Brackish Water Fish Research Articles

Prevalence of Bacterial Microbiota in Tilapia Guineensis Harvested from Buguma Brackish Water Environment River State, Nigeria

Brackish water fishes usually harbour human pathogenic bacteria particularly the enterics and coliform groups in their mucosal surfaces. Thus, this study was undertaken to investigate the prevalence of skin and gills microbiota of Tilapia guineensis as to understand their microbial assemblages and as well provide useful insights into the broad dynamics of the fish host-microbial relationship and health status. Thirty samples of Tilapia guineensis were collected from Buguma brackish water environment, River State, Nigeria. The skin and the gills of the tilapia were analyzed microbiologically. Specimen were collected by swabbing aseptically over the skin and gills segment of the fish and then processed for total bacterial count, followed by isolation and identification of isolated bacteria. Microbial load analysis revealed that the total viable count of bacteria ranged from 2.4 to 7.6 x 105 cfu/ml for skin and 2.1 to 5.7 x 106 cfu/ml for gills, and it was observed to fall within the recommended microbiological standard safety limit. A total of thirty-seven (37) bacteria, belonging to fifteen different genera in the family of Vibrionaceae, enterobacteriaceae and Morganellaceae were isolated from the fish. The prevalent rate of the bacterial shows that Proteus vulgaris recorded the highest frequency of occurrence of 16.22%, followed by Vibrio parahaemolyticus with 10.81% occurrence and Provindencia rettgeri, Serratia mercescens and Salmonella sp. trailed them with 8.11%. Kluyyera ascorbate, Citrobacter amalonaticus, Proteus mirabilis, Enterobacter aerogenes, plesiomonas shigelloides and Pseudomonas sp. have the least frequency of occurrence with 2.7% respectively for each. Though the bacterial count of Tilapia guineensis harvested from the water and fish sample did not exceed the standard recommended safety limit. There were several potential pathogenic and spoilage bacteria isolated as part of the fish flora. The presence of these bacteria could poses or constitute a public health risk.

The current state of aquatic biological resources and fisheries in the lower Dniestr and Dniestrovskiy liman

The fish species composition and structural characteristics of the ichthyofauna of the Lower Dniester and Dniesterovskiyliman are presented. In total 79 species of fish from 16 orders, 24 families, 61 genera were observed in 2006–2018.The largest number of species in two orders: Cypriniformes and Perciformes (40.5 and 25.3%, respectively); largest number of genera and species in families: Cyprinidae – 22 genera and 29 species, Gobiidae – 7 genera and 13 species,and Percidae – 5 genera and 5 species. Ichthyofauna of Lower Dniester and Dniesterovskiy liman is represented byfour main faunal complexes. The dominant complex is the Ponto-Caspian, combining brackish and marine fish species.Ichthyofauna of the Lower Dniester is formed mainly by freshwater (55.7% of the total number of identified species)and brackish-water fish (26.6%). Most of species (77.2%) are demersal and bottom dwelling, phytophiles (34.2%)and lithophiles (22.8%), benthophages and carnivores. The remaining groups are represented by fewer species.The analysis of the current state of aquatic bioresources are presented. From 16 to 28 species of fish are recorded inthe commercial catches of the Lower Dniester and Dniestrovskiy liman. The dynamics of catches of the main commercialfish species are presented according to official statistics. Significant increase in the catch of gibel carp, an increase inthe catch of common carp? roach and common bream, and a decrease in the number of populations of predatory fishspecies was observed. The total catch of aquatic biological resources from 2013 to 2017 increased sharply from 547.9 to2344.3 tons per year. Gibel carp Carassius gibelio (Bloch, 1782) is the dominant fish species in the Lower Dniester.The catches of this species increased significantly (up to 1967.8 tons). The age and sex composition, as well as the sizemasscharacteristics of the main commercial species are presented. A decrease in the age composition of the populationsof the main commercial fish species as a result of an increase in the intensity of fishing was observed. The commercialfish mortality rates and stocks of the main commercial species are presented. The stock of gibel carp is set at 5,000–6,000 tons, bream – 630 tons, roach – about 150-200 tons, common carp about 200–250 tons, pikeperch – 20–25 tons.Forecasts of the allowable catch of the main commercial fish species of the Lower Dniester are presented.

