Growth patterns of the golden loach, Sabanejewia balcanica were examined in the Rijeka River in Central Croatia on a total of 77 specimens collected in a single sampling session in June 2006. No significant difference was found in total body length between males and females. Age was determined from otoliths. Both males and females live 4 years, though due to the sampling period, no 0+ age fish were found in this study. The length-weight relationship was calculated as W=2x10-6TL3.3229 for males and W=3x10-6TL3.2811 for females, indicating positively allometric growth. According to the growth factor k, growth of males was three times faster than that of females.
An assessment of DNA integrity in erythrocytes using the alkaline comet assay was carried out to estimate the impacts of water pollution on Balkan loaches (Cobitis elongata Heckel et Kner, 1858) inhabiting the Sava and Kupa Rivers, rivers of varying different water quality. The amount of DNA damage in cells was estimated from three different parameters comet tail length as the extent of genetic material migration, tail intensity (% DNA in comet tail) and tail moment. The results suggest a genotoxicity of the aquatic environment in the Sava River and demonstrated significantly lower levels of DNA damage in fish captured from the Kupa River. This study confirmed that the comet assay, applied to fish erythrocytes, is a useful tool in determining potential genotoxicity of water pollutants. Although a good DNA damage pattern for Balkan loach was obtained, due to its global and regional conservation status, only restricted use of a small number of specimens per sampling site could be permitted.
This study describes the of distribution and level of endangerment of the genus Gobio in Croatia. Four species of the genus Gobio live in the Croatian Danube River basin: Gobio Gobio - common gudgeon, G. albipinnatus - whitefin gudgeon, G. kesslerii - sand gudgeon and G. uranoscopus - stone gudgeon, while in the Croatian Adriatic Sea basin lives only G. Gobio. According to IUCN methodology and the level of endangerment, in the Red List of Threatened Plants and Animals of Croatia G. Gobio is considered to be of the least concern (LC). G. uranoscopus and G. kesslerii are in the category of near threatened (NT) while G. albipinnatus is considered as data deficient (DD).
This review updates the information on the actual status and distribution of freshwater gobies in Bosnia and Herzegovina. The available literature has been critically reviewed to provide more complete and up-to-date information. Consequently four species are proposed for removal from the national checklist, given the lack of any data to support their presence: Knipowitschia panizzae, Pomatoschistus microps, Proterorhinus marmoratus and Zosterisessor ophiocephalus. Therefore, the freshwater gobiid fauna is confirmed to include seven species from six genera. The Adriatic Sea basin (Neretva River catchment) is inhabited by three endemic species: Knipowitschia radovici, Orsinigobius croaticus and Ninnigobius canestrinii, while the Black Sea basin (Danube River catchment) is inhabited by the invasive species: Babka gymnotrachelus, Neogobius fluviatilis, Neogobius melanostomus and Ponticola kessleri. However, due to the possibility of misidentify the finding of B. gymnotrachelus is questionable and needs confirmation. Distribution of both endemic Knipowitschia and Orsinogobius species is restricted to small areas in the lower Neretva River catchment on both sides of the Croatia-Bosnia and Herzegovina border. The vulnerability of these species is discussed, and the IUCN conservation and units meriting conservation attention were identified. The invasive character of other species is highlighted. This review indicates that the knowledge on the Bosnia-Herzegovinian freshwater gobiid fauna is still far from complete, hence this up-to-date checklist can serve as a basis for further ecological and zoogeographical studies. For better species inventory, finer scale distribution surveys are needed, followed by detailed morphological, molecular phylogenetic and ecological studies.
