Search Results (7)

Despite being one of the most speciose fish families in the Mediterranean Sea, knowledge about the diversity of gobies (Actinopterygii: Gobiidae) in this sea is still unsatisfactory, as documented by recent descriptions of a number of new species. Although very common in shallow water, Gobius incognitus Kovačić & Šanda, 2016, had escaped attention until 2016, when it was discovered. Due to its overall superficial morphological similarity, G. incognitus used to be confused with a much rarer species, Gobius bucchichi Steindachner, 1870, which was considered one of the most common shallow-water gobies in the Mediterranean Sea. In this work, we tested the suitability of the genetic data (mitochondrial gene encoding cytochrome b) for identifying and distinguishing between these two goby species, and assessed the congruency between the distribution records based on genetic data and those based on morphological identification. We analysed material of 304 specimens of G. incognitus and G. bucchichi from 49 localities covering a considerable part of the Mediterranean Sea, Black Sea, and the Atlantic Ocean near Gibraltar, representing 19 geographically well-separated areas. We detected 270 sequences of G. incognitus, and only 34 of G. bucchichi. In both species, a high haplotype variability was observed. The sequence species identity matched morphological identification for all specimens for which vouchers were available. The mean uncorrected p-distance between G. incognitus and G. bucchichi was 13%, while the mean intraspecific distances were much lower (0.63% and 0.68%, respectively). We found 79 fixed mutations between these two species. Data on distribution based on genetic identification are completely congruent with published results based on morphological identification. The results of this study support molecular methods as a reliable tool for distinguishing morphologically similar fish species, which is particularly useful when only tissue is available for determination. Full article

Gymnesigobius medits is reported for the first time after a recent description recorded from the Balearic Islands and from the slope of the Gulf of Vera on the Iberian Peninsula coast. The record from the Emile Baudot seamount on the Balearic Islands represents the deepest positive benthic gobiiform species record in general. The presence of the membrane connection between the pelvic fins in Gymnesigobius medits, presumed on the damaged fin in the original description, was confirmed. The recently described Gobius xoriguer is the first record from the Pitiusas and Columbretes islands and from the Iberian Peninsula coast. It appears to be widely distributed in the circalittoral bottoms, preferentially in red algae beds. Morphological identification of both species was confirmed using molecular analyses based on the sequencing of the mitochondrial cytochrome c oxidase subunit I (DNA barcode) gene. The deepest records of gobiiform fishes in oceans and seas are reviewed. The European seas, a well-studied area with eight gobiid species recorded deeper than 200 m, show high bathyal gobiid species richness compared to other areas. The real worldwide diversity of bathyal gobies, although only a fraction of the shallow water species richness of this taxon, is probably much larger than presently known. Full article

After the description of Gobius incognitus Kovačić & Šanda, 2016, all previous knowledge about the geographic distribution of Gobius bucchichi Steindachner, 1870, as well as its ecology and biology, became obsolete, since it represented the data from the mixture of two species. The known geographic distribution of G. bucchichi and G. incognitus is revisited by validating previously published records, but also and foremost by integrating many new photographic records posted by anglers and divers on social media and on citizen science databases. The present research uses only positively identified records with exact data on locality, coordinates and date of collecting. A total of 1024 confirmed records were collected and retained for inferring distribution maps: 805 records of G. incognitus and 219 records of G. bucchichi. Gobius incognitus is a widespread Mediterranean Sea species with limited presence in the Lusitanian province of the Eastern Atlantic Ocean. It is absent from the Sea of Marmara and the Black Sea. Gobius bucchichi is recorded only in the eastern half of the Mediterranean Sea, from the Adriatic to the Aegean Sea, and in the Black Sea and Sea of Marmara. Full article

