Mugil Cephalus Research Articles

Ecosystem and Commercializing of Fish in a Rich-Minerals, Low-Salinity Closed Lake

Wadi El Natrun is an elongated narrow depression in the Western Desert of Egypt. The depression characterized by many ancient alkaline salt lakes. These lakes are filled with water in winter and dried up in summer. Recently, some lakes become permanently dried, while others become submerged throughout the year as El Bieda Lake. El Bieda Lake has undergone ecological changes due to the prolonged extraction of minerals and the continual discharging of freshwater. This study investigates the recent biotic and abiotic changes of this lake and discusses its fisheries opportunities. The lake’s water is well-oxygenated, rich with different inorganic nutrients, and characterized by a low salinity. Sodium and chloride ion concentrations are lower than the equivalent surface seawater, while magnesium, calcium, potassium, sulfate, and bicarbonate ions are higher. The lake has low plankton species richness with high biomass and high nutritional values. More recently, two cichlid species, Oreochromis aureus and Coptodon zillii, have colonized the lake. Summer characterized by a very low mortality for Oreochromis aureus and a poor representation of Coptodon zillii. However, both species shared the catch the rest of the year. The high biomass and nutritional quality of plankton communities, as well as the dense phytobenthic film, indicate that the lake is currently below its carrying capacity. The well-oxygenated water, high biomass of plankton and phytobenthic diatoms, and the expected changes in salinity suggest that introducing the euryhaline, commercially valuable, and fast-growing Mugil cephalus or Chelon ramada in El Bieda Lake is highly advisable.

Comparison of physical properties and fishing performance between biodegradable PLA and conventional PA trammel nets in grey mullet (Mugil cephalus) and red-lip mullet (Liza haematocheila) fishery

Marine plastic pollution and continuous capture of marine animals, so-called “ghost fishing”, by abandoned, lost, or otherwise discarded fishing gear (ALDFG) are global concerns. This study investigated whether biodegradable polylactic acid (PLA) monofilaments can be used to replace conventionally used non-biodegradable polyamide (PA) in trammel net fishery for limiting ALDFG associated effects. It evaluated the physical properties of PLA and PA monofilaments and compared fishing performance of PLA and PA trammel nets in a commercial mullet fishery in the Yellow Sea, China. Although PA monofilament exhibited superior physical properties, no significant differences in catch efficiency between PA and PLA trammel nets were observed. Fish of both species were mainly captured by pocketing which can further explain observed similar catch efficiency. These initial results suggest a potential for applying biodegradable materials in trammel net fisheries. Therefore, further long-term testing is encouraged to investigate whether this promising performance is persistent over long-term.

Intestinal Enzyme Activity and Enzyme Producing Microbial Flora in Relation to Feeding Behaviour in Some Brackishwater Teleosts

Estimation of digestive enzyme activity, isolation and enumeration of aerobic microbial flora from the gastrointestinal tract of five brackishwater fish species (Mugil cephalus, Liza macrolepis, Mugil Lade, Chanos chanos, Lates calcarifer and Oreochromis mossambicus) of different feeding habits were carried out. The herbivorous (M. cephalus, C. chanos, M. Lade and L. macrolepis) and omnivorous (0. mossambicus) showed marked protease activity, whereas moderate protease activity was recorded in carnivorous L. calcarifer. In the herbivorous and omnivorous fish species the concentration of amylase was moderate to high. A very weak amylase activity was recorded in L. calcarifer. Cellulase activity has been found to be more pronounced in C. chanos, whereas, 0. mossambicus, M. cephalus, M. fade and L. macrolepis showed only moderate cellulase activity. Cellulase activity was weak in L. calcarzfer. Proteolytic, amylolytic, lipolytic and cellulolytic microflora were identified from the culture plates using selective media. The isolates were qualitatively screened on the basis of their extracellular enzyme producing ability. The selected isolates were further quantitatively assayed for protease, amylase and cellulase activities. Proteolytic activity was high in 0. mossambicus, whereas the activity of amylase and cellulase was high in the gastrointestinal tract of C. chanos. Protease activity was exhibited by almost all the bacterial isolates. Maximum activity of protease was exhibited by an isolate from L. macrolepis, followed by an isolate from L. calcartfer. Isolates isolated from 0. mossambicus and C. chanos exhibited high cellulase and amylase activity. Study indicated a distinct microbial source of the digestive enzymes (protease, amylase and cellulase) apart from endogenous sources in fish gut.