The Results of Zmiinyi Island (Black Sea) Coastal Waters Ichtiofauna Monitoring in 2016-2017

Purpose. To study the state of ichthyofauna in the Zmiinyi Island coastal waters in 2016-2017. Methods. Standard methods of ichthyofauna sampling, determination, abundance and biomass estimation. Results. During the period of studies, 68 species of marine, brackish-water and freshwater fish were found in the Zmiinyi Island area belonging to 18 orders, 41 families and 55 genera. The biggest number of taxa belongs to Perciformes order. The representatives of this order make one-half of all the species found near the island. Indicators of ichthyofauna species diversity in the Zmiinyi Island area were gradually decreasing in the period from 2003 to 2009. In 2015-2016 all those indicators grew significantly. Biodiversity level (Shannon index values calculated coming out of number) in 2016 varied from 0.86 to 3.06 making in the average 2.06; in 2017 – from 2.40 to 2.54 making in the average 2.47. Minimal values of biodiversity indicators were registered in the end of autumn and in winter, maximal – in May-June. In the Zmiinyi Island coastal waters 30.9% of all the fishes registered in the Black Sea were found. The fishes caught near the island belonged to 5 ecological groups. The basis of ichthyofauna in the area was formed by marine fish species – 52 species (76.5 % of the total number of species). Most of species (54 species or 89.4%) were bottom-dwelling or near-bottom. Pelagophylic and protecting species prevailed and their numbers were almost equal (24 species or 35.3% and 23 species or 33.8% respectively). On the type of feeding, predatory (37%) and benthos-eating (33%) species prevailed. Out of 68 species found in the island area, 16 species are included into the Red Book of Ukraine, 22 species – into the Black Sea Red Data Book, 7 species – into the IUCN Red List. More than one-half of the species registered in the area (36 species or 52% of all the species) have a protected status. Сonclusions. Results of analysis of biodiversity, structural characteristics and taxonomic composition of ichthyofauna in the Zmiinyi Island coastal waters have been presented. Seasonal dynamics of its number and biomass has been studied. The results of the analysis of some aspects of ecology and biology of the main mass species of fish are presented. Recommendations are given to improve monitoring of the ichthyofauna of coastal waters. Quality of bottom communities monitoring in the Zmiinyi Island coastal waters can be increased significantly by development and implementation of non-contact low-budget video-monitoring methods to solve the problem of fish stock and biodiversity studying in inaccessible areas. It is anticipated that the method developed will help high precision assess of fish stock in inaccessible shelf areas where application of other methods is connected with technical difficulties, high cost and can lead to unreliable results. Elaboration of the method aimed at development of video materials received computer processing algorithms will significantly simplify the analysis of the data collected.

Environmental sensitivity index mapping as a prevention strategy against oil spill pollution: A case study on the coastal area of South Sumatera Province in Indonesia

Coastal areas are vulnerable to oil spill pollution from tanker accidents or unappropriated operational procedures from the oil and gas industry. This study was aimed to develop a prevention strategy to minimize damage and to ensure vulnerable natural resources and local community fisheries economic activities in coastal areas are protected. The local community utilizes fisheries resources in coastal waters of South Sumatera Province as their main livelihood. The potential of fish and shrimp resources in this area is quite abundant due to the existence of good mangrove ecosystems and located in the high-organic environment of Musi River estuary. On the other hand, the area is highly potential to be threatened by oil spill accident from the nearby of Bangka Strait just right in front of the Musi Estuary. A model named Environmental Sensitivity Index (ESI) has been developed to classify the level of sensitivities along the shoreline and habitats of the study area to protect such area. Environmental sensitivity index takes into account the vulnerability, biological and socio-economical characteristics for each coastal environmental feature such as fisheries resources and mangrove ecosystem. These three fundamental ESI elements are transferred into three indexes, i.e. Vulnerability Index, Ecological Index and Social Index. Spatial analysis through the geographic information system of overlay technique is applied to determine each environmental feature to produce ESI Map. The results of the ESI analysis show that coastal waters which are habitat of brackish water fishes and shrimps harvested by passive fishing gear such as Kelong (a combination of Guiding Barrier and Fixed lift net) and Sero (Guiding Barrier) are categorized as the sensitive category, while other offshore waters are classed as moderate level. Shoreline type and mangrove ecosystems classified as very sensitive. As consequences, this area must be a top priority in protecting the area from any of oil spill pollution. ESI analysis can be used as an appropriate tool in the determination of priority area need to be protected from any oil spill events.

