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1.
Sensors (Basel) ; 21(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207715

RESUMO

The multi-sensor artificial lateral line system (ALLS) can identify the flow-field's parameters to realize the closed-loop control of the underwater robotic fish. An inappropriate sensor placement of ALLS may result in inaccurate flow-field parametric identification. Therefore, this paper proposes a method to optimize the sensor placement configuration of the ALLS, which mainly included three algorithms, the feature importance algorithm based on mean and variance (MVF), the feature importance algorithm based on distance evaluation (DF), and the information redundancy (IR) algorithm. The optimal sensor placement performance selected by this method is verified by simulation. In addition, further experimental verification was conducted using the ALLS. Compared with the uniform sensor placement configuration mentioned in recent studies, the experimental results suggest that the optimal sensor placement method can achieve a more effective prediction of the flow-field parameters, therefore strengthening the underwater robotic fish's perception and control function.


Assuntos
Sistema da Linha Lateral , Algoritmos , Animais , Simulação por Computador , Peixes , Hidrodinâmica
2.
Molecules ; 26(12)2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34205746

RESUMO

This work addressed the preservative behaviour of different icing media containing extracts from the alga Bifurcaria bifurcata. A comparative study of the antimicrobial and antioxidant effects of aqueous and ethanolic extracts of this macroalga was carried out. Whole hake (Merluccius merluccius) pieces were stored in ice containing either kind of extract and analysed for quality changes throughout a 13-day storage period. A progressive loss of microbial and biochemical quality was detected in all batches as chilling time increased. A significant inhibitory effect (p < 0.05) on microbial activity could be observed as a result of including the aqueous (lowering of psychrotrophic and lipolytic counts and pH value) and ethanolic (lowering of psychrotrophic and lipolytic counts) extracts. Additionally, both kinds of extract led to a substantial inhibition (p < 0.05) in the lipid hydrolysis rate (formation of free fatty acids), greater in the case of the batch containing ethanolic extract. Concerning lipid oxidation, a similar inhibitory effect (p < 0.05) on the formation of secondary compounds (thiobarbituric acid substances) was noticed in fish specimens corresponding to both alga extracts; however, more (p < 0.05) peroxide formation was detected in fish corresponding to the ethanolic extract batch. A preservative effect can be concluded for both kinds of extract; this effect agrees with previous studies reporting the presence of hydrophilic and lipophilic bioactive compounds in B. bifurcata.


Assuntos
Produtos Biológicos/farmacologia , Conservantes de Alimentos/farmacologia , Feófitas/efeitos dos fármacos , Alga Marinha/química , Animais , Antioxidantes/farmacologia , Produtos Biológicos/química , Etanol/química , Peixes , Conservação de Alimentos/métodos , Gadiformes , Oxirredução/efeitos dos fármacos , Alimentos Marinhos , Água/química
3.
An Acad Bras Cienc ; 93(2): e20190565, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34259790

RESUMO

The aging process of reservoirs has been extensively investigated; however, little is known about how fish populations are adjusted after many years of impoundment. Thus, this study aimed to compare the diet, length-weight relationship, sizes classes, variation in size, and age of Astyanax lacustris Lütken, 1875 collected from lotic and lentic habitats of an aging reservoir. The study group consisted of 730 captured fishes. We found that specimens collected from lotic habitats had a wider range of size classes (1.0 to 12.0 cm), were linked to a high frequency of juveniles (48.7%), and had greater feeding activity (higher stomach fullness). In contrast, fishes collected from lentic environments exhibited high rates of capture (78.4%), increased frequency of adults (87.3%), and higher values of mean standard length. The length-weight relationship indicated that lentic fishes were heavier than fish collected from lotic areas. Moreover, we observed 37 food items in A. lacustris diet, mainly plant material, algae, Cladocera, Hymenoptera, Coleoptera, and Ephemeroptera. Differences among the diet of fishes between sites were evidenced with Permanova (p < 0.05). Astyanax lacustris can be considered a persistent species in Chavantes Reservoir after aging, encountering conditions to complete its life span and adjusting to food resources.


