Liza Saliens Research Articles

Genetic diversity and adaptability of two species of Mugilidae (Teleostei: Perciformes) of the Po river delta coastal lagoons

Molecular polymorphisms (allozyme and amplified fragment length polymorphisms (AFLP)) were investigated in the mullet specie's Liza ramada and Liza saliens to determine levels of genetic variability and assess possible correlations between the population genetic structure and the specie's adaptability to shallow water environments. The thinlipped ( L. ramada) and the sharpnose ( L. saliens) mullets are diadromous species that enter coastal lagoons during early life stages to complete growth previous to sexual maturation. Bi-monthly samples ( n = 30–50) were collected in the period 2000–2002 in different sites of the Sacca di Goro (Po river delta) and a nearby aquaculture lagoon (Valle Bertuzzi). Biochemical analyses were carried out by means of starch gel electrophoresis (SGE) on 24 genetic loci corresponding to 15 gene–enzyme systems. In addition, molecular species-specific AFLP (15 primer combinations) were obtained by means of capillary electrophoresis. The degree of allozyme variability determined at three polymorphic loci, GPI-A, GPI-B and G3PDH in L. saliens and L. ramada (polymorphic loci P = 0.08; mean heterozygosity H = 0.010–0.022) and AFLP diversity ( P = 0.110–0.430), seems lower than the one reported in the literature for ecologically similar teleost species. The identification of diagnostic alleles at GPI-A, G3PDH, AK-2, CK-A, CK-B, AAT, IDH, PGM-1, PGM-2 loci in the two mullet species was used for the taxonomic classification of L. saliens and L. ramada. Molecular taxonomy (allozyme and AFLP) demonstrated that the presence of small individuals inside the lagoons previously identified according to morphological characters has often been misinterpreted. The results are discussed in relation to the adaptive role of genetic variation and the migratory characteristics of Mugilidae.

Age determination and growth of leaping mullet, (Liza saliens R.1810) from the Messolonghi Etoliko lagoon (western Greece)

This study is the first detailed work on the age and growth of the leaping mullet (Liza saliens, Risso 1810) in the central Mediterranean. During the period 1991-1995 the age and growth of leaping mullet from the Messolonghi -Etoliko lagoon system (western Greek coast) were studied. Age and growth determinations were based upon otolith samples taken from 537 fish. Marginal increment analysis was used to validate age determination. Annulus formation took place around November each year. The back-calculated lengths at age estimated from the otoliths showed no differences between sub-areas of the lagoon system and the recorded limited between-years variability showed no persistent temporal pattern. The maximum age of leaping mullet in the Messolonghi - Etoliko lagoon was 5 years for males and 6 years for females. The von Bertalanffy equation (L‡=32.99±1.25 cm, k=0.258 ±0.017 year-1, t0=-0.47±0.04 year) accurately describes the growth of the total length of leaping grey mullet for all life stages (fry, juveniles and adults). A large spread and length overlap characterized the age groups. The estimated Length-Weight relationships were common for the two sexes (W=0.0079L3.01).

Genetic divergence and phylogenetic relationships in grey mullets (Teleostei: Mugilidae) based on PCR-RFLP analysis of mtDNA segments.

The genetic differentiation and phylogenetic relationships among five species of the Mugilidae family (Mugil cephalus, Chelon labrosus, Liza aurata, Liza ramada, and Liza saliens) were investigated at the mtDNA level, on samples taken from Messolongi lagoon-Greece. RFLP analysis of three PCR-amplified mtDNA gene segments (12s rRNA, 16s rRNA, and CO I) was used. Ten, eight, and nine restriction enzymes were found to have at least one recognition site at 12s rRNA, 16s rRNA, and CO I genes, respectively. Several fragment patterns were revealed to be species-specific, and thus they could be useful in species taxonomy as diagnostic markers, as well as for further evolutionary studies. Seven different haplotypes were detected. The greatest amount of genetic differentiation was observed at the interspecific level, while little variation was revealed at the intraspecific level. The highest values of nucleotide sequence divergence were observed between M. cephalus and all the other species, while the lowest was found between C. labrosus and L. saliens. Dendrograms obtained by the three different methods (UPGMA, Neighbor-Joining, and Dollo parsimony), were found to exhibit in all cases the same topology. According to this, the most distinct species is M. cephalus, while the other species are clustered in two separate groups, thefirst one containing L. aurata and L. ramada, the other L. saliens and C. labrosus. This last clustering makes the monophyletic origin of the genus Liza questionable.