Evaluating the distribution of freshwater fish diversity using a multispecies habitat suitability model to assess impacts of proposed dam development in Gabon, Africa

AbstractData scarcity impedes a comprehensive impact assessment of the 38 dams currently proposed within the highly biodiverse central African nation of Gabon. Here, we present a multiple‐species MaxEnt distribution modeling approach to assess species richness for freshwater fishes at the landscape level and demonstrate its utility in identifying proposed dam sites in Gabon that fall in highly diverse areas. We modeled habitat suitability for 202 of Gabon's fresh and brackish water fish species based on georeferenced presence data from museum specimens and a set of ecologically meaningful environmental conditions. We removed poor performing species from the model and compiled the distributions of 114 well‐performing species to generate a new metric, the species pseudorichness index (pR), defined as the cumulative number of species that are highly suited to the habitat in a given segment of river. We used pR as a proxy for true species richness and use this metric to evaluate the distribution of freshwater fish diversity relative to the proposed dam development in Gabon. We found that more than 80% of the proposed dams in Gabon overlap with areas of high pR, implying that planned hydroelectric development in Gabon may disproportionately affect high diversity areas. These dams deserve more focused baseline assessments and conservation action. This approach provides a rapid way to initiate a landscape‐scale assessment of freshwater fish diversity to inform conservation decisions in areas that are species rich, but data poor.

Environmental characteristics and management challenges of brackishwater fish ponds in Cirebon Regency, West Java Province, Indonesia: a fine-scale GIS Approach

This study presents a fine-scale Geographic Information System (GIS) method to explore existing environmental and farm management constraints at extensive brackish water aquaculture ponds located in Losari District, Cirebon Regency, and West Java Province. The sampling method followed a detailed survey method, employing high-resolution satellite imagery of worldview-2 and GIS. Detailed pond unit and layout canal maps were used to guide soil and water sampling, measurement of land elevation and tide observation. The result showed that the existing pond canals were not able to supply 4,800,000 m3 daily required quantity of culture water for the total 2,360 ha pond area due to high sedimentation at the mouth and along the canals. The result of spatial analysis of soil and water variables also indicated that, despite generally good soil and water quality, some existing environmental variables could potentially limit the productivity and sustainability of the existing brackishwater ponds. The soil variables such as phosphate (PO4-P) content (79.16 ± 28.34 mg / L) exceeded the optimum standard value of 35-46 mg/L, whilst total nitrogen (Total-N) content (0.07 ± 0.025 %) was lower than the optimum value of > 0.2%, for brackishwater aquaculture. Water quality variables comprising (NO2-N), total ammonia nitrogen (NH3-N) and nitrate (NO3-N) were also identified as limiting factors. Without a significant improvement in pond engineering and better understanding and management of existing environmental limiting factors, the increase in productivity and the sustainability of brackishwater fish ponds in the region seem almost impossible.

An update to the inventory of shore-fishes from the Parque Nacional Sistema Arrecifal Veracruzano, Veracruz, México.

Data on marine and brackish-water fishes recorded in the area of the Parque Nacional Sistema Arrecifal Veracruzano in the southwest Gulf of Mexico were extracted from online aggregators of georeferenced location records, the recent ichthyological literature reviewed, and collections and observations made to provide a more complete faunal inventory for that park. Those actions added 95 species to a comprehensive inventory published in 2013, and brought the total to 472 species, an increase of 22%. Seventy-four percent of the additions came from online aggregators of georeferenced species records, which clearly demonstrates the value of reviewing and incorporating such data into species inventories. However, different aggregators recorded different sets of species, and some of their data were linked to outdated taxonomy or included identification errors. Hence individual records from multiple aggregators need to be obtained and reviewed for such issues when using such data to compile and revise faunal inventories. Existing lists also need to be carefully reviewed to ensure that errors are not perpetuated during updates.

The Morphological and Molecular Description of Acanthogyrus (Acanthosentis) fusiformis n. sp. (Acanthocephala: Quadrigyridae) from the Catfish Arius sp. (Ariidae) in the Pacific Ocean off Vietnam, with Notes on Zoogeography.

