Scaphanocephalus spp. (Trematoda: Opisthorchiidae) in intermediate and definitive hosts of the Yucatán Peninsula, Mexico, with a re-description of Scaphanocephalus expansus.

Scaphanocephalus is a small trematode genus belonging to the family Opistorchiidae. The genus currently contains only three species associated with marine fish as intermediate hosts and fish-eating birds as definitive hosts. Here, specimens of Scaphanocephalus were collected from the Osprey, Pandion haliaetus, and the White mullet, Mugil curema in the Yucatán Peninsula, Mexico. We report for the first-time DNA sequences of adult specimens of Scaphanocephalus, particularly S. expansus, as well as a sequence of a different species sampled as metacercaria. Morphological comparisons of Scaphanocephalus expansus confirmed the identity of the adult specimens, with minor morphological variations; Scanning electron photomicrographs were included, and the species was re-described. Phylogenetic analysis based on 28S rDNA sequences showed that Scaphanocephalus is monophyletic within Opisthorchiidae and consists of three independent lineages. Sequences of adults are identical to those of S. expansus. Instead, the sequence of the metacercaria sampled from the mesentery of Mugil curema nested with specimens reported as Scaphanocephalus sp. from a labrid fish in the Mediterranean Sea, herein named it as Scaphanocephalus sp. 2.

GC-MS comparison of fatty acids profile of oils extracted from viscera of Tainha (Mugil liza) and Tambaqui (Colossoma macropomum).

The commercial activity of the grey mullet (known as Tainha: TAI) and Tambaqui (TAM) generates tons of waste that can be turned into valuable resources. Therefore, this work aimed to chemically characterize and quantify the fatty acids profiles of the two fishes. GCMS quantification was performed by using calibration curves built from a standard that contains 19 FAME. The analysis revealed that visceral wastes from both fishes contain 16 fatty acids (FA) consisting of saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA). However, their compositions were different as FA side chains in TAI and TAM contain 12 to 20 and 13 to 22 carbon atoms, respectively. Also, the SFA amount in TAI was greater than in TAM. On the other hand, TAM is richer in MUFA and PUFA compared to TAI. Both have similar chemical compositions of ω-3 and ω-6 in PUFA and ω-5, ω-7, and ω-9 in MUFA.

Hipoplasia testicular em Mugil curema / Testicular hypoplasia in Mugil curema

Mugil curema valenciennes, 1836 (Osteichthyes: Mugilidae) é um peixe cosmopolita e é conhecido popularmente como parati no Sudeste e Sul do Brasil e como tainha no Nordeste, sendo encontrado em mar aberto e em estuários. Esta espécie não expressa dimorfismo sexual entre machos e fêmeas externamente. Machos e as fêmeas possuem um par de gônadas (testículos e ovários, respectivamente), as quais são alongadas, fusiformes e simétricas. Este trabalho descreve a ocorrência de hipoplasia testicular em um peixe da espécie Mugil curema, procedente da Baía da Babitonga, Santa Catarina, Brasil. Foi identificada hipoplasia testicular unilateral, a qual macroscopicamente, estava diminuído de volume e, microscopicamente, apresentava atividade espermatogênica ausente e redução do número de espermatozoides. Não foi possível determinar os fatores que possam ter contribuído para o desenvolvimento de tal alteração reprodutiva. Porém, como a espécie animal pode ter suas características de vida e reprodutiva influenciadas pela ação antrópica, é importante um estudo contínuo da vida dos peixes nesse ambiente. Existem poucos estudos direcionados à espécie, principalmente aos aspectos reprodutivos. Desta forma, este relato contribuirá para elevar o histórico de informações a respeito desta espécie na região.

Mugil curema valenciennes, 1836 (Osteichthyes: Mugilidae) is a cosmopolitan fish popularly known as parati in Southeast and South Brazil and as mullet in Northeast, being found in the open sea and estuaries. This species does not express sexual dimorphism between males and females externally. Males and females have a pair of gonads (testes and ovaries, respectively), which are elongated, fusiform, and symmetrical. This paper describes the occurrence of testicular hypoplasia in a fish of the species Mugil curema, from Babitonga Bay, Santa Catarina, Brazil. Unilateral testicular hypoplasia was identified, which macroscopically showed a decrease in testis volume and, microscopically, the absence of spermatogenic action and a reduction in the number of spermatozoa. It was not possible to determine the factors that may have contributed to the development of such reproductive alteration. However, as the living and reproductive traits of this animal species may be influenced by anthropic action, a continuous study of its life in this environment is important. There are few studies directed at this species, mainly on its reproductive aspects. Thus, this report will contribute to raising the information historic about this species in the region.

