Accumulation of metals (Fe, Zn, Cu, Mn, Pb, Cd and Ni) in the muscles and gills of Oreochromis niloticus , Oreochromis aureus and Tilapia zillii was assessed based on seven locations in the Qahr El-Bahr area in Lake Al-Manzalah. The average accumulation of metals was in the following order: Tilapia zillii > Oreochromis aureus > Oreochromis niloticus . To determine the risk of fish consumption, the

Metabolic activities such as breathing and digestion, resulting from natural functions of the body through oxidation, lead to the formation of free radicals that cause cancer, premature cardiac aging and some chronic diseases. Antioxidants are substances that remove free radicals and prevent cell damage. Seafood significantly contributes to the elimination of free radicals, especially owing to its

The present study investigated the trophic ecology of two species living in an alluvial lake ecosystem in terms of season, length groups, sex, and mouth morphology. The fish were caught in a coastal lake area between December 2014 and March 2016 using a seine. In general, C. aquaedulcis was the most important prey for S. abaster , accounting for 10.99% of all prey, while amphipods accounted for 54

One of the economically important species is Penaeus kerathurus (Forskål, 1755), which is widespread in the Mediterranean ecosystem. This paper presents results of research on reproductive biology of Penaeus kerathurus in the Sea of Marmara. A total of 1404 specimens were dissected to determine the maturity stages, reproduction time, and length at first reproduction. The female-to-male ratio was 1:0

European huchen ( Hucho hucho ) is a representative of large and rare migratory salmonid fish, which has become endangered due to extensive anthropogenic changes in freshwater ecosystems. Numerous broodstocks of the European huchen have therefore been established throughout the species’ range in recent years to supplement wild fisheries of this species. Unfortunately, this conservation management strategy

The first data on the Lemanea genus in Serbia come from the late 20th century. Only one species, L. fluviatilis , was reported from 10 localities in Serbian riverine ecosystems between 1991 and 2017. Extensive research on this genus was performed in April–November 2017–2019, surveying 150 localities in 97 upland and mountain rivers. During this study period, the Lemanea genus was recorded at 14 localities

It is becoming increasingly important to monitor zoobenthic biodiversity in seas that are under industrial and anthropogenic pollution pressure, such as the Black Sea and the Marmara Sea. This study covers crustacean species in the Turkish waters of the Black Sea and the Marmara Sea, both of which are closed systems. Sampling was carried out in July–August 2019 and yielded 32 crustacean species from

Macrophytes are one of the main components of the aquatic ecosystem. They are used in several countries as metrics for the ecological assessment of hydrosystems. The objective of our study was to evaluate the suitability of the Macrophyte Biological Index for Rivers (IBMR) to determine a trophic level in the upper Oum Er Rbia basin (Morocco) and to understand physicochemical parameters of water that

The present study was carried out to determine gonadal stages and quality of pearl oyster meat ( Pinctada imbricata radiata , Leach, 1814) in Izmir Bay (Turkey). Pearl oyster samples were collected from the study area at a depth of ~5 m between February 2013 and January 2014. The highest and lowest temperature was measured in July and January as 27°C and 14.2°C, respectively. The maximum chlorophyll

The abundance and distribution of microphyto-plankton and related physicochemical factors were assessed monthly in Obhur Creek, the central Red Sea. Sampling was carried out near the entrance, the middle and end parts of the creek. During the course of the present study, the Red Sea was characterized by predominantly oligotrophic conditions. Nutrient concentrations were relatively higher in the end

Abstract Invasive species are those that have been transferred by humans out of their natural range. Native crayfish species in Polish waters include: Astacus astacus and Pontastacus leptodactylus, whereas invasive species are: Pacifastacus leniusculus, Faxonius limosus, Procambarus clarkii and Procambarus virginalis. The objective of this study was to determine how abiotic and biotic environmental

Abstract Wiedemannia ljerkae Ivković et Sinclair, 2017 is recorded from Albania for the first time (Sarandë District). The updated checklist of aquatic Empididae (Clinocerinae and Hemerodromiinae) from this country is provided. The potential diversity of the Albanian fauna of dance flies is discussed based on a comparison with faunas of neighboring countries.

