Iranian Journal of Fisheries Sciences
Volume:22 Issue: 2, Mar 2023

In this study, the effect of glazing with Arthrospira (Spirulina) platensis extract (SPE) were evaluated on the quality characteristics of Fenneropenaeus (Penaeus) indicus at frozen temperature. Three different concentrations of SPE (0.3, 1.0, and 1.3%) were used and compared with water glazing (WG) and unglazing conditions (UG). Shrimp quality was measured by pH, peroxide value (PV), total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), textural properties (hardness and cohesiveness), and sensory characteristics for five months of frozen storage. Results illustrated that the glazing treatment reduced the quality loss of shrimp in the course of frozen storage, compared to the unglazed control sample. Variation range of pH, PV, TVB-N, and TBA after 150 days increased to 7.68–7.79, 2.70–2.74 meq per kg O2 lipid, 28.12–30.08 mg/100g, 2.53–2.88 mg per kg MDA, respectively. The values of cohesiveness, hardness and sensory of all groups decreased after 150 days. As regards the glazed samples, those treated with SPE showed lower TVB-N, PV, TBA, and higher textural and sensory properties. However, further research is necessary to optimize the use of SPE in the glazing system.

Noctiluca is a dinoflagellate genus that causes algal bloom and is distributed in the tropical coastal waters of the Pacific and the Indian Oceans. The blooming of the species on the southeastern coast of Iran (the north part of the Oman Sea) is usually green and happens in the cold seasons. A dense harmful bloom of Noctiluca scintillans was reported in February and March 2020 along the coastal waters of Chabahar Bay (Iran) on a significant scale. Sampling was carried out from three stations located in the bloom areas. This study aimed to evaluate the distribution of the bloom in Chabahar Bay using field data and remote sensing, as well as examining N. scintillans cells and identifying the species that were present in the bloom area. The results of microscopic counting revealed a high density of N. scintillans. The bloom duration was about 22 days; with a density of 2.37 × 105 cells L-1. Apart from N. scintillans, 20 species of phytoplankton including 10 species of dinoflagellates, 9 species of diatoms, and 1 other phytoplankton species were identified. The bloom caused the mortality of marine organisms including jellyfish, crabs, and green sea turtles. Although N. scintillans is classified as a non-toxic species, it can lead to the mortality of marine organisms such as fish and invertebrates by causing severe hypoxia and ammonia release.

Regarding to the roles of prebiotics and probiotics in feeding the aquatic animals, the aim of this study was to evaluate the effects of Pediococcus acidilactici, Mannan-oligosaccharide prebiotic and Beta-glucan on hematologic and immunologic parameters of the trout. 720 healthy rainbow trout were divided into four groups as the control group and groups treating with prebiotics, probiotics and both. After the treatment, immunologic, hematologic, growth-nutritional parameters were measured with various stressors indicating the positive effects of simultaneous probiotic and prebiotic treatment on all above-mentioned parameters and stress prevention in the trout.

This study aimed to evaluate the effects of Coronavirus disease (COVID-19) on different parts of the shrimp industry in Bushehr Province in Iran. This disease has threatened both human health and many industries around the world. Data were collected via an online web-based questionnaire about each of the effective indicators in shrimp hatcheries, farms, and processing centers. The data were categorized into five categories: without effect, low effect, medium effect, effective, and high effect. The results showed that the greatest effect of COVID-19 on shrimp hatchery centers was related to a section of services such as supplying air tickets for foreign experts and delays in importing larval feed and equipment into the country, which led to a decrease in shrimp larval production in the early period. In farms, despite the lack of post-larvae at the beginning of the rearing period, the most significant effect of COVID-19 on this section was the delay in investment return due to the lack of crop sales. The most important factors influencing the processing sector were an increase in the costs and prevention of packaging contamination with Coronavirus, non-sale of products, and a decrease in shrimp prices. As a result of an increase in infection among shrimp industry activists, contamination of shrimp packages with Coronavirus, a loss of customers on the global market, and a decrease in foreign exchange income, the shrimp industry may face bankruptcy if COVID-19 is not controlled in the country. To prevent bankruptcy in the industry, the governmental authorities must take protective actions after the public has been vaccinated.