Prejuveniles of Mugil liza (Actinopterygii; Fam. Mugilidae) show digestive and metabolic flexibility upon different postprandial times and refeeding.

Many animals face periods of feeding restrictions implying fasting and refeeding. The determination of digestive/metabolic and body condition parameters at different times of food deprivation and after refeeding allows to evaluate the postprandial dynamics, the transition from feeding to fasting and the capacity to reverse digestive and metabolic alterations. In spite of its physiological importance, studies on estuarine-dependent detritivore fish are lacking. We determined total mass (TM), relative intestine length (RIL), hepatosomatic index (HSI), digestive enzymes activities in the intestine and energy reserves in liver and muscle at 0, 24, 72, 144 and 240 h after feeding and at 72 h after refeeding in prejuveniles of Mugil liza (Mugilidae) as a model species. After feeding, a decrease occurred in: TM (144 h, 25%), RIL (144 h, 23%); amylase and maltase (72 h, 45 and 35%), sucrase (24 h, 40%) and lipase (24 h, 70%) in intestine; glycogen and free glucose (72 h, 90 and 92%) in liver. In muscle, glycogen (72-144 h) and free glucose (144 h) (170% and 165%, respectively) peak increased; triglycerides decreased at 24-240 h (50%). After refeeding TM, RIL, carbohydrases activities in intestine, glycogen and free glucose in liver were recovered. In muscle, glycogen and free glucose were similar to 0 h; lipase activity and triglycerides were not recovered. Trypsin and APN in intestine, triglycerides in liver, protein in liver and muscle and HSI did not change. The differential modulation of key components of carbohydrates and lipid metabolism after feeding/refeeding would allow to face fasting and recover body condition. Our results improve lacking knowledge about digestive and metabolic physiology of detritivore fish.

Folk taxonomy of the gray mullets (Mugilidae: Mugiliformes) in a marine extractivist reserve of northern Brazil

Fish local knowledge is important to recognize species and contribute to conservation and management strategies. Thus, our aim was to provide diagnostic information for the rapid identification of Mugilidae species in Caeté-Taperaçu Extractive Reserve in Bragança (PA) in northern Brazil. A total of 28 fishers were interviewed using semi-structured questionnaires. Most of the interviewees have lived in their resident village since birth and have been involved in artisanal fishers for at least 12 years. Eight generic folk taxa were identified, including 'tainha', which was the vernacular name most used to define the Mugil genus. Each scientific species had at least two folk generic taxa and one species. Mugil curema, M. rubrioculus, and M. trichodon were all included in the same ethnospecies, 'tainha chata'. Most of the scientific species were referred to at least once as the ethnospecies 'caica', this name was applied most often to Mugil brevirostris, which is the smallest species found in northern Brazil. The principal characteristics used by the fishers were morphological traits, however, some behavioral characteristics were also taken into account. These findings should contribute to the elaboration of ethnotaxonomic keys that facilitate the rapid identification of Mugil harvested by the region's artisanal and industrial fisheries.(AU)

O conhecimento local sobre peixes é importante para reconhecer espécies e contribui para estratégias de conservação e manejo. Nosso objetivo foi fornecer informações diagnósticas para a rápida identificação das espécies de Mugilidae da região da Reserva Extrativista Marinha Caeté Taperaçu (PA), Norte do Brasil. Um total de 28 pescadores foi entrevistado por meio de questionários semiestruturados. A maioria dos entrevistados vive na sua aldeia residente desde o nascimento e está envolvida na pesca artesanal há pelo menos 12 anos. Oito táxons populares genéricos foram identificados por esses pescadores, incluindo 'tainha', que era o nome vernacular mais usado para definir o gênero Mugil. Cada espécie científica tinha pelo menos dois táxons genéricos populares e uma espécie. Mugil curema, M. rubrioculus e M. trichodon foram todos incluídos na mesma etnoespécie, 'tainha chata'. A maioria das espécies científicas foi referida pelo menos uma vez como etnoespécie 'caica', este nome foi aplicado mais frequentemente a Mugil brevirostris, que é a menor espécie encontrada no Norte do Brasil. As principais características utilizadas pelos pescadores foram os traços morfológicos, porém, algumas características comportamentais também foram levadas em consideração. Esses achados devem contribuir para a elaboração de chaves etnotaxonômicas que facilitem a rápida identificação de Mugil capturadas pela pesca artesanal e industrial da região.(AU)

Plastic debris and natural food in two commercially important fish species from the coast of Peru.

