International Journal of Aquatic Biology
Volume:10 Issue: 5, Oct 2022

Diatoms are highly diverse and versatile, with members growing under different environmental conditions including extreme environments. Although diatom communities in some extreme environments have been investigated recently, little is known about their community structure within the hot springs of soda lakes in Ethiopia. The study aimed to assess the diversity and distribution of diatoms from Lake Shala and inflowing hot springs in relation to physico-chemical variables. Water and diatom samples were collected from Lake Shala and three inflowing hotsprings. The mean pH, temperature, EC, salinity, TDS, DO, NO3 -+NO2 - , NH3+NH4 + , SRP, TP and SiO2 were significantly different among the stations. The significant variations in these factors could be attributed to their heterogeneous geological characteristic and the hydrology of the study area. A total of 45 diatom taxa were identified, with the highest species observed in Shala Hora Mid Hotspring sites (37) and the lowest in Shala Gike Hotspring (29). Diatom community structure was also examined and it was found that the diatom community of Lake Shala and inflowing hotsprings are highly influenced by environmental water conditions. Characteristic taxa including Anomoeoneis sphaerophora, Nitzschia spp., Rhomboids gibberula, R. gibba, R. acuminata, R. operculata, Navicula spp. and Frustulia rhomboids, showed a wide tolerance to pH, salinity, EC, TDS, temperature, nitrogen and phosphate. RDA analysis found a number of discriminating taxa and salinity, conductivity, pH, DO SRP and temperature were key factors that accounted for a significant variation in the diatom community structure.

The Crassostreine oyster Magallana gryphoides (Bivalvia: Ostreidae) has been recorded for the first time on the Kerala coasts from Dharmadomestuary, Kannur, Kerala, India. The report indicates the range extension of M. gryphoideson the South-west coast of India. The external morphological characters were phenotypic and insufficient for species identification as it resembles Magallana bilineata. However, internal shell characters gave important information, especially the adductor muscle scar. The accurate species determination was achieved from the mitochondrial COI and 16S gene sequencing, followed by molecular phylogenetic analysis. The native oyster M. bilineataand M. gryphoideswere found to co-exist in the same habitat sharing similar ecological conditions, sharing a sister group relationship.

The present study aimed to evaluate the effect of parasitism on the condition factor of Astyanax bimaculatus (Linnaeus 1758)(Characiformes, Characidae), in Batateirasriver, Salgado River basin, northeastern Brazil. A total of 242 host specimens were collected between August 2018 and February 2020. The host presented a community of metazoan parasites of 14 taxa, totaling 1,750 specimens collected, with a mean total abundance of 7.23 specimens per fish, being the class Monogenea, the most predominant taxonomic group. The relative condition factor (Kn) differed significantly between parasitized and non-parasitized individuals, in which the parasitized hosts presented higher values of Kn. The abundance of the monogeneans Characithecium costaricensisand Diaphorocleidussp. showed positive and significant correlations with the Kn. Considering the sex of the host, males had a higher parasite burden than females, although females present higher values of Kn. The parasitic burden of hosts did not show significant differences between seasonal periods

Saprolegniaspp. infect common carp(Cyprinus carpio L.)eggs in hatcheries. Therefore, this study aimed to evaluate the antifungal effect of biosynthesized zinc oxide nanoparticles (ZnNPs) against Saprolegniaspp. as an eco-friendly treatment. Biosynthesized ZnNPs were characterized using atomic force microscope (AFM), size distributor and Ultra Violate-Visible spectrometer (Uv-Vis), and Scanning Electron Microscope (SEM). Biosynthesized (ZnNPs) had a spherical shape with diameters ranging 10-70 nm. Antifungal activity was tested by fungal radial growth inhibition on corn meal agar. The highest concentration of 100 ppm of ZnNPs showed a remarkable inhibition rate of 79% against Saprolegnia spp., demonstrating similar efficiency as the positive control i.e. malachite green in the inhibitionpercentage rate of fungal growth. This study showed that biosynthesized zinc oxide nanoparticles had a significant antifungal effect (P<0.05) and can be used as an alternative option to control Saprolegniaspp. in fish hatcheries.

The present note reports for the first time the finding of two species of marine Heterobranchia within a ghost net. The stretch of the net was repeatedly wrapped in itself and formed a large tangle of spherical shape. This created several "layers" of meshes wrapped in each other, where the following species of marine heterobranchs were found: Aplysia depilansand Umbraculum umbraculum. In particular, of the former, an alive specimen was foundtied to the wire of the net, and a dead specimenfloating within the ghost net. Of the second species, only the shell was found

This study aims to evaluate the effect of nano titanium dioxide and microplastics, alone and in combination, on immune system function and oxidative stress of juvenile Nile tilapia, Oreochromis niloticus.For this purpose, fish were randomly divided into 27 100L tanks using a 3×3 factorial design, including three concentrations of Nano titanium dioxide (0, 1, and 5 mg/l) and three concentrations of microplastic (0, 0.5, and 1 mg/l) separately and together each in triplicate. The results showed that immunoglobulin, malondialdehyde(MDA), and glutathione reductase (GR) had significant effects in all groups (P<0.05). Lysozyme, total antioxidant capacity (TAC), and glutathione peroxidase (GPx) showed significant differences between the combined groups and the control (P<0.05). No significant differences were observed in C3 and C4 between groups exposed to MPs and Nano-TiO2 and the control (P>0.05). Superoxide dismutase (SOD) showed significant differences between the group exposed to MPs and Nano-TiO2 alone and the control group (P<0.05). In conclusion, the results showed that MPs could have a synergistic effect on the toxicity of Nano-TiO2.

