Dormitator Maculatus Research Articles

Evaluation of the aquaculture potential of Dormitator maculatus (Bloch, 1792) from the Alvarado lagoon, Veracruz, Mexico

Evaluation of the aquaculture potential of Dormitator maculatus (Bloch, 1792) from the Alvarado lagoon, Veracruz, Mexico

Fish biodiversity of a tropical estuary under severe anthropic pressure (Doce River, Brazil)

Abstract The Doce River has undergone severe changes over the last centuries (e.g., flow regulation, pollution, habitat and species loss). Here, we present the first comprehensive fish biodiversity assessment of the Doce River estuary and a summary of the main impacts and their drivers for the whole river since the early 18th century. Carangiformes, Siluriformes and Eupercaria incertae sedis were the most representative orders for the 115 species recorded. Most species are native (87.8%), euryhaline/peripheral (80%) and zoobenthivorous (33.9%). Threatened (Paragenidens grandoculis, Genidens barbus, and Lutjanus cyanopterus) and near threatened (Cynoscion acoupa, Dormitator maculatus, Lutjanus jocu, Lutjanus synagris, and Mugil liza) species are peripheral. Thirteen species are exotic at the country (Butis koilomatodon, Coptodon rendalli, and Oreochromis niloticus) or the basin level (e.g., Pygocentrus nattereri and Salminus brasiliensis). The catfish Cathorops cf. arenatus is reported for the first time on the eastern coast of Brazil and Paragenidens grandoculis, considered extinct in the Doce River, was discovered in the estuary.

Identifying Early Stages of Freshwater Fish with DNA Barcodes in Several Sinkholes and Lagoons from the East of Yucatan Peninsula, Mexico

Our work shows the efficacy of DNA barcoding for recognizing the early stages of freshwater fish. We collected 3195 larvae and juveniles. Of them, we identified 43 different morphotypes. After DNA barcodes of 350 specimens, we ascertained 7 orders, 12 families, 19 genera, 20 species, and 20 Barcode Index Numbers, corresponding to putative species. For the first time, we reported the presence of the brackish species, Gobiosoma yucatanum in Lake Bacalar. Specimens of the genus Atherinella sp. and Anchoa sp. are possibly new species. Using both methods, morphology, and DNA barcodes, we identified 95% of the total larvae collected (2953 to species, and 78 to genus), and all of them were native. From them, the order Gobiiformes represented 87%. The most abundant species were Lophogobius cyprinoides and Dormitator maculatus, followed by Gobiosoma yucatanum and Ctenobius fasciatus. The Muyil and Chuyanché lagoons have the highest number of species. We present for the first time a short description of Cyprinodon artifrons and Floridichthys polyommus. This information conforms an indispensable baseline for ecological monitoring, to evaluate impacts, and developing management and conservation plans of biodiversity, principally in areas under human pressure such as Sian Ka’an, and Lake Bacalar, where tourism is high and growing in disorder.

Feeding ecology and coexistence dynamics in a community of fishes in a temperate temporary water body

AbstractTemporary water bodies are temporally variable ecosystems supported primarily by rainwater. The biota supported by such water bodies present a range of capacities to remain in this environment for all or part of their life cycles. During floods, temporary pools can connect with permanent streams, promoting changes in trophic networks in the aquatic food webs. The aim of this research was to analyse the feeding ecology of a fish community in a temporary pool near of Tlacotalpan, in the Mexican southeast, in order to understand the dynamics of the feeding habits. First, we identified feeding habits that can be interpreted as guilds of the fishes in the temporary pool: the annual killifish Millerichthys robustus (the only autochthonous species) is planktophagous; Cynodonichthys tenuis and Astyanax aeneus are insectivores; Dormitator maculatus and larvae of amphibians (Lithobates sp.) are mainly detritivorous; and Poecilia mexicana is planktophagous and insectivorous. We then estimated the effect of coexistence on niche breadth and overlap. The niches of M. robustus and P. mexicana evidenced overlap, but the breadth was adjusted inversely, suggesting feeding specialisation in M. robustus in response to competition. We documented the existence of two cohorts of M. robustus; the niche breadth of the first and second cohorts suggesting different strategies probably related to competition under variable conditions. The niche of C. tenuis and A. aeneus, and D. maculatus and tadpoles overlapped, following a pattern of feeding generalisation in response to competition.