The aim of this study was to evaluate the presence of plastic debris in the stomach contents of two commercially important species Ethmidium maculatum and Mugil cephalus from Peru and relate their characteristics to their diet. The contents of 1820 stomachs were analyzed visually to detect the presence of plastics and prey. Of the analyzed samples, 0.3% contained nine microplastic fragments (0.72-4.54 mm) and one mesoplastic fragment (6.65 mm). Green and blue plastics of polyethylene and polypropylene were the most common. In E. maculatum, copepods were the main prey, followed by diatoms and decapods, and they exhibited the highest amount of plastics. In M. cephalus, the main prey were diatoms, copepods, and dinoflagellates, and they exhibited only one type of microplastic. Although the characteristics of the plastics and the prey of these species may be related (sizes-colors), more research is required to understand this problem in commercially important fishery resources in Peru.

Phylogenetic affinities of Forticulcitinae (Haploporidae) parasites of mullet from the Americas, with the description of three new species and notes on the genera and key species.

Members of Forticulcitinae Blasco-Costa, Balbuena, Kostadinova & Olson, 2009 include endoparasites of mullet fishes distributed worldwide. Adult specimens were collected from the intestines of white mullet (Mugil curema) and flathead grey mullet (Mugil cephalus) from five localities in the Gulf of Mexico and a single locality in Venezuela. Photogenophores were sequenced for two nuclear molecular markers, the large subunit (LSU) and second internal transcribed spacer (ITS2) of nuclear rDNA. The new sequences were aligned with other sequences downloaded from GenBank. The maximum likelihood and Bayesian inferences were deduced using the combined dataset (LSU + ITS2). The phylogenetic analyses revealed four new lineages belonging to Forticulcitinae. Three new species are described in the present study. Ekuarhuni mexicanus n. sp. can be differentiated from its congeneric species by presenting a longer hermaphroditic sac length (136-180 µm) and a wider testis (91-123 µm). Forticulcita macropharyngis n. sp. and Forticulcita venezuelensis n. sp. are the 8th and 9th species described in Forticulcita. Both species belong to the diminutive morphotype of Forticulcita. Forticulcita macropharyngis n. sp. can be morphologically distinguished from the other congeneric species by the presence of a massive and muscular pharynx (46-110 µm long, 74-106 µm wide). Forticulcita venezuelensis n. sp. is the second species of the studied genus recorded in South America and can be differentiated from congeneric species by possessing the largest testis (138-201 µm long, 83-100 µm wide). Finally, the fourth lineage corresponds to Overstreetoides Andrade-Gómez & García-Varela, 2021; however, few specimens of this lineage were collected, precluding any description of the species. In addition, a key is proposed for differentiating the genera and species of Forticulcitinae.

Understanding the early ontogenetic stages of Mugil liza (Mugilidae): Morphological traits and digestive/metabolic profile of pre-juveniles after recruitment.

The family Mugilidae consists mainly of diadromous species, whose reproduction occurs in offshore waters. Pre-juveniles shift their diet in the surf zone (zooplanktophagous to iliophagous). Later, during their recruitment into estuaries, huge changes take place in their digestive system. However, digestive and metabolic characteristics and some morphological traits at recruitment are unknown for Mugilidae. We performed comparative studies on early and late pre-juveniles of Mugil liza recruited in Mar Chiquita Coastal Lagoon (37°32'-37°45'S, 57°19'-57°26'W, Argentina). We determined digestive enzyme activities (intestine), energy reserves (liver/muscle), total/standard length, total weight, intestinal coefficient, hepatosomatic index and retroperitoneal fat. Pre-juveniles exhibited amylase, maltase, sucrase, lipase, trypsin and aminopeptidase-N (APN) activities, which were maintained over a wide range of pH and temperature, and exhibited Michaelis-Menten kinetics. In late pre-juveniles, amylase (422 ± 131 µmol maltose min-1 mgprot-1 ), sucrase (86 ± 14 mg glucose min-1 mgprot-1 ), trypsin (84 ± 9 µmoles min-1 mgprot-1 ) and APN (0.58 ± 0.08 µmoles min-1 mgprot-1 ) activities were higher (42%, 28%, 35% and 28%, respectively) than in the early stage. Also, the intestinal coefficient was higher in late (3.04) compared to early (2.06) pre-juveniles. Moreover, the liver appeared to be a main site of glycogen and triglyceride storage in late pre-juveniles, muscle being the site of storage in early pre-juveniles, exhibiting higher glycogen, free glucose and protein concentrations (92%, 82%, 32%, respectively). The results suggest that pre-juveniles of M. liza exhibit an adequate digestive battery to perform complete hydrolysis of various dietary substrates, availability of energy reserves and morphological characteristics to support their feeding habit and growth after recruitment. Our results represent an important contribution to knowledge of the ecology and digestive physiology of pre-juveniles of Mugilidae in the wild.