Intestinal microbiota of the four omnivorous fishes revealed by 16S rRNA metabarcoding from the habitats of oyster reefs

The habitats of oyster reefs had played various ecological services functions, as an important means of marine ecological restoration and fishery resources conservation, which had been widely used worldwide. And the characteristics of microbial communities would be inevitably affected by habitat of oyster reefs. The aim of this study was to reveal the relationship between oyster reefs and the intestinal microbiota of fish (Takifugu ocellatus, Acanthopagrus latus, Clupanodon thrissa, and Mugil cephalus). Here, based on 16S rRNA sequencing, this research analyzed the microbial communities of fishes gut in the oyster reefs from the most crucial estuary economic zone in Southern China. It was significantly lower that the bacterial alpha-diversity in the fish intestines than in the sediments of oyster reefs. The non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) results showed that intestines microbiota of T. ocellatus and A. latus were more homologous to sediments microbiota, but intestines microbiota of C. thrissa and M. cephalus were more similar to the water microbiota. There were obvious differences in the contribution of oyster reefs habitat to intestinal microorganisms of four fishes. Source tracking analysis as well reached the similar conclusion. For instance, contribution of water to T. ocellatus and A. latus was lesser than sediments, which was related to their benthic habits. Based on the differences in microbial community compositions, the functional prediction analysis had demonstrated that special functional pathways and independent core indicators had been formed separately from oyster reefs and fish intestines. Overall, these findings highlighted the characteristics of microbial diversity and functions from the omnivorous fish living in oyster reefs habitats. This research proposed new insights into the function of oyster reefs habitats, which have enriched the ecological service value of oyster reefs from microbial ecology and provided a reference for the application of oyster reefs habitats in other estuaries.

Drug residue profiles of Cefquinome in the mullet (Mugil cephalus) in saltwater at 24 °C.

Drug residue profiles of Cefquinome in the mullet (Mugil cephalus) in saltwater at 24 °C.

The Presence of Microplastics and Plasticizers in Different Tissues of Mullet (Mugil cephalus) Along the East Java Coast in Indonesia

The Presence of Microplastics and Plasticizers in Different Tissues of Mullet (Mugil cephalus) Along the East Java Coast in Indonesia

Organoleptic evaluation of wet-salted marine fishes Mugil cephalus, Chanos chanos and Gerres oyena from Port Sudan coast

Organoleptic evaluation of wet-salted marine fishes Mugil cephalus, Chanos chanos and Gerres oyena from Port Sudan coast

Fishery-based adaption to climate change: the case of migratory species flathead grey mullet (Mugil cephalus L.) in Taiwan Strait, Northwestern Pacific.

The flathead gray mullet (Mugil cephalus L.) is a cosmopolitan fish that lives in warm and temperate zones over 42°N-42°S. It is a key fish species for industrial fishing off coastal Taiwan. Gray mullets enter the coastal waters of the southeastern Taiwan Strait (22°N-25°N) to spawn in winter and feed in the coastal and tidal waters of China (25°N-30°N). From 1986 to 2010, the annual catch of gray mullet decreased substantially and remained low. Although the Pacific Decadal Oscillation and El Niño-Southern Oscillation are recognized to affect gray mullet migration, the increase in sea surface temperature may be the main cause of the aforementioned decrease. We explored how weather changes affect fishing conditions and patterns at the gray mullet fishing grounds in Taiwan's coastal areas. Because of the decrease in gray mullet catches, the most common method for catching gray mullet in Taiwan's coastal areas between 1990 and 2010 was the use of drift or trawl nets instead of two-boat purse-seiner fleets. Since 2012, purse-seiner fleets have become the most common method for catching gray mullet. This trend indicates that the local fishing industry is adapting to changing environmental conditions.

