In fish, species identity can be encoded by sounds, which have been thoroughly investigated in European gobiids (Gobiidae, Gobius lineage). Recent evolutionary studies suggest that deterministic and/or stochastic forces could generate acoustic differences among related animal species, though this has not been investigated in any teleost group to date. In the present comparative study, we analysed the sounds from nine soniferous gobiids and quantitatively assessed their acoustic variability. Our interspecific acoustic study, incorporating for the first time the representative acoustic signals from the majority of soniferous gobiids, suggested that their sounds are truly species-specific (92% of sounds correctly classified into exact species) and each taxon possesses a unique set of spectro-temporal variables. In addition, we reconstructed phylogenetic relationships from a concatenated molecular dataset consisting of multiple molecular markers to track the evolution of acoustic signals in soniferous gobiids. The results of this study indicated that the genus Padogobius is polyphyletic, since P. nigricans was nested within the Ponto-Caspian clade, while the congeneric P. bonelli turned out to be a sister taxon to the remaining investigated soniferous species. Lastly, by extracting the acoustic and genetic distance matrices, sound variability and genetic distance were correlated for the first time to assess whether sound evolution follows a similar phylogenetic pattern. The positive correlation between the sound variability and genetic distance obtained here emphasizes that certain acoustic features from representative sounds could carry the phylogenetic signal in soniferous gobiids. Our study was the first attempt to evaluate the mutual relationship between acoustic variation and genetic divergence in any teleost fish.

Throughout their history humans “tamed” not only the Danube River basin land, but also the river and its associated wetlands, drastically influencing their characteristic habitats, associations, communities, and species. One of these flagship endemic fish species in this respect is the European mudminnow (Umbra krameri Walbaum, 1792), influenced by Danube Basin geography, history, politics, and ecology. A study about this European community concern species in the context of long term human impact on its specific habitats, with potential synergic negative effects of climate change, was treated as highly needed, in an international researchers group initiative to support the efforts to provide hope for preserving this fish species and its ecosystems, and brought it back from the brink of extinction. All the characteristic inventoried wetlands which were or some of them still are natural, semi-natural, or accidental anthropogenic habitats, reveal an accentuated diminishing trend of this species areal continuity; fragmentation being the force which skewed it drastically untill now, and inducing diminishing the specific habitats quantitative and qualitative characteristics in the Danube Basin where these fish fight for survival. The main categories of human activities which impacted the climate changes in the context of this species’ habitats are: water regulation, pollution, dredging, draining, and introduction of non-native species. Overall, the diverse human impact in a climate changes in the context of this species’ habitats, Umbra krameri wetlands, creates serious perspectives on negatively influencing this at a very high scale and level. All the inventoried wetlands where Umbra krameri still survive can be considered an ecologically managed as a refuge and stepping stone wetlands, especially in the increasing climate change trend situation. Supplementary inventory studies in the field should be done for the identification of some may be unknown Umbra krameri habitats and populations.

This paper presents a critical assessment of the current status and geographical distribution of loaches (Cobitidae, Nemacheilidae) in Bosnia and Herzegovina. This closes a gap in research knowledge with only general distribution data currently available. In the Danube catchment four cobitid (Cobitis elongata, C. elongatoides, Misgurnus fossilis, Sabanejewia balcanica) and one nemacheilid species (Barbatula barbatula) were recorded, while the Adriatic Sea catchment hosts three spined loaches: C. narentana, C. illyrica, and C. herzegoviniensis and nemachilid B. barbatula. Cobitis elongatoides was found to be the most common and distributed throughout the northern Bosnia and Herzegovina; i.e. in the rivers Sava, Drina, Bosna, Vrbas, Una (Danube catchment). Sabanejewia balcanica was recorded in the same area but less frequently. Recent bibliographic evidence forces us to exclude C. taenia from the current checklist. On the other hand, cobitid species from the Adriatic Sea catchment are endemic with...

This is the first report of the early development for the endemic Krbava minnow Delminichthys krbavensis from a karstic field in Croatia, and the first report of any species of the genus Delminichthys. The description is based on basic morphometric measures and meristic counts during a 48-day observation of embryos and larvae acquired from successful spawning and rearing in an aquarium. The mean total length of larvae at the time of hatching was 3.12 mm. Mouth opening and independent feeding and intestinal function were observed after day 11 post-hatching (PH) at which time the yolk sac was completely absorbed in all individuals. Flexion of the urostyle began after day 18 PH and was completed by day 23 PH. Pectoral fins developed on day 7 PH, pelvic fins begin to develop by day 44 PH and the formation of caudal, dorsal and anal fin was complete by day 48 PH, when individuals presented the full set of soft rays. Understanding its early development is particularly valuable in assessing the environmental impacts on this endangered species and is essential for its effective monitoring and conservation.