This study proposed a method for detecting vegetation changes and establishing geospatial management zones based on the 10-year phenology analysis using normalized difference vegetation index (NDVI) long-term trends from Landsat 8 multispectral imagery in Nature Park Kopački rit. The main components of the proposed method include phenology analysis and NDVI anomaly detection supported by unsupervised k-means classification of vegetation management zones. The reference monthly NDVI values (2013-2019) with three test years (2020-2022) strongly indicated very high heterogeneity in vegetation activity. A 100 m spatial resolution and a monthly temporal resolution were used. The results of unsupervised k-means classification in five vegetation activity classes indicated that three of these classes have considerably high negative NDVI anomalies, covering 64.1% of the study area. While the proposed method ensures the detection of vegetation changes and vegetation activity zones, a comprehensive field observation is required to determine the potential environmental and/or anthropogenic causes. However, the proposed approach significantly reduces the need for extensive fieldwork, allowing biologists to focus their efforts on areas with detected abnormal vegetation activity.

Concerns have been escalating over the increase in heavy metal levels in the environment due to anthropogenic impacts. Toxic heavy metals (As, Cd, Hg and Pb) are especially dangerous, as they negatively affect organisms and cause outbreaks of diseases. The hare has been proven to be a good indicator of environmental heavy metal contamination. The liver and kidney are the tissues most commonly used in biomonitoring. Hares inhabiting a contaminated habitat have higher concentrations of heavy metals in these tissues than those from a referential habitat. As is mostly accumulated in the nails and hair, Cd in the kidney, Hg in the brain and kidney, and Pb in the brain and diaphragm. Cd and Hg concentrations in hare liver and kidney increased with animal age. In most countries, hare meat is safe for human consumption, while the consumption of entrails is not recommended.

Three FA indices showed correlations with age and magnitude of traits, but not in general. Significant correlations between magnitude of traits and their FA were more pronounced in AFA (12 traits) than in RFA (10 traits) in all age classes except yearlings. For the tray tine form (curvature), FA significantly correlated with its magnitude in young, middle-aged and ripe stags, which indicates that the trait is a reliable indicator of asymmetry. Significant differences in AFA among age classes were found in four traits (weight of dry antlers, volume of antlers, distal circumference of beams and total length of crown tines). By RFA, a significant difference among age classes was only found for the distal circumference of beams. Thus, AFA is a more vulnerable condition index. Contrary to other research findings, developmental instability was more pronounced in older age classes. In yearlings, no significant FA dependence on the trait of antler size was detected, but in certain traits, an asymmetry detected at an early age remains visible later as well, although in stags grown under relatively optimal (especially trophic) environment conditions, developmental instability was present anyway. This proposes two hypotheses for further research: Competition may be manifested even under controlled conditions, which might jeopardize the developmental stability of certain individuals, or some traits will show developmental instability regardless of relatively good environmental conditions.

The record is confirmed of a "Clariobranchus" hybrid Clarias gariepinus x Heterobranchus sp. specimen in the River Danube in Croatia. Clarias gariepinus was introduced to Europe for farming and research purposes. Because of their faster growth and short time to achieve market size, "Clariobranchus" hybrids have gained attention in European aquaculture. To date, no record has been found in the literature of "Clariobranchus" hybrid escapees in inland waters of Europe. The present finding suggests that the "Clariobranchus" hybrid escaped from an unprotected aquaculture system or open pond farm. The threat of establishment of a population of this hybrid in suitable environments, such as thermal ponds, cannot be ruled out.

Bees (Apis mellifera) are the main pollinators of many plants and play a key role in agriculture. Although bees are not targeted organisms in the use of protective agents in the field, unfortunately they are heavily influenced by pesticides. The objectives of this study were to determine the species and concentration of pesticides in bees, and whether there were differences in levels of insecticides and fungicides. In total, 40 samples from 4 regions of Varazdin County were analysed, as well as two control samples from the Sisak-Moslavina County (Lonjsko Polje) and Karlovac County (Bosiljevo). Each of the samples was analysed on 78 active substances using gas chromatography with GC-MS mass spectrometry and highly effective liquid chromatography HPLC technique. The samples were prepared using the modified Quechers method EN 15662:2018. Fifteen different active pesticide substances were identified and quantified in 40 samples. The mass content of pesticides in bee samples was 0.035-295 mu g/bees. The results obtained and the identified differences in fungicide levels related to the location distribution in bee samples indicate a significant difference in fungicide levels in bee samples (P=0.039), while there is no statistically significant difference in the analysed levels of insecticide. The pesticide residues were not identified in the control samples. This work contributes significantly to environmental protection by pointing out that honey bees are an excellent bioindicator, and that they can be used to investigate environmental pollution with pesticides.