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.

Chromosomal evolution in Mugilidae: karyotype characterization of Liza saliens and comparative localization of major and minor ribosomal genes in the six Mediterranean mullets

This study continues a comparative cytogenetic analysis of the fish family Mugilidae, reporting the karyotype characterization of the leaping mullet, Liza saliens, by C-banding, Ag- and fluorochrome-staining, and completing the fluorescence in situ hybridization (FISH)-mapping of the 18S and 5S rRNA genes (rDNA) to the chromosomes of the six Mediterranean mullets, namely L. saliens, L. ramada, L. aurata, Mugil cephalus, Chelon labrosus and Oedalechilus labeo. In all species, except M. cephalus, the 5S rDNA sites were localized on a medium-sized acrocentric chromosome pair, which was considered homeologous in all of them. In L. saliens, an additional 5S rDNA site was detected in a location close to the one shown by major ribosomal genes in M. cephalus, i.e. the subtelomeric region of chromosome pair 1. The 5S rDNA site in M. cephalus is located on the smallest chromosome pair of the complement, which, on the other hand, though on a different position, bears 18S rDNA in all the species of Liza and Chelon examined. The heterochromatin composition and the major and minor ribosomal gene locations suggest that the karyotype of L. saliens (subgenus Protomugil) can be considered intermediate between the karyotype of the more primitive M. cephalus and those of the other Liza (subgenus Liza) species and of the representatives of the more derived genera Chelon and Oedalechilus.

Induced CYP1A mRNA, protein and catalytic activity in the liver of feral fish, leaping mullet, Liza saliens

In this study, we examined whether levels of P4501A mRNA expression were naturally induced in feral fish, Liza saliens, and whether CYP1A protein levels and associated enzyme activity, EROD, were also increased. Induction of mRNA was measured using a nucleic acid hybridization technique. For the hybridization studies, a new 33-mer oligonucleotide probe 5′-dCTC ATC CAG CTT CCT GTC CTC GCA GTG ATC AAT-3′ was designed, which corresponded to the totally conserved amino acid motif of CYP1A protein from positions 291 to 301 among the various fish species. Results of Northern blot analysis revealed that RNA isolated from the liver of mullet collected from the highly contaminated region of Izmir Bay with a dissolved and dispersed petroleum hydrocarbon content of 12.45 μg l −1 gave a strong hybridization signal, whereas only a weak hybridization signal was detected in the liver RNA of fish caught from the reference site containing less than 1 μg l −1 of petroleum hydrocarbons. Similarly, fish from the contaminated site had approximately 80 times more EROD activity than the feral fish captured from the reference site. Studies using polyclonal antibodies produced against purified mullet CYP1A also showed the similar trend. In conclusion, feral leaping mullet caught from contaminated water displayed induction of CYP1A at three levels of expression, namely, mRNA, apoprotein and catalytic activity.

Cloning, sequencing, and characterization of CYP1A1 cDNA from leaping mullet (Liza Saliens) liver and implications for the potential functions of its conserved amino acids.

A 2,037 bp CYP1A1 cDNA (GenBank AF072899) was cloned through screening of a lambdaZipLox cDNA library constructed from the liver of a leaping mullet (Liza saliens) fish captured from Izmir Bay on the Aegean coast of Turkey using rainbow trout CYP1A1 cDNA as a probe. This clone has a 130 bp 5'-flanking region, a 1,563 bp open reading frame (ORF) encoding a 521-amino acid protein (58,972 Da), and a 344 bp 3'-untranslated region without a poly (A) tail. Alignment of the deduced amino acids of CYP1A1 cDNAs showed 58% and 69-96% identities with human and 12 other fish species, respectively. Southern blot analysis suggested that this CYP1A1 cDNA was from a single-copy gene. Based on the comparison with CYP1A1 genes reported for fish and mammals, the leaping mullet CYP1A1 gene is probably split into 7 exons. The intron insertion sites were predicted. Alignment of the CYP1A1 cDNA encoded amino acids from 13 fish and 7 mammalian species disclosed differences in highly conserved amino acids between aquatic and land vertebrates. The possible associated secondary structure; conserved motifs and substrate-binding sites were discussed. The phylogenetic relationships of CYP1A1s among 13 fish species were analyzed by a distance method.