Abstract Microorganisms play an important role in the circulation of phosphorus (P) in the sediment of coastal wetland ecosystems. In this study, solution 31P nuclear magnetic resonance (NMR) was used to determine different forms of P in the sediments of four different seagrass meadows and a bare tidal flat, while high-throughput 16S and ITS rRNA gene sequencing was used to determine the microbial

Abstract Chlorophyll-a (Chl-a) concentration is an important issue in ocean ecosystem management and research. This study investigates seasonal and annual variability in Chl-a and its relationship with sea surface temperature (SST) and river discharge in the shelf region of the Northern Bay of Bengal (BoB), as well as validates satellite data against in-situ data. Moderate Resolution Imaging Spectroradiometer

Abstract Akashiwo sanguinea, a cosmopolitan red tide-forming dinoflagellate, is reported for the first time as a bloom from the Cochin estuary along the South Eastern Arabian Sea. Monthly sampling showed the continuous presence of A. sanguinea with occasional blooms. Blooms of A. sanguinea with the highest abundance of 2.8 × 105 cells l−1 were observed during the monsoon season (June 2019) with chlorophyll

Abstract The objective of this study was to determine growth parameters, such as age–length and length–weight relationships, as well as condition factors and sex ratio, of the Carassius gibelio (Bloch, 1782) population in Lake Marmara (western region of Turkey), which is one of the most important fishing areas. Fish were caught on a monthly basis by gillnets and trammel nets (mesh size 10–50 mm) between

Abstract In order to understand the effects of some physical (temperature and salinity) and chemical (dissolved oxygen, nitrate and chlorophyll a) factors on the abundance and distribution of cladoceran species, zooplankton samples were seasonally collected between August 2015 and July 2016 from three stations near the entrance to the Boğaziçi Lagoon in Güllük Bay (Aegean Sea, Turkey) using a WP2 plankton

Abstract An accurate estimation of the sea surface temperature (SST) is of great importance. Therefore, the objective of this work was to develop an adaptive neuro-fuzzy inference system (ANFIS) model to predict SST in the Çanakkale Strait. The observed monthly air temperature, evaporation and precipitation data from the Çanakkale meteorological observation station were used as input data. The Takagi–Sugeno

Abstract Small water bodies play a specific role in the landscape, as they increase the mosaic pattern of a given area, retain water and affect hydrological regime in adjacent soils. These water bodies are the most important in landscapes that have been largely transformed by man, such as agricultural and urban landscapes. The author of this study assessed the ecological status of small water bodies

Abstract Human disturbance and nutrient runoff lead to water pollution, particularly in downstream waters and reservoirs. We hypothesized that increased human activity in summer would affect the trophic state of downstream reservoirs, affecting the interannual species composition of rotifers. We used long-term data for the Unmun Reservoir in South Korea (2009–2015), which is increasingly affected by

Abstract The effectiveness of two artificial habitat collectors, crab condo (HC1) and habitat crate (HC2), providing a refuge for small mobile fauna, was tested along with two commercial baited traps, Chinese box trap (BT1) and Gee’s Minnow trap (BT2) recommended for only single deployments under a harmonized survey of the Baltic and the North-East Atlantic. Our objective was also to determine whether

Abstract The paper presents the results of the analysis of diatoms from surface sediments (stones, sands) and macroflora (seagrass, macroalgae) collected at 16 sampling sites located along the inner coastal zone of Puck Bay (southern Baltic Sea) along the Hel Peninsula. The main diatom species of epilithon, epipsammon and epiphyton were characterized with respect to their autecological preferences