Most (82%) of the 46 recognized species of Acanthogyrus (Acanthosentis) Verma and Datta, 1929 are known from Asian freshwater fishes. Only three species of Acanthosentis are known from marine or brackish water fishes from India and Pakistan. We have discovered another marine species of Acanthosentis in the Pacific Ocean, off Vietnam. The purpose is to describe the new species morphologically and molecularly and provide new information of its evolutionally relationships with other species of the subgenus. Standard methods of collection and examination of marine hosts, processing and illustrating of specimens, and taxonomic identification of parasites using the extensive collection of the lead author were used. Specimens were further studied using energy-dispersive X-ray analysis and ion sectioning of hooks, SEM analysis, and molecular sequencing. Type specimens were deposited at the Harold W. Manter Lab. collection, Lincoln, Nebraska. Acanthogyrus (Acanthosentis) fusiformis n. sp. is described from the catfish, Arius sp. (Ariidae: Siluriformes) off the Pacific Coast of Vietnam at Bac Lieu in the Gulf of Thailand. The three other marine Indian species include A. (A.) arii Bilqees, 1971 which is also described from a similar catfish, Arius serratus Day off the Karachi coast in the Arabian Sea, Indian Ocean. Our new species from Vietnam is distinguished from the other 46 species by a combination of characters including a small fusiform trunk, complete circles of small hollow spines covering the entire trunk, prominent double apical organs often extending posteriorly past posterior hooks, middle and posterior hooks of equal size slightly smaller than anterior hooks, large neck continuous with the outline of the proboscis without distinct separation, big drop-shaped cephalic ganglion, extension of the proboscis receptacle anteriorly past the base of the proboscis up to the insertion point of the posterior hooks, presence of two para-receptacle structures (PRSs), free unattached thick lemnisci, short female reproductive system with filamentous attachment of the distal end of the uterine bell to the ventral body wall, and small narrowly ellipsoid eggs with thickened polar ends. Partial sequences of the 18S and internal transcribed spacers (ITS1-5.8S-ITS2) of ribosomal RNA were generated and used for phylogenetic analyses to confirm the taxonomic identity of Acanthogyrus (Acanthosentis) fusiformis n. sp. We describe unique morphological features of A. fusiformis never before known in the subgenus Acanthosentis. The uniqueness of A. fusiformis is further demonstrated by its EDXA fingerprint characterized by high levels of calcium and phosphorous in hooks. The zoogeography of species of Acanthosentis is elucidated in the Indian subcontinent, the Caribbean, China, and Africa. Molecular data have been available only in few species of Acanthogyrus (Acanthosentis) to date on GenBank database. For 18S, only two sequences from unknown Acanthosentis sp. from India are available, while for the ITS1-5.8S-ITS2 region, only sequences of A. cheni from China and of two unidentified species from Malaysia are available. Additional studies of species of Acanthosentis based on morphological and molecular genetic data will be needed to reconstruct the evolutionary history and phylogenetic affinities of this group of acanthocephalans.

Field Studies on Amyloodiniosis in Red Sea Cultured Asian Seabass (Lates calcarifer) and Hamour (Epinephelus polyphekadion).

Amyloodinium ocellatum infects the gills and skin of both marine and brackish water fishes. The aim of the present study was to examine pathogenesis, prevalence, trials for treatment and histopathological alterations of Amyloodinosis in naturally infested Asian Seabass Barramundi Lates calcarifer and Hamour Epinephelus polyphekadion in Ismailia Governorate, Egypt. A total number of 1447 Red Sea cultured Seabass (Lates calcarifer) broadstock and a total number of 53 Red Sea cultured Hamour, Epinephelus polyphekadion broadstock were collected and subjected for the study. Fishes showed symptoms of sudden death and respiratory distress besides Amyloodiniosis on gills and skin. All fishes were treated with various treatment protocols while gills of naturally infected fishes were examined histopathologically. The clinical signs of infested fishes were flashing, surfacing, off food and respiratory distress. The intensity of infestation of Amyloodiniosis was more sever in Asian Seabass than Epinephelus polyphekadion while treatment of choice was copper sulphate (prolonged bath), freshwater bath and formalin consequently. Treatment of choice for Amyloodinium ocellatum infestation in Asian Seabass was copper sulphate (prolonged bath) followed by freshwater bath then formalin.

Morphological and Molecular Identification of Stellantchasmus dermogenysi n. sp. (Digenea: Heterophyidae) in Thailand.