Spatiotemporal and physiochemical influences on the abundances and diversity of ichthyoplankton were assessed in the Thermaikos Gulf and edge habitats surrounding the Pieria (Northern Greece) artificial reef complex. The collection of data was performed in edge habitats in the marine protected area near the artificial reef offshore of Kitros. Sampling trips occurred in each season of the spring, summer, and autumn in each year from 2015–2017. This artificial reef complex lies at a distance offshore of 11.5 km from Kitros and the delta of River Aliakmonas. A bongo net sampler was used to sample ichthyoplankton over a network of 16 sampling stations. Seventy species of larval fish were identified. The greatest measures of ichthyoplankton diversity were found during warmer seasons. Non-metric multidimensional scaling showed that seasons play a significant role in species assemblages, as months during the spring, summer, and autumn from different years clustered together. Ten groups of larvae were identified to the family or genus level, such as Arnoglossus spp., Callionymus spp., Crenilabrus spp., Gobius spp., Liza spp., Scorpaena spp., Solea spp., and Spicara spp. Overall, the species with the greatest abundance was the larvae of the European anchovy (Engraulis encrasicolus). The second genera (in order of highest abundance) were Gobius spp. followed by relatively abundant (but lesser numbers of) larvae representing the families Callionymidae, Centracanthidae, and Bothidae. The largest total abundances were found in July 2015 and September 2016. The biodiversity index indicated that measures of diversity were greater in July 2015, which was the only sampling performed in the middle of the summer, and indicated higher diversity in autumn 2015. The aim of this study was to present the assemblages of fish larvae in the marine protected area surrounding the artificial reef of Kitros Pierias as the result of a 3-year sampling program (2015–2017). The novelty of this study is that it is the only study of Ichthyoplankton ever performed in Greece with seasonal repetitions and densely located stations around a coastal marine protected area. Full article

Gobies and their ectoparasitic monogenean flatworms are promising models for species diversification because of their species richness. Recent decades have seen the discovery of several new species of Gyrodactylus (Monogenea: Gyrodactylidae) on European gobies, mostly in the sand goby lineage and especially in the eastern Mediterranean. However, the monogenean fauna of other gobies is much less understood. Therefore, we inspected five gobiid species (34 specimens, vouchered, with some representatives sequenced), sampled in Greece, for monogenean ectoparasites. Only specimens of the giant goby, Gobius cobitis, were infected; they harbored Xenoligophoroides cobitis (Monogenea: Dactylogyridae) on their gills. Here, we provide the first record from Greece, and the first ITS rDNA and COI sequences of the representative of this monotypic genus. Additionally, 28S rDNA was sequenced and compared with published data from across its known distribution, suggesting clinal variation. No sister-group for Xenoligophoroides could be proposed, nor could we explain the presence of a single known member of this genus on gobies, due to a lack of sequence data of closely related dactylogyrid monogeneans in public databases. Possible hypotheses include either the ancestral long-term presence on gobiids but “missing the boat” of the diversification events in the “Gobius-lineage”, or a recent host switch from a non-gobiid host. Full article

Invasive alien species (IAS) are one of the greatest causes of native species extinction. Indeed, they represent a global threat for biodiversity and can also affect the economy and human health. The colonization success of IAS is presumably not only due to their biological and ecological characteristics, but also to the lack of predators and/or parasites in the invaded new areas. In the present work, we demonstrate evidence of predation of the invasive alien crab Percnon gibbesi (H. Milne Edwards, 1853) by the Rock Goby Gobius paganellus Linnaeus, 1758. The diet of G. paganellus was studied analyzing the stomach content of 162 specimens collected in the central Mediterranean Sea. The results obtained from the calculation of the diet indices, namely, frequency of occurrence (%F), percentage weight (%W), percentage abundance (%N), and the Index of Relative Importance (%IRI), showed that small benthic crustaceans were the main prey types. Additionally, these indices and the Levins’ index (Bi) clearly indicated that the invasive crab P. gibbesi was by far the most abundant prey type in the diet of G. paganellus. The relevance of this predator–prey interaction and the role of native species for the biological control of invasive ones are discussed. We also provide a general view on the diet of G. paganellus and other biological and ecological aspects of specimens studied from the central Mediterranean Sea. Full article

Gobies (Gobiiformes: Gobiidae) are the most species-rich family of fishes in general, and the most abundant fish group in the European seas. Nonetheless, our knowledge on many aspects of their biology, including the population genetic diversity, is poor. Although barriers to gene flow are less apparent in the marine environment, the ocean is not a continuous habitat, as has been shown by studies on population genetics of various marine biota. For the first time, European marine goby species which cannot be collected by common fishery techniques were studied. The population genetic structure of two epibenthic species, Gobius geniporus and Gobius cruentatus, from seven localities across their distribution ranges was assessed, using one mitochondrial (cytochrome b) and one nuclear gene (first intron of ribosomal protein gene S7). Our results showed that there is a great diversity of haplotypes of mitochondrial gene cytochrome b in both species at all localities. Global fixation indices (F_ST) indicated a great differentiation of populations in both studied gobies. Our results did not show a geographic subdivision to individual populations. Instead, the data correspond with the model of migration which allow divergence and recurrent migration from the ancestral population. The estimated migration routes coincide with the main currents in the studied area. This matches well the biology of the studied species, with adults exhibiting only short-distance movements and planktonic larval stages. Full article