Basic Biological Aspects of Dormitator maculatus “Naca” (Bloch, 1792) from the Alvarado Lagoon in Veracruz, Mexico

D. maculatus is an artisanal fishing resource of great economic and gastronomic importance in the area, although its annual availability is erratic due to the deterioration and contamination of its habitat, in addition to poor management of its fishery; the latter because it is easily captured during its breeding season. Basic biological aspects of D. maculatus were estimated, such as size composition, sex ratio, and type of growth. A total of 700 organisms, 364 males and 336 females, were collected and analyzed during 12 continuous months. As a result, sizes between 4.4 to 17.0 cm were obtained, averaging 10.2 cm. The most common length range in females was 8.1 - 9.0 cm and 9.1-10.0 cm in males. The annual sex ratio was 1M: 0.87F; with significant differences from July to October (2M:1F) and January (1M:2F). It was observed that the species tends to form aggregations, however, it maintains a 1M:1F ratio in the remaining period. The length-weight relationship parameters show that D. maculatus presents positive allometric growth (r2 = 0.93452) for both sexes. Males were slightly larger and heavier than females. The minimum size of sexual maturity obtained was Lm50 = 8.21 and 8.41 cm for females and males, respectively.

High chromosomal evolutionary dynamics in sleeper gobies (Eleotridae) and notes on disruptive biological factors in Gobiiformes karyotypes (Osteichthyes, Teleostei).

The order Gobiiformes is made up of more than 2200 species, representing one of the most diverse groups among teleost fishes. The biological causes for the tachytelic karyotype evolution of the gobies have not yet been fully studied. Here we expanded cytogenetic data for the Eleotridae family, analyzing the neotropical species Dormitator maculatus, Eleotris pisonis, Erotelis smaragdus, and Guavina guavina. In addition, a meta-analytical approach was followed for elucidating the karyotype diversification versus biological aspects (habitat and egg type) of the Gobiiformes. The species E. smaragdus and E. pisonis present 2n = 46 acrocentric chromosomes (NF = 46), D. maculatus 2n = 46 (36sm + 4st + 6a; NF = 86), and G. guavina, the most divergent karyotype, with 2n = 52 acrocentric chromosomes (NF = 52). Besides numeric and structural diversification in the karyotypes, the mapping of rDNAs and microsatellites also showed noticeable numerical and positional variation, supporting the high chromosomal evolutionary dynamism of these species. In Gobiiformes, karyotype patterns which are more divergent from the basal karyotype (2n = 46a) are associated with characteristics less effective to dispersion, such as the benthic habit. These adaptive characteristics, connected with the organization of the repetitive DNA content in the chromosomes, likely play a synergistic role in the remarkable karyotype diversification of this group.

Sex Chromosomes and Internal Telomeric Sequences in Dormitator latifrons (Richardson 1844) (Eleotridae: Eleotrinae): An Insight into their Origin in the Genus.

The freshwater fish species Dormitator latifrons, commonly named the Pacific fat sleeper, is an important food resource in CentralSouth America, yet almost no genetic information on it is available. A cytogenetic analysis of this species was undertaken by standard and molecular techniques (chromosomal mapping of 18S rDNA, 5S rDNA, and telomeric repeats), aiming to describe the karyotype features, verify the presence of sex chromosomes described in congeneric species, and make inferences on chromosome evolution in the genus. The karyotype (2n = 46) is mainly composed of metacentric and submetacentic chromosomes, with nucleolar organizer regions (NORs) localized on the short arms of submetacentric pair 10. The presence of XX/XY sex chromosomes was observed, with the X chromosome carrying the 5S rDNA sequences. These heterochromosomes likely appeared before 1 million years ago, since they are shared with another derived Dormitator species (Dormitator maculatus) distributed in the Western Atlantic. Telomeric repeats hybridize to the terminal portions of almost all chromosomes; additional interstitial sites are present in the centromeric region, suggesting pericentromeric inversions as the main rearrangement mechanisms that has driven karyotypic evolution in the genus. The data provided here contribute to improving the cytogenetics knowledge of D. latifrons, offering basic information that could be useful in aquaculture farming of this neotropical fish.

