Length–weight relationships for 22 fish species of the Mar Menor coastal lagoon (western Mediterranean Sea)

Length–weight relationships were estimated for 22 species of the Mar Menor coastal lagoon (south‐eastern Spain): Lipophrys dalmatinus, Salaria pavo, Callionymus pusillus, Aphanius iberus, Engraulis encrasicolus, Gobius cobitis, G. niger, G. paganellus, Pomatoschistus marmoratus, Symphodus cinereus, Chelon labrosus, Liza aurata, L. ramado, L. saliens, Mugil cephalus, Diplodus puntazzo, D. sargus sargus, Lithognathus mormyrus, Sarpa salpa, Sparus aurata, Hippocampus guttulatus and Syngnathus abaster. The captures were made in shallow areas of the lagoon during 2002–2004. Significant length–weight relationships were found for all species.     

Isolation and characterisation of new polymorphic microsatellite markers for the striped sea bream (Lithognathus mormyrus)

The striped sea bream (Lithognathus mormyrus) is a coastal marine teleost of commercial importance from the family Sparidae, for which information on stock boundaries is currently lacking. We developed two multiplex PCR for the collective screening of nine polymorphic microsatellite markers for this species. Five primer pairs are specific to L. mormyrus, the remaining four are identical to previously isolated sequences in Sparus aurata and Pagellus bogaraveo. The number of alleles among 40 individuals from the Western Mediterranean ranged from 8 to 20 and observed heterozygosity values ranged between 0.65 and 0.92. F _ST estimate obtained between two separate geographic locations indicate that the loci should prove very useful to study genetic population structure in L. mormyrus.     

The opecoelidae (Digenea) of sparid fishes of the western Mediterranean. II. Pycnadenoides yamaguti, 1938 and Pseudopycnadena Saad-Fares & Maillard, 1986

The genera Pycnadenoides Yamaguti, 1938 and Pseudopycnadena Saad-Fares & Maillard, 1986 are redefined and their validity discussed. Two forms, currently considered to be Pycnadenoides senegalensis Fischthal & Thomas, 1972, one from Lithognathus mormyrus and Diplodus vulgaris off Corsica (Scandola) and one from Sparus aurata off Provence and Languedoc, are described separately, as some preliminary biochemical studies suggest that they might be distinct. This species is commented upon in relation to Distomum mormyri Stossich, 1885, D. umbrinae Stossich, 1885, Pycnadenoides pagrosomi Yamaguti, 1938 and P. ghanensis Fischthal & Thomas, 1968. Pseudopycnadena fischthali Saad-Fares & Maillard, 1986 is redescribed from Diplodus vulgaris, D. annularis and D. sargus off Corsica (Scandola).

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Résumé Les auteurs redéfinissent et discutent la validité des genres Pycnadenoides Yamaguti, 1938 et Pseudopycnadena Saad-Fares & Maillard, 1986. Deux formes considérées actuellement comme Pycnadenoides senegalensis Fischthal & Thomas, 1972, l'une parasite de Lithognathus mormyrus et de Diplodus vulgaris des côtes de Corse (Scandola), l'autre parasite de Sparus aurata des côtes de Provence et du Languedoc, sont décrites séparément. Des études biochimiques préliminaires suggèrent qu'il pourrait s'agir de deux espèces différentes. Cette espèce est discutée par rapport à Distomum mormyri Stossich, 1885, D. umbrinae Stossich, 1885, Pycnadenoides pagrosomi Yamaguti, 1938 et P. ghanensis Fischthal & Thomas, 1968. Pseudopycnadena fischthali Saad-Fares & Maillard, 1986 est redécrit à partir d'exemplaires provenant de Diplodus vulgaris, D. annularis et D. sargus des côtes de Corse (Scandola).