Mangrove ecosystems all around the globe are affected by microplastic (MPs) pollution. The Sundarban Biosphere reserve, the world’s largest mangrove forest is not an exception. The study aims to identify the occurrence of MPs in the gastro-intestinal tract (GI tract) of estuarine fish from Indian Sundarbans and the relationship between the presence of MPs with the morphology and feeding niche of fish. Total of 13 fish species were collected from the Saptamukhi River near Lothian Island, India and MPs were isolated from GI tract contents. Morphological parameters like body size, mouth aperture length, eyeball diameter and GI tract length of fish were measured. Niche breadths and niche overlapping of these 13 species were analyzed using Levin niche breadth and Pianka niche-overlap indices. The fiber-shaped MPs were ubiquitously detected in all fish species followed by films and fragments. The size of MPs was ranged from 100µm to <5mm. A significant variation (p<0.0001) in respect of the trophic morphology of fish and length of MPs (p<0.05) were found. The length of MPs had a positive correlation with body size and mouth aperture but in the case of GI tract length and eyeball diameter, the correlation was negative. It was noticed that the presences of MPs in GI tract of those 13 estuarine fish species did not bother their niche breadth and niche overlap.

The present study aimed to investigate the effect of salinity and ammonia interactions on oxidative stress response in the liver of Nile tilapia (Oreochromis niloticus). Nile tilapia were exposed to different ammonia and salinity concentrations including C (control group without ammonia and salinity), T1 (50% 96 h LC50 of ammonia and 1 ppt salinity level), T2 (50% 96 h LC50 of ammonia and 4 ppt salinity level), T3 (30% 96 h LC50 of ammonia and 1 ppt salinity level), and T4 (30% 96 h LC50 of ammonia and 4 ppt salinity level) for 96 h). Results showed significant increase for activities of superoxide dismutase (SOD), malondialdehyde (MDA), isocitrate dehydrogenase (ICDH), and malic enzyme (ME) in T1 and T2 groups compared to the control (p<0.05). As well, catalase (CAT) activity in accompany with reduced glutathione (GSH), and reduced/oxidized glutathione ratio (GSH/GSSG) showed remarkable reduction in T1 and T2groups Compared to the control (p<0.05).  In T3 and T4 groups, only MDA content showed a significant decrease compared to the control (p<0.05). There were no differences in other parameters. In summary, results of this study showed that 96h exposure to 30% LC50 of ammonia plus 4 ppt saline increase antioxidant defense in Nile tilapia.

This study analyzed the stomach contents of Chub mackerel, Scomber japonicus, collected from purse seine and set net fisheries samples in the South Sea of Korea in March 2020 to February 2022 for juvenile, mature, and older fish, which are useful to identify ecosystem functions and study food competition, interspecific feeding relationships, and the food web. The size of S. japonicus samples ranged from 5.5 to 46.6 cm in fork length. S. japonicus were a carnivore that feed mainly on euphausiids and pisces. The estimated average trophic level of S. japonicus ranged from 3.65±0.64 to 4.00±0.78. Examination of the feeding habits according to ontogenic feeding patterns of S. japonicus revealed that the mean weight of prey (mW/ST) continuously increased. There were differences in the composition of the stomach contents of S. japonicus by the sampling period and size class, and also the interaction between them. S. japonicus were specialized feeders with pisces and euphausiids as their dominant prey.

Cytological parameters including whole sets of chromosomes, known as karyology, has become increasingly prevalent in resolving taxonomic issues for uncertain species. This study focuses on the karyological analysis of haploid and diploid chromosomes in two amphibious fish species, Periophthalmus waltoni and Boleophthalmus dussumieri which inhabit muddy beaches of the Persian Gulf. This survey is the first to report on the chromosome number of P. waltoni. To achieve this task, 10 male and 10 female specimens were collected from the beaches of Musa estuary, Persian Gulf, Iran. Mitotic chromosomes and haploid chromosomes were obtained from branchial and testicular tissue samples in males, respectively. The chromosomes were stained using the traditional Giemsa staining technique. The diploid chromosome number for P. waltoni was determined to be 2n=44 in both males and females, with a fundamental number (NF) of 82, whereas the numbers for B. dussumieri were 46 and 82. The karyotype of P. waltoni consisted of 14 large metacentrics, four large sub-metacentric, eight large sub-telocentric, four medium metacentric, six medium sub-metacentric, two medium telocentric, two small sub-telocentric, and four small telocentric chromosomes. In contrast, the karyotype of B. dussumieri comprised 18 large metacentrics, eight large sub-metacentric, two large telocentric, eight medium metacentric, two medium sub-metacentric, two medium telocentric chromosomes, and four microchromosomes. No sex chromosomes were identified in either species. Notably, the results revealed that the chromosome count and morphology differed among the species within the same genus, and the use of the Ag-NOR banding technique accentuated these differences.