Ichthyofauna of Ceará-Mirim River basin, Rio Grande do Norte State, northeastern Brazil.

Ichthyological studies in coastal basins of the Mid-Northeastern Caatinga ecoregion were first conducted in the early 20th century, including collections from the Ceará-Mirim River basin, in northeastern Brazil. Besides a few systematics and ecological studies, the knowledge on fishes from this watershed is still considered partial and restricted to the freshwater portion. Thus, the objective of this paper was to conduct a comprehensive ichthyological survey of the entire Ceará-Mirim River basin, from the headwaters to the estuarine area. Fish surveys were conducted from 2011 to 2016 using varied fishing gear, resulting in the record of 63 native species (24 freshwater, 15 estuarine, and 24 marine species) and two introduced species. Four species are putatively endemic to the ecoregion, and 48 consist of new records for the basin. According to the Brazilian’s threatened fish list, three species are currently classified as ‘vulnerable’ (Megalops atlanticus, Hippocampus reidi and Mycteroperca bonaci), four as ‘near threatened’ (Kryptolebias hermaphroditus, Dormitator maculatus, Lutjanus sygnagris and L. jocu) and three as ‘data deficient’ (Cheirodon jaguaribensis, Mugil curema and Sphoeroides testudineus). The Ceará-Mirim River basin does not have any protected areas and has been suffering multiple anthropogenic impacts, however the "Centro Tecnológico de Aquicultura" (Aquaculture Technological Center) of the Universidade Federal do Rio Grande do Norte (CTA/UFRN) at the lower portion of the basin may help in the conservation of the estuarine and estuarine fish species.

Spatial distribution and seasonality of ichthyoplankton and anthropogenic debris in a river delta in the Caribbean Sea.

Temporal changes in larval fish species composition and abundance compared with other components of the seston are described in four estuarine habitats in the Atrato Delta, Colombia. In comparison with zooplankton, fish larvae and egg density and anthropogenic debris abundance were low in the South Atrato Delta. Transparency, water temperature and chlorophyll a were the major factors influencing the spatiotemporal distribution of ichthyoplankton in the delta. The most abundant fish larvae were Astyanax sp. 1, Anchovia clupeoides, Cetengraulis edentulus, Anchoa sp., Bathygbius curacao, Dormitator maculatus, Hyporhamphus sp., Atherinella blackburni, Gobiosoma sp. 1 and Menticirrhus americanus (92·8% of total abundance). Spatial temporal analysis shows that in this delta, shrub (arracachal) and grass (eneal) habitats are important for freshwater and estuarine species, whilst mudflat and mangrove are important for estuarine species and estuarine-marine species, since most flexion and post-flexion stages of these species were found there. Anthropogenic debris density never surpassed the total ichthyoplankton density, but was ubiquitous. Shrub and mangrove habitats had higher densities of anthropogenic debris, since these are flood-stem habitats that trap solids.

Exploring the molecular diversity of Eleotridae (Gobiiformes) using mitochondrial DNA

Summary Species with wide geographic distributions can consist of different lineages or even of different species. The present study evaluated the molecular diversity of the family Eleotridae by analyzing sequences of the COI gene from species collected in different locations in a Neotropical region as well as sequences from BOLD and GenBank. The analysis revealed the distinction and differentiation of a variety of species with high statistical support, including Gobiomorus dormitor (two lineages), Dormitator maculatus (three lineages) and Eleotris fusca (three lineages), and a number of different lineages of Microphilypnus. This indicates the existence of a number of unknown cryptic species that have not been reported previously, increasing the potential diversity of eleotrid species in the Neotropics.

Morphological and molecular analyses of a new species of Saccocoelioides Szidat, 1954 (Haploporidae Nicoll, 1914) in the fat sleeper Dormitator maculatus (Bloch) (Perciformes: Eleotridae) from the Gulf of Mexico.