     

Phylogenetic relationships of nine mullet species (Mugilidae) in the Mediterranean Sea

Phylogenetic relationships among four genera and nine species (Mugil cephalus, Mugil soiuy, Liza ramada, Liza aurata, Liza abu, Liza saliens, Liza carinata, Chelon labrosus, Oedalechilus labeo) of the Mediterranean mullets (Mugilidae) were investigated by means of allozyme electrophoresis using a seven-enzyme system (CK*, GAPDH*, G3PDH*, IDHP*, ME*, MDH*, PGM*) comprising eleven putative loci. The highest genetic divergence was 1.299, detected between M. cephalus and L. aurata and the lowest (0.280) was found between L. carinata and L. saliens. The amount of genetic divergence between the genera Chelon and Oedalechilus did not appear to be high (0.285). In a UPGMA tree, all nine species were grouped in two main branchings. In the first branch, C. labrosus and O. labeo clustered as closest taxa and were sister group to L. ramada. The other four Liza species produced two sub-branching in this group; L. carinata branched together with L. saliens, and L. aurata branched together with L. abu. In the second branch the two species of the genus Mugil, M. cephalus and M. soiuy, clustered together and were clearly isolated from the other three genera.     

Bio‐economic analysis of the Mar Menor (Murcia,SE Spain) small‐scale lagoon fishery

An integrated fisheries management tool based on a bio‐economic model was applied to the demersal fishery in the Mar Menor coastal lagoon in SE Spain, with the objective of exploring solutions to ensure the sustainability of this activity. The hypothesis is that excess harvesting in recent years by fishers trying to offset growing production costs has led to the inefficient use of lagoon fishery resources. The authors established the basic bio‐economic conditions of the fishery in 2012 by means of field sampling and personal interviews with producers, and analyzed the response of several biological and economic indicators (target species biomass and yield, fleet profits) to a management scenario based on limiting the fishing season of one of the main types of fishing gear (fish traps, locally known as ‘paranzas’). Results show that a reduction in fishing mortality of two overexploited species (Sparus aurata and Lithognathus mormyrus) will help recover the biomass of these stocks by more than 40% as well as increase the economic value of the fishery, with profits increasing by 17% over a 4‐year period.     

INFLUENCE OF FRESHWATER FLOW REGIME ON FISH ASSEMBLAGES IN THE GREAT FISH RIVER AND ESTUARY

Summary

Two and a half years of data were collected from the lower Great Fish River, head region and estuary to determine the fish species composition within these areas. Gilchristella aestuaria, Liza dumerilii, Rhabdosargus holubi and Pomadasys commersonnii were the four most abundant species captured, with riverine flow rate having an important effect on both species composition and numbers of fishes in the different regions. Most marine species displayed a strong inverse relationship between catch per unit effort and elevated freshwater inputs. Euryhaline marine species dominated the catches at all sampling sites during low flows but were less common during high flow periods when catadromous species were most abundant. Based on the available evidence it is suggested that for most marine species in the river this decline in abundance is related to low conductivity levels following floods rather than avoidance of elevated flows. The impact of elevated suspensoid concentrations and lowered dissolved oxygen concentrations on freshwater and estuarine fish populations during major river flooding is also discussed.     

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 was found 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.     

An initial survey on the occurrence of staphylococcal infections in Turkish marine aquaculture (2013–1014)

A tentative survey on selected marine fish farms was undertaken to delineate the extent to which infections with Staphylococcus species occur in Turkish aquaculture systems. To determine the presence and the distribution of fish pathogenic staphylococci, representative farm types such as marine cages as well as inland pond farms working with saline-ground water and a large hatchery were selected. Field sampling was performed in a total of 13 commercial fish farms that are located in the most-popular aquaculture sites of Turkey. Samples were taken between October 2013 and August 2014. Almost all size classes of the most commonly marine cultured fish species in Turkey were investigated, including Dicentrarchus labrax, Sparus aurata, Argyrosomus regius, Diplodus puntazzo, Dentex dentex, Onchorhynchus mykiss and Salmo labrax. After a visual check, specimens with various clinical signs were sampled for bacteriological and histopathological investigations. Mixed infections of staphylococci along with Vibrio and Aeromonas representatives were detected in Dicentrarchus labrax, Sparus aurata and Diplodus puntazzo samples obtained from 7 farms. The following pathogens were identified: Staphylococcus. epidermidis, S. aureus, S. capitis subsp. capitis, S. lentus, S. hominis subsp. hominis and S. sciuri subsp. sciuri. Main clinical and histopathological effects of the infections in fishes were revealed. The pathogenicity of some isolates was confirmed with in vivo pathogenicity assay and SDS-PAGE analysis.     