The genetic population structure of  Capoeta aculeata from the Zagros Basin including three rivers (Beshar, Khersan, and Maroun) was investigated using the partial mitochondrial DNA (mtDNA) control region (D-loop) sequences (n=90) and eight microsatellite markers (n = 120). To address this issue, genetic structure differences between the three populations were evaluated by haplotype diversity and pairwise comparison based on allelic distribution. Both methods used were concordant in that they showed low to moderate levels of genetic variation and suggested that C. aculeata populations were partly diversified. For the mtDNA method, the average haplotype diversity (h) and nucleotide diversity (π) were 0.846±0.027 and 0.0037±0.005, respectively. For the microsatellite markers approach, the average number of alleles per locus ranged from 4 to 14, while the average observed heterozygosity (Ho) at various loci varied between 0.212 and 0.579. The Hardy-Weinberg test showed that the microsatellite loci deviated significantly in the populations indicating a deficit of heterozygotes. Besides, the results of pairwise FST estimated and analyzed molecular variance (AMOVA) alongside neighbor-joining and structure analyses showed that most of the variations occurred between samples and finally significant genetic differentiation between populations for both mtDNA and microsatellite markers. At least two genetically distinct management units were observed using the two methods among the sampling sites. The non-significant differentiation between C. aculeata samples from the Khersan and Beshar rivers can be explained by a relatively recent disconnection of these two populations and/or small amounts of contemporary gene flow between the two gene pools. The analyses of both mtDNA and microsatellite markers provided potential markers for identifying probable populations and characterizing the conservation genetics of C. aculeata.

Developing aqua/ animal feeds from underutilized fish and agricultural by-products using hydrolyzed technology is an excellent way to provide proteins for aquaculture/ animal farming. This study reports development of a new protein feed supplement, based on fish protein hydrolysate and agricultural residues, on a pilot scale and investigates physicochemical properties, microbial quality, and shelf-stability of the product. The production conditions were based on lab-scale experiences. Accordingly, fish protein hydrolyzed solution containing 16.58% crude protein, 63.35% moisture, and 15.52% fat was mixed with agricultural by-products, i.e. sesame meal, rice bran, and soybean meal as fillers (60:40 w/w) and dried at 40°C for 6 h. The dried mixture was grounded after cooling, then packed in sealed plastic bags, and stored for 180 days at ambient temperature. The protein feed supplement contained 58.23% crude protein, 16.18% fat, 8.85% moisture, 9.10% ash, 2.6% fiber, 1.489% calcium, 0.89% phosphorous, and 5.34% carbohydrates of dry weight. Total essential and non-essential amino acids were 19.41g/ 100g and 20.36 g/ 100g of dry weight respectively. The protein feed supplement contained significant essential fatty acids. Levels of pH and TVB-N of the protein feed supplement increased to 5.30 and 65.20 mg/100g at the end of the study. After 180 days, there were no yeast and mold in the samples and it was still pathogen-free.

The present study aimed to investigate the effect of seasonal variations in physicochemical parameters of seawater including temperature, pH, dissolved oxygen, electrical conductivity, total suspended solids, total nitrogen, and total phosphate, on the antioxidant capacity of the green, brown, and red algae from the northern coasts of the Persian Gulf. The algal collection involved 34 samples (18, 9, and 7 green, brown, and red macroalgae, respectively) from 4 different months of the year 2016 (March, May, October, and December). Antioxidant activity was evaluated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay. Total phenolic and flavonoid contents were determined using the Folin-Ciocalteu’s reagent and the colorimetric method, respectively. Water sampling was performed at two-day intervals on days 6, 4, and 2 before algal sampling. Results revealed that the highest phenolic content and antioxidant capacity were observed in October for the sampled brown algae, whereas for red algae the highest antioxidant capacity was obtained in December. Higher levels of flavonoids were noticed in the green algae in October. In both green and red algae, there was a negative significant correlation between IC50 and flavonoids, whereas in the brown algae a negative significant correlation was observed between IC50 and phenolic content. In a multivariate regression model, the main and interaction effects of each variable were examined. The antioxidant parameters were influenced by temperature, dissolved oxygen, and total nitrogen. pH at different levels of algal groups showed different effects on IC50, phenolic, and flavonoid contents.