Saccocoelioides olmecae n. sp. is described from specimens recovered from the intestine of the fat sleeper Dormitator maculatus (Bloch) (Perciformes: Eleotridae) collected in six localities along the coast of the Gulf of Mexico. The new species is mainly distinguished from the other three described species of Saccocoelioides Szidat, 1954 from North and Middle America (i.e. S. sogandaresi Lumsden, 1963, S. chauhani Lamothe-Argumedo, 1974 and S. lamothei Aguirre-Macedo & Violante-González, 2008) by having an elongated body, a sac-like caecum, a uterus that extends to the first third of body and by having vitelline follicles longitudinally elongated reaching the posterior end of the body. Sequences of the large subunit (LSU) of the ribosomal DNA, including the domain D1-D3, and the internal transcribed spacer 2 (ITS2) were used independently and concatenated to corroborate the morphological distinction among S. olmecae n. sp., S. chauhani and S. lamothei from freshwater and brackish-water fish from Middle America. The genetic divergence estimated among the three species of Saccocoelioides was very low: 1% for LSU and from 1 to 4% for ITS2. Maximum likelihood and Bayesian inference analyses for each dataset and both datasets combined revealed that S. olmecae n. sp. represents an independent clade with moderate bootstrap support and posterior probabilities. This is the third species of Saccocoelioides described in Mexico, and the 17th species from the Americas.

Niche specificities of eleotrid fishes in a tropical estuary

Five species belonging to the teleost fish family Eleotridae (sleepers) are known to coexist in the Tortuguero estuary of Caribbean Costa Rica and adjacent estuaries. Three of these forms, Dormitator maculatus , Eleotris amblyopsis , and Gobiomorus dormitor are found amongst the root masses of water hyacinths along the borders of the lower estuary. The study was carried out to determine how these forms divide their environmental resources to avoid competition. Field investigations were carried out at Tortuguero in September of 1977. Results suggest that Eleotris amblyopsis is the dominant species in the hyacinth root masses and is largely carnivorous, feeding on invertebrates and larval fishes. Only small individuals of Dormitator milculatus are found in this habitat and these forms utilize plant materials in addition to invertebrates. Gobiomorus has feeding habits similar to E. amblyopsis but occupies benthic areas sheltered by the hyacinth mats. A fourth eleotrid in the system, Eleotris pisonis , has food habits similar to E. amblyopsis , but appears restricted to fresh-water tributarics of the estuarine system where E. amblyopsis is less abundant. The fifth eleotrid species, Leptophilypnus fluviatilis , appears to inhabit benthic arcasof the lower estuary, but is extremely uncommon in this system.

Morphological and molecular data reveal a new species of Neoechinorhynchus (Acanthocephala: Neoechinorhynchidae) from Dormitator maculatus in the Gulf of Mexico

Neoechinorhynchus (Neoechinorhynchus) mexicoensis sp. n. is described from the intestine of Dormitator maculatus (Bloch 1792) collected in 5 coastal localities from the Gulf of Mexico. The new species is mainly distinguished from the other 33 described species of Neoechinorhynchus from the Americas associated with freshwater, marine and brackish fishes by having smaller middle and posterior hooks and possessing a small proboscis with three rows of six hooks each, apical hooks longer than other hooks and extending to the same level as the posterior hooks, 1 giant nucleus in the ventral body wall and females with eggs longer than other congeneric species. Sequences of the internal transcribed spacer (ITS) and the large subunit (LSU) of ribosomal DNA including the domain D2+D3 were used independently to corroborate the morphological distinction among the new species and other congeneric species associated with freshwater and brackish water fish from Mexico. The genetic divergence estimated among congeneric species ranged from 7.34 to 44% for ITS and from 1.65 to 32.9% for LSU. Maximum likelihood and Bayesian inference analyses with each dataset showed that the 25 specimens analyzed from 5 localities of the coast of the Gulf of Mexico parasitizing D. maculatus represent an independent clade with strong bootstrap support and posterior probabilities. The morphological evidence, plus the monophyly in the phylogenetic analyses, indicates that the acanthocephalans collected from intestine of D. maculatus from the Gulf of Mexico represent a new species, herein named N. (N.) mexicoensis sp. n.

