In this study, we aimed to assess the population status of bleak (Alburnus spp.) over the Western Balkan Peninsula in terms of its sustainable use. A second objective was to determine key factors ...important for fishery management planning. Two different basins, continental (the Danube Basin and the Sava River sub-basin) and marine (the Adriatic and the Aegean Sea Basins) were examined. A sustainability assessment and factor analysis were conducted using the adjusted ESHIPPOfishing model, extended with additional socio-economic sub-elements, and the categorical principal components analysis (CATPCA), respectively. The results of the assessment revealed the bleak populations in the Danube Basin and the Sava River sub-basin to be highly sustainable. The population characteristics with abiotic and biotic factors were responsible for this status, while the influence of socio-economic factors was insignificant. The sustainability status of the bleak populations of the Mediterranean basin varied, with the populations from Ohrid and Skadar Lakes showing a high and those from Prespa and Dojran Lakes a medium status. Socio-economic factors with traditional fishing were the most important for the Mediterranean bleak populations.
Display omitted
•We assessed the sustainability of bleak populations over the Western Balkan Peninsula.•Bleak populations were highly sustainable in the continental basin.•The sustainability of bleak populations in the Mediterranean basin varied.•Socio-economic factors were significant for Mediterranean bleak populations.•The Danube Basin bleak populations are safe for utilization in the human diet.
The morphological variability of European perch from Lake Skadar was evaluated based on 19 morphometric measurements. Analysis of variance and covariance showed that seven morphometric characters ...were different among sexes: head length, preorbital distance, predorsal distance of first dorsal fin, predorsal distance of second dorsal fin, first dorsal fin height, second dorsal fin height and pectoral fin length. Characters: head length, preorbital distance, predorsal distance of first dorsal fin and predorsal distance of second dorsal fin showed no value overlap among males and females, which indicated significant differences between sexes in these characters. Growth analysis of individual morphometric parameters versus total length showed that: head length, preorbital distance, predorsal distance of first dorsal fin and predorsal distance of second dorsal fin have more or less isometric growth for both sexes and were mainly dependent on fish total length. This study determined that females have larger heads compared to males of the same age.
Recent studies of these species have been related to taxonomic status and length-weight relationships (Marić & Radujković, 2009; Milošević et al, 2011; Milošević et al, 2012; Milošević & Talevski, ...2016)....there was no research dealing with the adaptation of the R. prespensis in this two, in many ways, different environments.A total of 20 morphometric characters were analyzed: TL - Total length, SL - Standard length, H - Maximum body height, h - Minimum body height, hc - Head height, lc - Head length, Oh - Horizontal eye diameter, iO - Interorbital distance, prO - Preorbital distance, poO - Postorbital distance, Lpc- Length of caudal peduncle, pV - Preventral distance, pD - Predorsal distance, poD - Postdorsal distance, ID - dorsal fin length, hD - dorsal fin height, IA - Anal fin length, hA - Anal fin height, IP - Pectoral fin length, IV - Ventral fin length.Genetic variation for a fixed phenotype has been hypothesized in stable environments (Smith, 1993).Besides genetic variation for a canalized phenotype, phenotypic plasticity, an environmentalinduced phenotypic change that occurs within an organism's lifetime (Stearns, 1989), is also likely to play an important role in the process of diversification (West-Eberhard, 1989)....phenotypic plasticity is regarded to be more beneficial in variable environments, where a single optimal phenotype may be favored instead of maintaining plasticity in traits (Schlichting & Pigliucci, 1998).
This study examined the relationship between the sagittal otolith morphometric variables (length, height and weight) and body growth of the European eel. Eels that were studied ranged in total length ...from 11.2 to 79.5 cm. The relationships between the sagittal otolith variables and fish somatic growth were described with a non-linear function. The resulting coefficients of determination \((r^2)\) ranged from 0.782 to 0.914. The variable most strongly related to fish size was found to be the sagittal otolith length (OL) with 91.4 % of the variability. The results of this study provide the first
comprehensive data regarding the relationship between the sagittal otolith morphometric variables with the body length of
Anguilla
anguilla
.