Genetic divergence and phylogenetic relationships in grey mullets (Teleostei: Mugilidae) using allozyme data.

Genetic divergence and phylogenetic relationships among five species of the Mugilidae family (Liza saliens, Liza aurata, Liza ramada, Chelon labrosus, and Mugil cephalus) were investigated, in the present study, on samples taken from Messolongi lagoon in Greece, using allozyme electrophoresis. Ten enzymic systems corresponding to 22 genetic loci were assayed, among which, four were found to be polymorphic in Liza saliens, Liza aurata, and Chelon labrosus, seven in Liza ramada, while only two were polymorphic in Mugil cephalus. Several loci showed different electrophoretic patterns among the species and thus, they can be useful in species taxonomy as diagnostic markers, as well as for further evolutionary studies. It must be underlined that among them the aGPD-2* locus proved to be species-specific, while the other ones can be also used in various combinations for the same purpose. The observed heterozygosity wasfound to range from 0.020 to 0.051. Allele frequencies of all loci were used to estimate Nei's (1972) genetic distance, which was found to range between 0.249 and 1.171 among the five species studied. UPGMA and NJ trees, obtained by genetic distance matrix methods, as well as, a tree based on the discrete character parsimony analysis were found to exhibit the same topology. Our result show that the three species of the genus Liza are clustered together, Chelon labrosus being closer to the previous clade, while Mugil cephalus being more distinct.

Effects of leaping grey mullet Liza saliens (Osteichthyes, Mugilidae) in the macrophyte beds of oligohaline Mediterranean coastal lagoons

Some mugilid fish are known to enhance small phytoplankton in freshwater macrophyte-free environments due to zooplankton depletion. This suggests that they may have negative effects on natural macrophyte beds of freshwater and oligohaline lagoons due to phytoplantkon enhancement. To test this hypothesis, we compared the ecosystems of control enclosures that contained no fish with those of enclosures stocked with Liza saliens at two different densities. The occurrence of L. saliens at a density of 321±92.42 kg ha−1 reduced cladoceran density, depleted epiphytic chironomid larvae, enhanced mayfly nymphs and cyclopoid copepods and reduced the organic matter content of sediment, all in comparison with control enclosures. At a density of 673±42.04 kg ha−1, L. saliens reduced total zooplankton density, depleted epiphytic and sediment dwelling chironomid larvae and enhanced mayfly nymphs. The organic matter contents of sediment was not affected. These results showed that L. saliens was very effective in reducing zooplankton density even when macrophyte biomass was high. However, these effects do not affect phytoplankton density, probably because zooplankton was dominated by species with low filter-feeding rates and macrophytes depleted nutrients.

Cloning, sequencing, and characterization of CYP1A1 cDNA from leaping mullet (Liza Saliens) liver and implications for the potential functions of its conserved amino acids

Cloning, sequencing, and characterization of CYP1A1 cDNA from leaping mullet (Liza Saliens) liver and implications for the potential functions of its conserved amino acids

Further immunochemical and biocatalytic characterization of CYP1A1 from feral leaping mullet liver (Liza saliens) microsomes.