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, the first 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.     

Fish communities in temporarily open/closed estuaries from the warm- and cool-temperate regions of South Africa: A review

The majority of estuaries along the coastline of southern Africa are termed temporarily open/closed estuaries (TOCEs) and are closed off from the sea for varying periods by a sandbar which forms at the mouth. It is therefore important to understand the processes occurring within TOCEs and their importance to fishes in order to make sound management recommendations. Estuaries along the coast of South Africa and their associated fish assemblages are biogeographically distinct and occur in either a subtropical, warm-temperate or cool-temperate zone. There are 125 TOCEs found within the cool-temperate and warm-temperate zones. Most fish species found in TOCEs are the juveniles of marine taxa that breed at sea. Permanently open estuaries generally have a higher diversity of species than TOCEs, but TOCEs still provide important nursery areas for many marine species and numerically often have a higher proportion of estuarine resident species. Important taxa in terms of abundance and biomass in warm-temperate TOCEs include the sparids Rhabdosargus holubi and Lithognathus lithognathus, several mugilid species, estuarine residents (particularly Gilchristella aestuaria and Atherina breviceps) and the freshwater cichlid Oreochromis mossambicus. The diversity of fishes in cool-temperate TOCEs is low when compared with warm-temperate systems and Liza richardsonii tends to dominate catches by number and mass in most systems. Several species recorded in TOCEs show clear longitudinal distribution trends. For example Atherina breviceps is generally more abundant in the lower reaches of estuaries. Mouth state, particularly the frequency, timing and duration of mouth opening plays a key role in determining species richness, composition, diversity and abundance in TOCEs. Mouth state is directly linked to freshwater input. Reduced river inflow leads to prolonged mouth closure and shorter open phases, which inhibits immigration and emigration of marine fish species between estuaries and the sea. Understanding of the effects of various processes occurring within these systems, particularly variation in freshwater input, on the biota of these important systems facilitates the development of informed management recommendations.     

Molecular Phylogeny of Grey Mullets (Teleostei: Mugilidae) in Greece: Evidence from Sequence Analysis of mtDNA Segments

Mitochondrial DNA sequence analysis has been used to explore genetic differentiation and phylogenetic relationships among five species of the Mugilidae family, Mugil cephalus, Chelon labrosus, Liza aurata, Liza ramada, and Liza saliens. DNA was isolated from samples originating from the Messolongi Lagoon in Greece. Three mtDNA segments (12s rRNA, 16s rRNA, and CO I) were PCR amplified and sequenced. Sequencing analysis revealed that the greatest genetic differentiation was observed between M. cephalus and all the other species studied, while C. labrosus and L. aurata were the closest taxa. Dendrograms obtained by the neighbor-joining method and Bayesian inference analysis exhibited the same topology. According to this topology, M. cephalus is the most distinct species and the remaining taxa are clustered together, with C. labrosus and L. aurata forming a single group. The latter result brings into question the monophyletic origin of the genus Liza.     