We tried a series of morphological and molecular approaches to identify a new species of Stellantchasmus (Digenea: Heterophyidae) originating from the wrestling half-beaked fish, Dermogenys pusillus of Thailand. Adult worm samples of the new species were recovered from hamsters experimentally infected with the metacercariae from D. pusillus in Thailand. Two isolates (Thai and Korean) of Stellantchasmus falcatus were used as comparative control groups. Worm samples of 3 Stellantchasmus groups were morphologically observed and molecularly analyzed with the mitochondrial cytochrome c oxidase 1 gene. The morphological characteristics of S. dermogenysi n. sp. are similar to S. falcatus originating from brackish water fish, but minor difference was noted including the absence of the prepharynx, position of the ovary near the ceca end, smaller body size, and shorter esophageal length. A phylogenetic tree derived from neighbor-joining and maximum-likelihood methods suggests that S. dermogenysi n. sp. is separated from S. falcatus supported by high bootstrap values. The relative divergences persist between these host-specific trematodes, which we suggest should be recognized as 2 distinct species. Comparisons of S. dermogenysi n. sp. with S. falcatus isolated from mullets in Thailand and Korea indicate a genetic divergence of mitochondrial DNA of 19.4% and 21.7%, respectively. By the present study, a new species, Stellantchasmus dermogenysi n. sp. (Digenea: Heterophyidae), is proposed in Thailand based on molecular evidences, in addition to minor morphological differences between S. falcatus and the new species.

Pathogenic Vibrio parahaemolyticus indiarrhoeal patients, fish and aquatic environments and their potential for inter-source transmission

The role of Vibrio parahaemolyticus in causing diarrhoeal disease is well known. However, phenotypic and genetic traits of this pathogen isolated from diverse sources have not been investigated in detail. In this study, we have screened samples from diarrhoeal cases (2603), brackish water fish (301) and aquatic environments (115) and identified V. parahaemolyticus in 29 (1.1%), 171 (56.8%) and 43 (37.4%) samples, respectively. Incidence of pathogenic V. parahaemolyticuswith virulence encoding thermostable-direct haemolysin gene (tdh) was detected mostly in fishes (19.3%) and waters (15.6%) than clinical samples (1.04%). The pandemic strain marker genes (toxRS and PGS-sequences) have been detected relatively more in water (6%) and fish (5%) samples than in clinical samples (0.7%). Majority of the V. parahaemolyticus isolates from clinical cases and fish samples (26.3%) belonged to classical pandemic serovars (O3:K6). In addition, several newly recognised pandemic serovars have also been identified. Pulsed field-gel electrophoresis (PFGE) analysis showed clonal relatedness (60–85%) of V. parahaemolyticus from different sources. The study observation revealed that the brackish water fishes and water bodies may act as a reservoir of pathogenic V. parahaemolyticus. Emergence of several new serovars of pandemic V. parahaemolyticussignifies the changing phenotypic characteristics of the pathogen.

The utilization of phenol in betel leaf (piper betle) as feed to reduce Aeromonas hydrophylla infection in dumbo catfish (Clarias gariepinus) and gourami (Ospronemus gouramy Lac.) fish cultivation

Aeromonas hydrophylla was one of pathogenic bacteria in fresh and brackish water fish that reduced fish production. Betel leaf contains phenol active substances (carvacrol, betel phenol and chavicol), which act as anti-septic, kill microorganisms and prevent bacterial infection. This research aimed to know the effect of betel leaf flour feed supplement in different concentrations namely 2, 4 and 6 % applied to catfish and gourami. The design used in this research was completely randomized design, each treatment repeated three times. Results showed that the weight of catfish was not affected by the concentration of betel leaf concentration in feed. In contrast, gourami fed with higher concentration of betel leaf, gained more weight. The survival percentage of catfish 82.2, 96, 80% and gourami was 93.0, 88.8, and 93.3 % for treatment one, two and three respectively

Assessing the Taxonomic Validity of Austrodiplostomum spp. (Digenea: Diplostomidae) through Nuclear and Mitochondrial Data