The most frequently utilized population quality indices in cervids were a fluctuating asymmetry or a branch length in yearlings. Nevertheless, unlike bovids, there has not been a reliable quality index so far that could also be applied at a later age. Therefore, an application reliability testing pertaining to certain elements of trophy measurement for the sake of difference detection between the cohorts was performed on a sample numbering 225 trophies of red deer stags from 11 cohorts. Although each of the nine trophy variables tested has succeeded in finding certain differences, the most reliable are the overall trophy value and circumferences (circumference of coronets, lower beam circumference and upper beam circumference). Since various trophy evaluation systems have been applied in the world, the implementation of the overall trophy value is limited only to the trophies evaluated pursuant to the CIC system. Hence, the most reliable indices are those based upon circumferences.

The Danube is the second-longest river in Europe that is subjected to various man-made alterations, including those related to hydro-power plants. We surveyed and analyzed the presence and abundance of macrophytes in the main channel from 2582 river kilometers (rkm) to 171 rkm. We also assessed selected habitat parameters in the sampled river stretches. Sixty-eight different plant species were recorded along the entire course. Among neophytes, we found Elodea nuttallii, E. canadensis, Vallisneriaspiralis and Azolla filiculoides. Based on similarity analysis, we distinguished 15 plant communities, most of which were defined as associations, which were classified into 5 alliances and represented three vegetation classes, namely vegetation of rooted hydrophytes Potamogetonetea, the vegetation of pleustophytes Lemnetea and vegetation of marshes Phragmitetea. The number and abundance of plant species, as well as plant communities recorded in single stretches, varied along the course. Canonical correspondence analysis (CCA) revealed that environmental parameters explained 21% of plant species composition. CCA runs with neophytes explained 41% of the variance, and current velocity, water transparency, species number and bank structure were significant variables. The present study revealed that the free-running sections of the river are poor in number and abundance of plant species, whereas impounded reaches mainly show an opposite result.

Hard ticks (Acari, Ixodidae), as the blood-feeding ectoparasites of wild and domesticated mammals, birds and reptiles, are known as a vector of many viral and bacterial pathogens that also affects human health. Climate changes modify seasonality in life cycle of hard ticks and cause the shift of their climatic niche in Europe, related to latitudinal and altitudinal range. The Eurasian Wild Boar (Sus scrofa L.) as the most widespread game species in Croatia can maintain tick populations. Tick sampling was done from wild boars, hunter-harvested in four hunting grounds: Spacva, Nova Gradiska, Vocin and Slunj. Total of 118 specimens were collected from 18 infested wild boars. The most abundant species was Dermacentor reticulatus (91%), followed by Ixodes ricinus (7%) and Ixodes hexagonus (2%). The largest number of collected ticks was in adult stage (97%), and 3% in the nymphal stage. An average infestation rate was 7 ticks per individual. The results of survey contribute to predicting the health risk of tick-borne diseases in Croatia.

Distribution of the European mudminnow, Umbra krameri, Walbaum 1792, in Croatia is scarce with only few confirmed localities. In order to confirm presence of the European mudminnow in amelioration canal network along the Drava River an electrofishing was conducted in the small Mlinski canal. Ten specimen of European mudminnow were caught During sampling. Using ImageJ software a truss network was constructed between landmark points on photographs of caught specimens. Total body lengths of caught European mudminnow ranged from 61 to 100 mm (72.00±11.52 mm) whereas standard one ranged from 52 to 85 mm (60.30±10.08 mm). Body weight were relatively small ranging from 1.81 to 7.59 g (3.80±1.89 g), while the Fulton condition factor ranged from 0.76 to 1.23 (0.96±0.15). This new locality of the European mudminnow is situated about 50 km downstream from the last confirmed site in Croatia.