Flathead grey mullet (Mugil cephalus) juveniles exhibit consistent proactive and reactive stress coping styles

Stress coping styles (SCS) are defined as a coherent set of individual physiological and behavioural differences in stress responses that are consistent across context and over time. Nowadays, an increased attention has been paid to fish welfare in aquaculture production and to consistent behavioural response to stress in captivity, since these aspects present direct implications on fish health, quality and farming productivity. Therefore, the present study aimed to evaluate the differences between proactive and reactive stress coping styles and their consistency over time and across contexts in flathead grey mullet Mugil cephalus juveniles reared in captivity. Fish were submitted to two runs of a set of behavioural tests, with a four-months interval: one group test (risk-taking test) and three individual tests (restraining, predator and confinement tests), followed by the quantification of blood cortisol and glucose concentrations (control and post-stress). Results confirmed the existence of proactive and reactive SCS in mullet juveniles and demostrated that behavioural responses in most of the tests were consistent over time (between runs) and across contexts (among tests). Fish that crossed from the safe to the risky area in the risk-taking test also displayed higher activity and escape attempts and lower basal levels of cortisol and glucose than fish than did not cross. This work reported for the first time the consistency of stress coping styles over time and across contexts in M. cephalus juveniles. Due to the increased interest in understanding adaptive mechanisms underlying consistent individual behaviours in response to stressful situations, are of interest for the aquaculture industry to improve productive performance of this fish species. Further studies are required to investigate how different selective pressures might influence the expression and consistency of SCS over time and across contexts.

Identification of potential breeding ground of flathead grey mullet, Mugil cephalus (Linnaeus, 1758), along the Mumbai coast, India, for ecological monitoring and conservation strategies.

Identifying the breeding grounds of fishes is crucial for the sustainable management of fisheries resources. The present study is aimed at identifying the potential breeding ground of Mugil cephalus along the estuary of the North Mumbai coast. A total of 1197 specimens of M. cephalus, including 546 eggs, 271 larvae, 235 juveniles, and 235 adults, were collected from four sampling stations in the Karanja estuary between January to October 2022. Water quality parameters, plankton dynamics in the estuary, and the reproductive and feeding biology of M. cephalus were also examined. The eggs, larvae, juveniles, and adults were identified using traditional morpho-meristic and DNA barcoding techniques. The results revealed a potential spawning ground of M. cephalus in the Karanja estuary. The results of reproductive biology also confirmed the occurrence of matured fishes during May-July. The abundance of eggs and larvae at the estuary's mouth and the presence of juveniles and mature individuals of M. cephalus dominantly in the Karanja estuary from May to July infer the presence of a spawning site. It is also recorded that M. cephalus spawn in higher salinity (35 ppt) and seawater temperature (33 °C) where the hatching of offspring takes place successfully. This study emphasizes the significance of DNA barcoding in guiding routine monitoring surveys and demonstrates its usefulness when combined with these techniques in identifying fish spawning grounds. The study findings will serve as baseline information to develop effective conservation and management strategies and protect the ideal spawning stock.

Applying Biofloc Technology in the Culture of Mugil cephalus in Subtropical Conditions: Effects on Water Quality and Growth Parameters

Mugil cephalus is an estuarine species that has been shown to acclimate to a diversity of environmental conditions being a good candidate to diversify aquaculture. The objective of this study was to evaluate the growth and water quality of M. cephalus juveniles in a biofloc technology system (BFT). Over a period of 87 days, mullet juveniles (117.36 ± 6.48 g) were reared in two experimental conditions: water exchange (control group) (50% three times a week) and BFT (C:N ratio of 15:1). M. cephalus juveniles were stocked at a density of 7.2 kg·m−3. Water quality parameters were monitored periodically. Fish were fed with a balanced artificial feed for marine fish (2% of the total biomass). The water quality parameters were similar between the treatments, with the exception of pH, alkalinity, TSS, and N-NO3 (p < 0.05). Zootechnical parameters WG, DWG, BG, SGR, condition factor, and survival did not show significant differences (p > 0.05). The biomass gain was higher in BFT (p < 0.05). Water quality variables did not appear to influence mullet survival under culture conditions. Mullet is a species that can be reared in BFT without compromising productive performance and having a significant saving of water.

