Population dynamics, diet and ecotoxicology of the GreatCormorant Phalacrocorax carbo (Linnaeus, 1758) in the Carska bara marshland

kormorana i naseljava sve kontinente izuzev Južne Amerike i Antarktika. Politipska je vrsta u okviru koje se razlikuje pet podvrsta, a Evropu naseljavaju dve: P. carbo carbo – naseljava obalu severnog Atlantika, i P. carbo sinensis – naseljava centralnu i južnu Evropu. Brojnost ove vrste konstantno raste od 70-ih godina prošlog veka. Veliki kormoran se u potpunosti hrani ribom. Rast broja kormorana širom Evrope doveo je do nezadovoljstva uzgajivača ribe i ribara, što je pokrenulo mnogobrojna istraživanja ove vrste u mnogim evropskim zemljama. U prošlosti, veliki kormoran se u Srbiji gnezdio u plavnim oblastima duž velikih reka (Obedska bara, Kovilj, Carska bara, Apatin...), ali je 60-ih i 70-ih godina prošlog veka, usled isušivanja močvara i meliorativnih radova, gotovo nestao kao gnezdarica. Sredinom 80-ih godina ponovo počinju da se formiraju kolonije velikog kormorana na području Vojvodine uz velike reke, i od tada je njegova brojnost u stalnom porastu. Početkom ovog veka počinju da se formiraju kolonije i južno od Save i Dunava. Istraživanja u okviru ove disertacije sprovedena su na području Specijalnog rezervata prirode „Carska bara“, u periodu od 2007. do 2010. godine. Brojnost gnezdeće populacije praćena je prebrojavanjem (cenzusom) aktivnih gnezda, dok je van tog perioda brojnost praćena prebrojavanjem ptica na zajedničkom noćilištu. Gnezdeća populacija je bila najbrojnija 2007. godine, kada je sastojala od 410 do 440 parova, dok je najmanja brojnost zabeležena 2010. godine, kada se gnezdilo 250 do 270 parova. Van perioda gnežđenja najveća brojnost velikih kormorana zabeležena je tokom novembra 2008. i 2009. godine (po 1950 jedinki). Ispitivanje ishrane velikih kormorana na području SRP „Carska bara“ vršeno je analizom gvalica i povraćenog želudačnog sadržaja. Ukupno je prikupljeno 587 gvalica, na osnovu kojih su identifikovani ostaci 2433 jedinke riba i 529 povraćenih riba. Registrovano je učešće 21 vrste riba u ishrani kormorana na ovom području, od čega 12 iz porodice Cyprinidae...The Great Cormorant Phalacrocorax carbo (L.) is the most widely distributed species of cormorants, as it inhabits all continents with the exception of South America and Antarctica. It is a polytypic species with five subspecies. Europe is inhabited by two subspecies: nominate P. carbo carbo – which inhabits the North Atlantic coasts, and P. carbo sinensis – which inhabits Central and Southern Europe. The abundance of Great Cormorant populations is constantly increasing since 1970s. The Great Cormorant is a fish eating bird. The increase in the number of cormorants has resulted in dissatisfaction of fish farmers and fishermen, which in turn instigated numerous studies aimed at assessing their actual impact on fish in many European countries. In the past, the Great Cormorant nested in floodplain areas along the large rivers in Serbia (Obedska Bara, Kovilj, Carska Bara, Apatin, etc.). However, in the 1960s and 1970s, due to drying of wetlands and melioration, it almost disappeared as a nesting species from this region. In the mid-1980s, Great Cormorants again began to form colonies in the province of Vojvodina along large rivers and, since then, the number of Great Cormorants in Serbia is constantly increasing. At the beginning of this century, Great Cormorants started to form colonies south of the Sava and the Danube rivers. Research activities within this dissertation were conducted in the Special Nature Reserve "Carska Bara" during 2007-2010. The abundance of the breeding population was monitored by counting active nests (census). Outside of this period, the number was determined by counting birds at overnight roosting locations. The breeding population was the largest in 2007, when it numbered 410 to 440 pairs, and the lowest in 2010, when 250 to 270 pairs were nesting. Outside of the nesting period, the highest number of Great Cormorants was observed during November 2008 and 2009 (1950 specimens each). Examination of the diet of Great Cormorants in the SRP "Carska Bara" was performed by analysis of pellets and regurgitated stomach contents. A total of 587 pellets were collected, in which remains of 2433 fish specimens were identified, as well as 529 regurgitated fish..

