the dog snapper were both associated with mangrove and reef habitats, with high densities registered in mangroves. Mature individuals of L. jocu were not registered in the study area. This pattern suggests preference for mangrove habitat in early life stages for both species. Ontogenetic movement between habitats was also recorded. This pattern denotes habitat selection across different life cycle of both species. Such information highlights the importance of directing management and conservation efforts to these habitats to secure the continuity of contribution to adult populations.

Indirect signals of spawning aggregations of three commercial reef fish species on the continental shelf of Bahia, east coast of Brazil

AbstractLutjanus analis (Mutton snapper), Lutjanus jocu(Dog snapper) and Mycteroperca bonaci (Black grouper) are reef fishes of high commercial value, and are among the principal exploited reef resources on the eastern and northeastern coast of Brazil. These species share the habit of forming transient spawning aggregations, predictable in time and space, which leaves them particularly vulnerable. The present study aimed to obtain indirect indicators of periods and places of spawning aggregations for these species, based on the exploratory analysis of available data on commercial catches and fishing efforts in Southern Bahia. Line fishery landings data were monitored in 12 locations in the region, and catch records of Mutton snapper (1320 landings), Dog snapper (654) and Black grouper (1162) were analyzed. A strategy was developed for exploratory analysis of monthly CPUE variation and individual distribution of CPUE per trip. The results showed the occurrence of aggregations in 26 specific sites, with values of relative abundance far above the annual mean, during spring/summer and autumn/winter. The occurrence of these anomalous catches was validated with the fishermen responsible for respective fishing trips. Additional studies are needed to confirm spawning activity at these sites. Analysis of inter-annual variation suggests a decreasing trend in relative abundance of Black grouper and Mutton snapper, possibly associated with unregulated fishing of spawning aggregations.

Ecological fishing networks in a marine protected area: One possibility for evaluating objectives

The consequences of human actions are a source of changes in ecosystems. These result from alterations in the structure and patterns of interaction of the ecosystem, often with negative consequences in terms of losses of ecosystem function and the extinction of species. As a result, establishing protected areas as Brazil's Extractive Reserves (Resex) is a necessity. Ecological networks can be used as a tool to assess whether the Resex are effective in conserving marine biodiversity and the livelihoods of fishers. By analysing the structure of networks, e.g., their nestedness and modularity, it is possible to understand how species interact with each other, both directly and indirectly. The aim of this study was to analyse and compare the interactions and the management activities affecting fishers and fish at the Canavieiras Resex. The data were collected between April and August 2012 through semi-structured interviews with fishers to identify their target species and the fishing gear that they use to identify the structural patterns of the fish-fisherman, fish-guilds, and functional-group-guilds networks. The target species were Centropomus spp., Lutjanus jocu, Eugerres brasilianus and Mugil spp. Cast nets and trammel nets were the types of fishing gear that were most frequently used. High nestedness and significative modularity patterns were observed in the networks, indicating that generalist and specialist fishers primarily capture their target species. These patterns also indicate the extent of harvesting pressure on these fish. The fishers who use these networks include a high level of fish biodiversity in their catches. The structural pattern that was found implied that fishing pressure on these species, coupled with a lack of management tools, has created a situation in which priority must be given to the development of scientific conservation techniques and sustainable management plans.

Ultrastructure of novel thrombocytes in the dog snapper Lutjanus jocu

Myxosporean cysts containing spores of Henneguya sp. were observed in the gills of the dog snapper Lutjanus jocu. Adjacent to the cysts were capillaries, allowing observation of peripheral blood cells. Numerous white blood cells displaying uncommon cytoplasmic projections were observed amongst the erythrocytes. Their morphology allowed them to be identified as thrombocytes (TCs). Each TC displayed 18-26 cytoplasmic projections, most of which were in close proximity to erythrocytes. At their apical end, each cytoplasmic projection presented an ellipsoidal vacuole (c. 0·6 µm × 0·3 µm) from which a secretory tubule, 0·3-0·4 µm long and c. 120 nm in total diameter, extended towards the periphery of the TC plasmalemma and fused with the cellular membrane. From this opening, contents of vacuoles were apparently released into the lumen of the capillaries. Other vacuoles with similar features, and containing an electron-lucent matrix, were observed in the cytoplasm of the TC. This is the first description of fish TC with these ultrastructural features and organization, which suggest that they perform a secretory function.

