Different Histories, Different Destinies‒Impact of Evolutionary History and Population Genetic Structure on Extinction Risk of the Adriatic Spined Loaches (Genus Cobitis; Cypriniformes, Actinopterygii).

The region of Balkans is often considered as an ichthyologic "hot spot", with a great number of species and high portion of endemics living in fresh waters in a relatively small area. The Adriatic watershed in Croatia and Herzegovina is inhabited by six spined loach species (genus Cobitis) whose extinction risk estimations were based solely on their extent of occurrence (and/or area of occupancy) and its fragmentation, and conservation proposals do not consider diversity below species level. In this investigation we employed molecular genetic methods to describe present genetic structure of the Adriatic spined loaches and reveal their demographic history. The divergence of the Adriatic lineages inside the genus Cobitis started in Miocene and lasted until Pleistocene epoch. Geological events responsible for shaping recent diversity of spined loaches in the Adriatic basin are: the Dinarid Mountains upwelling, the evolution of Dinaric Lake system, local tectonic activity, river connections during glaciations and differences in sea level. Even though all the investigated species inhabit karstic rivers located in the same geographic area and that were subject of similar geological events, the results obtained reveal great differences in their genetic diversity and structure and point out the necessity of different conservation measures to ensure their future viability. High level of genetic polymorphism is characteristic for species located more to the south. Two species comprised of more than one population have completely different intraspecific structure; populations of C. illyrica are genetically distinct and represent separate evolutionary significant units, whereas intraspecific structure of C. narentana corresponds to metapopulational pattern. Without population genetic data, evolutionary significant units could be easily misidentified. Furthermore, the obtained results affirm that population genetic measurements are able to detect differences among closely located and related species and estimate extinction risk even more accurately than currently applied IUCN criteria.

New data about distribution of Sabanejewia balcanica (Karaman, 1922) (Cobitidae) in Croatia.

Data are presented on the distribution of the goldside loach, Sabanejewia balcanica, in upper and lower parts often small rivers and brooks of the Danube drainage in central Croatia. The species was registered in relatively small numbers in most of the streams inspected. Results suggest that anthropogenic factors caused the disappearance ofthe goldside loach from most streams in the lower parts of their course. Therefore, S. balcanica should be listed as an endangered species in the Croatian fauna.

Morphometric and meristic characteristics of the goldside loach Sabanejewia balcanica (Cobitidae) in Central Croatia.

We studied sixteen morphometric and eight meristic characteristics of forty-five goldside loaches from two rivers in central Croatia, the Bijela and the Petrinjcica, belonging to the Sava River basin. We found significant differences (P<0.01) in all the morphometric characteristics of the populations from these two rivers. While the mean total length (TL) of the goldside loache population from Petrinjcica (mean TL = 60.4 mm, min-max = 52.8 - 70.2 mm) is comparable with TL in other populations described in Europe, individuals from the Bijela seem to be significantly larger (mean TL = 91.8 mm; min-max = 76.4 mm- 102.4 mm) and are among the longest specimens in Europe. Although we can not be sure if this is a result of phenotype variability or some specific taxonomic quality, the position of the Bijela on the old isolated massif of Mt Papuk may have led to the specific morphometric characteristics of this goldside loach population.

Loaches in a long term study of the Drava River in Croatia.

The diversity, species composition and structure of the fish community were studied in the vicinity of three power plant reservoirs in the middle part of the Drava River in Croatia. Over a period of twenty years in a collection of 25,913 fishes, 56 different fish species belonging to 16 families were recorded. The family Cobitidae is represented by two species: Cobitis elongatoides and Misgurnus fossilis, while the family Balitoridae is represented by only one species, Barbatula barbatula. The presence of the Cobitidae family was recorded in eleven of seventeen investigated localities, while Balitoridae was found in six localities. In the studied fish community, the percentage of C. elongatoides is 1.41% of the total number of individuals, and B. harbatula is 1.02%. M. fossilis is a rare species (0.03 %). Both C. elongatoides and B. barbatula were not caught at the beginning of investigation. C. elongatoides and B. harhatula were first caught in 1985, while M. fossilis was first caught in 1996. The proportion of C. elongatoides in the entire community increased, while the proportion of B. barhatula decreased in later years.

