Morphometric analysis and genetic identification of Hysterothylacium larvae (Nematoda) in marine fish in the Aegean Sea

Anisakid nematodes are the most infamous parasites occurring in seafood with ability to infect humans. In the present study, the infective stages of five anisakid larval types, including Anisakis types I and III, Terranova types I and II and Contracaecum larval type, as well as adult Anisakis paggiae are reported from 16 host species from New Caledonian waters. The specific identity of the larval types was investigated using ITS sequence data. Anisakis larval types I and III were identified as Anisakis typica and Anisakis brevispiculata, respectively, based on identical ITS sequences. However, the specific identity of the Terranova larval types and Contracaecum larval type remains unknown until a matching ITS sequence from a well-identified adult is available. Several fish host species are reported for the first time for anisakid larval types found in this study. Considering that third-stage larvae of anisakids are known to be the infective stage of the parasite for humans and the popularity of seafood in New Caledonia, presence of these parasites in New Caledonian fish is of high importance in terms of public health and raising awareness among various stakeholders. Although adult nematodes in the present study were identified as Anisakis paggiae, the spicule length is shorter in our specimens and falls within the range reported for Anisakis oceanicus previously reported in Pacific waters from black fish (genus Globicephala) and later synonymised with Anisakis physeteris. However, our specimens are different from A. physeteris in morphology of ventriculus. Anisakis paggiae has been reported from whales in southern hemisphere and this is the first report from the Pacific regions.

Occurrence of ascaridoid nematodes in selected edible fish from the Persian Gulf and description of Hysterothylacium larval type XV and Hysterothylacium persicum n. sp. (Nematoda: Raphidascarididae)

Aberrant otoliths in four marine fishes from the Aegean Sea, Black Sea, and Sea of Marmara (Turkey)

We analysed data collected on board commercial purse seine vessels in the Aegean and Ionian Seas (eastern Mediterranean Sea, Greece) in 13 seasonal sampling periods from 2003 to 2008 in order to describe the composition of the retained and discarded catch and shed light on discarding practices. In each area, five species constituted the majority of the marketable catch (> 97%): sardine (Sardina pilchardus), anchovy (Engraulis encrasicolus), round sardinella (Sardinella aurita), bogue (Boops boops) (in both areas), mackerel (Scomber japonicus; in the Aegean Sea) and picarel (Spicara smaris; in the Ionian Sea). Discarded quantities were on average 4.6% and 2.2% of the total catch in terms of weight in the Aegean and Ionian Seas respectively. Discards on the marketable ratio fluctuated over years and seasons without showing any particular trend. At the species level, sardine and mackerel were seldom discarded while large amounts of anchovy were discarded only during its recruitment period (autumn), when juvenile fish dominate the population. The discarding ratio for bogue, picarel and round sardinella ranged from zero to total discarding because they constitute a supplementary source of income for the fishers. Discarded fish comprised mainly small individuals for all species considered with the exception of round sardinella. However, the lengths at which 50% of the individuals were discarded were generally small, often smaller than the species minimum landing sizes. Geographical coordinates and marketable catch explained part of the variability of the discarded quantities, as revealed by generalized additive models. Discarding practices and implications for management of purse seine fisheries are also discussed.

The retention-releasing patterns of the double-grid grating sieve placed on the deck of the purse seiners were revealed for four case species (Sardina pilchardus, Sardinella aurita, Engraulis encrasicolus and Boops boops) using a simulated data predicted from total length (TL) – maximum height (Hmax) and TL – maximum width (Wmax) regressions. To calculate these relationships, samples were collected during commercial purse seine operations between 3 April 2017 and 21 March 2018 in Izmir Bay, Aegean Sea (Turkey). Optimal Bar Spacing (OBS) values corresponding to minimum landing sizes or the length at first maturity were calculated separately for each species. OBS values were found 10.97 mm for sardine (Sardina pilchardus), 11.29 mm for round sardine (Sardinella aurita), 7.78 mm for anchovy (Engraulis encrasicolus) and 17.89 mm for bogue (Boops boops). The bar spacing regulations may constitute a promising management measure to release undersized fish for the purse seine fishery in the Aegean Sea.

