Fluktuacije ulova nekih pelagičnih vrsta riba u Mediteranu

U radu su analizirani 63 godine dugački podaci o ulovu tune (Thunnus thynnus) i srdele (Sardina pilchardus) u Mediteranu, metodom spektralne (Fourierove) analize i kros korelacjom. Analiza je pokazala da ulov tune sadrži ciklične komponente od 2.6, 3.65, 5.64, 7.75, 10.34 and 15.5 i verovatno 31 godinu, dok su u ulovu srdele najizraženije bile amplitude od 2.44, 3.65, 6.2, 7.75 i 10.34 godina. Prema tome, oba su vremenska niza bila koherentna u ciklusima od 3.65, 7.75 i 10.34 godina. Takođe je ustanovljeno da je ulov tune koherentan sa indeksom severoatlantske oscilacije (NAO) i to u periodima od 2, 3.35, 4.43, 6.89, 10.34 i verovtno 31 godina. Ovo ukazuje da klimatski ciklusi utiču na fluktuacije populacije ove ribe. Nadalje, upoređenje fluktuacija ulova tune u zapadnom i istočnom Mediteranu je pokazalo da su one potpuno sinhrone

Spectral sensitivity of the perch (Perca fluviatilis) from the Danube

In spectral sensitivity studies, electroretinograms (ERG) were recorded from the in situ eyecup of immobilized perch (Perca fluviatilis) electrofished in the floodplain zone of the Danube River. It is shown that the ERG b-wave is a good indicator of spectral sensitivity, although it reflects the activity of photoreceptors indirectly. With a maximum around 542 mm, the scotopic spectral sensitivity of perch obtained using fitted amplitude-log intensity functions for threshold calculation and two models developed in our laboratory for computer-assisted fitting of spectral sensitivity curves did not differ from the sensitivity determined using the microspectrophotometric and isolated pigment methods (maximum around 541 nm)

Review of sterlet (Acipenser ruthenus L. 1758) (Actinopterygii: Acipenseridae) feeding habits in the River Danube, 1694-852 river km

The aim of this work is to present the variation in the sterlet's (Acipenser ruthenus L. 1758) diet along the course of the River Danube, from 1694 to 852 river km. The diet of sterlet mostly comprised 12 bottom fauna taxa. Sterlet in the Danube feed mainly on larvae of Trichoptera, Chironomidae (Diptera) and Gammaridae (Amphipoda), with a reduction in food composition variability close to the Djerdap I dam and in the reservoir between the two dams. The other components of the diet were Corophium sp., Asselus sp., Mollusca, Oligochaeta, Annelida, Insecta, Nematoda and Hirudinea. The organisms typical of lithorheophilic and psammorheophilic biocoenoses play a considerable role in the diet of the sterlet. Composition of bottom fauna as food items varies due to changes in environmental conditions induced mainly by the construction of two dams: Djerdap I (943river km, 1970) and Djerdap II (863river km, 1984).Ministry of Education, Science and Technical development of the Republic of Serbia {[}173045

Figure 2 in Review of sterlet (Acipenser ruthenus L. 1758) (Actinopterygii: Acipenseridae) feeding habits in the River Danube, 1694-852 river km

Figure 2. Relative abundance of food items (bottom fauna taxa) found in the stomach contents of sterlet sampled from the River Danube.Published as part of Djikanovic, V., Skoric, S., Lenhardt, M., Smederevac-Lalic, M., Visnjic-Jeftic, Z., Spasic, S. & Mickovic, B., 2014, Review of sterlet (Acipenser ruthenus L. 1758) (Actinopterygii: Acipenseridae) feeding habits in the River Danube, 1694-852 river km, pp. 411-417 in Journal of Natural History 49 (5) on page 414, DOI: 10.1080/00222933.2013.877991, http://zenodo.org/record/400412

Growth and Weight-Length Relationship of Burbot Lota lota (L.) (Lotidae) in the Danube River at Backa Palanka (Serbia)

The basic life history data of the burbot inhabiting the Danube River at the Baoka Palanka locality were studied. Totally, 124 specimens (45.2\% males, 48.4\% females and 6.4\% of undeterminable sex) were collected from commercial landings. The total length and weight ranges were 22.5-63 cm and 92-1709 g, respectively, while the age range was 1-6 years (otolith readings). For each age class, there were no differences in the average length and weight between sexes. The average length-at-age and weight-at-age were 26.97 cm, 32.35 cm, 38.34 cm, 52.5 cm and 139.8 g, 225.2 g, 371.8 g and 1041 g for the age classes 1, 2, 3 and 6, respectively. The weight-length relationship was described as W = 0.01 TL2.861 (r(2) = 0.9566). The von Bertalanffy growth parameters were L-infinity = 66.58 cm, k = 0.17, t(0)= -2.01, and the phi-prime index was calculated as Phi = 2.88. The obtained data were compared with available results from elsewhere.Ministry of Education, Science and Technological Development {[}TR37009]; Serbian Academy of Sciences and Art

Review of sterlet (Acipenser ruthenus L. 1758) (Actinopterygii: Acipenseridae) feeding habits in the River Danube, 1694-852 river km

Djikanovic, V., Skoric, S., Lenhardt, M., Smederevac-Lalic, M., Visnjic-Jeftic, Z., Spasic, S., Mickovic, B. (2014): Review of sterlet (Acipenser ruthenus L. 1758) (Actinopterygii: Acipenseridae) feeding habits in the River Danube, 1694-852 river km. Journal of Natural History 49 (5): 411-417, DOI: 10.1080/00222933.2013.87799

Polarization mode control of long-wavelength VCSELs by intracavity patterning

Polarization mode control is enhanced in wafer-fused verticalcavity surface-emitting lasers emitting at 1310 nm wavelength by etching two symmetrically arranged arcs above the gain structure within the laser cavity. The intracavity patterning introduces birefringence and dichroism, which discriminates between the two polarization states of the fundamental transverse modes. We find that the cavity modifications define the polarization angle at threshold with respect to the crystal axes, and increase the gain anisotropy and birefringence on average, leading to an increase in the polarization switching current. Experimental measurements are explained using the spin-flip model of VCSEL polarization dynamics. (C) 2016 Optical Society of Americ

Growth and Weight-Length Relationship of Burbot Lota lota (L.) (Lotidae) in the Danube River at Backa Palanka (Serbia)

The basic life history data of the burbot inhabiting the Danube River at the Baoka Palanka locality were studied. Totally, 124 specimens (45.2\% males, 48.4\% females and 6.4\% of undeterminable sex) were collected from commercial landings. The total length and weight ranges were 22.5-63 cm and 92-1709 g, respectively, while the age range was 1-6 years (otolith readings). For each age class, there were no differences in the average length and weight between sexes. The average length-at-age and weight-at-age were 26.97 cm, 32.35 cm, 38.34 cm, 52.5 cm and 139.8 g, 225.2 g, 371.8 g and 1041 g for the age classes 1, 2, 3 and 6, respectively. The weight-length relationship was described as W = 0.01 TL2.861 (r(2) = 0.9566). The von Bertalanffy growth parameters were L-infinity = 66.58 cm, k = 0.17, t(0)= -2.01, and the phi-prime index was calculated as Phi = 2.88. The obtained data were compared with available results from elsewhere.Ministry of Education, Science and Technological Development {[}TR37009]; Serbian Academy of Sciences and Art