Assuntos
Characidae , Caraciformes , Animais , Biologia , Dieta , Ecossistema , Peixes , Rios
4.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204216

RESUMO

From mammals to fish, reproduction is driven by luteinizing hormone (LH) and follicle-stimulating hormone (FSH) temporally secreted from the pituitary gland. Teleost fish are an excellent model for addressing the unique regulation and function of each gonadotropin cell since, unlike mammals, they synthesize and secrete LH and FSH from distinct cells. Only very distant vertebrate classes (such as fish and birds) demonstrate the mono-hormonal strategy, suggesting a potential convergent evolution. Cell-specific transcriptome analysis of double-labeled transgenic tilapia expressing GFP and RFP in LH or FSH cells, respectively, yielded genes specifically enriched in each cell type, revealing differences in hormone regulation, receptor expression, cell signaling, and electrical properties. Each cell type expresses a unique GPCR signature that reveals the direct regulation of metabolic and homeostatic hormones. Comparing these novel transcriptomes to that of rat gonadotrophs revealed conserved genes that might specifically contribute to each gonadotropin activity in mammals, suggesting conserved mechanisms controlling the differential regulation of gonadotropins in vertebrates.


Assuntos
Peixes/genética , Hormônio Foliculoestimulante/genética , Regulação da Expressão Gênica , Gonadotropinas/genética , Hormônio Luteinizante/genética , Hipófise/metabolismo , Animais , Biomarcadores , Separação Celular , Biologia Computacional/métodos , Peixes/classificação , Imunofluorescência , Perfilação da Expressão Gênica , Anotação de Sequência Molecular , Filogenia , Hipófise/citologia , Ratos
5.
Ying Yong Sheng Tai Xue Bao ; 32(6): 2035-2044, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34212609

RESUMO

Engraulis japonicus, an important fishery resource, is a key species in ecosystem trophodynamics studies. In this study, we examined stomach content of E. japonicusby stable isotope analyses, with samples collected from the East China Sea in 2008-2009 and 2020. The aim of this study was to demonstrate their diet composition, diel and ontogenetic changes in feeding habits and trophic level. Results of the stomach content analysis showed that E. japonicus mainly fed on planktonic crustaceans and small fish. The main prey species were Euphausia pacifica [index of relative importance (IRI)=87.6%; frequency(F)=57.6%], Paracalanus parvus (IRI=3.2%, F=15.3%), and Themisto gracilipes (IRI=2.1%, F=13.1%). Results of the stable isotope analysis showed that Copepoda were the main food source of E. japonicus, followed by Euphausiacea, and the contribution rate of Amphipoda was the least, which was less than 1%. There was significant diel change in diet composition. Feeding intensity was higher in the daytime than at night, with the highest in the dusk and the lowest at midnight. Ontogenetic change in feeding habit occurred when fork length reached 90 mm, over which the fish fed both zooplankton and small fishes. The δ13C of E. japonicus was between -21.66‰ and -18.14‰, with an average of (-19.92±0.86)‰. The δ15N of E. japonicus ranged from 4.07‰ to 10.78‰, with an average of (8.14±2.48)‰. Both δ13C and δ15N values were positively correlated with fork length. Trophic level of the fish was 3.4 with stomach content analysis and 2.7 with stable isotope analysis. The results would provide important reference for understanding nutritional status of pelagic small fish, and offer some basic data to establish ecopath model.