CYP1A is known to play important roles in the metabolism, detoxification and bioactivation of carcinogens and other xenobiotics in animals including fish. In our laboratory, CYP1A1 was obtained in a highly purified form with a specific content of 15-17 nmol P450 per mg protein from liver microsomes of feral fish, leaping mullet (Liza saliens). Purified mullet CYP1A1 showed a very high substrate specificities for 7-ethoxyresorufin and 7-methoxyresorufin in a reconstituted system containing purified fish P450 reductase and lipid. In addition, effects of each individual components of the reconstituted system, i.e., CYP1A1 and P450 reductase on 7-methoxyresorufin O-demethylase (MROD) activity were studied. 7-ethoxyresorufin O-deethylase (EROD) activity was strongly inhibited by alpha-naphthoflavone (ANF). At 0.5 and 2.5 microM. ANF inhibited EROD activity by 90 and 98%, respectively. Mullet CYP1A1 did not catalyze monooxygenations of other substrates such as aniline, ethylmorphine, N-nitrosodimethylamine and p-nitrophenol. Antibodies produced against CYP1A1 orthologues in fish such as trout and scup showed strong cross-reactivity with the purified mullet CYP1A1. In addition, anti-L. saliens liver CYP1A1 produced in our laboratory inhibited both the EROD and MROD activities catalyzed by L. saliens liver microsomes but stronger inhibition was observed with EROD activity. On the other hand, anti-mullet CYP1A1 antibodies showed very weak cross-reactivity with two proteins (presumably CYP1A1 and CYP1A2) in 3MC-treated rat liver microsomes. Moreover, 3MC-treated rat liver microsomal EROD activity was weakly inhibited by the anti-L. saliens liver CYP1A1. These results strongly suggested that the purified mullet CYP1A1 is structurally, functionally and immunochemically similar to the CYP1A1 homologues purified from other teleost species but functionally and immunochemically distinct from mammalian CYP1A1.

Seasonal changes in the food quality, diel feeding rhythm and growth rate of juvenile leaping grey mullet Liza saliens

A population of leaping grey mullet Liza saliens was studied in order to test whether growth rates decrease in summer owing to a reduction in food quality. A total of 330 juveniles of the 2-year age group were collected for measuring monthly changes in standard length, total weight, length growth rate and weight growth rate. Another 160 fish of the same age were caught monthly in February, April, August and November to measure food quality and calculate energy intake. Food quality changed as predicted. The organic matter content of the diet on a dry matter basis was 9.7 % in April, 7.9 % in August and 11.7 % in November. The protein content of the diet on a dry matter basis was 9.0 % in April, 6.4 % in August and 9.3 % in November. The carbohydrate content of the diet on a dry matter basis was 0.6 % in April, 0.7 % in August and 1.8 % in November. The lipid content of the diet on a dry matter basis was 0.2 % in April, 0.2 % in August and 0.6 % in November. The energy content of the diet was 2.63 kJ .g -1 in April, 2.21 kJ .g -1 in August and 3.13 kJ .g -1 in November. All the analysed mullet stomachs were empty in February, which suggests that they starve in winter. Daily rations increased when food quality decreased (4 % of body weight in April, 6 % in August and 1.4 % in November). This allowed mullet to show high growth rates from June to August and to overcome a possible food limitation in the warm season. However, we do not know whether they would have grown even faster if food with a higher quality had been available.

Age and growth of leaping grey mullet (<i>Liza saliens</i> (Risso, 1810)) in Minorca (Balearic Islands)

A population of leaping grey mullet (Liza saliens (Risso, 1810) was studied in order to measure seasonal and annual growth rates. The annual growth rates were similar to those reported for other populations from the central Western Mediterranean and intermediate between those living in northern and southern areas. As usual, the growth rate of adult males was slower than that of females. Males reached adulthood in their third summer. Females of the same age showed a moderate gonadal development, but did not ripen until the next summer. Mullets of all ages gained weight only when the water temperature was higher than 20°C. However adults and immature fish showed reduced growth in mid-summer, when that of the juveniles peaked. This difference is not a consequence of the reproductive cost, because the growth rate of immatures was greatly reduced although they did not spawn.

Hepatic cytochrome P4501A and 7-ethoxyresorufin O-deethylase induction in mullet and common sole as an indicator of toxic organic pollution in Izmir Bay, Turkey

