Grey Mullet Species Research Articles

Environmental Investigations and Tissue Bioaccumulation of Heavy Metals in Grey Mullet from the Black Sea (Bulgaria) and the Ionian Sea (Italy).

Simple SummaryThe environmental monitoring of dangerous chemicals and how these affect the aquatic biota is of fundamental importance in defining the health status of fish. Pollution with chemical elements is of great environmental concern, since fish and marine organisms can uptake various toxicants and subsequently transfer them to man through the food web. Moreover, the accumulation of toxic elements could be a cause of pathology insurgence in fish. These organisms represent a good indicator of the status of coastal water. Flathead grey mullet (Mugil cephalus) is a coastal species, bottom dwelling and feeding on detritus, invertebrates, and algae. The main aim of the present study was to determine the total concentration of nine elements (Cd, Cr, Pb, Ni, Al, Cu, Fe, Mn, and Zn) in the fish species M. cephalus and in coastal marine waters collected from various sampling points along the Black Sea (Bulgaria) and the Ionian Sea (Italy) and to apply those results to the prediction of the pollution status of those coastal marine environments. To achieve this goal, metal concentrations were analyzed in various fish tissues (gills, liver, and muscle) of grey mullet (M. cephalus) and in marine water samples collected from the sampling stations across both areas (Ionian Sea (Italy) and Black Sea (Bulgaria)). The results revealed significant differences within the tissues examined and the marine water samples, principally attributable to the pollution of the area, the bioavailability of metals, and the hydrological conditions. The present study represents the first attempt to compare the data obtained from analyzing sampling points in order to define the different elemental concentrations in M. cephalus muscle tissue and how they reflect environmental ones.The environmental monitoring of chemical toxicants has been a widely studied topic in the last few decades. The main aim of the present study was to determine the total concentration of nine elements (Cd, Cr, Pb, Ni, Al, Cu, Fe, Mn, and Zn) in the fish species grey mullet (M. cephalus) and in the coastal marine waters collected from various sampling points along the Black Sea (Bulgaria) and the Ionian Sea (Italy). Further, those results were applied to predict the pollution degree in those coastal marine environments. The fish samples were subject to acid digestion followed by appropriate analytical determination. The metal concentrations in marine water samples collected from the Black Sea (Bulgaria) and the Ionian Sea (Italy) were also analyzed. Unpaired Student’s t-test and the one-way ANOVA were applied for the statistical analysis of the data. The statistical results revealed a significant variation (p < 0.0001) in the concentration of various fish tissues. The accumulation of toxic and essential elements differs significantly in grey mullet species caught from the Black Sea (Bulgaria) and the Ionian Sea (Italy). The results from this study may serve as a convenient approach during marine pollution programs set by both countries (Italy and Bulgaria).

Age, growth, mortality, reproduction, and exploitation rates for fishery management of grey mullet species in the Köyceğiz Lagoon–Estuary (Mediterranean coast)

Age, growth, mortality, reproduction, and exploitation rates for fishery management of grey mullet species in the Köyceğiz Lagoon–Estuary (Mediterranean coast)

Assembly rules of helminth parasite communities in grey mullets: combining components of diversity

Organisms aggregate in ecological communities. It has been widely debated whether these associations are explained by deterministic or, in contrast, random processes. The answer may vary, depending on the level of an organisational scale (α, β and γ) and the facet of diversity considered: taxonomic, functional and phylogenetic. Diversity at the level of a sampling unit (i.e. host individual) is the α diversity; β diversity represents the extent of dissimilarity in diversity among sampling units (within a level of an organisational scale, β1; between levels of an organisational scale, β2); and the total diversity of a system is γ diversity. Thus, the combination of facets and levels of a scale may be useful to disentangle the mechanisms driving the composition of a parasite community. Using helminth parasite taxonomic, functional, and a proxy for phylogenetic diversity of three species of grey mullets (Teleostei: Mugilidae) from the Mediterranean Sea, we show that random and deterministic processes of different nature explain the assemblage of parasite communities. The parasite community at a host individual (α) was invariably a random subset of the total diversity in the community for the three facets of diversity. At the β1 level, taxonomic diversity was lower than expected by chance, whereas functional diversity and the proxy for phylogenetic diversity were random. At the β2 level, diversity patterns suggested environmental filtering of the parasite assemblage: species, trait, and phylogenetic compositions of parasite communities seemed to depend primarily on the species of host, but also on the locality and season. Our study shows that parasite communities are not totally understood if any of the components (i.e. facets and levels) of diversity is neglected.

