Tomislav Kralj

• Rudjer Boskovic Institute

1. Allochthonous organic matter is an essential resource of aquatic food webs, and freshwater amphipods, particularly species of the genus Gammarus, play a significant role in leaf litter decomposition. However, this important ecological function may be affected by the invasion of alien amphipods such as Dikerogammarus villosus, which has been repo...

The impact of the long-term historical contamination of the Mrežnica River with textile industry wastewaters on metal/metalloid bioaccumulation in the muscles of the young northern pike (Esox lucius) (0+ to 3+) was evaluated, as well as the association of bioaccumulated metal/metalloid concentrations in the muscle with fish physiology. Increased le...

Although Europe is the continent with the highest proportion of karst areas, where hydrological systems are essential but extremely sensitive, data on the ecological status of karst riverine catchments are scarce. The aim of the present study was to assess the spatial and temporal (long-term and seasonal) variability of the physico-chemical and org...

The distribution and density/abundance of invasive aquatic animals (fish and macroinvertebrates) were studied from 2012–2023 in the basin of the karst Dobra River in central Croatia, including three reservoirs. The following methods were used: hand net, Ekman grab and quadrat census for molluscs, snorkelling and LiNi traps for crayfish, electrofish...

Increased contamination of aquatic ecosystems with pharmaceuticals could have been expected due to the COVID-19 pandemic. Surface water from three domains (rural, semirural, urban) of the Mrežnica River (Croatia) was screened for 253 pharmaceuticals by SPE-UHPLC-MS/MS. At the beginning of the pandemic, the highest concentration of drugs (excluding...

The common approach of measuring only the total concentrations of macro- and trace elements in biological materials does not provide complete information about their bioavailability and toxicity, which is mostly associated with their binding to essential molecules in the cytosol [1]. The aim of this study was to apply and validate multielement anal...

Peracarid crustaceans contribute to the homogenization of macroinvertebrate communities as one of the most important group of aquatic invaders. This study investigated the relationship between alien peracarids and physical and chemical parameters indicative of nutrient and organic pollution, and their contribution to biocontamination of macroinvert...

The remnants of historical industrial contamination can be detected in many aquatic ecosystems worldwide even at present time. Mrežnica is a river in Croatia that has been, for more than a hundred years, continually exposed to effluents of various industries, which have, in modern time, mostly ceased to operate. Our aim was to establish the level o...

The appearance of COVID disease and the introduction of subsequent measures and specific medical treatments throughout the world in 2020 could have been expected to cause the drug content changes in the surface waters. We have studied the lower course of the Croatian Mrežnica River at three areas (rural, small town, and large town domains) in three...

Contribution of alien peracarid crustaceans to the biocontamination of benthic macroinvertebrate assemblages in Croatian large rivers Peracarid crustaceans (orders Amphipoda, Isopoda and Mysida) are one of the most important groups of invaders in fresh and brackish waters. Although large rivers in Croatia have been heavily invaded by peracarid crus...

Alien aquatic macroinvertebrates, especially invasive crustaceans and molluscs, have heavily impacted native species and ecosystem processes in freshwaters worldwide. Knowledge on alien species distribution is necessary to understand their dispersal dynamics and prevent future invasions, and to predict and reduce undesirable impacts. Literature dat...

The shallow Vrana Lake (max depth -3, 9 m a.s.l.) is the largest natural lake in Croatia by surface area. It is located in the Dinaric karst in close proximity to the Adriatic Sea to which it is directly connected by the Prosika canal, constructed in the 18th century. Climate change caused increased fluctuations of water level during the last two d...

Macroinvertebrates assemblages in Croatian section of the Drava River have been drastically changed by habitat modification for the purpose of hydropower plants (construction of reservoirs and artificial channels) as well as alien invasive species. In this study we investigated macroinvertebrate assemblages structure at the upstream distribution fr...

In this study we investigated longitudinal distribution changes and density of native and alien Peracarida (Amphipoda and Isopoda) in Croatian large rivers and their proportion in total density of benthic macroinvertebrate assemblages. Qualitative and quantitative benthos samples collected using hand net (25x25 cm, ᴓ500 µm) in five major large rive...

Ponto-Caspian amphipods are one of the most successful groups of invaders in European freshwaters, but rates of their spread and especially their impacts are still understudied in Croatia. The aims of this study were to establish longitudinal distribution changes of invasive amphipods Dikerogammarus haemobaphes, D. villosus, Chelicorophium curvispi...

Peracarid crustaceans (orders Amphipoda, Isopoda and Mysida) represent one of the most important group of invaders in European freshwaters that largely contribute to the homogenization of macroinvertebrate fauna. The aims of this study were to investigate distribution, density and assemblages of native and alien Peracarida in Croatian large rivers,...