Event Abstract Back to Event First record of North African catfish (Clarias gariepinus) in Croatian inland waters Marina Piria1, Dinko Jelkić2*, Ana Gavrilović1, Ivan Špelić1, Anđelko Opačak2 and Siniša Ozimec2 1 Faculty of Agriculture, University of Zagreb, Croatia 2 Faculty of Agrobiotechnical Sciences, Josip Juraj Strossmayer University of Osijek, Croatia The North African catfish Clarias gariepinus (Burchell 1822) is native to South Africa, Israel, Syria and south of Turkey. It was widely introduced to other parts of Africa, Europe and Asia (Froese and Pauly, 2019). For the first time in Europe it has been introduced in Netherlands 1977 because of aquaculture purposes (Povž, 2007). Until 1990, several European countries started with North African catfish farming: Belgium, Germany, Hungary, Poland, Slovakia, Czechia and Russia (Froese and Pauly, 2019). In the same period the first occurrences of this species in inland waters have been reported, for example in 1985 in Czechia (Lusk et al., 2004). Furthermore, North African catfish have occurred in Slovenia since 1997 in gravel pits near the Hungarian border, likely as a consequence of sport fishing activities (Povž, 2007), and in 2007 was recorded in the Ovcharitza Reservoir in Bulgaria (Uzunova and Zlatanova, 2007). The status of those introductions is unknown. In Croatia, North African catfish was introduced in 2010 at the Draganići fish farm for aquaculture purposes, but, so far, there have been no records of this species in inland waters. One specimen of North African catfish was caught on 29 September 2016 by gillnet in the Danube River (1418 rkm, near Zmajevački dunavac) by commercial fisherman during the regular fishing activity (Fig. 1.). Immediately after being caught, an undetermined specimen was frozen at -10°C and sent to laboratory of Faculty of Agrobiotechnical Sciences. In laboratory the specimen was measured for total length (TL, in cm) and weight (W, in g). Stomach content was removed, measured and prey items determined to the lowest possible systematic category. Assessment of the fish diet was based on the frequency of occurrence (F%) and numerical frequency (N%). Condition factor (CF), was calculated as W TL -3100 (Ricker, 1975). Captured specimen was male, TL=67 cm and W= 2184 g. The stomach of this specimen was full; the dominant portion consisted of Macrophyta (F%=25), Gastropoda (N%=33, F%=25), Crustacea (N%=67, F%=25) and detritus (F%=25). Its condition factor (CF) was 0.73. This caught specimen could be escapee from fish farms placed in the Danube River basin of Croatia or from other surrounding countries (Hungary or Czechia). For example, in Hungary this species is farmed in open ponds for the last 30 years. In Draganići fish farm in Croatia, which also belongs to the Danube River Basin, North African catfish also are placed in open ponds. North African Catfish is omnivorous fish species and its presence in inland waters may cause several negative impacts on native fish species, aquatic biodiversity and environment. Nevertheless, it is supposed that species can’t survive low winter temperatures under the European climate conditions, thus in most of European countries North African Catfish probably extinct from inland waters. However, this record highlight needs for better regulation of farming of alien species and to setup closed recirculation systems (RAS) for new introduction of alien fish species, which is only way how to prevent such escapes in our inland waters. Fig. 1. Captured specimen of North African catfish in the Danube River in Croatia Figure 1 Acknowledgements We would like to thank to commercial fisherman Milić Miro who provide this specimen to Faculty of Agrobiotechnical Sciences Osijek. This research was supported by EIFAAC project "Management / Threat of Aquatic Invasive Species in Europe". References Froese, R. and D. Pauly. Editors. 2019. FishBase. World Wide Web electronic publication. www.fishbase.org, version (02/2019). Lusk, S., L. Hanel and V. Lusková, 2004. Red list of the ichthyofauna of the Czech Republic: Development and present status. Folia Zool. 53(2):215-226. Povž, M. (2007). North African catfish Clarias gariepinus (Burchell, 1822). Ribič, 5, 120–121. Ricker WE (1975) Computation and interpretation of biological statistics of fish populations. Bulletin of the Fisheries Research Board of Canada 191: 382 Uzunova, E., & Zlatanova, S. (2007). A review of the fish introductions in Bulgarian freshwaters. Acta Ichthyologica et Piscatoria, 37, 55–61. Keywords: Non-native fish, Inland water, Danube River, North African catfish, Stomach content Conference: XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019. Presentation Type: Poster Topic: THREATS AND CONSERVATION Citation: Piria M, Jelkić D, Gavrilović A, Špelić I, Opačak A and Ozimec S (2019). First record of North African catfish (Clarias gariepinus) in Croatian inland waters. Front. Mar. Sci. Conference Abstract: XVI European Congress of Ichthyology. doi: 10.3389/conf.fmars.2019.07.00142 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 May 2019; Published Online: 14 Aug 2019. * Correspondence: Mx. Dinko Jelkić, Faculty of Agrobiotechnical Sciences, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia, djelkic@fazos.hr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Marina Piria Dinko Jelkić Ana Gavrilović Ivan Špelić Anđelko Opačak Siniša Ozimec Google Marina Piria Dinko Jelkić Ana Gavrilović Ivan Špelić Anđelko Opačak Siniša Ozimec Google Scholar Marina Piria Dinko Jelkić Ana Gavrilović Ivan Špelić Anđelko Opačak Siniša Ozimec PubMed Marina Piria Dinko Jelkić Ana Gavrilović Ivan Špelić Anđelko Opačak Siniša Ozimec Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The protection of habitats makes an integral part of the nature conservation policy in the European Union. The updated digital Habitat Map of Croatia shows the spatial overview of natural and semi-natural, non-forest terrestrial and inland freshwater habitats at a scale of 1: 25 000. The field validation of habitats was carried out during 2015 and 2016. The size of the surveyed area in eastern Croatia is 10 262.02 km(2). Total 5032 field points were collected by using a tablet with GIS/GPS and Habitat Mapper application. The composition and distribution of the main habitat type classes were analysed in the surveyed area of 10 262.02 km(2). Dominating habitats belongs into categories of cultivated habitats (47.4%), and forests (40.0%), followed by constructed and industrial habitats (3.59%), inland surface water and wetlands (3.54%), grasslands (2.83%) and scrubs (2.59%). The knowledge on habitat structure and interpretation of the habitat map is an important tool for the sustainable management of natural resources in agriculture, forestry, hunting and freshwater fisheries.