Using mitochondrial DNA (mtDNA) variations, the phylogenetic position of Croatian populations of spined loaches within the European genus Cobitis was assessed. Spined loaches from the Matica, Neretva, Cetina, Zrmanja, Jadova, Sava, Drava and Kupa Rivers are included in two previously described groups: a) Cobitis sensu stricto group, and b) Adriatic group. The Danubian populations of C. elongatoides and its hybrids from the Kupa and Drava Rivers are related to the species included in the Cobitis s. str. group, whereas all other analysed populations clustered within the Adriatic group, which is divided into the “Bilineata”, “Elongata” and “Ohridana-zanandreai” clades. The Croatian spined loaches from the Adriatic watershed are included in the first two clades. Four mitochondrial lineages were revealed within the “Bilineata” clade: 1. ”C. bilineata” lineage containing loaches from the Zrmanja River and Italian and Spanish representatives of C. bilineata; 2. “Neretva-Cetina” lineage included loaches from the Cetina River (C. dalmatina) and the Neretva River (C. narentana); 3. “Jadova” lineage included specimens from the Jadova River; and 4. “Matica” lineage comprised spined loaches from the Matica River. Cobitis elongata from the Kupa and Drava Rivers belonged to the “Elongata” clade with two sublineages. Allozyme analyses of the C. taenia complex revealed the presence of both C. elongatoides and its all-female triploid hybrids in the Danube basin of Croatia.
The karyotype and major ribosomal sites as revealed by silver staining and CMA3-fl uorescence of Croatian leuciscine cyprinid endemic to Cetina River, Telestes ukliva were studied. The diploid chromosome number was invariably 2n = 50. Karyotype consisted of eight pairs of metacentric, 13 pairs of submetacentric and four pairs subtelocentric chromosomes. The largest chromosome pair of the complement was subtelocentric, which is a characteristic cytotaxonomic marker for all representatives of the cyprinid lineage Leuciscinae. The nucleolar organizer regions (NORs) were detected in the telomeres of two pairs of mediumsized submetacentric chromosomes. Staining with CMA3 revealed four positive signals that corresponded to NOR sites. No heteromorphic sex chromosomes were found. The karyotype pattern of T. ukliva is nearly identical to that found in most other representatives of the Eurasian leuciscine cyprinids, while the multiple NOR phenotype appears to be more derived as opposed to a uniform one NOR-bearing chromosome pair, ubiquitous in this group.
Taxonomic analyses of four Sabanejewia balcanica populations from Croatia included morphological (morphometric, meristic, phenotypical) and mitochondrial DNA analyses. Comparative analyses of 24 morphometric characters revealed some differences between populations. The specimens from the Drava River are significantly larger than specimens from other populations, whereas the individuals from the Voćinska River represent the smallest European S. balcanica specimens. Due to similarities in morphometric ratios, in the Tree Diagram of Euclidean distances, the Drava and Petrinjčica Rivers populations formed a separate cluster, while the populations from the Rijeka and Voćinska Rivers formed a second cluster. These morphometrical differences are also corroborated by t-test results. Differences among fishes from different populations also exist in external morphology characters, such as spots on the caudal peduncle and the position of the suborbital spine. Mitochondrial DNA analyses enabled us to infer the phylogenetic placement of four Croatian populations within the genus Sabanejewia. All Croatian samples clustered within the two sublineages of the Danubian-Balkanian complex. Samples from the Voćinska River, as well as one sample from the Drava River were included in the “S. balcanica” (VI) sublineage. The remaining samples, including the two remaining haplotypes from the Drava River, were comprised within “S.montana-S.bulgarica-S.balcanica” (III) sublineage.
A new spined loach species Cobitis jadovaensis is described from the Jadova River in Croatia. This species differs from its congeners in the Croatian Adriatic basin with a unique set of characters: a very short dorsal fin base; short anal fin base; narrow head; a single lamina circularis; a single small prominent dark inclined spot on the upper part of the caudal base; all four Gambetta zones well developed and reaching beyond the dorsal base; zones Z1 and Z3 with many irregular spots; zone Z1 narrower than Z2; zone Z2 as wide as Z3; zone Z2 with spots larger than a pupil size fuses with Z3 on caudal peduncle; zone Z4 wider than Z2 and Z3, with 11 – 14 roundish to oval blotches.