Adults of the genus Austrodiplostomum are parasites in cormorants of the New World, whereas metacercariae are parasites from eye globe and brain of freshwater and brackish water fishes. In this study, specimens of Austrodiplostomum mordax from South America (type-species) were analyzed together with other specimens of Austrodiplostomum spp. collected from several locations across Middle America and North America. Partial DNA sequences of the mitochondrial gene cytochrome c oxidase subunit I ( COI), the internal transcribed spacers ( ITS1, ITS2, and 5.8S gene), and the D2-D3, domains of the large subunit ( LSU) of nuclear ribosomal DNA, were generated for both developmental stages and compared with available sequences of Austrodiplostomum spp. Phylogenetic analyses inferred with each molecular marker using maximum likelihood and Bayesian inference revealed the existence of 4 lineages representing 2 described species, A. mordax and Austrodiplostomum compactum (syn. Austrodiplostomum ostrowskiae) and 2 undescribed species of Austrodiplostomum recognized in previous studies. The COI haplotype network inferred with 172 sequences detected 28 haplotypes divided into 4 clusters, separating each other by 33 and 40 substitutions and with a genetic divergence ranging from 9 to 12%. The largest group included specimens identified as A. compactum plus those identified as A. ostrowskiae, supporting the synonymy of both species. As a result, we conclude that A. compactum is widely distributed across the Americas, in locations of the United States, Mexico, El Salvador, Honduras, Costa Rica, Venezuela, Peru, and Brazil. The other 2 undescribed species of the genus Austrodiplostomum were previously recorded in the United States and now are reported in Mexico. These 2 species cannot be described because adult forms have not been found in their definitive hosts. Finally, the species A. mordax has been found only in some lakes from Argentina, and it was validated in this study through molecular analyses.

Molecular characterization of Neoechinorhynchus cylindratus Van Cleave, 1913 (Acanthocephala: Neoechinorhynchidae), a parasite of the largemouth bass (Micropterus salmoides) in northern Mexico.

Members of the genus Neoechinorhynchus Stiles & Hassall, 1905 are endoparasites of freshwater fishes, brackish water fishes, and freshwater turtles distributed worldwide. In North America, 33 species have been described. One of the most widely distributed species in the eastern United States and Canada is Neoechinorhynchus (Neoechinorhynchus) cylindratus, a common acanthocephalan that infects centrarchid fishes. In the current study, adult specimens of N. (N) cylindratus were collected from largemouth bass (Micropterus salmoides) from the Purificación River in northern Mexico. In the same freshwater system, two additional congeneric species (Neoechinorhynchus (Neoechinorhynchus) emyditoides and Neoechinorhynchus (Neoechinorhynchus) panucensis) were collected and analysed. Sequences of the large subunit, internal transcribed spacers ITS1 and ITS2, 5.8S from nuclear DNA, and sequences of the cytochrome c oxidase subunit I (cox 1) from mitochondrial DNA were generated and aligned with other sequences obtained from GenBank. Maximum likelihood and Bayesian inference analyses inferred for each dataset showed that N. (N) panucensis, N. (N) emyditoides and N. (N) cylindratus were nested within several clades, indicating that these species do not share a common ancestor. Our phylogenies also revealed that the genus Neoechinorhynchus is paraphyletic, requiring further taxonomic revision using phylogenetic systematics and re-examination of morphological and ecological data. The presence of several N. (N) cylindratus adults in northern Mexico allowed us to typify this species for the first time using a combination of morphological and molecular characteristics. The current record shows a wide distribution range of N. (N) cylindratus across Canada, the United States and Mexico in the Nearctic region.

Redescription of three species of nematodes (Nematoda) parasitising fishes in the USA, with a key to the species of Dichelyne Jägerskiöld, 1902 parasitic in freshwater and brackish-water fishes of North America.

Three species of parasitic nematodes are redescribed based on light and scanning electron microscopical (SEM) examinations of newly collected specimens in fishes of South Carolina, USA: Dichelyne (Cucullanellus) bullocki Stromberg & Crites, 1972 from Fundulus heteroclitus (Linnaeus) (Fundulidae); Dichelyne (Dichelyne) diplocaecum Chandler, 1935 from Ictalurus furcatus (Valenciennes) (Ictaluridae); and Hysterothylacium pelagicum Deardorff & Overstreet, 1982 from Coryphaena hippurus Linnaeus (Coryphaenidae). For the first time, intraspecific variations in the number of intestinal caeca were observed in D. bullocki, as well as previously unknown males and gravid females of D. diplocaecum are described; this enabled to synonymise D. mexicanus Caspeta-Mandujano, Moravec & Salgado-Maldonado, 1999 with D. diplocaecum. Unlike most congeneric species, H. pelagicum has no double postanal papillae, as confirmed by SEM. A key to the species of Dichelyne Jägerskiöld, 1902 parasitic in freshwater and brackish-water fishes in North America is provided.