Length-Weight Relationship and Condition Factor of Ethmalosa fimbriata (Bowdish, 1825) and Mugil cephalus (Linnaeus, 1758) in Coastal Waters of Ondo State

The study aimed at examining the Length-Weight Relationships (LWRs) and Condition factor of M. cephalus and E. fimbriata. 240 fish specimens were collected from November 2021 to April 2022 from Obi, Idiegbin, Okesiri and Araromi following standard methodologies subjected to length-weight relationship and condition factor analysis. The results showed that the mean total length of M. cephalus ranged from 30.96 ± 0.56cm (Araromi) to 23.80 ± 1.16cm (Okesiri) and weight ranged from 118.86 ± 9.36g (Araromi) to 71.32 ± 18.12g (Okesiri). E. fimbriata total length ranged from 21.04 ± 0.74cm (Araromi) to 13.96± 0.38cm (Okesiri) and weight ranged from 150.90 ± 1.14g (Araromi) to 70.54 ± 5.76g (Okesiri). The regression coefficient (b) revealed that both M. cephalus (2.19-1.97) and E. fimbriata (2.06-1.05) sampled in Araromi, Okesiri, Idiegbin and Obi respectively exhibited negative allometric growth. Condition factor range (2.41-1.50) recorded for E. fimbriata was higher than (0.50-0.45) range value recorded for M. cephalus. The study concluded that the two species exhibited negative allometric growth pattern and the environment was for conducive for E. fimbriata than for M. cephalus. The variations in growth of the species could be attributed to prevailing ecological conditions of the environment. Therefore, sustainable fish stock management should be carried out.

Seasonal and spatial contamination of trace elements in sediments and fish tissues (Mugil Chephalus) from Annaba gulf (North East of Algeria)

This research is devoted to assessing the pollution within a Mediterranean Sea area in the East coast of Algeria, which is known for its port and industrial activities. This study aims to assess the health status of the Gulf of Annaba located in the extreme North-East of Algeria by examining the contamination level by trace elements (Cu, Zn, Pb, Cd, Hg) in the sediments and muscles of Mugil cephalus fish. The obtained results manifest significant variations in metal levels in the sediments throughout the stations and the sampling seasons. The contamination by (Zn, Cu, Pb, Cd) of Joannonville and Sidi Salem stations is observed during both seasons whereas at the Chapuis station occurs only during the summer. The contamination indices are higher than 3, hence classifying the sediments of these three stations as “sediments at risk”. Joannonville station manifests high levels of Hg only during the summer. For the muscles of M. cephalus, the contamination levels are found to be dependent on the species and the studied station. The fish inhabiting Joannonville and Sidi Salem show higher levels of (Zn, Pb, Cd) compared to the FAO/WHO standards, whereas the Pb level at Chapuis exceeds the standard during summer. Accordingly, the consumption of fish from Joannonville, Sidi Salem and Chapuis stations presents a serious threat regarding the toxicological risks based on the observed levels of contamination.

Potential Effects of Microalgae-Supplemented Diets on the Growth, Blood Parameters, and the Activity of the Intestinal Microbiota in Sparus aurata and Mugil cephalus