Kopački rit Nature Park is a large fluvial-marshy floodplain, situated in the northeastern Croatia, between courses of the Danube and the Drava Rivers. Due to exceptional biological and ecological values of this floodplain area in the middle course of the Danube River, it had been protected since 1967; proclaimed as Nature Park in 1999 and from 2012 is a part of the UNESCO Transboundary Biosphere Reserve Mura-Drava-Danube. This paper lists a total of 522 vascular plant taxa, classified in 295 genera and 96 families, recorded for Kopački rit Nature Park. The list is completed according to checked literature records and data for 114 new taxa, found during the floristic investigation carried outfrom 2010 to 2018. Taxonomic, ecological and phytogeographical analyses are presented. Hemicryptophytes dominate (39.3%) in the biological spectrum, followed by therophytes (23.8%), geophytes (12.6%) and hydrophytes (12.5%). In the chorological spectrum, the most numerous are plants of Eurasian floral elenent (32.8%), followed by Cosmopolites (27.4%), and European floral element (10.7%). Out of 53 recorded allochthonous plants, 26 are invasive alien plant species. According to protection and conservation status at the national level, 55 taxa are listed in the RedBook of Vascular Plants of Croatia and 53 taxa are strictly protected. One species, Marsilea quadrifolia, is listen in Annex II of the Habitat Directive.

The presence of mesocercarial stage of a trematode Alaria alata (Goeze, 1782) in wild boar meat represents the possible human health risk. The parasitological monitoring was done in the period 2006-2011, with an aim to determine the presence of A. alata mesocercariae in wild boars and water frogs. The survey area comprised three hunting grounds in eastern Croatia: Spacva, Podunavlje-Podravlje and Breznica, characterised with different orographic, hydrological and habitat conditions. The muscle tissue samples, collected from 761 wild boars and 43 water frogs, were examined. Prevalence of A. alata mesocercariae in wild boar was 42% (Spacva); 7% (Podunavlje-Podravlje) and 1% (Breznica). The average number of mesocercariae ranged 2.4-6.5 per 30 g of meat. Prevalence in water frogs was 11% (Spacva); 56% (Podunavlje-Podravlje), and 0% (Breznica). The presence of mesocercariae was higher in animals living in the lowland, periodically flooded areas with mixed forests and wetland habitats. From the viewpoint of food safety and consumer exposure to this potential food-borne hazard, further monitoring is required to assess the infestation rate and propose measures for the parasite reduction.