ISHRANA VELIKOG KORMORANA (PHALACROCORAX CARBO) U SPECIJALNOM REZERVATU PRIRODE „CARSKA BARA“, SA POSEBNIM OSVRTOM NA UDEO ŠARANA (CYPRINUS CARPIO) U ISHRANI

Veliki kormoran se u potpunosti hrani ribom. Dnevna količina hrane koju veliki kormoran pojede kreće se između 425-700 grama, odnosno u proseku od 15 do 17 % svoje telesne težine. Opsežnija istraživanja ishrane velikih kormorana u Srbiji nisu vršena. Jedini podaci o ishrani kormorana i drugih ihtiofagnih vrsta ptica kod nas odnose se na štete koje one nanose proizvodnji ribe na ribnjacima. Podaci o ishrani kormorana van ribnjaka odnose se na ishranu tokom sezone gnežđenja u koloniji u Kopačkom ritu i zimsku ishranu na akumulaciji Gruža. Analiza ishrane velikog kormorana i značaj šarana u njegovoj ishrani rađena je na području Specijalnog rezervata prirode „Carska bara”. U periodu od 2007 do 2010 godine prikupljane su gvalice za analizu ishrane velikog kormorana. Gvalice su prikupljane u dve sezone: sezona gnežđenja (mart-jun) i jesenje-zimskom periodu (oktobarfebruar). Prikupljane su na mestima gde se ptice odmaraju i u samom mestu gnežđenja. Analiza gvalica je najčešće korišćen metod analize ishrane kod kormorana. U periodu oktobar– februar, 2007 – 2010. godine prikupljeno je 507 gvalica iz kojih su identifikovani ostaci 2433 jedinke od 16 različitih vrsta riba, od kojih je 9 vrsta bilo iz familije Cyprinidae, zatim tri vrste iz familije Percidae i po jedna vrsta iz familija Gadidae, Esocidae, Ictaluridae i Gobiidae. Ostaci šarana identifikovani su u 184 gvalice (36,29%). Šaran je u ovom periodu bio zastupljen sa 18,10%, u pogledu brojnosti. Po masenom udelu u plenu najznačajnija je vrsta, sa učešćem od 36,24%. Tokom sezona gnežđenja od 2007. do 2010. godine prikupljeno je 80 gvalica. U plenu, identifikovanom iz gvalica, po brojnosti su dominirale dve vrste, babuška i šaran, a registrovano je prisustvo 11 vrsta riba iz 5 familija (6 Ciprinidae, 1 Ictaluridae, 1 Esocidae, 2 Percidae,1 Gobiidae). Ostaci šarana su registrovani u 44 (55%) gvalica. Šaranske vrste riba su još značajnije zastupljene u ishrani kormorana tokom sezone gnežđenja nego u jesenjem i zimskom periodu. Tako, one čine 85% ukupnog broja ulovljenih jedinki, a udeo u biomasi plena je oko 90%. Rezultati istraživanja ishrane velikih kormorana na području Carske bare u skladu su sa mnogim studijama sprovedenim širom Evrope

SEZONSKA VARIBILNOST POKAZATELJA KVALITETA VODE AKUMULACIJE MEĐUVRŠJE

Istraživanja su vršena u leto i jesen 2014. godine na akumulaciji Međuvršje na tri lokaliteta: brana, Vidovski tunel i Zagrađe. Multiparametarska sonda (YSI 6600 V2) korišćena je za merenje temperature, koncentracije rastvorenog kiseonika, pH, totalno rastvorenih čestica, konduktiviteta i koncentracije hlorofila-a od površine do 10m dubine, sa intervalom od 1m. U obe sezone, najveće variranje temperature, koncentracije rastvorenog kiseonika, konduktiviteta i totalno rastvorenih čestica zabeleženo je kod brane. Na svim lokalitetima su tokom leta zabeležene više vrednosti temperature, konduktiviteta i koncentracija hlorofila-a u poređenju sa jesenjom sezonom. Zabeležene su niže vrednosti koncentracija rastvorenog kiseonika i pH u letnjoj sezoni.This study was conducted in the summer and autumn of 2014 at Međuvrsje at three locations: dam, Vidovski tunnel, and Zagrađe. A multiparameter probe (YSI 6600 V2) was used to measure temperature, dissolved oxygen concentration (DOC), pH, total dissolved solids (TDS), conductivity, and chlorophyll-a concentration from the surface to 10m depth, with an interval of 1m. In both seasons, the highest variations in temperature, DOC, conductivity, and TDS were recorded at the dam. At all sampling sites, the highest values of temperature, conductivity, and chlorophyll-a concentration were recorded in summer. The lowest DOC and pH values were recorded in summer