Thicklip (Chelon labrosus) and flathead (Mugil cephalus) grey mullets fry production in Tunisian aquaculture

For several years Tunisia has opted to breed freshwater fish in reservoirs and artificial lakes, created for irrigation, as a strategy of providing high quality aquatic protein to the interior regions and providing work opportunities for local communities. The aim of this study was to summarize the main results accumulated by the last 20 year efforts made by the members of the National Institute for Marine Science and Technology (INSTM)-Aquaculture Laboratory to develop thicklip (Chelon labrosus) and flathead (Mugil cephalus) grey mullets fry production from captive broodstocks intended for stocking inland reservoirs (artificial lakes) and grow-out purposes Administration of human chorionic gonadotropin (hCG) at a priming dose of 10.000 IU kg−1 female bw, followed by 10.000 IU hCG and (100 or 200 μg kg−1 female bw of thicklip or flathead grey mullet respectively) as resolving dose resulted at the highest egg production for both species. Mean fecundity was 494.655 eggs kg-1 bw for thicklip grey mullet and 418.945 eggs kg-1 bw for flathead grey mullet. Fertilization rate of eggs produced was high (mean rate 83 % and 63 % for thicklip and flathead grey mullet respectively) and larvae hatched from those eggs at high rates (77 % and 88 %, respectively). The green method was more efficient than clear method to produce thicklip and flathead grey mullet fry, (i.e larvae had higher growth rate and better survival rates). The results of this study demonstrate the possibility to control reproduction and produce grey mullet fry in captivity. However, further research is needed to optimize the production protocol of eggs and fry of both grey mullet species.

Length-Weight, Length-Length Relationships and Condition Factor of commercial grey mullet species from Köyceğiz Lagoon in Turkey

The relationships between length weight, length length parameters and condition factor were given for 4 grey mullet species that caught in Köyceğiz Lagoon area between January 2017 and December 2017. Total length and weight were recorded and they ranged from 6.2-39.3 cm and 2.34-508.38 g for Liza aurata, 8.9-47.6 cm and 8.61-1006.5 g for Mugil cephalus, 5.0-37.7 cm and 1.62-478.90 g for Chelon labrosus and 3.8-35.2 cm and 0.52-462.88 g for Liza saliens. The length-weight relationships were determined for L. aurata, M. cephalus, C. labrosus and L. saliens as W=0.0087L2.96, W=0.0106L2.95, W=0.0073L3.065 andW=0.0067L3.045 respectively. All the fish species showed isometric growth (b=3). There were strong correlations between total length, fork length and standard length of 4 fish species (P&amp;lt;0.001). Also the condition factor values significantly (P&amp;lt;0.001) range between 0.56-1.30 for L. aurata, 0.66-1.22 for M. cephalus, 0.64-1.30 for C. labrosus, 0.57-1.06 for L. saliens.

GENETIC DIVERSITY OF FISH (MUGIL CEPHALUS L.) IN VIETNAM USING SSR MARKERS

The flathead grey mullet species (Mugil cephalus L.) Vietnam is an euryhaline fish whose distribution ranges from the North to the South. Currently, M. cephalus is facing the threat of overexploitation, and the number of individuals in most populations is declining fast. In order to conserve the species in Vietnam, it is necessary to evaluate its genetic diversity. Therefore, this study was carried out in Vietnam from August 2012 to June 2015. The results of our study provided the analysis for 12 locus microsatellites (SSR) from 70 mature individuals (standard length &gt; 25 cm). The study also identified a total of 35 alleles for all loci studied, among which 10 loci were polymorphic. Average value of polymorphic information content (PIC) for each polymorphic marker was 0.2889 (0.0289 to 0.5918). Coefficient heterozygous gene Ho = 0.942; He = 0.517; Fst = 0.216; Fis = - 0.8211 (Fis &lt; 0). The genetic relationship of 70 specimens or M. cephalus in Vietnam were divided in three main groups according to three specific geographic distributions in the country, the Gulf of Tonkin, the Central and the South. There were also mixed clusters observed among the three studied regions. Individuals in close geographical distance often clustered together and formed separate groups, in which the level of molecular changes were quite low, 29% among populations, and 71% among individuals within the same population.