Effects of substratum type on fish assemblages in shallow areas of a tropical estuary

AbstractWhile there is already a comprehensive understanding of the effects of environmental variables, such as dissolved oxygen, temperature and salinity, on the structure, biomass and metabolism of aquatic biota in estuarine habitats, the effect of sedimentation, a harmful underlying factor, remains unclear. The aim of this study was to assess the differences in fish assemblages along the freshwater to salt water gradient of a large tropical estuary, and to evaluate the effects on them of habitat disturbance associated with shallow water sedimentation in the intertidal areas. Fish and environmental variables were recorded in the upper, middle and lower salinity zones of the estuary at ebb tide in both the dry and wet seasons. Sediment samples associated with different levels of habitat disturbance were analysed using granulometry, and their organic content and dissolved oxygen levels were quantified. Water temperature, salinity, pH and dissolved oxygen levels were also measured. Habitat disturbance was found to be correlated with the density, biomass and richness of fish assemblages. A total of 77 species were recorded, forming two distinct fish assemblages, with the Eleotridae family dominating in the upper zone, and Gerreidae, Gobiidae and Tetraodontidae the most common in the middle and lower estuary. Changes in the structure of fish assemblages, including reductions in density, biomass and richness, were associated with disturbance to natural features, where muddy sediment was replaced by sandy sediment and the quantity of organic matter fell. Atherinella brasiliensis was the species which showed a preference for the disturbed areas in the middle and lower zones, while Dormitator maculatus showed a preference for them in the upper estuary. They may be taken as indicators of habitat disturbance due to shallow sedimentation.

Pisces, Perciformes, Eleotridae, Dormitator maculatus (Bloch, 1792): distribution extension for Patos-Mirim lagoon system, state of Rio Grande do Sul, Brazil

We present here the record of Dormitator maculatus (Bloch, 1792) to the Patos-Mirim lagoon system, Rio Grande do Sul, Brazil. This is also the southernmost occurrence in South America, extending species range ca. 150 km from the previously known localities.

Evidence of an XX/XY sex chromosome system in the fish Dormitator maculatus (Teleostei, Eleotrididae)

The fish Dormitator maculatus has a chromosomes number of 2n = 46, females having a karyotype of 14 M, 28 SM, 2 ST and 2A and males 13 M, 28 SM, 3 ST and 2A. The presence of a heteromorphic pair in the males and a corresponding homomorphic pair in the females suggest the occurrence of an XX/XY sex chromosome system in D. maculatus. The putative X chromosome has a pericentromeric C-band positive segment and the putative Y chromosome a C-band positive short arm.

Intraspecific Karyotypical Diversity in Brackish Water Fishes of the Eleotridae Family (Pisces, Perciformes)

The Eleotridae family consists of 35 genera and 150 species distributed in freshwaters/brackish waters, estuaries or shores of tropical and subtropical regions. A few species are found in the Central America and South America. Cytogenetic analyses were performed on sympatric species Dormitator maculatus (12 individuals; 9 males and 3 females) and Eleotris pisonis (5 individuals; 2 males and 3 females) collected in the lower course of the Pium River, Northeastern Brazil. Both the species have 2n=46 with striking differences for the chromosome formulas (D. maculatus, 40m-sm+6st-a and E. pisonis, 46a). The two species revealed preferentially centromeric or telomeric heterochromatic regions and absence of structural chromosome heteromorphisms between the sexes. The NORs are located on the short arm of a submetacentric pair (pair 4) in D. maculatus and in intersticial position on a medium acrocentric (pair 21) in the E. pisonis. Meiotic analyses carried out on D. maculatus and E. pisonis showed a modal value of 23 in both MI and in MII. Comparison with cytogenetic data of Mexican populations (D. maculatus, 34m-sm+12st-a; E. pisonis, 2m-sm+42st-a) indicated that the karyotypical changes among the populations from Northeastern Brazil and the Mexican coast are mainly due to pericentric inversion, although translocations, fission and fusion are involved in the karyotypic diversification of the group. The differences observed among the karyotype macrostructure of South and Central American forms suggest the existence of distinct species in these two regions.