The herbextract ofBroccoli,Brassica oleraceawas used to feed common carp(19.75±0.057 g) at four incremental levels of 0, 1, 2, and 3% of the diet for 56days. Fish were fed twice a day at a rate of 3% diets containing 32.7-33.7% crude protein and digestible energy (16.037-16.595Mj/Kg). At the end of the study, the groups fed 2% broccoli extract were significantly better in weight gain (3.36±0.16 g), relative growth rate (17.02±0.77%), specific growth rate (0.30±0.01% day), food conversion ratio (7.74±0.39) and food conversion efficiency (12.93±0.65%). In terms of hematological parameters, albumin showed significant enhancements in 1, 2, and 3% broccoli extract (P≤0.05). However,globulinlevels were not affected by broccoli extract inclusion (P≥0.05). Total protein and A/G ratio showed significant enhancements in the 2% broccoli extract group (P≤0.05). According to the findings, using 2% broccoliextract was the best option for growth and blood profile in common carp rearing. Therefore, the present study recommends adding 2% of broccoli extract to improve nutrient efficiency, growth performance, and hematological parameters in C. carpiofingerlings.

This study aims to assess the pollution of Shatt AL-Arab River using histology and some other biochemical parameters of gill in Nile tilapia (Oreochromis niloticus) caught in winter 2021 at four locations as water pollution biomarkers.Some water quality parameters were determined in these sites, and the results showed that sites 2 and 3 are polluted at levels above the World Health Organization's guideline. The enzymatic and metabolism activity, histological status, and cytogenetic mutation over time in the gills were assessed. Biotransformation enzymes level showed total cytochrome p450 and Ethoxyresurofin–O–demethylase (EROD) activities are significantly increased in gills of tilapia in site 1, 2 and 3. The antioxidant enzymes activities were recorded significantly high in fish gills of catalase (CAT) and glutathione -S-transferase (GST) in polluted sites of 1, 2, and 3, while superoxide dismutase (SOD) were significantly higher only in site 3 compare with reference site of 4. The metallothionein-like protein (MTLP) was significantly higher in gills at site 3. Also, lipid peroxidation (LOP) and micronucleus analysis showed that sites 2 and 3 samples site the most affected. Gill tissue index was appeared severe alterations levels at sites 2 and 3, followed by site 1 with a relatively lower level of damage, while site 4 (reference one) showed minor or invisible changes in gill tissue. The histological alterations in the gills of Nile tilapia fish at sites 2 and 3 showed atrophy of cellular, hemorrhage, congestions, hyperplasia, and hypertrophy of the filament lamellae epithelium.

The study on the antibacterial activity of fruit, peel, stem, and core of the pineapple, Ananas comosuscrude extract against Aeromonas hydrophilaand the effect of supplementing the diet with pineapple waste crude extract on growth performance and resistance against A. hydrophila in Nile tilapia, Oreochromis niloticuswere conducted. The best result of antibacterial screening was performed by disc method and the minimum inhibitory concentration was found in pineapple fruit extract with an inhibition zone of 7.96±0.20 mmand the minimum inhibitory concentration value was 125 mm per liter. The minimum bactericidal concentrationvalue was not observed in all parts of the pineapple extract at any concentration.Furthermore, Nile tilapia (2.34±0.82 g) werestocked in 12 aquariaand fed a diet supplementedwith 4different doses of pineapple peel extract(0, 1, 2and 3%)for 8weeks.The results revealed that thebest value of weight gain, average dailyweight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and feed utilization efficiencywas observed in fish fed 1% pineapple peel extract andadditionally, the mortality of fish challenged by Aeromonashydrophilawas recorded for 10 days after the challenge. The result showed that fish-fed diet containing 1% pineapple peel extract had significantly the lowest mortality and the highest relative survival percentage.

The present study was conducted to evaluate the fish community and diversity status in the Euphrates River between Medina and Qurna cities, northwest of Basrah Province, Iraq. In addition, the relationship between some environmental parameters, including water temperature, dissolved oxygen, salinity, pH, and turbidity, and fish abundance were investigated by sampling from November 2020 to October 2021.Based on the results, there were no significant differences (P>0.05) in the environmental factors between the two studied sites except for salinity and turbidity.During the study, a total of 7387 fishes were collected belonging to 12 families, 21 genera, and 22 species. The Cyprinidae was dominated by seven species, followed by the Luciscidac with three species, the Cichlidae and Mugilidae families with two each, and the rest with one species each. There were ten natives, eight exotics, and four marine fish species.Planiliza abuc wasdominat species with 26.11 % of the total catch. Significant differences (P<0.05) were found in species richness and number of the collected individuals between two sites. Based on the results, fish species can be classified into three groups based on their distribution; common species with nine species, accounting for 98,66%; seasonal species with four species accounting for 0.798% and rare species, with nine species accounting 0.541% of total richness. Three species of P. abu, Coptodon zillii andCarassius auratuswere dominant species with 63.110% of the total catch.