In this research, spiral babylon (Babylonia spirata L.) specimens were collected by special circular traps from different depths up to 60 m based on the snail distribution from September 2021 to May 2022. The snails were sampled monthly and transferred to the laboratory after counting and washing. The examination of stomach contents showed that this snail species had a scavenger diet and mostly fed on animal corpses including oysters, clams, squids, and shrimps, as well as fish such as Leiognathidae. The length at sexual maturity for females and males were 31.1 and 32.5 mm, respectively. B. spirata had a reproductive potential in all seasons and therefore, this is a gonochronic species with internal fertilization. The females had two spawning peaks with the weakest in autumn and the strongest in winter. Also, the main spawning season for this species was estimated from November to March 2022. At the breeding season, the majority of the stomachs were empty with poor feeding.

Leech is an important aquatic animal parasite that poses a great threat to the aquaculture industry. However, leech (Whitmania pigra) is an important traditional Chinese medicine and has been widely used to treat cardiovascular or other chronic diseases. Although there has been a growing interest in W. pigra rearing in the South and East of China, the technology of artificial breeding of W. pigra during overwintering is still imperfect. In this study, various soil water contents (30%, 40%, 50%, 60%, and 70%) were tested on W. pigra during a 104-day overwintering period, and their physiological responses were evaluated. During the trial period, the survival rate of W. pigra varied under different soil water contents and the highest and lowest survival rates were 86.67±5.77 and 23.33±11.55 % at the soil water content of 50 and 70%, respectively. The weight-loss rate of W. pigra decreased when the soil water content increased. The activities of antioxidant enzymes, superoxide dismutase and catalase of the leech at 50% soil water content were lower than those in other groups, however, the highest activities of the immune enzyme, alkaline phosphatase, and lysozyme were obtained in the five groups. These results suggest that soil water content is a key environmental factor that affects W. pigra during overwintering and 50% soil water content is the optimal level for W. pigra during the overwintering period.

Molecular adaptation of mudskippers to land living is undoubtedly a complex multifactorial phenomenon, and the skin is one of the most influential factors. This study explores the behavior of collagen type-I (CT1) from the structural and functional point of view using an in-silico approach and discusses its possible role in the adaptation to aerial respiration. The approach was started by finding the CT1 triple helix gene and protein of Boleophthalmus pectinirostris, Periophthalmus magnuspinnatus, and Danio rerio (as the reference sample), followed by homology modeling and 100 ns molecular dynamics simulation. Subsequently, the trajectories were analyzed for RMSD, RMSF, Rg, H-bond, and SASA. The results all together showed that the flexibility of the CT1 of Danio rerio is considerably greater than Boleophthalmus, and the latter is more flexible than Periophthalmus. This difference in flexibility is also evident in the morphology of their skin since Zebrafish's skin is more elastic than the two mudskippers. The skin of Boleophthalmus is as well slightly softer than Periophthalmus. Our findings demonstrate that the more terrestrial species have the less flexible CT1 in the skin that saves them from desiccation. However, the skin structure of mudskippers makes a balance between the capability of respiration and saving them from desiccation. The results reveal one of the phenotypic adaptations of mudskippers for living on land, which is congruent with the morphological and physiological distinctive features.

The effect of different concentrations of Ocimum basilicum extract supplement on growth and survival of Western white leg shrimp (Litopenaeus vannamei), juveniles was investigated. Shrimps were separated into four experimental groups of 0 (Controls), 60, 120 and 240 ppm extracts of O. basilicum. The photoperiod was regulated to a 12:12 dark/light cycle and molts, feces and dead shrimps were daily removed and 30% of water in each tank was exchanged by new sea water. Biometry was done once a week. Extract supplemented diet did not have any significant effect on weight gain (%), final weight (g), growth performance, feed utilization and body composition of L. vannamei when compared to shrimp in the control diet. It was also observed that the shrimp fed the diet containing 120 ppm O. basilicum extract obtained the highest weight gain (%) 6.23 ± 0.12% and the lowest rate (5.7 ± 0.1%) was for 240 ppm extract. In conclusion, dietary O. basilicum extract supplementation had no significant effects on the growth performance, survival rate, feed utilization and carcass composition of Western white leg shrimp juveniles. The positive results obtained encourage conducting further research on the administration of O. basilicum extract on Western white leg shrimp or other economically important species but with longer duration of culture period.