Development of a Gill Assay Library for Ecological Proteomics of Threespine Sticklebacks (Gasterosteus aculeatus)

A data-independent acquisition (DIA) assay library for quantitative analyses of proteome dynamics has been developed for gills of threespine sticklebacks (Gasterosteus aculeatus). A raw spectral library was generated by data-dependent acquisition (DDA) and annotation of tryptic peptides to MSMS spectra and protein database identifiers. The assay library was constructed from the raw spectral library by removal of low-quality, ambiguous, and low-signal peptides. Only unique proteins represented by at least two peptides are included in the assay library, which consists of 1506 proteins, 5074 peptides, 5104 precursors, and 25,322 transitions. This assay library was used with DIA data to identify biochemical differences in gill proteomes of four populations representing different eco- and morpho-types of threespine sticklebacks. The assay library revealed unique and reproducible proteome signatures. Warm-adapted, low-plated, brackish-water fish from Laguna de la Bocana del Rosario (Mexico) show elevated HSP47, extracellular matrix, and innate immunity proteins whereas several immunoglobulins, interferon-induced proteins, ubiquitins, proteolytic enzymes, and nucleic acid remodeling proteins are reduced. Fully-plated, brackish-water fish from Westchester Lagoon (Alaska) display elevated ion regulation, GTPase signaling, and contractile cytoskeleton proteins, altered abundances of many ribosomal, calcium signaling and immunity proteins, and depleted transcriptional regulators and metabolic enzymes. Low-plated freshwater fish from Lake Solano (California) have elevated inflammasomes and proteolytic proteins whereas several iron containing and ion regulatory proteins are reduced. Gills of fully-plated, marine fish from Bodega Harbor (California) have elevated oxidative metabolism enzymes and reduced transglutaminase 2, collagens, and clathrin heavy chains. These distinct proteome signatures represent targets for testing ecological and evolutionary influences on molecular mechanisms of gill function in threespine sticklebacks. Furthermore, the gill assay library represents a model for other tissues and paves the way for accurate and reproducible network analyses of environmental context-dependent proteome dynamics in complex organisms.

Multi-cluster analysis of Crabs and Ichthyofaunal Diversity in relation to habitat distribution at Tropical Mangrove ecosystem of the Indian Sundarbans

Mangroves have enormous ecological significance and socio-economic importance as promising hub for tropical marine and estuarine biotope. Therefore, mangroves are considered one of the world’s richest resources of biological and genetic diversity. Although, crabs and fishes significantly occur among the other macrofauna of the Sundarbans mangrove ecosystem, supportive information on resource and diversity of mangrove’s macrofauna are insufficient due to their non judicious exploitation in unscientific ways. Concerning that, the present survey based experimental research find out the localized endemic composition and bio-distribution of crabs and estuarine fish species which are prevalent in the tropical Sundarbans mangrove systems. A special drive has also been taken to characterize the variation of such species in course of spatial and environmental changing scenario. The consequences of this research concluded a total 115 numbers of crab species and 312 numbers of brackish and marine water fish species were available at Sundarbans. Which are identified, categorically assessed showing their predominant positions in the localized mangrove-associated estuary of 17 different specified clusters or survey areas. Apart from that, the Multivariate Cluster Analysis was performed on the available fish and crab diversity, up to the Family and Species level following their present conservation status.

Fish Scales as a Bioindicator of Potential Marine Pollutants and Carcinogens in Asian Sea Bass and Red Tilapia within the Coastal Waters of Pahang, Malaysia

Rahman, S.A.; Abdullah, N.A.; Chowdhury, A.J.K., and Yunus, K., 2018. Fish scales as a bioindicator of potential marine pollutants and carcinogens in Asian sea bass and red tilapia within the coastal waters of Pahang, Malaysia. In: Ashraf, M.A. and Chowdhury, A.J.K. (eds.), Coastal Ecosystem Responses to Human and Climatic Changes throughout Asia.Fish scales are inedible and hence thrown away as industrial waste, which is one of the major sources of pollution in the natural environment. The concept of a sustainable ecosystem, along with the growth of developing countries in the tropics, has made it essential to devise schemes to turn waste products into viable biotechnology materials. This study looked into potential biomaterial safety by investigating the levels of heavy metals and accumulation of potential carcinogens from the marine environment in scales of two brackish water fishes: red tilapia (Oreochromis niloticus) and Asian sea bass (Lates calcarifer). The closed acid digestion method was used to measure the levels of lead, zinc, copper, and cadmium using the inductively coupled plasma mass spectrometer. Mean concentrations obtained indicated that L. calcarifer scales contained higher levels of the heavy metals, and it was observed that essential metals accumulated at higher concentrations compared to nonessential heavy metals in both fishes. Significant relationships (p < 0.001) were found between fish type and heavy metal accumulation for all metals assessed except for lead. Nevertheless, the metal concentrations were still lower than the national and international standard maximum permissible limits for human consumption. Thus, it can be concluded that fish scale waste could be treated as wealth in biotechnological industries for the reduction of toxic materials from waste effluents.