This work aimed to assess the suitability of a microalgal blend as a dietary ingredient for feeding juveniles of marine carnivorous and herbivorous teleost, as is the case of Sparus aurata and Mugil cephalus, respectively, and to isolate microorganisms from different media and characterize them on the base of their enzymatic activities and their antagonism against important fish pathogens. Thirty juveniles of each species (70 ± 3.2 g S. aurata mean weight and 47 ± 2.8 g M. cephalus mean weight) were distributed in four tanks (15 individuals each) corresponding to four independent dietary treatments (control and microalgae diets designed for each species). Fish were fed their corresponding diets ad libitum for 108 days. At the end of the trial, fish were weighed, and plasma, liver, perivisceral fat, and the entire intestines were obtained for the evaluation of growth performance and metabolic assessment. Furthermore, 117 bacterial strains were isolated in different culture media from the gastrointestinal tract of S. aurata fed the microalgae blend and further characterized for their potential use as probiotics in aquaculture. S. aurata fed the microalgae-supplemented diet (25% dietary inclusion) showed a significant increase in weight gain, specific growth rate, feed efficiency, hepatosomatic, and intestine length indices. However, growth performance and somatic indices in M. cephalus were not affected by the experimental diets. Plasma samples from S. aurata fed the microalgal diet revealed higher levels of glucose and triglycerides and a decrease in cortisol levels. No significant differences were found in any biochemical parameters among the experimental diets in M. cephalus. In conclusion, both species demonstrated a favorable adaptation to the nutritional formulation employed in this study, and bacterial strains UMA-169 and UMA-216 (both identified as Bacillus pumilus) could be considered for use in aquaculture as they might benefit host health by improving digestion and absorption of different energy sources and by minimizing the colonization of pathogenic species.

Risk assessment of toxic residues among some freshwater and marine water fish species.

Egypt has several beaches, as well as the Nile River and a few lakes; therefore, it could compensate for the lack of protein in red meat with fish. Fish, however, may become a source of heavy metal exposure in humans. The current study was to assess the level of five toxic metals, lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), and aluminum (Al), in six species, namely, Oreochromis niloticus (O. niloticus), Mugil cephalus (M. cephalus), Lates niloticus (L. niloticus), Plectropomus leopardus (P. leopardus), Epinephelus tauvina (E. tauvina), and Lethrinus nebulosus (L. nebulosus), collected from the El-Obour fish market in Egypt. The residual concentrations of the tested toxic metals in the examined O. niloticus, M. cephalus, L. niloticus, E. tauvina, P. leopardus, and L. nebulosus species were found to be higher than the European Commission's maximum permissible limits (MPL) for Pb and Cd by 10 and 20%, 15 and 65%, 75 and 15%, 20 and 65%, 15 and 40%, and 25 and 5%. In contrast, 30% of L. niloticus exceeded the MPL for Hg. It was shown that the average estimated daily intake (EDI) and the target hazard quotient (THQ) in fish samples are below safety levels for human consumption and hazard index (HI < 1). From the human health point of view, this study showed that there was no possible health risk to people due to the intake of any studied species under the current consumption rate in the country.

Bacterial Co-Infection as a Potential Threat to Farmed Flathead Grey Mullet (Mugil cephalus): Phenotypic and Molecular Diagnosis, Histopathology, Immunity Response, and In Vitro Antibacterial Evaluation

Vibrio alginolyticus, Vibrio chlorea, and Enterococcus cloacae were the main bacterial pathogens investigated during recurrent episodes of mortalities among farmed flathead grey mullet (Mugil cephalus) in the Bahar El-Baqar area, Sharqia governorate, Egypt, during the summer season in 2021. Nevertheless, the contamination of water with heavy metals was evaluated. In this study, a total number of sixty moribund and freshly dead Mugil cephalus were examined clinically and upon post-mortem. Then, the bacterial isolates were subjected to bacteriological phenotypic examination, 16S rRNA gene sequencing, and antibiotic sensitivity testing. Histopathological screening and the immunity response of naturally infected M. cephalus were also implemented. In areas where bacterial strains were recovered in a high percentage, water contamination with Cu, Fe, and Ni was higher than the permissible limit. The results showed a high similarity (99–100%) to Vibrio and E. cloacae strains using phylogenetic analysis of 16S rRNA. Most isolates exhibited sensitivity to florfenicol, ciprofloxacin, and norfloxacin, while they were resistant to erythromycin and amoxicillin. Hemorrhage, oedema, hemosiderosis, and melanomacrophage activation in most affected tissues of infected M. cephalus were detected by light microscopy. Nevertheless, higher levels of AST and ALT, as well as serum inflammatory markers, CRP, and lysozyme activity, were shown in infected fish. There were higher MDA levels, along with a reduction of GSH, SOD, and catalase, in the gills and brain of infected M. cephalus, compared to the control fish. Our obtained data confirmed the high prevalence of Vibrio serovars and E. cloacae in infected grey mullets, describing their histopathological alterations, higher inflammatory response, and oxidative stress impact. These results could be useful indicators for understanding the pathogenesis of these pathogens in correlation with water parameter deterioration. Thus, the emergence of Vibrio and E. cloacae species in this study threatens the brackish water aquaculture industry in Egypt and poses a public health concern.