Morphology and phylogeny of Henneguya jocu n. sp. (Myxosporea, Myxobolidae), infecting the gills of the marine fish Lutjanus jocu

Henneguya jocu n. sp. (Myxosporea, Myxobolidae) is described from the gill lamellae of the marine teleost fish Lutjanus jocu, with a focus on ultrastructural and molecular features. This myxosporean forms subspherical cysts up to ∼260μm×130μm long, and develops asynchronously. Mature myxospores ellipsoidal with a bifurcated caudal process. Myxospore length 10.9±0.4μm (n=50); width, 8.2±0.3μm (n=50); and thickness, 2.9±0.5μm (n=50). Two equal caudal processes, 34.1±1.0μm long (n=50); and total myxospore length, 45.2±1.0μm (n=50). Two symmetric valves surround two ellipsoidal polar capsules, 5.0±0.3×1.4±0.2μm (n=20), each containing an isofilar polar filament forming 4–5 coils along the inner wall of these structures, as well as a binucleated sporoplasm presenting a spherical vacuole and several globular sporoplasmosomes. Both the morphological data and molecular analysis of the SSU rDNA gene identify this parasite as a new species of the genus Henneguya. Maximum Likelihood and Maximum Parsimony analyses further indicate that the parasite clusters within others marine Myxobolidae species, forming a group alongside other Henneguya species described from marine hosts.

A barcode for the authentication of the snappers (Lutjanidae) of the western Atlantic: rDNA 5S or mitochondrial COI?

The increasing demand for fishery resources in recent years has stimulated a growth in the output of processed products, which has made the fraudulent substitution of species a common practice. In the present study two different protocols were evaluated for the molecular authentication of lutjanid species, one based on the banding pattern of the nuclear rDNA 5S gene, and the other on the sequences of the mitochondrial Cytochrome Oxidase subunit I (COI) gene. A total of 132 samples were analyzed from specimens identified previously as belonging to seven lutjanid species (Lutjanus purpureus, Lutjanus synagris, Lutjanus vivanus, Lutjanus jocu, Lutjanus analis, Ocyurus chrysurus, and Rhomboplites aurorubens), as well as unidentified individuals. The results indicate the absence of a species-specific rDNA 5S banding pattern in lutjanids. However, the 1131 bp fragment of the COI gene not only discriminated the identified lutjanid species systematically, but also defined the species of the unidentified specimens, identifying another two species from the database, Lutjanusbucanella and Lutjanuscyanopterus. The species were represented by well-defined consensual clades in the phylogenetic trees, supported by the interspecific distances and the mutations characteristic of each species. This segment of the COI gene proved to be a robust tool for the molecular authentication of lutjanid species.

Reef fishes captured by recreational spearfishing on reefs of Bahia State, northeast Brazil

Although recreational spearfishing is a growing activity, its impacts are poorly understood. This paper aims to present data on reef fishes captured by recreational spearfishing in the Bahia State, Northeastern Brazil. We analyzed 168 photos of spearfishing conducted in the reefs of this region between 2006 and 2008. A total of 1.121 fish belonging to 48 species were captured in three sub-regions of the Bahia coastline: Litoral Norte (LN), Salvador (SSA) and Baixo Sul (BS). The main species caught were: Scomberomorus brasiliensis (n = 191), Sphyraena barracuda (n = 153), Lutjanus jocu (n = 150) and Caranx bartholomaei (n = 141); these four species represented 56.5% of total captures. Over the sampling period, the highest values of catch rates per day were observed at BS, followed by SSA and LN. There were significant between-sites differences in the number of fish in the number of species caught. However, there were no significant between-years differences in the number of fish and numbers of species caught. The trophic classification of fish showed that carnivores (n = 623) were more frequently captured, followed by piscivores (n = 371), herbivores (n = 101) and invertivores (n = 26). The results showed that high sized, top predatory fishes, were the main targets, although other trophic levels were also captured.