Growth of Cobitis narentana Karaman, 1928 in the Neretva River, Croatia.

Age and growth of Cobitis narentana were examined in the delta of Neretva River in Croatia. Maximum observed length was 100.4 mm for females and 63.5 for males. Five age classes were determined, from 0+ to 4+. For both females (61.0%) and males (53.8%), the greatest proportion of specimens were in the 1+ age category. Growth was faster in males in the first year of life, while females grew at a faster rate than males after the first year. The Fulton condition factor was determined (CF=0.588 for males and CF=0.618 for females). The length-weight relationship was determined for females (W=8xl0(-5)L2.9325) and males (W=2x l0(-5)L2.6431). The parameter b was calculated as less than b=3.0, thus establishing that growth in both males and females was allometric. Growth rate was determined using the von Bertalanffy growth rate curves for females (Lt=101.1[ 1-e(-0.5(t-0.94)]; r2=0.99) and for males (Lt=65.3[1-e(-0.54(t-2.27)]; r2=0.97). The resulting growth rate coefficient (K) was found to be slightly higher in males (0.54) than in females (0.5).

Combining morphology and genetics in resolving taxonomy--a systematic revision of spined loaches (Genus Cobitis; Cypriniformes, Actinopterygii) in the Adriatic watershed.

Taxonomic investigation of spined loaches from Dalmatia and Herzegovina was conducted on specimens from 14 localities. The results of the detailed morphological investigations were combined with genetic data (based on one mitochondrial and two nuclear genes) in order to resolve the taxonomic status of each Cobitis population. Among the investigated features of external morphology, the appearance of spots on the caudal fin base turned out to have the greatest diagnostic value. Furthermore, the number of branched fin rays enabled the discrimination of several species. No morphometric character alone could ensure determination of any Cobitis species. Nevertheless, groups of populations that are more similar in their body shapes correspond to mitochondrial phylogenetic lineages. Based on molecular genetic markers, Dalmatian and Herzegovinian spined loaches form independent lineages inside the Adriatic phylogenetic group. Mitochondrial DNA phylogenetic reconstruction revealed six monophyletic lineages, corresponding to six species distributed in the investigated area. The population distributed in Mostarsko blato karstic field in Bosnia and Herzegovina is described as a new species based on a unique combination of morphological characters: a single triangular Canestrini scale; usually 51/2 branched anal fin rays, 61/2 branched dorsal fin rays, 14 branched caudal fin rays; no spots in the surface pigmentation layer on the caudal fin base; scales on the body very small.

Identity of Squalius (Actinopterygii, Cyprinidae) from Istra Peninsula in Croatia (Adriatic Sea basin).

A chub of previously ambiguous identity from the Boljunscica and Pazincica rivers (south-eastern Istra Peninsula) was studied and compared with geographically close Squalius squalus, Squalius zrmanja, and Squalius janae recently described from the Dragonja River drainage in the Adriatic Sea basin in Slovenia. It was shown that the chub from the south-eastern Istra Peninsula differs from all know species of Squalius but one: Squalius janae. Three samples examined from Boljunscica and Pazincica rivers and Squalius janae from its type locality, Dragonja River, show the following characters typical for the latter species: a long head (the head length 27-32% SL); a pointed conical snout with a clearly projecting upper jaw; a long straight mouth cleft, the lower jaw length (39-45% HL) exceeding the caudal peduncle depth; a large eye; commonly 9? branched anal-fin rays; commonly 44 total vertebrae (24+20 or 25+19); bright silvery colouration, scales easily lost; iris, pectoral, pelvic and anal fin pigmentation with yellow shades. The data on the distribution of Squalius chubs in the northern Adriatic basin support the assumption that the range of Squalius janae is determined by the geology of the Trieste Flysch Basin and the Pazin Flysch Basin forming the base of the Istra Peninsula. The distribution pattern of this species does not support a simple model of fish dispersal and a complete connectivity within the whole Palaeo-Po historical drainage. Indeed, it indicates a disrupted surface palaeohydrography that was heavily fragmented by karstification in the whole Dinaric area.