In this study, the degree of induction of cytochrome P4501A-associated 7-ethoxyresorufin O-deethylase (EROD) activity and immunochemical detection of cytochrome P4501A in leaping mullet ( Liza saliens) and common sole ( Solea vulgaris) were used as biomarker for assessment of polycyclic aromatic hydrocarbon (PAH) or/and polychlorinated biphenyl (PCB) type organic pollutants along the Izmir Bay on the Aegean Sea coast, Turkey. Fish were captured in May 1995 and February and June 1996. Mullet caught from Pasaport, a highly urbanized and industrial section of the Bay, had approximately 62 times more EROD activity than the feral fish sampled from an uncontaminated site in the Outer Bay. Mullet caught along the pollutant gradient at the three other sites in the Bay exhibited less but highly significant induced EROD activity. An inverse relationship was found between the EROD activity in the fish and the distance between the catch point and the discharge region of polluted rivers and of industrial and domestic wastes into the Harbour. Studies using the polyclonal antibodies produced against mullet cytochrome P4501A showed a similar trend. In addition, EROD activities of benthic fish, common sole, captured from three different sites of the Bay also confirmed and extended the results obtained with those of mullet. Except that, common sole caught from site 5, the edge of Gediz river, exhibited higher EROD activity than that of fish caught from site 4, Tuzla. Although, detailed qualitative and quantitative analyses of organic chemicals in the waters and sediments of Izmir Bay are not available, the results of this study indicate that Inner and Middle Bays of Izmir Bay are highly contaminated with PAH and/or PCB type organic pollutants.

The morphology of Ichthyophonus sp. in their mugilid hosts (Pisces: Teleostei) and following cultivation in vitro. A light and electron microscopy study.

The morphology of Ichthyophonus sp., a parasite of Mugil capito and Liza saliens, was investigated by light and transmission electron microscopy. The most frequent stage found in the fish hosts was the multinucleate spore, though germinating stages, hyphae, and endospores were also found. Different development patterns were observed in the media assayed for in vitro culture. Optimal growth and development were obtained in Eagle's minimum essential medium (MEM) supplemented with 10% fetal bovine serum at pH 7. Ultrastructural features of multinucleate spores, both in the fish host and in culture, were a fibrillar thick wall and an electron-lucent matrix, with large glycogen granules, some electron-dense bodies, large vacuoles, lipid inclusions, and endoplasmic reticulum mainly appearing among the nuclei. Mitochondria with scarce tubulovesicular cristae were observed in the different stages, mainly near the wall and the germinating sites. Condensed heterochromatin was rarely seen. A nucleus-associated organelle (NAO) was frequently observed, and dictyosome cisternae and vesicles appeared in its vicinity.

Preparation of highly purified cytochrome P4501A1 from leaping mullet ( Liza saliens) liver microsomes and its biocatalytic, molecular and immunochemical properties

Cytochrome P4501A1 was purified to electrophoretic homogeneity from the liver microsomes of feral fish leaping mullet ( Liza saliens) collected in İzmir Bay, Aegean coast of Turkey. Purification of cytochrome P4501A1 involved anion exchange chromatography of Emulgen 913-cholate solubilized microsomes on first- and second-DEAE-cellulose columns, hydrophobic interaction chromatographies of the partially purified cytochrome P4501A1 on Porapak Q and phenyl-Sepharose CL-4B and further purification on adsorption chromatography on the hydroxylapatite column. Finally, it is further concentrated and purified on the third DEAE-cellulose column. The purified cytochrome P4501A1 was characterized with respect to spectral, electrophoretic, immunochemical and biocatalytic properties. Cytochrome P4501A1, purified 32-fold with a specific content of 15–17 nmoles P450 (mg protein) −1, produced a single band on SDS-polyacrylamide gel electrophoresis having monomer molecular weight of 58 000±500. Absolute absorption spectrum of the purified cytochrome P4501A1 fractions showed maximal absorption at 417.5 nm and CO-difference spectrum of dithionite-reduced cytochrome P4501A1 gave a peak at 448 nm. Purified P4501A1 was found to be active in the O-deethylation of 7-ethoxyresorufin in the reconstituted system containing purified fish liver cytochrome P450 reductase and synthetic lipid. However, it was unable to catalyze the oxidation of the other monooxygenase substrates such as benzphetamine and aniline known to be specific for the other isozymes. Purified L. saliens liver microsomal cytochrome P4501A1 showed strong cross-reactivity with the antibodies directed against the cytochrome P4501A1 homologues purified from other teleost species such as rainbow trout and scup. Spectral, electrophoretic, immunochemical and biocatalytic properties of the purified cytochrome P4501A1 strongly suggested that it is the CYP1A1 in the L. saliens liver.