Molecular Identification of Grey Mullet species in the Mediterranean Sea of Egypt

Molecular Identification of Grey Mullet species in the Mediterranean Sea of Egypt

One cryptic species of grey mullet (Mugil cephalus mitotype: NWP3) from Taiwan’s waters is worth cultivating for large roes using aquaculture

The grey mullet, Mugil cephalus, is an important aquaculture species in Taiwan. They were thought to be a single fish species in terms of the morphology-based taxonomy; however, three cryptic species of grey mullet (mitotype: NWP1, NWP2 and NWP3) have been identified within the Taiwan waters. In general, the NWP2 females are known to have small body sizes with large developed ovaries regardless of the cultivation time, whereas the NWP1 females have large body sizes with small ovaries. In this study, the NWP3 females are found to have significantly larger body and ovary weights than do the NWP2 females under the same aquaculture conditions. Therefore, even though the NWP2 females are good fish for producing large ovaries, this study indicates that the NWP3 females have even more potential to produce huge ovaries than do the NWP2 females.

SPAWNING IN CONDITION OF THE NORTH-WESTERN PART OF THE MIDDLE CASPIAN OF BLACK SEA ACCLIMATIZED FAMILY MUGILIDAE. TWO SPECIES OF THE GENUS LIZA (L. AURATUS) AND (L. SALIENS)

Due to the number of migration changes, adaptive and plastic peculiarities of Mugilidae family two species of grey mullet from Liza family the acclimatization of which in the Caspian Sea formed the shoal of quite valuable marketable fish. Grey mullet sexual puberty in the Caspian Sea happens at the age of 3 or 4. The length and the rate of growth increases. The weight of the Caspian-sea grey mullet is bigger than that of the Black-sea grey mullet.

Bulgarian Marine and Freshwater Fishes as a Source of Fat-Soluble Vitamins for a Healthy Human Diet.

The aim of the present study evaluates the fat-soluble vitamins all-trans retinol (vitamin A), cholecalciferol (vitamin D3) and α-tocopherol (vitamin E) content in the fresh edible tissue of Bulgarian fish species: marine—grey mullet (Mugil cephalus) and bonito (Sarda sarda), and freshwater—rainbow trout (Oncorhynchus mykiss) and common carp (Cyprinus carpio). The sample preparation procedure includes alkaline saponification, followed by liquid-liquid extraction with n-hexane. All-trans retinol, cholecalciferol and α-tocopherol were analyzed simultaneously using RP-HPLC\\UV\\FL system with analytical column C18 ODS2 Hypersil™. The fat soluble vitamins content (μg per 100 g wet weight) in the fresh edible fish tissue of analyzed fishes are in the ranges: vitamin A from 2.7 ± 0.4 to 37.5 ± 3.4 μg/100 g ww; vitamin D3 from 1.1 ± 0.1 to 11.4 ± 0.6 μg/100 g ww; vitamin E from 121.4 ± 9.6 to 1274.2 ± 44.1 μg/100 g ww. Three fat-soluble vitamins occur in higher amounts in rainbow trout and grey mullet species. According to recommended daily intake (RDI), they are a good source of cholecalciferol.

Oogenesis in five species of grey mullets (Teleostei, Mugilidae) from natural and landlocked habitats.

ABSTRACT The seasonal histological changes in the ovaries of specimens of five species of Mugil caught in natural habitat were compared with those of specimens in fish ponds and Lake Tiberias. Specimens of Mugil cephalus and Mugil capito confined to fresh water do not ovulate. The Gonado-Somatic Index (GSI) of the various species of mullets was compared. Throughout the year, the GSI is about 1. A steep rise of the GSI begins in the months proceeding the spawning season in the specimens caught in their natural habitat. In Mugil cephalus specimens from freshwater ponds the GSI does not exceed 1. In specimens of Mugil capito from freshwater ponds and from Lake Tiberias, as well as in specimens of Mugil cephalus from Lake Tiberias, the GSI is very high during the spawning season. In these specimens, unable to ovulate, the high GSI is due to accumulation of atretic oocytes. Histograms showing percentages of stages of oocytes of the various species of mullets are compared and the factors responsible for the inf...

Length-Weight Relationship and Growth Parameters of Grey Mullets (Pisces: Mugilidae) in Two Estuaries in Ghana