Abstract In the study, archive data on the maximum annual ice extent in the Baltic Sea (MIB) for the period 1961–2018 were used. They were obtained from the FIMR database. Data on ice parameters for the four largest southern Baltic coastal lakes: Jamno, Bukowo, Gardno and Łebsko, and for Szczecin, Puck, and Vistula Lagoons, come from the Maritime Branch of Institute of Meteorology and Water Management

Abstract This study was conducted to determine the selectivity of hooks (galvanized, tin, carbon, nickel) used for Atlantic bonito (Sarda sarda Bloch, 1793) in the Gallipoli Peninsula and the Dardanelles during the 2015 and 2018 fishing seasons (spring and autumn). The Atlantic bonito was fished with hooks of size 1/0, 2/0, 3/0, and 4/0. A total of 604 bonitos were caught, including 201 individuals

Abstract Phytoplankton structure was studied in five ponds (located in the Oleksandriya Nature Park, Ukraine), which significantly differed in the level of their contamination. The concentration of ammonium (NH4+-N) in the studied water bodies was 0.02–74.00 mg l−1, of nitrite (NO2−-N) – 0.002–1.750 mg l−1, nitrate (NO3−-N) – 0.13–58.00 mg l−1, inorganic compounds of phosphorus (Pinorg) – 0.041–0.160

Abstract The majority of Polish studies on freshwater cyclopoids focused on surface water fauna. There are relatively few data on copepods of subterranean waters. Thus, in our research, copepods were collected from 37 different, mostly groundwater-dependent habitats (i.e. caves, springs, wells, interstitial and overhead environments) over a period of five years between 2005 and 2010. A total of 22

Abstract The analyzed organosilicon derivatives of electrostatically stabilized silanates belong to a group of pentacoordinated compounds. These derivatives are: 1-(N-morpholiniomethyl)spirobi(1-sila-2,5-dioxacyclopentan-3-on)at, 1-(N-morpholiniomethyl)spirobi(1-sila-2,5-dioxa-4-methylcyclopentan-3-on)at, 1-(N-morpholiniomethyl) spirobi(1-sila-2,5-dioxa-4-(i-propyl)cyclopentan-3-on)at. In the course

Abstract The objective of this paper is to determine the trend and to estimate the streamflow of the Gökırmak River. The possible trend of the streamflow was forecasted using an autoregressive integrated moving average (ARIMA) model. Time series and trend analyses were performed using monthly streamflow data for the period between 1999 and 2014. Pettitt’s change point analysis was employed to detect

Abstract Research on the impact of heavy metals and their accumulation in ecosystem elements of Lake Burullus is still scarce. Therefore, this study focuses on the relationship between the levels of heavy metals in the lake water, plankton communities and Nile tilapia (Oreochromis niloticus). The mean annual concentrations of Fe, Zn, Cu, Mn, Pb and Cd in water and fish samples were 527.8, 366.7, 162

Abstract The study aimed to determine the annual reproductive cycle of Siganus rivulatusfi females based on monthly variation of the gonadosomatic index (GSI) and histological changes in gonads. A total of 240 fish samples were collected monthly from small-scale (trammel nets) and recreational (angling and pot fishery) fishing from Gökova Bay, the southern Aegean Sea, between July 2017 and June 2018

Abstract Seasonal distribution and diversity of surface phytoplankton have been studied in relation to anthropogenic activities at seven locations along the coastal waters of Jeddah, Saudi Arabia in 2017. The concentration of nitrite, nitrate, ammonia, phosphate and silicate varied over wide ranges: 0.04–20.27, 0.05–29.3, 0.22–78.16, 0.02–25.90 and 43–24.50 μmol l−1, respectively. Inorganic nutrients

Abstract The present study was carried out to determine the spat efficiency in the pearl oyster (Pinctada radiata, Leach, 1814) in surface and bottom water at Karantina Island (Izmir/Turkey). Polyethylene mesh bags were used as collectors. An annual average of 175.16 ± 11.32 spat m−2 was obtained from PSC (placed surface collectors) and 82.65 ±3.89 spat m−2 was obtained from PBC (placed bottom collectors)