Fish assemblage of the Mamanguape Environmental Protection Area, NE Brazil: abundance, composition and microhabitat availability along the mangrove-reef gradient

Reefs, mangroves and seagrass biotopes often occur in close association, forming a complex and highly productive ecosystem that provide significant ecologic and economic goods and services. Different anthropogenic disturbances are increasingly affecting these tropical coastal habitats leading to growing conservation concern. In this field-based study, we used a visual census technique (belt transects 50 m x 2 m) to investigate the interactions between fishes and microhabitats at the Mamanguape Mangrove-Reef system, NE Brazil. Overall, 144 belt transects were performed from October 2007 to September 2008 to assess the structure of the fish assemblage. Fish trophic groups and life stage (juveniles and adults) were recorded according to literature, the percent cover of the substrate was estimated using the point contact method. Our results revealed that fish composition gradually changed from the Estuarine to the Reef zone, and that fish assemblage was strongly related to the microhabitat availability, as suggested by the predominance of carnivores at the Estuarine zone and presence of herbivores at the Reef zone. Fish abundance and diversity were higher in the Reef zone and estuary margins, highlighting the importance of structural complexity. A pattern of nursery area utilization, with larger specimens at the Transition and Reef Zone and smaller individuals at the Estuarine zone, was recorded for Abudefduf saxatilis, Anisotremus surinamensis, Lutjanus alexandrei, and Lutjanus jocu. Our findings clearly suggests ecosystem connectivity between mangrove, seagrass and reef biotopes, and highlighted the importance of Mamanguape Mangrove-Reef System as a priority area for conservation and research, whose habitat mosaics should be further studied and protected.

‘Following the leader’: first record of a species from the genus Lutjanus acting as a follower of an octopus

This is the first record of an octopus ( Octopus insularis ) being followed by a Lutjanus species ( Lutjanus jocu ). The interaction was observed within the limits of the Fernando de Noronha Marine National Park, north-western Brazil and lasted for approximately 30 minutes, covering a distance of 40 metres. Similar food preferences and benthic foraging habits between the species appear to have motivated the occurrence of this behaviour.

Multi-scale habitat occupancy of invasive lionfish (Pterois volitans) in coral reef environments of Roatan, Honduras

The Indo-Pacific lionfish species [Pterois volitans (Linnaeus, 1758) and P. miles (Bennett, 1828): Family Scorpaenidae] are the first nonnative marine fishes to establish in the Western North Atlantic and Caribbean Sea. Despite the continued documentation of its range expansion and highly publicized invasion (including public-driven removal efforts) there remains a paucity of basic information on lionfish ecology. This knowledge gap limits effective long-term management. In this study we conducted a multi-scale investigation of habitat occupancy of a newly established population of lionfish in Roatan, Honduras. Based on field surveys and citizen sightings in Roatan Marine Park we found that lionfish occurred more frequently on aggregate coral reef habitats (54% of sightings) compared to patch reef habitats (30%) and sea grass lagoons (16%). In general, these aggregate and patch reef habitats contained adults (mean total length =118.9 mm and 114.7mm, respectively) whereas sea grass habitats contained juveniles (mean total length=89.5 mm). At the micro-habitat scale lionfish occupied areas dominated by hard coral and overhanging structure; the same microhabitats containing native fishes of concern – grouper (Nassau grouper, Epinephelus striatus; yellow fin grouper, Mycteroperca venenosa) and snapper (dog snapper, Lutjanus jocu; mutton snapper, Lutjanus analis). Results from this study contribute information on basic habitat requirements of lionfish and inform current management removal efforts focused on containing spread and mitigating their impacts on native species.