Grey mullet populations in the rivers Pra and Volta estuaries in Ghana were studied to provide information on their length-weight relationship and growth parameters. Fish samples were collected monthly for 18 months from local fishermen using cast net, drag net and gill nets. Six species of grey mullets were identified: sickle fin mullet, Liza falcipinnis (Valenciennes, 1836), large-scaled mullet, Liza grandisquamis (Valenciennes, 1836), grooved mullet, Liza dumerilii (Steindachner, 1870), white mullet, Mugil curema Vallenciennes, 1836, banana mullet, Mugil bananensis (Pellegrin, 1928) and striped mullet, Mugil cephalus Linnaeus, 1758. Length-weight relationship for the various species in the Volta and Pra estuaries, respectively, were: L. falcipinnis, BW = 0.0158 SL3.06 and BW = 0.0255 SL2.85; L dumerillii, BW = 0098 SL3.24 and BW = 0.0223SL2.92; M. bananensis, BW = 0.0191SL3.03 and BW = 0.0175 SL3.10; M. cephalus, BW = 0.0574 SL3.14 and BW = 0.0134 SL3.17; M. curema, BW = 0.0311 SL2.85 and BW = 0.0247 SL2.5. That for L. grandisquamis, which was found only in the Pra estuary, was BW = 0.0204 SL3.01, indicating isometric growth since the regression coefficient b was not significantly different from 3.0 (P &gt; 0.05). The regression coefficient b for the other species was either significantly higher or lower than 3.0 (P &lt; 0.01), suggesting allometric growth. Except L. dumerilli, L&yen; and K for the same species from the two estuaries differed. The highest L&yen; of 56.6 cm (SL) and growth performance index (&empty;) of 4.99 were estimated for M. cephalus. The L&yen; estimated in the study indicates that the sizes of grey mullets in the two estuaries were smaller compared to the same species from other countries in the tropics.

Juvenile bottlenecks and salinity shape grey mullet assemblages in Mediterranean estuaries

Previous research has suggested that competitive bottlenecks may exist for the Mediterranean grey mullets (Osteichthyes, Mugilidae) at the fry stage with the exotic Cyprinus carpio (Osteichthyes, Cyprinidae) playing a central role. As a consequence, the structure of grey mullet assemblages at later stages is thought to reflect previous competition as well as differences in osmoregulatory skills. This paper tests that hypothesis by examining four predictions about the relative abundance of five grey mullet species in 42 Western Mediterranean estuary sites from three areas (Aiguamolls de l'Empordà, Ebro Delta and Minorca) differing in the salinity level and occurrence of C. carpio. Field data confirmed the predictions as: (1) Liza aurata and Mugil cephalus were scarce everywhere and never dominated the assemblage; (2) Liza saliens dominated the assemblage where the salinity level was higher than 13; (3) Liza ramado always dominated the assemblage where the salinity level was lower than 13 and C. carpio was present; and (4) Chelon labrosus dominated the assemblage only where the salinity level was lower than 13 and C. carpio was absent. The catch per unit effort of C. labrosus of any size was smaller in the presence of C. carpio than where it had not been introduced, which is in agreement with the juvenile competitive bottleneck hypothesis. Discriminant analysis confirmed that the assemblage structure was linked to the salinity level and the occurrence of C. carpio for both early juveniles and late juveniles as well as adults. The data reported here reveal that the structure of grey mullet assemblages inhabiting Mediterranean estuaries is determined by salinity and competitive interactions at the fry stage.

Genetic identification of grey mullet species (Mugilidae) by analysis of mitochondrial DNA sequence: application to identify the origin of processed ovary products (bottarga).

Mitochondrial DNA sequencing was used to identify and distinguish four species of commercially important Mediterranean grey mullets. Partial cytochrome b and D-loop sequences were obtained from the four fish species, and these were used to perform phylogenetic analysis and to determine species-specific DNA fingerprints. Species-specific amplification primers were designed from these fingerprints, and these were used to characterize the species origin of several samples of commercial, processed mullet ovary products. In addition to differentiating between food products from different species, this method is also sensitive enough to distinguish food products from mullets of the same species from different regions.

New species and new records of Ergasilus Nordmann (Copepoda: Ergasilidae) from the gills of grey mullet (Mugilidae).

Four new Ergasilus species are described from five host species of grey mullet, family Mugilidae, held in the fish collections of The Natural History Museum, London. Ergasilus extensus n. sp. was found on Myxus petardi (Castelnau) from Australia, E. sittangenesis n. sp. on Sicamugil hamiltoni (Day) from Burma, E. piriformis n. sp. on Sicamugil cascasia (Hamilton Buchanan) from India, and E. ecuadorensis n. sp. on Mugil curema Valenciennes and M. hospes Jordan & Culver from Ecuador. New records of E. cyanopictus Caravalho, E. magnicornis Yin, E. orientalis Yamaguti and E. rostralis Ho, Jayarajian & Radhakrishnan on grey mullet are also given.