Simulated transport of flathead grey mullet Mugil cephalus eggs: Effects of density and duration

Flathead grey mullet has a great potential as a low trophic level aquaculture species, however captive rearing is still hampered by the lack of well-established production protocols. Here we examined the effects of transport time and egg loading density on water quality, egg survival, hatching success and early larvae performance when shipped for 8, 16 and 24 h at 500 and 1500 eggs L−1. When no water conditioners were used, survival immediately after transport was consistently over 60% up to 16 h shipment for both densities tested, with minimum values of 40% for 1500 eggs L−1. Density and transport time did not influence hatching rate (p > .05) which ranged between 31 and 54% after 8 and 16 hour transport. However, manipulation after 8 and 24 h transport led to a significant drop in early larvae survival regardless the density tested (20% and 5% respectively) compared to 16 h transport (40%) (p < .05). Hence, the results indicate that grey mullet is sensitive when manipulated as early hatched larvae and when eggs undergo blastophore closure at circa 20 h post-fertilization.The tested egg stocking densities do not deteriorate water quality to lethal levels in terms of pH, NO2 and NO3 especially for short and medium transportation times, however, 24 h transportation induces an accumulation of ammonia affecting the long-term survival of larvae. When basic technology is available (i.e. no water conditioners, refrigerated vehicles), we suggest manipulating grey mullet eggs at 28 h post fertilization for best results in terms of hatching rate and early larvae survival.

Decontamination of Marketed Mullet (Mugil cephalus) Infected with Aeromonas hydrophila by Organic Acids

Decontamination of Marketed Mullet (Mugil cephalus) Infected with Aeromonas hydrophila by Organic Acids

Misidentification of Three Mullet Species Under Family Mugilidae Due to Differential Pigmentation Pattern

The mullet species under the family Mugilidae, considered to be a commercially important teleost, are mostly found in coastal waters throughout the world, distributed in tropical, subtropical and temperate areas. In terms of taxonomic study, biogeography and distribution pattern of mullets remain unclear due to difficulty in separating the species based on morphological characters. Thus, there is a need to study the taxonomy of Mugilidae. Further, phylogeny of family Mugilidae also exceptionally obscure at inter and intraspecific levels challenges exist in species under the family. The present study, has brought a new observation in form of temporary black dots (patrial pigmentation abnormality), especially in three species of Mugilidae were observed. Sometimes these pigmentation pattern can lead to misidentification or identification as different species. Further, DNA Barcoding (COI gene) and morpho-meristic analysis performed to resolve the ambiguity in the species identification, confirmed these species as Mugil cephalus, Planiliza sp., Osteomugil perusii. Present study will help to avoid the misidentification of species, which will assist biologists and managers for acquiring more information their distribution and life history pattern.

The asymmetry in the sagitta of four mugilid species obtained from Köyceğiz Lagoon, Aegean Sea, Turkey.

Otolith features such as size and weight were analysed in 656 fish specimens of Chelon auratus, Chelon labrosus, Chelon saliens and Mugil cephalus collected from the Köyceğiz Lagoon System, Aegean Sea, southwest Turkey. The aim was to calculate the asymmetry value of the otolith length (OL), otolith width (OW) and otolith weight (OWe). The asymmetry value of OL was greater than that of OW and OWe. The asymmetry value of the three otolith parameters increased with an increase in the fish's length. The probable cause of asymmetry in the otolith parameters investigated has been determined relative to the variability in growth prompted by ecological impact linked with the disparity in water temperature, salinity, depth and contaminants existing in the Köyceğiz Lagoon System.