Genome size estimation of brackishwater fishes and penaeid shrimps by flow cytometry.

Flow cytometry was used for estimating the genome size of five brackishwater finfish and four shrimp species. The genome size for Lutjanus argentimaculatus was 0.95 ± 0.10 and 0.79 ± 0.01pg for Scatophagus argus. The genome sizes for Chanos chanos (0.72 ± 0.01pg), Etroplus suratensis (1.71 ± 0.16pg) and Liza macrolepis (0.87 ± 0.02pg) which are important aquaculture species are reported for the first time in this study. The phylogenetic tree constructed using sixty-seven sequence accessions of cytochrome c oxidase subunit 1 (COI) gene of Lates calcarifer revealed two separate clades. The Indian Lates calcarifer species with estimated genome size of 0.44 ± 0.02pg belonged to a clade different than that of South East Asia and Australia reported to have larger genome size. The genome size for the four major species of genus Penaeus (Penaeus monodon, Penaeus indicus, Penaeus vannamei and Penaeus japonicus) were found in similar range. The genome size of female shrimps ranged from 2.91 ± 0.03pg (P. monodon) to 2.14 ± 0.02pg (P. japonicus). In male shrimps, the genome size ranged from 2.86 ± 0.06pg (P. monodon) to 2.19 ± 0.02pg (P. indicus). Significant difference was observed in the genome size between male and female shrimp of all species except in P. monodon. The highest relative difference of 12.78% was observed in the genome size between the either sex in P. indicus. The interspecific relative difference of 30.59% in genome size was highest between the male shrimps of P. monodon and P. indicus and 35.98% between the female shrimps of P. monodon and P. japonicus. The stored gills and pleopod tissues could be successfully used up to 3 weeks to estimate the genome size in shrimps.

Levels of Organochlorine Pesticides in Brackish Water Fish from Niger River, Nigeria.

Investigation of the levels of organochlorine pesticides (OCPs) in fish samples was carried out to assess the contamination status of Niger River. Ten different brackish water species of fish (6 samples for each, making a total of 60) were purchased from landing sites at the Delta area of Niger River. These were Drapane africana, Mochokus niloticus, Chrysichthys nigrodigitatus, Pristipoma jubelini, Vomer septapinis, Pseudotolithus senegalensis, Mugil cephalus, Pseudotolithus elongatus, Sphyraena piscatorum, and Lutjanus goreensis. OCPs were determined using standard methods. Certified reference standards from Accustandard USA were used for the instrument calibration and quantification of OCPs. Twenty OCPs, namely, α-HCH, β-HCH, γ-HCH, δ-HCH, endrin, endrin aldehyde, endrin ketone, heptachlor, heptachlor epoxide, aldrin, dieldrin, endosulfan I, endosulfan II, endosulfan sulfate, methoxychlor, α-chlordane, γ-chlordane, DDE, DDT, and DDT, were identified/quantified using Gas Chromatography (GC) (Hewlett Packard GC 5890 series 11 with electron capture detector). Confirmation was done using Shimadzu GCMS QP2010. The highest concentration of ∑OCPs in the brackish fish samples of the Niger River, 4302±2066 µg/kg fresh weight, with a range of 2237-6368 µg/kg, was detected in Drapane africana, while the lowest concentration, 2320±876.4, with a range of 1006-3288 µg/kg, was found in Mochokus niloticus. The concentration of total OCP compounds varied markedly amongst the different fish species. The guideline value of 2000 µg/kg fresh weight by WHO/FAO was exceeded and therefore implied potential harmful effects on humans. Since contamination of the fish samples was an indication of contamination of the river, the quality of the water for public water supply should be of concern; and therefore further monitoring is suggested.