Unexpected morphological and molecular diversity of trematode (Haploporidae: Forticulcitinae) parasites of mullets from the ocean Pacific coasts in Middle America.

Two new genera and four new species from subfamily Forticulcitinae are described from the intestines of white mullet (Mugil curema) and flathead grey mullet (Mugil cephalus) collected in 27 localities across a wide geographical range on Pacific Ocean slopes comprising three countries in Middle America: Mexico, Guatemala and Costa Rica. The new genera Ekuarhuni n. gen. and Overstreetoides n. gen. had to be erected to accommodate two new species, Ekuarhuni papillatum n. sp. and Overstreetoides pacificus n. sp., with unique morphological traits that differentiate them from the two genera described previously. In addition, two new species, Forticulcita minuta n. sp. and Forticulcita isabelae n. sp., were described, which were characterized as exhibiting a small body size (< 1100 µm long). These new species were classified as the diminutive morphotype, together with three other congeneric species of Forticulcita. Forticulcita minuta n. sp. is distinguished by being the smallest species within the genus (< 305 µm). Meanwhile, Forticulcita isabelae n. sp. is distinguished by its body size and testis length. In specimens of the four new species, sequencing was performed with two molecular markers, the large subunit (LSU) and the internal transcribed spacer 2 (ITS2) of nuclear rDNA, and the results were compared with other sequences available in GenBank. Phylogenetic analyses performed with the combined dataset of the two nuclear molecular markers (LSU + ITS2) placed all the analysed species within the clade of Forticulcitinae with strong bootstrap support (100%) and a high Bayesian posterior probability (1.0). The four new species showed differences in abundance in their definitive hosts and were widely distributed along the Pacific Ocean coasts of Mexico, Guatemala and Costa Rica, in Middle America.

First report of Myxobolus episquamalis Egusa, Maeno & Sorimachi, 1990 (Myxozoa: Bivalvulida) in Lebranche mullet Mugil liza Valenciennes, 1836 (Teleostei: Mugiliformes) from Neotropical region.

In the current study, Myxobolus episquamalis Egusa, Maeno & Sorimachi, 1990 (Myxozoa: Bivalvulida) is reported from the Lebranche mullet Mugil liza Valenciennes, 1836 in the estuarine region of the Maricá Lagoon, State of the Rio de Janeiro, southeastern Brazil. To date, this myxozoan species was reported in mullets from Asia, Africa, Europe, and Oceania. The characteristics of M. episquamalis previously reported are similar to the findings of the present study. DNA sequences of the nuclear small subunit ribosomal DNA (SSU rDNA) had 99.7-100% similarity with the sequences of M. episquamalis from North Africa and Asia. Therefore, strong morphological and molecular similarities ensure the identification of M. episquamalis in the current study. Finally, this finding records a new host and locality, revealing the worldwide distribution of this myxozoan species.

Trypanorhynch cestodes parasitizing Mugil liza (Mugiliformes: Mugilidae) commercialized in the state of Rio de Janeiro, Brazil / Cestoides Trypanorhyncha parasitando Mugil liza (Mugiliformes: Mugilidae) comercializados no estado do Rio de Janeiro, Brasil

Abstract The aim of the present study was to identify, through morphological and morphometric analyses, the species of trypanorhynch cestodes found as plerocerci in the intestinal serosa of Mugil liza and to determine their parasitic indices. One hundred and fifty specimens of this mullet collected off the coast of the state of Rio de Janeiro were necropsied and the trypanorhynch cestodes found were fixed and preserved as whole mounts for morphological analysis. The plerocerci were identified as Callitetrarhynchus gracilis and Pterobothrium crassicole, both with a prevalence of 0.67%, an intensity of 1 and abundance of 0.0067, in single infections. This is the first record of a trypanorhynch cestode parasitizing M. liza in Brazil. Although the parasitic indexes were low, from a hygienic-sanitary perspective the plerocerci of these species are visible to the naked eye, and thus can disgust consumers and make marketing the fish unfeasible.