Purification and characterization of cytochrome P450 reductase from liver microsomes of feral leaping mullet (Liza saliens).

NADPH-cytochrome P450 reductase was purified to electrophoretic homogeneity from detergent-solubilized liver microsomes from the leaping mullet (Liza saliens). The purified reductase was characterized with respect to spectral, electrophoretic, and biocatalytic properties. In addition, effects of pH, ionic strength, and the substrate concentration on the NADPH-dependent cytochrome c reductase activity of the purified fish liver cytochrome P450 reductase were studied. Cytochrome P450 reductase was purified 438-fold with a yield of 17.5% with respect to the initial amount present in the fish liver microsomes. The specific activity of the enzyme was found to be 52.6 mumol cytochrome c reduced per minute per mg protein. The monomer molecular weight of the purified enzyme was calculated to be 77,000 +/- 1000 when electrophoresed on polyacrylamide gels under the denaturing conditions in the presence of SDS. The absorption spectrum of fish reductase showed two peaks at 378 and 455 nm. NADPH-dependent cytochrome c reductase activity of the purified Liza saliens liver cytochrome P450 reductase was found to be maximal when pH was between 7.4 and 7.8. The apparent K(m) of the purified enzyme was found to be 7.69 microM for cytochrome c when the enzyme activity was measured in 0.3 M potassium phosphate buffer, pH 7.7, at room temperature, and the enzyme was fully saturated by its substrate, cytochrome c, when the substrate concentration was at or above the 70 microM. Furthermore, the purified enzyme was biocatalytically active in reconstituting the 7-ethoxyresorufin O-deethylase activity in the reconstituted system containing purified mullet liver cytochrome P4501A1 and lipid. These results suggested that the purified fish liver cytochrome P450 reductase is similar to its mammalian counterparts with respect to spectral, electrophoretic, and biocatalytic properties.

Comparison of the change in morphological pattern during the growth in length of the grey mullets Liza ramada and Liza saliens from western Greece

This paper deals with the relationship of allometric growth, differential increase of certain morphometric characters to the total length, and of the weight to the total length during growth in length of the grey mullets Liza saliens (Risso) and Liza ramada (Risso). Specimens of both sexes were collected in the Messologhi-Etoliko lagoon in western Greece. The equation used for the morphometric character Y was dY dTL = a × b × TL b − 1 which gives information on the tendency of each morphometric character to grow in relation to total length and also gives a quantitative expression of this and the size of each character. The equation used for length-weight relationship was W = a × TL b . It is shown that the differential increase in the morphometric characters in relation to the increase in total length gives a tendency for the body of L. saliens to be slender and the body of L. ramada to be spherical. This was confirmed by data on length-weight relationships.

Comparative growth in relation with the age assessed by skeletochronology in two mullet fishes of genus Liza

AbstractWe propose a new method for determining age in mullet fishes taking the thoracic spines as material of analysis. The relations length-age and tueight-age were evaluated by von Bertalanffy and logarithmic regressions. Both methods closely agreed with the observed data but the von Bertalanffy's model showed the best R2 values in both species. Two parameters related to growth speed; the K coefficient of von Bertalanffy's model and the slope of logarithmic regression, were higher in Liza ramada than in Liza saliens. However, our results show that mullet have both high rates of size-growth and weight-production, in comparison with other marine fishes.

Zschokkella mugilis N. Sp. (Myxosporea: Bivalvulida) from Mullets (Teleostei: Mugilidae) of Mediterranean Waters: Light and Electron Microscopic Description

ABSTRACTA new Myxosporea, Zschokkella mugilis n. sp., was found in the gall bladder of several mugilids. It is distinguished from all previously reported Zschokkella from mugilids by the absence of valve ornamentation and from other species by the size of the spores. Prevalence of infection was 62.5% for Mugil capito, 70% for M. cephalus and 64.3% for Liza saliens. Plasmodia with rhizoids attached to epithelial cells appeared to compromise the host as evidenced in light and transmission electron micrographs presented herein. General ultrastructure and disporous sporogenesis of Z. mugilis resembled other Myxosporeans, but sporogonic cells did not seem to be formed in pansporoblasts.