The composition and community structure of the ichthyofauna of the upper Scheldt estuary: synthesis of a 10-year data collection (1991–2001)

Fish collections on the cooling water filter screens of the Doel power plant were used to analyse temporal trends in estuarine fish populations of the upper Scheldt estuary, Belgium. Between 1991 and 2001, 62 species shared the estuary, with 15 species present at any one time. Identified were 23 marine stragglers, 16 freshwater species and four diadromous species, but their contribution to the total catch was insignificant. In terms of numbers, marine estuarine opportunists (17 species) mainly occurring as juveniles and estuarine residents (two species) were the dominant life cycle categories. Six fish species contributed to >97% of the total catch: three Pomatoschistus species [P. minutus (32%), P. microps (30%) and P. lozanoi (6%)], two Clupeidae [Clupea harengus (16%) and Sprattus sprattus (8%)] and Syngnathus rostellatus (5%). Abundance of almost all species in the estuary was highly seasonal and characterized by pronounced abundance peaks. Ordination of the data showed that variability in the temporal structure of estuarine fish community was first determined by differences in annual recruitment and then by predictable, cyclical patterns of species abundance.     

Saturnius minutus n. sp. and S. dimitrovi n. sp. (Digenea: Hemiuridae) from Mugil cephalus L. (Teleostei: Mugilidae), with a multivariate morphological analysis of the Mediterranean species of Saturnius Manter, 1969

Three species of the bunocotyline genus Saturnius Manter, 1969 are described from the stomach lining of mugilid fishes of the Mediterranean and Black Seas. Two of the species are new: S. minutus n. sp. occurs in Mugil cephalus off the Mediterranean coast of Spain; and S. dimitrovi n. sp., a parasite of M. cephalus off the Bulgarian Black Sea coast and the Spanish Mediterranean coast, was originally described as S. papernai by Dimitrov et al. (1998). In addition, S. papernai Overstreet, 1977 is redescribed from M. cephalus off the Spanish Mediterranean coast and from Liza aurata and L. saliens off the Bulgarian Black Sea coast. The three species are distinguished morphometrically using univariate and multivariate analyses. These results were verified using Linear Discriminant Analysis which correctly allocated all specimens to their species designations based on morphology (i.e. 100% successful classification rate) and assigned almost all specimens to the correct population (locality). The following variables were selected for optimal separation between samples: the length of the forebody, ventral sucker and posterior testis, the length and width of the posteriormost pseudosegment, and the width of the muscular flange at ventral sucker level.     

Phenetic relationships of six species of mullets (<Emphasis Type="Italic">Mugilidae</Emphasis>) from the south Adriatic,as inferred from the study of the visceral and dermal skeleton

This study examines the interspecific variability and phenetic relationships in six southern Adriatic mullet species: Mugil cephalus (Linnaeus, 1758), Chelon labrosus (Risso, 1826), Liza aurata (Risso, 1810), Liza ramada (Risso, 1826), Liza saliens (Risso, 1810), and Oedalechilus labeo (Cuvier, 1829). Twenty-three morphometric characteristics of the visceral skeleton and the dermatocranium of mullets were analyzed. The major distinguishing characters were those of the jaws. M. cephalus was clearly separated from the other species; O. labeo differed to a somewhat smaller extent; and C. labrosus was the least distinguished species. The species of the genus Liza were phenetically most similar, while the other species of mullet differed significantly from them. The greatest distances were between M. cephalus and C. labrosus, as well as between M. cephalus and O. labeo. This text was submitted by the authors in English.     

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.     

Multivariate analyses of the biometric features from Philippine sardines – implications for the phylogenetic relationships of the freshwater Sardinella tawilis (Teleostei,Clupeomorpha)*

Philippine sardines are members of the commercially important Sardinella genus (Family Clupeidae). Sardines are mostly marine species with a very few exception like the Philippine freshwater sardine, Sardinella tawilis, of Lake Taal. This species is believed to have immigrated from Balayan Bay some 250 years ago. To determine the relationship of freshwater S. tawilis to the marine forms, 35 biometric features were investigated. The variables were subjected to univariate (mean, standard deviation and coefficient of variance) and multivariate analyses [Principal Component Analysis (PCA) and Hierarchical Cluster Analysis]. Results from univariate tests revealed that the number of ventral fin ray can discriminate Sardinella lemuru from the rest of the sardines. Multivariate PCA, on the other hand, showed discrete separation of the marine sardines. Sardinella tawilis, however, cannot be clearly separated from the marine species, Sardinella albella. The same clustering was recovered in HCA, thus providing evidence that S. albella is the closest marine relative of the freshwater S. tawilis.     