U ovom radu se opisuje odnos između morfometrijskih varijabli sagitalnog otolita (duljina, visina i težina) i rasta tijela europske jegulje. Proučavane jegulje imale su raspon ukupne dužine od 11,2 do 79,5 cm. Odnos između sagitalnih otolitskih varijabli i somatskog
rasta ribe opisani su nelinearnom funkcijom. Dobiveni koeficijenti određivanja \((r^2)\) kretali su se od 0,782 do 0,914. Varijabla koja je najsnažnije povezana s veličinom riba utvrđena je na temelju sagitalne duljine otolita (OL) s 91,4% varijabilnosti. Rezultati ove studije pružaju prve sveobuhvatne podatke o odnosu između morfometrijskih varijabli sagitalnog otolita sa dužinom tijela
Anguilla anguilla
.
Here we present a discovery of a new fish from the family Gobiidae in Lake Prespa, which is known as a European hotspot for biodiversity and endemism. This is the first detection of a fish species ...from this family, not only regarding this lake but also in the territory of the Republic of North Macedonia in general. The close examination of the recorded specimens revealed the presence of perianal organ surrounding the anus. This unique organ and various other observed morphometric and phenotypic characteristics point out to the genus Economidichthys. The two known fish species from this genus are currently considered endemic only to the rivers and lakes of western Greece. This new finding could be an evidence of alien species introduced in this lake, or an evidence of native species that are not recorded yet because of their characteristic life habits. Either way, this is a very important finding for the taxonomy and biogeographical distribution of the freshwater gobies in the Balkans.
The anti-quorum sensing activities towards the bacterium Pseudomonas aeruginosa PA01 (pyocyanin production, biofilm formation and twitching and flagella motility) of two crude extracts (methanol and ...acetone) of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937) were evaluated in vitro for the first time. Both extracts demonstrated P. aeruginosa pyocyanin inhibitory activity, reducing its production for 49.90% and 42.44%, respectively. In addition, they both showed higher anti-biofilm activity (48.29% and 53.99%, respectively) than ampicillin (30.84%). Finally, O. rotunda extracts effectively reduced twitching and flagella motility of P. aeruginosa. Taken all together, these results suggest that endemic sponge species from the oldest lake in Europe may offer novel bioactive natural products with promising medicinal potential towards P. aeruginosa infections.
Studies on the identification, properties and function of chitin in sponges (Porifera), which are recognized as the first multicellular organisms on Earth, continue to be of fundamental scientific ...interest. The occurrence of chitin has so far been reported in 21 marine sponge species and only in two inhabiting fresh water. In this study, we present the discovery of α-chitin in the endemic demosponge Ochridaspongia rotunda, found in Lake Ohrid, which dates from the Tertiary. The presence of chitin in this species was confirmed using special staining, a chitinase test, FTIR, Raman and NEXAFS spectroscopy, and electrospray ionization mass spectrometry (ESI-MS). In contrast to the case of marine sponges, chitin in O. rotunda has been found only within its holdfast, suggesting a role of chitin in the attachment of the sponge to the hard substratum. Isolated fibrous matter strongly resemble the shape and size of the sponge holdfast with membrane-like structure.
The antimicrobial activity of five crude extracts (aqueous, methanol, ethyl acetate, acetone and methylene chloride) of the freshwater sponge Ochridaspongia rotunda (Arndt, 1937) was evaluated in ...vitro by using microdilution method against eight bacterial and eight fungal strains for the first time. The extracts were proven to be active in varying degrees against all the bacteria and fungi tested. O. rotunda methanol extract exhibited the highest antibacterial activity (minimum inhibitory concentration (MIC) 7.5-15.0 μg/mL and minimum bactericidal concentration 15-30 μg/mL), while its acetone extract exhibited the most promising antifungal activity (MIC 7.5-45.0 μg/mL and minimum fungicidal concentration 15-60 μg/mL). The extracts were more effective against the bacteria and fungi screened compared with the positive controls (streptomycin and ampicillin for bacteria and bifonazole and ketoconazole for fungi, respectively). According to the experimental data obtained, this deepwater sponge species may be considered as a gold mine of new antimicrobial substances with significant and broad-range activity.
PDF