Assuntos
Ecossistema , Conteúdo Gastrointestinal , Animais , Isótopos de Carbono/análise , China , Comportamento Alimentar , Peixes , Cadeia Alimentar , Conteúdo Gastrointestinal/química , Isótopos de Nitrogênio/análise
6.
Mar Environ Res ; 169: 105364, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34087761

RESUMO

Coastal areas in north-western Europe have been influenced by elevated nutrient levels starting in the 1960s. Due to efficient measures, both nitrate and phosphate levels decreased since the mid-1980s. The co-occurring declines in nutrient loadings and fish productivity are often presumed to be causally linked. We investigated whether four resident fish species (twaite shad, bull-rout, thick-lipped grey mullet and eelpout), that spend the majority of their life in the vicinity of the coast, differed in growth between the historic eutrophication period compared to the recent lower nutrient-level period. Based on Von Bertalanffy growth models of length at age, and the analysis of annual otolith increments, we investigated the difference in sex-specific growth patterns and related these to temperature, eutrophication level (Chlorophyll a), growth window and fish density. In all four species, annual otolith growth rates during the early life stages differed between the two periods, mostly resulting in larger lengths at age in the recent period. All species showed significant correlations between increment size and temperature, explaining the observed period differences. The lack of an effect of total fish biomass provided no evidence for density dependent growth. A correlation with chlorophyll was found in bull-rout, but the relationship was negative, thus not supporting the idea of growth enhanced by high nutrient levels. In conclusion, we found no evidence for reduced growth related to de-eutrophication. Our results indicate that temperature rise due to climate change had a greater impact on growth than reduced food availability due to de-eutrophication. We discuss potential consequences of growth changes for length-based indicators used in management.


Assuntos
Eutrofização , Peixes , Animais , Biomassa , Bovinos , Clorofila A , Europa (Continente) , Masculino
7.
Science ; 372(6546): 1105-1107, 2021 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-34083491

RESUMO

Shark populations have been decimated in recent decades because of overfishing and other anthropogenic stressors; however, the long-term impacts of such changes in marine predator abundance and diversity are poorly constrained. We present evidence for a previously unknown major extinction event in sharks that occurred in the early Miocene, ~19 million years ago. During this interval, sharks virtually disappeared from open-ocean sediments, declining in abundance by >90% and morphological diversity by >70%, an event from which they never recovered. This abrupt extinction occurred independently from any known global climate event and ~2 million to 5 million years before diversifications in the highly migratory, large-bodied predators that dominate pelagic ecosystems today, indicating that the early Miocene was a period of rapid, transformative change for open-ocean ecosystems.


Assuntos
Ecossistema , Extinção Biológica , Tubarões , Animais , Peixes , Fósseis , Sedimentos Geológicos , Oceanos e Mares , Paleodontologia , Dente/anatomia & histologia
8.
Braz J Biol ; 82: e238096, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34133555

RESUMO

Pakistan is the country with mega freshwater fish diversity of native and alien species. In the presence of enormous native fishes varies species of exotic fishes have been introduced into the freshwater bodies of Pakistan which are competing with native freshwater fish fauna and making them deprive of food and habitat as well. Intentional or accidental introductions of animals, plants and pathogens away from their native niche is considered as major leading problem for biodiversity of invaded habitat. Three years study (from January 2017 to December 2019) was conducted in freshwater bodies of Province Punjab, Pakistan. Study was designed to know exotic species impacts on the distribution of native species of fishes. During current survey a total of 68 (indigenous and exotic) fish species belonging to 14 families were recorded from head Qadirabad, head Baloki, Islam headworks and Rasul barrage. Statistical analysis showed that Shannon-Wiener diversity index was the highest (1.41) at both Rasul barrage and Islam headworks but, invasive species were present in very less number in these study sites i.e. Oreochromis mozambicus, O. niloticus, Hypophthalmichthys nobilis, Carassius auratus, Ctenophryngdon idella, Cyprinus carpio and H. molitrix. The diversity index showed that comparatively low diversity was present in both area head Qadirabad (1.30) and head Baloki (1.4) due to high pressure of invasive species. Direct observation of species and statistical analysis showed that aliens' species produced negative impact on the local fish fauna diversity, evenness, and numbers. It is concluded that many factors are impacts on the diversity of native fishes, but alien (invasive) species also play a major role to reduction of native species, because aliens' species produce competition for native species. So it is urgent need to analysis the aliens and native food web and roosting sites in Pakistan, in future.