Resumo O presente estudo objetivou determinar taxonomicamente as espécies de plerocercos de cestoides Trypanorhyncha encontradas na serosa intestinal das tainhas Mugil liza, através do estudo morfológico e morfométrico e indicar seus índices parasitários. Foram coletados 150 espécimes desta espécie de tainha do litoral do estado do Rio de Janeiro. Após as necropsias, os cestoides Trypanorhyncha encontrados foram fixados e preservados em montagens permanentes para permitir a análise de suas estruturas morfológicas. Os plerocercos foram identificados como Callitetrarhynchus gracilis e Pterobothrium crassicole e ambas as espécies apresentaram prevalência de 0,67%, intensidade de 1 e abundância de 0,0067, em infecções únicas. Este é o primeiro registro de cestoides Trypanorhyncha parasitando M. liza no Brasil. Quanto ao aspecto higiênico-sanitário, vale ressaltar que, embora os índices parasitários registrados tenham sido baixos, os plerocercos dessas espécies estavam visíveis a olho nu, podendo causar repugnância ao consumidor e inviabilizar a comercialização do pescado.

Redescription of Mugil setosus Gilbert 1892 with comments on the occurrence of Mugil curema Valenciennes 1836 in the Pacific Ocean (Teleostei: Perciformes: Mugilidae).

Mugil setosus Gilbert 1892 was originally described by Gilbert based on specimens from Clarion Island, in the western and most remote of the Revillagigedo Islands, about 1,000 km off the western Pacific coast of Mexico. Examination of the type of material and recently collected specimens from Ecuador and Peru, resulted in the redescription provided herein. Diagnostic characters of the species were mainly: tip of the pelvic fin reaching beyond the vertical through the base of the third dorsal-fin spine, the pectoral-fin rays with ii+13-14 rays, the anterodorsal tip of second (soft) dorsal fin uniformly dark, and an external row of larger teeth, and more internally a patch of scattered smaller teeth, visible mainly in adults 150 mm SL. The expansion of geographic distribution of Mugil setosus and occurrence of Mugil curema Valenciennes 1836 in the Pacific Ocean are discussed.

Coastal zone use and migratory behaviour of the southern population of Mugil liza in Brazil.

We analysed the ratios Sr:Ca and Ba:Ca in the otoliths of 55 adults of the southern population of Mugil liza in Brazil (Paraná to Rio Grande do Sul) to investigate its coastal zone use and migratory behaviour. All individual M. liza analysed had Sr:Ca and Ba:Ca values indicating that their birth was in the marine environment, which is consistent with the southern population migration to spawn in the ocean,. Juveniles exhibited at least three coastal use and recruitment strategies (contingents): the majority (89%) of M. liza juveniles migrated toward brackish water. They entered the estuary before completing the first year of life (64%) or after (25%) their first year of life. The remaining 11% did not appear to enter brackish or freshwater water as a nursery or at any point in their life cycle. Some adults returned to the estuary after spawning in the ocean but others (of both sexes) never returned to the estuary after spawning, remaining in the marine environment. The pattern of juvenile habitat use in the Brazilian southern population of M. liza seems to be recurrent throughout the extent of its distribution as a consequence of the reproductive spawning aggregation behaviour, which mixes all contingents (with marine or estuarine preferences).

Baja variabilidad y diferenciación genética poblacional en la "lisa", Mugil incilis (Teleostei: Mugilidae) del Caribe colombiano