Helminths from Dormitator maculatus (Pisces: Eleotridae) in Alvarado Lagoon, Veracruz, Mexico, and Supplemental Data for Clinostomum complanatum Rudolphi, 1814 from Egretta caerulea (Aves: Ardeidae)

Fishes are important hosts of helminths with aquatic life stages, yet little information is available on host-parasite relationships in tropical low salinity ecosystems. In this paper we report helminth parasites of the fat sleeper, Dormitator maculatus, in the Alvarado lagoon system, Veracruz. Mexico. Four parasite species were recorded from D. maculatus, including trematode metacercariae of Clinostomum complanatum, as well as nematode larvae of Spyroxis sp. and Camallanus sp. and adults of Neochinorhynchus golvani. In addition, we obtained adult C. complanatum from the esophagus of the little blue heron, Egretta caerulea. Dormitator maculatus is a new host for all helminth species reported, and the Alvarado lagoonal system is a new location for these parasite relationships. The prevelance of the 2 most commonly occurring parasites, C. complanatum and N. golvani, was high throughout the year (> 60% and > 43%, respectively). Intensity of infection was highest for C. complanatum in May (92 worms/host) and for N. golvani in October 1993 (33.8 worms/host). The trophic position and habits of D. maculatus contributes to recruitment of trematode and nematode larval stages.

Fish Assemblage Structure in Relation to Environmental Variation in a Texas Gulf Coastal Wetland

We described seasonal fish-assemblages in an estuarine marsh fringing Matagorda Bay, Gulf of Mexico. Habitat zones were identified by patterns of fish species abundance and indicator species optima along gradients in salinity, dissolved oxygen (DO), and depth in our samples. Indicators of the lower brackish zone (lower lake and tidal bayou closest to the bay) were gulf menhaden (Brevoortia patronus), bay anchovy (Anchoa mitchilli), silver perch (Bairdiella chrysoura), and spotted seatrout (Cynoscion nebulosus) at salinity >15‰, DO 7–10 mg l−1, and depth 10 mg l−1, and depth 1.5 m. In brackish zones, seasonal variation in species diversity among sites was positively correlated with temperature, but assemblage structure also was influenced by depth and DO. In the freshwater zones, seasonal variation in species diversity among sites was positively correlated with depth, DO, and salinity, but assemblage structure was weakly associated with temperature. Species diversity and assemblage structure were strongly affected by the connectivity between freshwater wetland and brackish zones. Uncommon species in diked wetlands, such as tarpon (Megalops atlanticus) and fat sleeper (Dormitator maculatus), indicated movement of fishes from the brackish zone as the water level rose during natural flooding and scheduled (July) releases from the diked wetland. From September to July, diversity in the freshwater wetland zone decreased as receding waters left small isolated pools, and fish movement became blocked by a water-control structure. Subsequently, diversity was reduced to a few species with opportunistic life histories and tolerance to anoxic conditions that developed as flooded vegetation decayed.

Patterns of reproduction and development of selected resident teleosts of Florida salt marshes

A wide variety of teleost fishes occur in tidal marshes of Atlantic and Gulf coasts of Florida, few of which breed in these habitats or remain there for extended periods of time. A significant fraction of teleosts that do so are members of one of five families. Eleven representative species belonging to these families, whose reproduction and development are considered here, include: Adinia xenica, Fundulus confluentus, F. grandis and F. similis (Fundulidae); Cyprinodon variegatus, Floridichthys carpio and Jordanella floridae (Cyprinodontidae); Gambusia holbrooki and Poecilia latipinna (Poeciliidae); Mugil cephalus (Mugilidae); and Dormitator maculatus (Eleotridae). Spawning or birth locations, patterns of growth and development, times of use of the salt marsh as a nursery area, and development of salinity tolerances/osmotic regulatory capabilities were evaluated for each, considering these in the context of variability of environmental conditions, especially of salinity. Five different patterns of reproduction are shown by these 11 species, and only A. xenica appears to be limited to reproducing in the salt marsh environment. Some of these species are capable of reproducing throughout the year. Several of the species are annuals, most others live only 2 or 3 years. Eight species (those other than M. cephalus, A. xenica and G. holbrooki) were found to show no size relationship, large juvenile to adult sizes, in osmotic regulatory capabilities.