Assuntos
Carpas , Espécies Introduzidas , Animais , Biodiversidade , Ecossistema , Peixes , Água Doce , Paquistão
9.
Braz J Biol ; 82: e239188, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34133557

RESUMO

Amazonian livelihoods are largely dependent on rivers, with local protein consumption mainly relying on several species of fish. The UJER (Upper Juruá Extractive Reserve - Reserva Extrativista do Alto Juruá) is located in the state of Acre, bordering Peru and several indigenous areas. Here we summarize the data we collected in 1993/1994 on the population living along the banks of the Juruá, Tejo, Bagé, Igarapé São João and Breu rivers on crop cultivation, animal husbandry, and use of game and fish resources. We interviewed 133 individuals (94 on the Juruá and Tejo, 16 on Bagé, 16 on Igarapé São João and 7 on Breu rivers). Our results include a comprehensive description on local livelihoods, including the most important fish species for local subsistence considering gender and seasonality, the main husbandry and game species, and the items cultivated on the local agriculture. Whenever more recent information was available in the literature, we compared changes in livelihoods over time in the same region and also with the recent patterns observed in the Lower and in the Middle Juruá River. We hope to provide useful information to understand temporal changes in local livelihoods, which can help adapt and shape the ecological management in the region.


Assuntos
Agricultura , Rios , Animais , Brasil , Peixes
10.
Braz J Biol ; 82: e242823, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34133567

RESUMO

Myxosporidiosis is an infectious disease caused by myxozoans of the Phylum Cnidaria, Class Myxosporea, and Order Bivalvulida, considered a common parasite in fresh and saltwater fishes that parasitize many organs, especially gills. In the present study, 49 specimens of fishes belonging to eight genera: Tetragonopterus, Leporinus, Myleus, Pirinampus, Rhapiodon, Pygocentrus, Ageneiosus, and Serrasalmus were collected and blood smears were made, fixed with absolute methanol, and stained with Giemsa 10% to survey hemoparasites. However, myxospores were found in the circulating blood of five (10.20%) fishes belonging to genus Tetragonopterus, Myleus, and Pygocentrus. Two morphological types of Myxobolus spp. were identified in all the five fish specimens analyzed. Usually, investigations on myxozoans in fish are carried out with the search for plasmodia or cysts in the fish organs and observation of the cavity of organs. Nevertheless, this study highlights the importance of also examining the blood of these animals, since these parasites can cause severe pathogenic diseases in fish. Thus, the blood analyses can proportionate preventive sanitary control for commercial fish avoiding economic loss.


Assuntos
Cnidários , Doenças dos Peixes , Myxobolus , Myxozoa , Doenças Parasitárias em Animais , Animais , Brasil , Peixes , Brânquias , Humanos , Filogenia
11.
Ecotoxicol Environ Saf ; 220: 112354, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34116335

RESUMO

Hydropower generation, a renewable source of electricity, has been linked to elevated methylmercury (MeHg) concentrations in impoundments and aquatic biota. This study investigates the impact of water level fluctuations (WLF) on MeHg concentrations in water, sediment, and fish. Using a set of controlled microcosm experiments emulating the drawdown/refill dynamics and subsequent sediment exposure to air experienced in reservoirs, we demonstrate that less frequent WLFs, and/or increased exposure of sediment to air, can lead to elevated MeHg concentrations in sediment, and total mercury (THg) and MeHg concentrations in water. In examining the effects of WLF frequency (two-day, weekly, and monthly), the monthly treatment displayed the highest THg and MeHg water levels, while the weekly treatment was characterized by the highest MeHg levels in the sediment. Our work supports emerging evidence that longer duration between WLF creates a larger surface area of sediment exposed to air leading to conditions conducive to higher MeHg concentrations in sediments and water. In contrast, THg, MeHg, and fatty acid trends in fish were largely inconclusive characterized by similar among-treatment effects and minimal temporal variability over the course of our experiment. This result could partly be attributed to overall low mercury levels and simple "worm-forage fish" food web in our experiment. To elucidate the broader impacts of water fluctuations on aquatic chemistry and biota, other factors (e.g., longer WLF cycles, dissolved organic matter, temperature, more complex food webs) which modulate both methylation rates and food web dynamics must be considered.