Because the genus Colletotrichum is among the most important groups of plant pathogenic fungi worldwide, the ability to accurately diagnose species is vital for the implementation of effective disease control and quarantine measures. Although the long-standing, unresolved taxonomic issues in the genus have recently begun to be addressed through multi-locus phylogenetic research, the tools most commonly used for Colletotrichum species identification are either insufficiently variable (e.g. morphology), or homoplasic (e.g. morphology and host range criteria). In this study, using the systematically well-defined falcate-spored, grass-associated group (FG) of Colletotrichum as a model, we test the utility of ITS sequence data to diagnose species affiliations through similarity-based searches of the NCBI GenBank database or by means of gene trees constructed using phylogenetic methods. 43% of all Colletotrichum sequences accessioned by GenBank are from the ITS region, making it the single most common sequence curated by the community; however, 34% of the ITS accessions existed only as sequence data in the database, with no associatedPUBLICation. Using Colletotrichum ITS sequence data from 53 FG defined isolates and 16 falcate-spored, non-graminicolous isolates to perform GenBank BLASTN searches, we found that erroneous identifications occurred for 86% of the 14 species tested. In contrast, the phylogenetic tree generated by the ITS sequence data, although poorly supported by bootstrap values, correctly grouped most of the species, but 10% of the individual isolates were incorrectly placed. From this study, we conclude that the currently available infrastructure of Colletotrichum ITS sequence data may yield unreliable species diagnoses, particularly if sequence similarity alone is the only criterion applied.

Spawning habitats of two eastern Mediterranean sardine, Sardina pilchardus (Walbaum, 1792), stocks (coastal waters of central Aegean and Ionian Seas) are characterized from daily egg production method (DEPM) surveys conducted during the peak of the spawning period. The latter occurs earlier in the Aegean Sea (December) than in the less‐productive Ionian Sea (February). Single‐parameter quotient analysis showed that the preferred bottom depth for spawning was 40–90 m in both areas but sardine selected sites of increased zooplankton in the Aegean Sea during December and increased fluorescence in the Ionian Sea during February. Estimates of daily egg production (P) and spawning stock biomass (B) were about four times lower for the Ionian Sea (P = 7.81 eggs m−2, B = 3652 tonnes) than the Aegean Sea (P = 27.52 eggs m−2, B = 16 174 tonnes). We suggest that zooplankton biomass might not be sufficient to support sardine reproduction in the highly oligotrophic Ionian Sea where the very small sardine stock may rely on the late‐winter phytoplankton bloom. Actively selecting sites with increased zooplankton or phytoplankton and feeding plasticity (the well‐known switching from selective particle feeding to non‐selective filter feeding in sardines) are interpreted as adaptations to grow and reproduce optimally at varying prey conditions. Despite differences in temperature and productivity regimes, reproductive performance of sardine in the Ionian Sea was very similar to that in the Aegean Sea during the peak of the spawning period. In comparing adult parameters from DEPM applications to Sardina and Sardinops stocks around the world, a highly significant linear relation emerged between mean batch fecundity (F) and mean weight of mature female (W, g) (F = 0.364W, r2 = 0.98). The latter implies that, during the peak of the spawning period, mean relative batch fecundity (eggs g−1) of sardine is fairly constant in contrasting ecosystems around the world.

Anisakis and Contracaecum species are fish borne zoonotic nematodes. In our previous studies, other larval anisakid and raphidascarid nematodes, Anisakis and Hysterothylacium species, were genetically identified in marine fish from Turkish waters. However, there is no information on molecular identification of larval Contracaecum species in marine fish from Turkey. Therefore, the aim of this study was only to investigate the presence and molecular identification of Contracaecum species in commonly commercialized marine fish from Turkish waters. A total of 475 marine fish, which belong to 21 different species, were sampled from the Aegean (FAO 37.3.1), Mediterranean (FAO 37.3.2), and Black Sea (FAO 37.4.2). The prevalence of Contracaecum L3 larvae in the Aegean Sea was identified as 10% in Mugil cephalus. All Contracaecum L3 larvae were molecularly characterized with RFLP targeting the ITS region and rrnS gene. Moreover, all larvae were analyzed by sequencing of ITS region, rrnS and cox2 gene. All Contracaecum larvae were identified as C. overstreeti based on the cox2 sequence analysis. This is the first report of C. overstreeti larvae in M. cephalus as paratenic and intermediate hosts. Furthermore, the analysis reveals novel information on ITS region. Additionally, the rrnS gene of C. overstreeti was also achieved and deposited in Genbank for the first time. The PCR-RFLP patterns of the ITS region and rrnS gene from C. overstreeti were presented in the present study. Consequently, the presence of C. overstreeti larvae in M. cephalus from the Aegean Sea may alsopotentially capable of inducing allergic sensitization in humans.