Use of Melanophore Patterns On The Ventral Side Of The Head To Identify Fry Of Grey Mullet (Teleostei: Mugilidae)

Examination of fry of five species of grey mullet revealed that the shape of the lower jaw and the melanophore patterns along the edge of the lower jaw and the ventral side of the head are species-specific. Mugil cephalus is characterized by an acute angle of the dentary symphysis and lightly pigmented ventro-opercular and gular regions of the head. In Liza aurata, the mandibular region has spots of pigment at the corners of the mouth, the gular region is lightly pigmented with a single row of melanophores, the ventro-opercular region of the head has two rows that form a distinct arch and, in specimens over 20 mm TL, at least one of these rows extends to the posterior ventro-opercular region. In Liza ramada, the pigmentation is darkest in the mandibular and gular regions of the head, the melanophores in the mandibular region in specimens of 30-40 mm TL are concentrated around the anterior tip of the jaw and the corners of the mouth, and the anterior ventro-opercular region usually has a single row of melanophores that may extend into the posterior ventro-opercular region. In Chelon labrosus, there are two rows of melanophores in the ventro-opercular region and one or two rows in the gular region which usually extend beyond the eye into the posterior sector. In Liza saliens, there are two rows of melanophores in the ventro-opercular region and two in the gular region which rarely extend beyond the eye to the posterior sector. These observations were used to create a key which may be useful for identifying fry of grey mullet species grown in aquaculture in the Mediterranean region.

Biogeography and phylogeny of Paraergasilus Markevich, 1937 (Copepoda: Ergasilidae) with descriptions of two new species from the gills of grey mullet

Two new species of Paraergasilus are reported from the gills of four species of grey mullet (Mugilidae). Paraergasilus dichotomus n. sp. was recorded on M. cephalus Linn. from New South Wales, Australia. Paraergasilus curtus n. sp. was found on the same host in Western Australia, on Valamugil cunnesius (Valenciennes) from the Philippines, on Valamugil seheli (Forsskal) from Sri Lanka and on Liza macrolepis (Smith) from Socotra, Yemen. Both new species differ from congeners in possessing a bifid antennary claw. The distribution of Paraergasilus species is summarized and the host specificity of Paraergasilus species is examined. Phylogenetic analysis of the relationships between Paraergasilus species indicated that there are two main lineages within the genus.

Metazoan parasites of grey mullets (Teleostea: Mugilidae) from the Mistras Lagoon (Sardinia - western Mediterranean)

A total of 127 specimens of grey mullets (Teleostea: Mugilidae) from the Mistras Lagoon (Sardinia - western Mediterranean) were examined for metazoan parasites. Five species of grey mullets were found: Chelon labrosus, Liza aurata, L. ramada, L. saliens and Mugil cephalus. Forty-one species of parasites were identified: 14 monogeneans, 5 crustaceans, 18 digeneans, 3 nematodes and 1 acanthocephalan; 26 of them being reported from Sardinia for the first time. Findings of faunal interest are: Ergenstrema sp. (Monogenea) in L. saliens; Caligus pageti (Crustacea) in L. aurata and L. saliens; Saturnius sp. (Digenea) in C. labrosus, L. aurata and L. saliens; Capillaria sp. (Nematoda) in C. labrosus, L. aurata and M. cephalus. The dynamics and distribution of ectoparasites were partially influenced by salinity, while the interpretation of the results for endoparasites was more complex. The data obtained show the richness of the parasite fauna of grey mullets from the Mistras Lagoon, providing additional environmental information on this body of water.

Non‐competitive coexistence between Mediterranean grey mullet: evidence from seasonal changes in food availability, niche breadth and trophic overlap

Five grey mullet species in the Albufera des Grau lagoon (Balearic Islands, Western Mediterranean), reacted to the spring‐summer reduction in the organic matter content of sediment by expanding their niche breadth, mainly due to higher algae consumption. However, trophic overlap did not change for most of the studied species pairs and when it did, overlap was higher in the warm than in the cold season. When all the assemblage was considered, niche overlap distribution was significantly skewed towards values higher than those predicted by null models, both in the warm and the cold season. These results are not consistent with the predictions from the niche theory, which suggests that grey mullet are under carrying capacity and hence competitive exclusion does not operate in the studied assemblage.

Description of a new Nipergasilus species (Family : Ergasilidae) from the gills of grey mullet

A new Nipergasilus species is described from the gills of the grey mullet Valamugil cunnesius from several localities in India and Pakistan. The new species is closely related to Nipergasilus bora (Yamaguti, 1939) which is also recorded here on three species of grey mullet. The genus Nipergasilus is redefined in order to accommodate the second species.