Assuntos
Mercúrio/análise , Movimentos da Água , Poluentes Químicos da Água/análise , Animais , Monitoramento Ambiental , Peixes/metabolismo , Cadeia Alimentar , Sedimentos Geológicos/química , Compostos de Metilmercúrio/análise , Água/química
12.
Zootaxa ; 4975(2): 389396, 2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-34186558

RESUMO

The new sardine Sardinella ventura n. sp. (Teleostei: Clupeiformes: Clupeidae) is described on the basis of 10 specimens collected from Mauritius. The new species is most similar to Sardinella dayi Regan 1917 in having non-deciduous scales with pores and discontinuous striae, a dark spot on the dorsal-fin origin, the pelvic fin with 8 rays, and similar number of gill rakers, in addition to very similar numbers of keeled scutes. However, the new species is distinguished from S. dayi by having a shorter caudal peduncle [6.27.6% SL (mean 7.0%) vs. 8.212.0% (9.2%) in S. dayi], larger eye [8.49.9% (9.0%) vs. 6.88.0% (7.4%)] and orbit [9.612.3% (10.7%) vs. 8.510.2% (9.3%)], longer pectoral [21.022.7% (21.5%) vs. 17.021.0% (19.8%)] and pelvic fins [12.513.5% (12.8%) vs. 10.412.2% (11.2%)], and a greater numbers of pseudobranchial filaments [1719 (modally 17) vs. 1822 (19)], lateral scale rows in longitudinal series [4143 (41) vs. 3842 (40)] and transverse scales [11 or 12 (12) vs. 11]. There were significant differences in seven meristic and 14 morphometric characters between the two species.


Assuntos
Peixes/anatomia & histologia , Peixes/classificação , Animais , Brânquias , Maurício
13.
Int J Food Microbiol ; 351: 109268, 2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34098467

RESUMO

The increase in multidrug-resistant Salmonella enterica and its spread from food to humans are considered a serious public health concern worldwide. Little is currently known about the prevalence of extended-spectrum ß-lactamase (ESBL)-producing S. enterica in fish in Africa. Therefore, this study aimed to investigate the existence of ESBL-producing S. enterica in retail fish in Egypt. In total, 200 fish samples were collected randomly from various retail fish markets in Egypt. S. enterica were detected in 19 (9.5%; 95% CI: 5.8-14.4) of the fish samples analyzed. Of the 19 non-repetitive S. enterica isolates, 18 were serologically categorized into eight S. enterica serovars and a non-typable serovar. All 19 S. enterica isolates (100%) showed multidrug-resistant phenotypes to at least three classes of antimicrobials, and 11 (57.9%) exhibited an ESBL-resistant phenotype and harbored at least one ESBL-encoding gene. The ESBL-producing S. enterica serovars were as follows: Kentucky (3 isolates; 15.8%), Enteritidis (2 isolates; 10.5%), Typhimurium (2 isolates; 10.5%), and 1 isolate (5.3%) each of Infantis, Virchow, Paratyphi B, and Senftenberg. The identified ß-lactamase-encoding genes included ESBL-encoding genes blaCTX-M-3, blaCTX-M-14, blaCTX-M-15, blaSHV-1, blaSHV-2 and blaSHV-12; the AmpC ß-lactamase-encoding gene blaCMY-2; and the narrow-spectrum ß-lactamase-encoding genes blaTEM-1 and blaOXA-1. All S. enterica isolates were negative for carbapenemase-encoding genes. Molecular analysis of plasmid transferability and replicon typing revealed that most plasmids (with ß-lactamase-encoding genes) were transferrable, and the most common incompatibility groups were IncI1, IncA/C, IncHI1, and IncN. To the best of our knowledge, this is the first report for molecular characterization of ESBL-producing S. enterica in fish in Egypt. The occurrence of ESBL-producing S. enterica in retail fish constitutes a potential public health threat with the possibility of transmission of these strains with resistance genes to humans. Such transmission would exacerbate the resistance to an important class of antibiotics commonly used in hospitals to treat typhoid and non-typhoidal Salmonella infections.