Abstract Long-term changes in hydrochemistry and community structure of phytoplankton and macrophytes were analyzed in the Sestroretskiy Razliv reservoir (northwestern Russia). The average content of total phosphorus (TP) in May–October increased from 73 μg P l−1 in 1980 to 163 μg P l−1 in 2000. A significant increase in average chlorophyll a content from 16.6 μg l−1 in 1980 to 84.7 μg l−1 in 2000

Abstract A number of small, shallow inland lakes in the Northern Hemisphere are acidic, soft-water water bodies, mostly fed by precipitation. Some of these lakes are home to Lobelia dortmanna and other aquatic macrophytes from the isoetid group. The present study identifies a plant species replacement trend along the main environmental gradient in such lakes, i.e. pH of water. In 70 lakes covered by

Abstract Muscles and livers of herring gulls (Larus argentatus) found in the coastal area of the southern Baltic Sea were tested for the presence of hexabromocyclododecane (HBCD) isomers. They were detected in the muscles (ΣHBCD = 42.82 ± 30.65 ng g−1 l.w.) and livers (ΣHBCD = 65.51±27.96 ng g−1 l.w.) of all examined gulls. The α-HBCD isomer dominates in all types of samples. Our study has shown that

Abstract In this study, muscle samples collected from Planiliza subviridis (Valenciennes, 1836) and Ellochelon vaigiensis (Quoy & Gaimard, 1825) caught on the Balochistan coast (Damb Harbor) between January and December 2015 (during the northeast monsoon, post-monsoon and pre-monsoon seasons, and the southwest monsoon) were analyzed to determine concentrations of heavy metals: iron, zinc, copper, manganese

Abstract Epizoic diatom communities were studied on four turtle species (Chelonia mydas L., Eretmochelys imbricata L., Lepidochelys olivacea Eschscholtz and Dermochelys coriacea Vandelli) from the Eastern Caribbean, the Equatorial West Atlantic and the South Pacific. In the present study, we focused on one taxon of Navicula Bory de Saint-Vincent, described here as a new taxon, which was found on seven

Abstract We have determined how Crustacea, zebra mussels (Dreissena polymorpha), fish and nutrients affect the trophic state in mesocosms filled with water collected from the pelagic zone of a eutrophic lake. We hypothesized that the pool of nutrients would increase both directly due to the input of phosphorus and nitrogen and/or indirectly due to the introduction of animal biomass. We used trophic

Abstract A total of 437 species (453 with infraspecific taxa) of algae and Cyanobacteria were identified in 2034 samples collected during the first research on nine thermokarst lakes in Yakutia carried out in 1986–1994 and 2001–2015. The richest algal flora was determined in Lake Aalah, represented by 241 taxa. Bacillariophyta species dominated in four lakes, whereas Chlorophyta and Cyanobacteria dominated

Abstract Upwelling occurs on several coasts of the world, but it has mostly been studied on eastern ocean boundaries. We investigated upwelling on a western ocean boundary for which limited information exists. Using daily in-situ data on sea surface temperature (SST), we found a marked contrast in coastal cooling between July 2014 (pronounced) and July 2015 (weak) at two locations 110 km apart on the

Abstract The paper presents the first data on the concentrations of heavy metals (Cd, Pb, Zn, Cu, Ni, Cr, Mn) and 137Cs and their contamination ratios (CR) in the most abundant species of macrophytes in the Vistula Lagoon. No significant differences in the concentrations of heavy metals and 137Cs between macrophyte taxa or the influence of rivers flowing into the Vistula Lagoon on heavy metal concentrations