La "Lisa" Mugil incilis, es uno de los recursos ícticos más importante de la industria pesquera artesanal del Caribe de Colombia. Sin embargo, sus poblaciones llevan siendo sobreexplotadas por décadas, que en conjunto con el deterioro de su hábitat podrían estar causando un efecto negativo en la variabilidad genética de las mismas. Con el objetivo de generar información científica que permita apoyar decisiones y políticas más adecuadas de manejo pesquero y conservación se evaluó la variabilidad y la estructura genética de M. incilis a lo largo de la costa del Caribe de Colombia. Se seleccionaron seis sistemas costeros, entre ellos tres lagunas costeras de acceso abierto a la pesca (Ciénaga La Virgen, Ciénaga La Caimanera y Bahía de Cispatá) y tres santuarios de fauna y flora de la red de Parques Nacionales Naturales de Colombia (los santuarios de fauna y flora Los Flamencos, Ciénaga Grande de Santa Marta y El Corchal). Se utilizaron siete loci microsatélites, los cuales revelaron 94 alelos con un promedio de 11.6 alelos por locus. Los valores de variabilidad genética en todos los sitios de muestreo fueron bajos (Ho = 0.108-0.402), aunque demostraron tener un alto potencial genético (He = 0.772-0.868). Se encontró que todos los loci presentaron desequilibrio de Hardy-Weinberg debido a una deficiencia de heterocigotos. Esto fue concordante con los eventos de cuellos de botellas recientes que se determinaron en todas las lagunas y las causas pueden ser la sobrepesca y la presencia de alelos nulos. Los resultados del análisis de estructuración genética demostraron la existencia de tres poblaciones, una conformada por las localidades ubicadas desde el sector de La Guajira hasta Sucre y una segunda en Bahía de Cispatá y la tercera en la Ciénaga La Caimanera. Este estudio sugiere que los procesos involucrados en el nivel de aprovechamiento pesquero, en el ciclo reproductivo y en las condiciones oceanográficas de la región del Caribe Sur determinan la variabilidad y estructura genética de M. incilis. Se proponen recomendaciones para el manejo y conservación de M. incilis.

The "Mullet" Mugil incilis is one of the most important fish resources of the artisanal fishing industry of the Colombian Caribbean. However, their populations are being overexploited for decades, which together with the deterioration of their habitat could be causing a negative effect on the genetic variability of their populations. In order to generate scientific information to support decisions and more appropriate fisheries management and conservation policies, the variability and genetic structure of M. incilis along the Caribbean coast of Colombia was evaluated. Six coastal systems were selected, including three coastal lagoon systems with open access to fishing (Ciénaga La Virgen, Ciénaga La Caimanera and Bahía de Cispatá) and three coastal lagoons belonging to fauna and flora sanctuaries of the network of National Natural Parks of Colombia (Los Flamencos, Ciénaga Grande de Santa Marta and El Corchal). Seven microsatellite loci were used, which revealed 94 alleles with an average of 11.6 alleles per locus. The values of genetic variability in all sampling sites were low (Ho = 0.108-0.402), although they showed a high genetic potential (He = 0.772-0.868). All the loci presented departures from the Hardy-Weinberg expectations due to a deficiency of heterozygotes. This was in agreement with the events of recent bottlenecks that were determined in all the lagoons and the causes could be overfishing and the presence of null alleles. The analysis of genetic structuring revealed the existence of two populations, one formed by the localities located from La Guajira to Sucre; a second in Bahía de Cispatá and the third one in Ciénaga La Caimanera. This study suggests that the processes involved in the level of fishing exploitation, in the reproductive cycle and in the oceanographic conditions of the South Caribbean region determine the genetic variability and structure of M. incilis. Recommendations for the management and conservation of M. incilis are proposed.

Ability of Vibrio vulnificus isolated from fish of the Lagoa dos Patos estuary in south Brazil to form biofilms after sublethal stress and bacterial resistance to antibiotics and sanitizers.

The present study aimed to investigate the presence of Vibrio vulnificus in fish captured at the Lagoa dos Patos estuary (RS, Brazil), to establish a correlation between bacterial biofilm formation and sublethal stress, and to assess the resistance of the isolates to antimicrobials and sanitizers. A total of 217 isolates characteristic of Vibrio sp. were analyzed. Isolates were identified and subsequently their ability to form biofilm, the impact of exposure to sublethal stress on their biofilm formation ability, and their resistance to antimicrobial and to sodium hypochlorite and chlorine dioxide sanitizers were evaluated. V. vulnificus was isolated from the fish Paralichthys orbignyanus and Micropogonias furnieri. The bacterial isolates examined were able to form biofilms. Biofilm formation ability of these strains was decreased or inhibited after being exposed to sublethal stress. The isolates were resistant to most antimicrobials. The sanitizer concentrations necessary to eliminate V. vulnificus were higher than those usually used in the fishing industry.

Inihibition of mullet (M. liza) brain acetylcholinesterase activity by in vitro polycyclic aromatic hydrocarbon exposure.