Assuntos
Peixes/microbiologia , Salmonelose Animal/microbiologia , Salmonella enterica/metabolismo , beta-Lactamases/metabolismo , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Egito/epidemiologia , Humanos , Plasmídeos/genética , Prevalência , Saúde Pública , Salmonelose Animal/epidemiologia , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética , Salmonella enterica/isolamento & purificação , beta-Lactamases/genética
14.
Ecol Lett ; 24(8): 1569-1581, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34110065

RESUMO

Identifying environmental predictors of phenotype is fundamentally important to many ecological questions, from revealing broadscale ecological processes to predicting extinction risk. However, establishing robust environment-phenotype relationships is challenging, as powerful case studies require diverse clades which repeatedly undergo environmental transitions at multiple taxonomic scales. Actinopterygian fishes, with 32,000+ species, fulfil these criteria for the fundamental habitat divisions in water. With four datasets of body size (ranging 10,905-27,226 species), I reveal highly consistent size-by-habitat-use patterns across nine scales of observation. Taxa in marine, marine-brackish, euryhaline and freshwater-brackish habitats possess larger mean sizes than freshwater relatives, and the largest mean sizes consistently emerge within marine-brackish and euryhaline taxa. These findings align with the predictions of seven mechanisms thought to drive larger size by promoting additional trophic levels. However, mismatches between size and trophic-level patterns highlight a role for additional mechanisms, and support for viable candidates is examined in 3439 comparisons.


Assuntos
Ecossistema , Peixes , Animais , Tamanho Corporal , Água Doce
15.
Parasitol Res ; 120(7): 2493-2503, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34115215

RESUMO

Recent anecdotal reports from seafood processors in eastern Australia have described an increased occurrence of post-mortem myoliquefaction ('jellymeat') in broadbill swordfish Xiphias gladius, and macroscopic cysts throughout the musculature of yellowfin tuna Thunnus albacares. A genus of parasitic cnidarians, Kudoa (Myxosporea, Multivalvulida), species of which are known to occur in economically important wild-caught fish species globally, can cause similar quality-deterioration issues. However, Kudoa sp. epizootiology within commercially harvested, high-value fish caught within Australia is poorly understood, despite the parasite's economic importance. To determine the causative agent responsible for the observed quality deterioration in swordfish and yellowfin tuna, muscle-tissue samples from seafood processors in Mooloolaba, Australia, collected from October 2019-February 2020, were examined for parasitic infection. Kudoid myxospores were identified from both hosts and were subquadrate in shape, with four equal-sized polar capsules. The SSU rDNA sequences from both fish shared > 99% identity to Kudoa species. Kudoa musculoliquefaciens was isolated from 87.1% of swordfish sampled, suggesting that it is a widespread parasite in swordfish from the southwest Pacific Ocean. This study provides the first molecular and morphological characterisation of Kudoa thunni in yellowfin tuna and K. musculoliquefaciens in swordfish harvested from the waters of eastern Australia, expanding the geographical distribution of K. thunni and K. musculoliquefaciens to include the Coral and Tasman Seas. We demonstrate that not all infected swordfish progress to jellymeat, show the usefulness of molecular tools for reliably identifying infection by Kudoa spp., and add to the overall knowledge of kudoid epizootiology in wild-caught fish.