Anthropogenic particles ingestion in fish species from two areas of the western Mediterranean Sea

The African genus Welwitschiella has traditionally been placed in tribe Heliantheae. Our phylogenetic analysis of chloroplast DNA ndhF sequence data, however, reveals that it is part of tribe Astereae. In order to assess the relationships of this genus within the tribe, we produced a phylogeny based on ITS (nrDNA) sequence data of a sample including Amellus, African Conyza, Chrysocoma, Felicia spp., Mairia, Poeciliopsis, Printzia, Welwitschiella and Zyrphelis. Both parsimony and Bayesian analyses were done. The Bayesian analysis showed that African genera form a basal grade in tribe Astereae along with the Chinese Nannoglottis and South American and New Zealand genera, with Printzia being the earliest diverging member of the tribe. Mairia occupies an isolated position. Amellus, Chrysocoma, Felicia, Poecilolepis and Zyrphelis belong to subtribe Homochrominae, a South African radiation that also includes the St Helena endemics Commidendron and Melanodendron. Pteronia appears isolated, though it might be close to the Homochrominae. Welwitschiella is placed in the latest diverging African clade, subtribe Grangeinae, which also includes Grangea, Psiadia, Nidorella, and the African Conyza species except C. gouani. This subtribe is sister to the Eurasiatic subtribe Bellidinae, and together they are sister to the Astereae crown lineages of Australasia-Asia and South and North America.

Helminthosporium species from submerged wood in streams in Yunnan Province, China were studied based on morphology and DNA sequence data. Descriptions and illustrations of Helminthosporium velutinum and a new species H. aquaticum are provided. A combined phylogenetic tree, based on SSU, ITS and LSU sequence data, place the species in Massarinaceae, Pleosporales. The polyphyletic nature of Helminthosporium species within Massarinaceae is shown based on ITS sequence data available in GenBank.

Phylogenetic implications and secondary structure analyses of Vigna mungo (L.) Hepper genotypes based on nrDNA ITS2 sequences

Molecular phylogenetics and delimitation of species in Cortinarius section Calochroi (Basidiomycota, Agaricales) in Europe

Plant life on serpentine soils has been a topic of research for decades, but the evolutionary dynamics of adaptation to such a stressful habitat is still incompletely understood, especially in old-world groups. We present a study addressing this issue using Onosma (Boraginaceae) as the model system and a molecular phylogenetic approach. Original ITS sequences were generated for all the obligate endemics allopatrically distributed on the ophiolitic “islands” of the southeastern Euro-Mediterranean region, in addition to most of the species facultatively growing on ultramafics and a broad sample of non-serpentine species. Parsimony and Bayesian reconstructions showed that obligate endemics belonged to six distantly related clades, five continental and one insular in the Aegean sea (Cyprus). Lack of a common ancestor and of correlation between geographic and genetic distances between the endemics suggested polyphyletic and polytopic evolution on the different outcrops. Preference for non-serpentine habitats appeared as the ancestral condition, but constitutive preadaptive traits such as drought tolerance and ability to cope with high soil concentrations of magnesium have probably favoured multiple events in the colonization of ultramafics. Tree topology and absolute age estimations suggest that xerophytic Onosma underwent a rapid radiation in correspondence with the Messinian salinity crisis of the Mediterranean (6–5.3 mya), and that the endemic lineages originated at the beginning of the Pleistocene. Serpentine “islands” may have acted as refugial habitats during the cold climatic phases, and then as major determinants of adaptive speciation due to isolation of populations and the selective pressure of soil constraints.

A taxonomic revision of Metarhizium based on a phylogenetic analysis of rDNA sequence data