Nest-site preference of griffon vulture (gyps fulvus) in Herzegovina

Although formerly an abundant species, the Eurasian Griffon (Gyps fulvus Hablizl, 1783) has undergone a dramatic decline in Herzegovina. Such an unfavorable trend may be associated with frequent poisoning incidents (consumption of poisoned baits), shortage of food and hunting. This species disappeared from its breeding habitats in Herzegovina during the last decade of the 20th century. The extinction was probably caused by military activities during the civil war. Using data that were collected over a period of long-term (1980-1991) monitoring of the breeding population, we discovered optimal environmental conditions for the nesting of the Eurasian Griffon Vulture in Herzegovina. Information on nest-site preference is valuable for conservation programs and the possible reintroduction of the Eurasian Griffon, not only in Herzegovina, but also to a much wider region. During the study period, we observed 61 nests and 252 nesting cases in four colonies of Eurasian Griffon Vulture. Most nests were located on limestone and dolomite rocks. The average altitude of nests was 378 m a.s.l.; most of nests (85%) were located below 500 m a.s.l. Also, the majority of nests were located on west-exposed sites

NEKE BIOLOŠKE ODLIKE SOMA (SILURUS GLANIS) IZ AKUMULACIJE „UVAC”

Som je najveća primarno slatkovodna vrsta ihtiofaune Srbije i u staništima koja naseljava predstavlja vrhunskog predatora. Ova vrsta ne spada u nativnu ihtiofaunu u vodama Rezervata Uvac, a vreme introdukcije, količina i uzrasni sastav unetih riba su nepoznati. Generalno, podaci o biologiji prirodnih populacija soma u otvorenim vodama u Srbiji su siromašni i do sada ne postoje studije o populaciji u akumulaciji Uvac. Ciljevi ovog istraživanja su određivanje starosne i polne strukture populacije somova i njegove distribucije u akumulaciji. Definisane su tri zone akumulacije u kojima je vršeno uzorkovanje, i to: zona I (gornji kanjonski deo akumulacije), zona II (srednji deo akumulacije sa ulivima dve pritoke) i zona III (donji deo akumulacije u oblasti brane). Mrežarskim alatima ulovljeno je ukupno 20 somova. Među ulovljenim jedinkama 7 je bilo mužjaka, 9 ženki i kod 4 jedinke nije bilo moguće makroskopski odrediti pol. Dužina je varirala od 60-86 cm kod mužjaka; 66-113 cm kod ženki i 51-57.5 cm kod polno nezrelih jedinki. Težina ulovljenih primeraka kretala se u opsegu 993-4 000 g kod mužjaka; 1 520-9 000 g kod ženki; i 652-984 g kod polno nezrelih jedinki. Među mužjacima su dominirale jedinke starosti 3+, dok su kod ženki sve starosne klase bile jednako zastupljene (2+-7+). Sve polno nezrele jedinke su bile starosti 2+. Som u akumulaciji Uvac dominantno naseljava gornji (kanjonski) deo, a na osnovu starosne structure populacije pretpostavlja se da je som u akumulaciju introdukovan pre više od 10 godina

Concentrations of metals and trace elements in different tissues of nine fish species from the Međuvršje Reservoir (West Morava River Basin, Serbia)

Element concentrations in selected fish species from different trophic levels were analyzed. The following fish species were analyzed: common nase (Chondrostoma nasus), roach (Rutilus rutilus), freshwater bream (Abramis brama), barbel (Barbus barbus), Prussian carp (Carassius gibelio), chub (Squalius cephalus), European perch (Perca fluviatilis), wels catfish (Silurus glanis) and northern pike (Esox lucius). Fish were collected from the Meduvršje Reservoir (West Morava River Basin, western Serbia) during 2012, and samples of liver, muscle and gills were analyzed for As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sr, and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES). The liver and gills had the highest measured element concentrations, with Cu, Zn, Fe and Sr being the most prominent. The bioaccumulation of metals was species-specific, with the accumulation exhibiting the following trends: Prussian carp > northern pike > freshwater bream > European perch > chub > common nase > barbel > roach > wels catfish; Li > Pb > Z n > Cu > Fe > Ba > Mn > Sr > Cr > As > Mo > Ni > B, in all examined species; for Co, Cd and Hg, the bioaccumulation factor (BAF) was 0. Results of this study point to the tissue-specific differences in element concentrations, and to distinct differences between fish species regarding the accumulation patterns: common nase, with the highest accumulation observed in the liver, and Prussian carp, with the highest accumulation observed in the gills.Archives of Biological Sciences (2016), 68(4): 811-81