Assuntos
Peixes/parasitologia , Myxozoa/classificação , Atum/parasitologia , Animais , Austrália , DNA Ribossômico/genética , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/parasitologia , Músculos/parasitologia , Myxozoa/anatomia & histologia , Myxozoa/genética , Oceano Pacífico , Doenças Parasitárias em Animais/epidemiologia , Doenças Parasitárias em Animais/parasitologia , Filogenia , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , Alimentos Marinhos/parasitologia , Especificidade da Espécie
16.
Parasitol Res ; 120(7): 2505-2521, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34170388

RESUMO

The present paper describes Filisoma argusum n. sp. (Cavisomatidae), an acanthocephalan parasite infecting the intestine of the spotted scat, Scatophagus argus (Linnaeus, 1766), in the south-west coast of India. The prevalence is 18% (mean intensity: 1.61 and abundance: 1-4 worms/host). Filisoma argusum n. sp. is morphologically characterized by a creamy-white, cylindrical, elongate, aspinose, and robust trunk; a collar-like neck; and a cylindrical proboscis with 18-20 longitudinal rows of hooks, with 19-22 hooks/row. Proboscis receptacle long, double-walled. Lemnisci digitiform, equal, longer than proboscis receptacle. Females 79.14 ± 33.69 × 0.593 ± 0.19 mm; males 32.62 ± 2.98 × 0.46 ± 0.071 mm. Males with four cement glands; bulbous muscular copulatory bursa with six digitiform rays. SEM studies revealed smooth hooks, sensory pits, and epidermal micropores. Histopathological changes at the site of parasite attachment included inflammation, hemorrhage, sloughing of epithelium, and detachment of mucosal layer of the intestine. In molecular and phylogenetic analyses, the parasite occupied an independent position within the Cavisomatidae clade with high bootstrap values for both ITS1-5.8S and ITS2, and mt-CO1 regions. Considering the morphologic and morphometric differences with previously described species of Filisoma along with its phylogenetic positioning, the present acanthocephalan is treated as a new species and the name Filisoma argusum n. sp. is proposed.


Assuntos
Acantocéfalos/classificação , Peixes/parasitologia , Acantocéfalos/anatomia & histologia , Acantocéfalos/genética , Animais , DNA Mitocondrial/genética , DNA Ribossômico/genética , Feminino , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/parasitologia , Helmintíase Animal/epidemiologia , Helmintíase Animal/parasitologia , Índia , Intestinos/parasitologia , Masculino , Filogenia , Especificidade da Espécie
17.
Mar Environ Res ; 169: 105379, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34119918

RESUMO

Cyclothone braueri (Stomiiformes, Gonostomatidae) is a widely distributed fish inhabiting the mesopelagic zone of marine tropical and temperate waters. Constituting one of the largest biomasses of the ocean, C. braueri is a key element in most of the ecological processes occurring in the twilight layer. We focused on the ecological processes linked to early life stages in relation to marine pelagic environmental drivers (temperature, salinity, food availability and geostrophic currents) considering different regions of the Central Mediterranean Sea. A multivariate morphometric analysis was carried out using six parameters with the aim of discerning different larval morphotypes, while a fragment of 367 bp representing the 12S ribosomal RNA gene was used to perform molecular analyses aimed at determining the intraspecific genetic variability. Analysis highlighted two geographically distinct morphotypes not genetically discernible and related to the different nutritional conditions due to spatial heterogeneities in terms of temperature and food availability. The body depth (BD) emerged as an appropriate morphometric parameter to detect the larval condition in this species. Molecular analysis highlighted a moderate genetic divergence in the fish population, showing the recurrence of two phylogroups not geographically separated.


Assuntos
Cilióforos , Peixes , Animais , Estruturas Genéticas , Larva/genética , Mar Mediterrâneo
18.
Mar Environ Res ; 169: 105381, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34139650

RESUMO

We investigated the main drivers of eggs and larvae distributions of European sardine and anchovy from the NW Mediterranean Sea. We used Generalized Additive Models and satellite environmental data. Mainly sea surface temperature, but also currents, surface height, and primary production were significantly correlated with both species' early stages distributions. Anchovy optimal temperature upper limit was not detected, but sardine eggs and larvae presented a small-ranged bell-shape curve relationship to SST with an upper SST threshold around 13 °C. Sardine spawning during winter appeared to be dependant not only on in-situ environmental conditions but also on summer conditions prior to the spawning event. Model predictions of the larval and spawning habitat distribution showed clear differences between developmental stages and between species, confirming a worsening of the sardine habitat with time. Considering the further increase of surface temperature predicted in the years to come, the survival of the sardine in the region could be compromised.