Polycyclic aromatic hydrocarbons (PAH) have been reported as acetylcholinesterase (AChE) inibitors, although in vitro studies on PAH effects on AChE activity are scarce and have only been performed using electric eel brain extracts. Thus, this study investigated PAH effects on brain AChE activity in a tropical fish species in Southeastern Brazil, mullet (Mugil liza). Mullet specimens were obtained from Guanabara Bay (N = 20), Rio de Janeiro, Brazil. Brain AChE was extracted and exposed to an environmentally relevant concentration of Pyrene, Chrysene, Phenanthrene, and Naphthalene, and PAH metabolites, 2-Naphthol and 1-OH-Pyrene. AChE activity inhibition was observed, although no difference was observed between high- and low- molecular weight PAH. 2-Naphthol was a less potent AChE inhibitor than Naphthalene, albeit non-significantly. Further studies are required, since only one PAH concentration was used herein. Mullet brain extracts seem to be adequate to assess possible neurotoxic PAH effects on fish AChE.

Composition, abundance and biomass of a fish assemblage in a southern Brazilian coastal stream during polyhaline/euhaline condition / Composição, abundância e biomassa de uma assembléia de peixes em um arroio costeiro do sul do Brasil durante condição polihalina/euhalina

Abstract: The coastal streams of southernmost Brazil, Rio Grande do Sul state, are marked by a period of regular marine intrusion resultant from intense oceanic winds. In the present study we aimed to investigate the species composition, abundance and relative biomass of the ichthyofauna in the lower stretch of a coastal stream during summer, a period of regular marine intrusion. Estreito is a coastal hydrological complex composed by lakes, swamps and a perennial stream, located at the central-south portion of the coastal plain of Rio Grande do Sul state. During the summer of 2018, the ichthyofauna of lower Estreito stream was sampled by beach hauls applied in 17 random points distributed in a stretch of ca. 2km. Measurements at the sampled stretch revealed salinities between 19.3 to 31.3 ppt, characterizing the studied system as polyhaline/euhaline during summer. The sample of 4,533 specimens revealed the occurrence of 20 species, being the great majority marine-dwelling. The most abundant species were the anablepid Jenynsia lineata (70.3%), the cichlid Geophagus brasiliensis (19.3%) and the the mugilid Mugil curema (7.5%). The highest relative biomass was recorded for J. lineata, followed by M. curema and G. brasiliensis. The dominance of marine-dwelling species in the assemblage composition and the high abundance of limnic-estuarine J. lineata corroborate previous studies conducted in other washouts of Rio Grande do Sul.

Resumo: Os arroios costeiros do extremo sul do Brasil, estado do Rio Grande do Sul, são marcados por um período de regular intrusão marinha resultante de intensos ventos oceânicos. No presente estudo nós tivemos como objetivo investigar a composição de espécies, abundância e biomassa relativa da ictiofauna no trecho inferior de um arroio costeiro durante o verão, período de regular intrusão marinha. Estreito é um complexo hidrológico costeiro composto por lagoas, pântanos e um arroio perene, localizados na porção centro-sul da planície costeira do Rio Grande do Sul. Durante o verão de 2018, a ictiofauna do baixo arroio Estreito foi amostrada por arrastos de praia aplicados em 17 pontos aleatórios distribuídos em um trecho de cerca de 2 km. Medidas no trecho amostrado revelaram salinidades entre 19.3 e 31.3 ppt, caracterizando o sistema estudado como polialino/euhalino durante o verão. A amostra de 4.533 espécimes revelou a ocorrência de 20 espécies, sendo a grande maioria habitantes marinhos. As espécies mais abundantes foram o anablepídeo Jenynsia lineata (70,3%), o ciclídeo Geophagus brasiliensis (19,3%) e o mugilídeo Mugil curema (7.5%). A maior biomassa relativa foi registrada para J. lineata, seguido por M. curema e G. brasiliensis. A dominância das espécies marinhas na composição da assembléia e a alta abundância da espécie límnica-estuarina J. lineata corrobora estudos prévios conduzidos em outros sangradouros do Rio Grande do Sul.

Trypanorhynch cestodes parasitizing Mugil liza (Mugiliformes: Mugilidae) commercialized in the state of Rio de Janeiro, Brazil / Cestoides Trypanorhyncha parasitando Mugil liza (Mugiliformes: Mugilidae) comercializados no estado do Rio de Janeiro, Brasil