Freshwater jellyfish craspedacusta sowerbyi lankester, 1880 (hydrozoa, olindiidae)-50 years' observations in Serbia

Detailed and relevant limnological investigations of Serbian waters were initiated in 1958 and have continued to the present. During the period 1971-2008 we monitored biological elements as a part of working studies/projects, including the distribution of the freshwater jellyfish Craspedacusta sowerbyi Lankester, 1880. We observed over 500 sampling sites in running and standing waters. Specimens of this hydro-medusa were found in five of them. Throughout the period of investigation, only the medusae stages were observed. Our purpose in this paper was to provide data of the records and distribution of this limnomedusa during the period 1958-2008 in inland waters of Serbia. These observations should contribute to knowledge on the limnofauna not only of the Balkan Peninsula but Europe as a whole

LENGTH-WEIGHT RELATIONSHIP AND CONDITION FACTOR OF THE WHITE BREAM (Blicca bjoerkna) IN THE DANUBE RIVER NEAR BELGRADE (1168-1170 RKM)

White bream is an important species in commercial and sport fishing that is caught in nets throughout the year. The analyzed samples of white bream (n = 377) came from commercial catches carried out between December 2014 and May 2015 at two locations in the Danube near Belgrade, Jojkića Dunavac (JD) – an armlet of the Danube, with slow water flow and Veliko ratno ostrvo (VRO) – the main channel of the Danube, with fast water flow. Total body length (TL, cm) and body weight (BW, g) of each fish were measured, and Fulton's condition factor (K = W/L3 x 100) was calculated. Average TL of the fish samples from the JD and VRO were 23.1±1.7 and 23.8±2.4, respectively, and average BW were 164.4±42.2 and 201.0±73.0, respectively. In general, fish from VRO were in better condition (K=1.44±0.16) compared to sample from JD (K=1.31±0.11). Individuals in the sample from JD had a negative allometric growth (a = -1.79, b = 2.93, r² = 0.85), while those from VRO have a positive allometric growth (a = -2.22, b = 3.28, r² = 0.89). Based on the results of this study, positive allometric growth (b > 3) and fish condition indicated that individuals from VRO increased body mass more than body length. The source of food, its availability, and better habitat conditions at VRO could be the reason for the differences in the growth and condition of the fish from the investigated locations

Analysis of allometry and condition factor of the white bream (Blicca bjoerkna) in the Danube river near Belgrade (1168-1170 rkm)

This study was conducted on individuals of White bream from commercial catches carried out between December 2014 and May 2015 at two locations in the Danube near Belgrade, Veliko ratno ostrvo (VRO) – the main canal of the Danube, with fast water flow and Jojkića Dunavac (JD) – an armlet of the Danube, with slow water flow. A total of 377 individuals were analysed. Total body length (L, cm) and body weight (W, g) of each sampled individual were measured, and Fulton's condition factor was calculated. Average TL of the fish individuals from the VRO and JD were 23.8±2.4 and 23.1±1.7, respectively, and average W were 201.0±73.0 and 164.4±42.2, respectively. In general, fish from location VRO were in better condition (K = 1.44±0.16) compared to sample from JD (K = 1.31±0.11). Individuals in the sample from VRO had a positive allometric growth (a = -2.22, b = 3.28, r² = 0.89), while those from JD had a negative allometric growth (a = -1.79, b = 2.93, r² = 0.85). Based on the results of this study, positive allometric growth (b > 3) and fish condition indicated that individuals from VRO increased body mass more than body length. The source of food, its availability, and better habitat conditions at VRO could be the reason for the differences in the growth and condition of the fish from the investigated locations. The presented results can be applied in fisheries management plans and sustainable exploitation of this fish species as it provides information on stock condition

SEASONAL VARIATION OF FISH COMMUNITY IN RIVERS PEŠTAN AND BELJANICA

Terenska istraživanja obavljena su na rekama Peštan i Beljanica tokom 2011. i 2012. godine, i obuhvatila su analizu sastava i strukture zajednica riba. Rezultati ukazuju na dominaciju ciprinidnih vrsta riba. Zajednica riba na ispitivanim lokalitetima je pod intenzivnim opterećenjem, te su podaci ovih istraživanja od važnosti za očuvanje i zaštitu ribolovnog resursa (područja).Field research of rivers Peštan and Beljanica have been done during 2011 and 2012, and were surveyed for ichthyofauna composition and structure. The results indicate the dominance of cyprinid fish species. Data on fish species diversity of the researched localities under high pollution is of value for conservation and protection of fishery sources