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Gill characteristics and the size and number of erythrocytes were observed for three species of goby: Neogobius melanostomus, N. fluviatilis and N. kessleri. While erythrocyte size was similar in all species, N. fluviatilis had a statistically higher erythrocyte count. Significant differences were found in gill apparatus structure, with N. melanostomus having 25% and 50% greater gill contact area than N. kessleri and N. fluviatilis, respectively. Secretory goblet cells, which produce a protective mucous, were also present in highest numbers in N. melanostomus gill tissues. These physiological and morphological differences may be one reason for differences observed in the invasiveness of these three species.

Three species of loaches (Cobitis L., 1758) were collected and examined for endohelminths from North Bulgaria. The most common was the trematode Allocreadium transversale (Rudolphi, 1802), which is reported for the first time in Bulgaria. Measurements and figures as well as host-species and locality details are presented. Allocreadium transversale was recorded from all three loach species: Cobitis elongatoides, C. elongata and C. strumicae, the last two being new host records for A. transversale. In addition, metacercariae of Clinostomum complanatum (Rudolphi, 1814) and one unidentified nematode were found. The helminth fauna of loach was quite depauperate, the factors of which have to be elucidated. [ABSTRACT FROM AUTHOR]

The River Bečva occurs at the confluence of Rožnovská Bečva and Vsetínská Bečva rivers in Valašské Meziříčí. Fishes inhabiting River Bečva present a typical fish composition characteristic for barbel zone. Ichthyological research of its both sources done in 1997 and 1999 has confirmed that the sources are the flows in which the barbel zone communities above the confluence progressively transform into grayling and trout inhabited waters having the high ratio of dominating brown trout, common minnow and, in the highest sections, europian bullhead, alpine bullhead respectively. The low transformation sections having barbel zone species present variable species, abundance and high ichthyocenosis biomass. There are 9–12 species in the River Vsetínská Bečva. The estimated biomass is 200–500 kg.ha-1 and the density 3–6 thousand units per hectare. The River Rožnovská Bečva presents 9–10 species, the estimated biomass 250–610 kg.ha-1 and the density 5.5–18.2 thousand units per hectare. The quantitative parameters of fish populations in the upper source sections are lower showing 1–5 species, the estimated biomass is usually below 100 kg.ha-1, exceptionally even 200 kg and the density ranging from 1.1 to 3.2 thousand units per hectare. Angling activities take place in both sources. There are brown trout and grayling introduced and even the not original rainbow trout in limited numbers. Source tributaries, which are inhabited by alpine bulhead populations, are used for the breeding of brown trout. [ABSTRACT FROM AUTHOR]

This article documents the addition of 123 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Brenthis ino, Cichla orinocensis, Cichla temensis, Epinephelus striatus, Gobio gobio, Liocarcinus depurator, Macrolophus pygmaeus, Monilinia vaccinii-corymbosi, Pelochelys cantorii, Philotrypesis josephi, Romanogobio vladykovi, Takydromus luyeanus and Takydromus viridipunctatus. These loci were cross-tested on the following species: Cichla intermedia, Cichla ocellaris, Cichla pinima, Epinephelus acanthistius, Gobio carpathicus, Gobio obtusirostris, Gobio sp. 1, Gobio volgensis, Macrolophus costalis, Macrolophus melanotoma, Macrolophus pygmaeus, Romanogobio albipinnatus, Romanogobio banaticus, Romanogobio belingi, Romanogobio kesslerii, Romanogobio parvus, Romanogobio pentatrichus, Romanogobio uranoscopus, Takydromus formosanus, Takydromus hsuehshanesis and Takydromus stejnegeri. [ABSTRACT FROM AUTHOR]