Assuntos
Ecossistema , Peixes , Animais , Larva , Mar Mediterrâneo , Alimentos Marinhos
19.
Mar Environ Res ; 169: 105399, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34175523

RESUMO

Overfishing is a key stressor in many coral reefs, affecting their function and ecosystem services. In the Gulf of California, 50 years of artisanal and recreational fishing have removed most of the largest and most vulnerable fish species, the Espiritu Santo Archipelago (ESA) is a marine protected area (MPA) where artisanal and recreational fishing are allowed in most of the natural reefs, while the artificial reefs (wrecks) are fully protected. An important question under such circumstances is whether artificial reefs can serve as surrogate habitats for the natural reefs. To address this question, we characterized the fish community (species richness, abundance, differences in taxonomic structure) and analyzed the obtained data by multivariate ordination and similarity analysis. The highest species richness was found in the artificial reefs, with total of 83 species, of which 21 species were exclusive. Contrary to the species richness, the total fish abundance was 20% higher at the natural reefs. The fish assemblages of the artificial reefs differ significantly from those of the natural reefs. The natural reefs of the ESA are dominated by few fish species from families of lower trophic levels. In contrast, the studied shipwrecks provide refuge to commercially important fish species (such as Snappers, Triggerfish, Jacks, and Groupers) including threatened species. The different fish compositions on the natural and artificial reefs is likely to be the outcome of differential fishing pressure. The non-fished areas (wrecks) of the ESA may represent a good strategy for reef restoration, enhanced fishing grounds (via spillover) and fishing management. However, the fish community structure of the artificial reefs differs from natural rocky reefs of the ESA, and therefore, should not be considered as surrogate habitats for natural reefs. The results point out the need to reassess the management effectiveness of the natural reefs of the ESA.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Animais , Recifes de Corais , Pesqueiros , Peixes , Alimentos Marinhos
20.
Molecules ; 26(9)2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066575

RESUMO

Despite progress achieved, there is limited available information about the antibacterial activity of constituents of essential oils (EOs) from different medicinal-aromatic plants (MAPs) against fish pathogens and the complex interactions of blended EOs thereof. The present study aimed to investigate possible synergistic antimicrobial effects of EOs from seven Greek MAPs with strong potential against Aeromonas veronii bv. sobria, a fish pathogen associated with aquaculture disease outbreaks. The main objective was to evaluate whether blending of these EOs can lead to increased antimicrobial activity against the specific microorganism. A total of 127 combinations of EOs were prepared and their effect on A. veronii bv. sobria growth was tested in vitro. We examined both the inhibitory and bactericidal activities of the individual EOs and compared them to those of the blended EOs. The vast majority of the investigated combinations exhibited significant synergistic and additive effects, while antagonistic effects were evident only in a few cases, such as the mixtures containing EOs from rosemary, lemon balm and pennyroyal. The combination of EOs from Greek oregano and wild carrot, as well as the combinations of those two with Spanish oregano or savoury were the most promising ones. Overall, Greek oregano, savoury and Spanish oregano EOs were the most effective ones when applied either in pure form or blended with other EOs.


Assuntos
Aeromonas veronii/efeitos dos fármacos , Antibacterianos/farmacologia , Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/prevenção & controle , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Animais , Apiaceae , Técnicas de Química Sintética , Daucus carota , Sinergismo Farmacológico , Cromatografia Gasosa-Espectrometria de Massas , Infecções por Bactérias Gram-Negativas/veterinária , Concentração Inibidora 50 , Melissa , Mentha , Testes de Sensibilidade Microbiana , Origanum , Plantas Medicinais/química , Rosmarinus , Satureja
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