Relationship between shape and trophic ecology of selected species of Sparids of the Caprolace coastal lagoon (Central Tyrrhenian sea)

Synopsis The shapes of juveniles of nine species of the family Sparidae (Diplodus annularis, Diplodus puntazzo, Diplodus sargus, Diplodus vulgaris, Lithognathus mormyrus, Pagellus acarne, Sarpa salpa, Sparus aurata, Spondyliosoma cantharus), collected in the tide channel of the Caprolace Lagoon (Central Tyrrhenian Sea—Italy) were studied using geometric morphometry. These species have different ecologies. The trophic ecology of each species, reported as TROPH values, are related to shape. For the first time the relationship between shape and trophic ecology in sparids was studied in a quantitative way giving an ecomorphological meaning to the shape differences. Mean shapes of carnivorous, omnivorous and herbivorous fish were extracted, analyzed and found to be unique. Strict herbivores such as Sarpa salpa have a small mouth gap; omnivores such as the four species of the genus Diplodus have a higher body (discoidal) and a caudal peduncle shorter and higher; carnivorous species such as Lithognathus mormyrus, possess a relatively larger head region, a larger mouth gap, a longer body and a caudal peduncle longer and narrower.     

Water quality requirements for first-feeding in marine fish larvae. I. Ammonia,nitrite, and nitrate

The tolerance of marine fish larvae to ammonia, nitrite, and nitrate was investigated using the decrease in first-feeding incidence following a 24-h exposure as the criterion of response. Seven species, all hatched from pelagic eggs collected at sea, were used in these experiments: two soleids (Heteromycteris capensis Kaup, Synaptura kleini (Bonapart)), a gadid (Gaidropsarus capensis (Kaup)), and four sparids (Diplodus sargus (L.), Lithognathus mormyrus (L.), Pachymetopon blochi (Val.), and an unidentified species). Concentrations that inhibited first-feeding are compared to 24-h LC₅₀'s for the same species, and to concentrations that are known to induce lethal and sublethal responses in other teleost species. Judging from its effect on first-feeding, un-ionized ammonia is considered to be a potential hazard in the rearing tank; nitrite and nitrate are non-toxic at levels likely to be encountered in practical marine fish culture. Data are presented on the age at first-feeding and point of no return for 10 species.     

A redescription ofLepidauchen stenostoma Nicoll, 1913 (Digenea), and a reassessment of the status of the genusLepidauchen Nicoll, 1913

The genusLepidauchen is discussed and defined. It is removed from the family Lepocreadiidae and placed in the family Acanthocolpidae based mainly on its possession of a uterine seminal receptacle. The type, and only valid species,L. stenostoma, is redescribed using material fromLabrus merula from Corsica. Material fromCoris julis andSymphodus tinca from the western Mediterranean off Marseille,L. merula from the western Mediterranean off Valencia,Diplodus annularis andLithognathus mormyrus from the Adriatic Sea off Montenegro, andArchosargus unimaculatus from Venezuela was also examined. Other nominal species are discussed, but none are considered valid within this genus.     

Developing jellyfish strategy hypotheses using circulation models

Four species of ergasilid copepods were collected from gill filaments of three species of fishes from Khor al-Zubair Lagoon, Iraq. The mugilid Liza subviridis hosted the new species Ergasilus iraquensis and Ergasilus pararostralis. Ergasilus synanceienis sp. n. was found on the synanceiid Leptosynanceia melanostigma(Day). The fourth species, Dermoergasilus varicoleus Ho, Jayarajan & Radhakrishnan, 1992 was found parasitizing the mugilid Liza abu, and is a new record for Iraq.