The aim of the present study was to identify, through morphological and morphometric analyses, the species of trypanorhynch cestodes found as plerocerci in the intestinal serosa of Mugil liza and to determine their parasitic indices. One hundred and fifty specimens of this mullet collected off the coast of the state of Rio de Janeiro were necropsied and the trypanorhynch cestodes found were fixed and preserved as whole mounts for morphological analysis. The plerocerci were identified as Callitetrarhynchus gracilis and Pterobothrium crassicole, both with a prevalence of 0.67%, an intensity of 1 and abundance of 0.0067, in single infections. This is the first record of a trypanorhynch cestode parasitizing M. liza in Brazil. Although the parasitic indexes were low, from a hygienic-sanitary perspective the plerocerci of these species are visible to the naked eye, and thus can disgust consumers and make marketing the fish unfeasible.(AU)

O presente estudo objetivou determinar taxonomicamente as espécies de plerocercos de cestoides Trypanorhyncha encontradas na serosa intestinal das tainhas Mugil liza, através do estudo morfológico e morfométrico e indicar seus índices parasitários. Foram coletados 150 espécimes desta espécie de tainha do litoral do estado do Rio de Janeiro. Após as necropsias, os cestoides Trypanorhyncha encontrados foram fixados e preservados em montagens permanentes para permitir a análise de suas estruturas morfológicas. Os plerocercos foram identificados como Callitetrarhynchus gracilis e Pterobothrium crassicole e ambas as espécies apresentaram prevalência de 0,67%, intensidade de 1 e abundância de 0,0067, em infecções únicas. Este é o primeiro registro de cestoides Trypanorhyncha parasitando M. liza no Brasil. Quanto ao aspecto higiênico-sanitário, vale ressaltar que, embora os índices parasitários registrados tenham sido baixos, os plerocercos dessas espécies estavam visíveis a olho nu, podendo causar repugnância ao consumidor e inviabilizar a comercialização do pescado.(AU)

Occurrence of halogenated natural products in highly consumed fish from polluted and unpolluted tropical bays in SE Brazil.

Natural compounds from the metabolism of marine organisms have been detected at high concentrations in environmental samples which are not the producers of these compounds. These natural substances are known as halogenated natural products (HNPs). HNPs are possibly toxic halogenated compounds analogous to POPs that may bioaccumulate and biomagnify along the food web and pose a further risk to human and environmental health. The present study analyzed the occurrence of HNPs in the edible muscle of the three most consumed commercial fish species in the state of Rio de Janeiro: sardine (Sardinella brasiliensis), whitemouth croaker (Micropogonias furnieri) and mullet (Mugil liza) from the highly polluted Guanabara Bay (GB) and the less polluted Ilha Grande Bay (IGB). The analytical steps included Soxhlet extraction, clean-up step and injection in a gas chromatography system coupled to a mass spectrometer operated in the electron-capture negative ion mode (GC/ECNI-MS). The compounds 2,4,6-TBP, 2,4,6-TBA, MHC-1, Q1, 6-MeO-BDE 47 and 2'-MeO-BDE 68 were found in the analyzed fish from both studied areas. Q1, 6-MeO-BDE 47 and 2'-MeO-BDE 68 showed the highest concentrations in samples. Q1 concentrations in the sardines from IGB were higher than the sardines from GB (p < 0.05) and higher than the other IGB species (p < 0.05). The differences found among the species may be related to their characteristic habitat and diet. It is noteworthy that most of these compounds do not have any toxicological reference value. Moreover, the HNPs are being detected in species of low trophic level and since this study has worked only with commercial species, these fish may be considered as a source for human exposure to these natural compounds.

No mullet, no gain: cooperation between dolphins and cast net fishermen in southern Brazil

We report on the interaction between common bottlenose dolphins, Tursiops truncatus (Montagu, 1821) and cast net fishermen in southern coast of Brazil. The fishery was monitored in the mouth of the Tramandaí River Estuary to investigate the seasonality of catches and their relationships with a set of variables: presence/absence and number of bottlenose dolphins, fishing area, temperature, salinity, wind and water flow direction in the channel. The mullet, Mugil liza Valenciennes, 1836 is the target species and was the dominant fish in the catches (77% of total catch; 50% in frequency; 0.2 ind. x f-1). The use of GLM models helped to reveal that the number of the bottlenose dolphins, time of year (months) and spatial variation of fishing activity were the main factors explaining the presence and abundance of mullet in the fishermen’s catches. The presences of bottlenose dolphins in the fishing area raise the probability of fishermen catch larger number of mullets with smaller fishing effort. However, the size of the mullet is influenced basically by seasonality. The mullets are the “currency” of bottlenose dolphins and fishermen interaction. There are reasons for concern about the sustainability of the southern Brazilian M. liza stock, once the decrease of this fishing resource can lead this rare and traditional fishery to the extinction.