Abstract A total of 15 Navicula taxa were recorded in epilithic communities occurring in seven rivers of Serbia, all of which are new to the diatom flora of Serbia. The most interesting of them are N. splendicula and N. moskalii. When observing N. splendicula specimens under SEM, we noticed a characteristic silicate tongue in the center of raphe ends, which had not been previously reported in the available

Abstract The present study describes a finding of the demodecid mite Demodex phocidi in the seal Phoca vitulina in the Baltic Sea. This is the first identification in Europe and the second in the world. This is also the first observation of the Demodecidae family in the pinnipeds outside North America. A high density of demodecid mites was observed in the skin of the examined seal, but no symptoms

Abstract Fishery resources are currently facing multiple stresses such as overfishing, pollution and climate change. Looking into processes and mechanisms of the dynamic fish community through detailed quantitative analyses contributes to effective conservation and management of fishery resources. The Min estuary plays an important role in maintaining fisheries in southeastern coastal China, therefore

Abstract Marine picoplankton, including prokaryotic and eukaryotic picoplankton, drive many biogeochemical processes, such as carbon, nitrogen and sulfur cycles, making them crucial to the marine ecosystem. Despite the fact that picoplankton is prevalent, its diversity and spatial distribution from the Straits of Malacca (SM) to the South China Sea (SCS) remain poorly investigated. This work explores

Abstract This study determines the length distribution, length– weight relationship, age, growth parameters, mortality rate, sex ratios, length at first maturity and reproduction of saddled seabream (Oblada melanura) collected monthly by fishermen around the Northern Aegean Sea between November 2017 and October 2018. The length–weight relationship was calculated as W=0.0091×L3.11 (R2=0.95) and positive

Abstract Samples of water, sediment and two native plants (Eichhornia crassipes and Ceratophyllum demersum), collected seasonally from eight sites, were analyzed to investigate the level of contamination with metals (Fe, Mn, Ni, Co, Zn, Cu, Cr, Pb and Cd) in the Nile River in the Cairo region, using heavy metal pollution and contamination indices in the case of water, and the geoaccumulation index

Abstract The research focuses mainly on the ichthyoplankton of the Baltic deeps – the inflow route from the North Sea. The ichthyoplankton was represented by eggs and larvae of nine fish species: sprat, cod, herring, European flounder, fourbeard rockling, longspined bullhead, straightnose pipefish, sand goby and great sandeel. The species composition of ichthyoplankton varied depending on the location

Abstract The Bahr Yusuf Canal is the life artery of the Fayoum Province, which provides the province with two thirds of the freshwater quota from the Nile River. The present work was carried out to assess the suitability of water in the Bahr Yusuf Canal for various purposes and to assess the potential health risk associated with metal content. The results showed that the water quality of Bahr Yusuf

Abstract Measuring the linear characteristics of chironomid larvae is easier and faster than measuring their mass. The relationships between them are approximated by parabolic equations. Generalized equations are provided for all chironomid larvae. However, these relations vary in different water bodies. Measurements of 1424 chironomid larvae representing several species were taken in Crimean waters

Abstract The effect of the wave-induced Stokes drift is not taken into account in traditional ocean circulation models used for SST simulations. The spectral parameterization scheme is considered to be the most accurate of the wave-induced Stokes drift calculation schemes. The numerical simulation results of sea surface temperature (SST) with the Stokes drift and SST without the Stokes drift in the

Abstract Using the field data collected in the Black Sea in September 2005–May 2013, the authors studied the spatial variability of the ratio of organic carbon to chlorophyll a (C:Chl a) in the sea surface layer (0–1 m). The C:Chl a ratio is an important parameter that reflects the phytoplankton adaptation to abiotic factors. Its maximum variations occurred in September–October 2005 and October 2010

Abstract The occurrence of the flexed verticord, Halicardia flexuosa (Verrill & S. Smith [in Verrill], 1881), is reported for the first time from the Bay of Biscay (North Iberian Peninsula). This rare bivalve was collected from deep waters (1200 m depth) of the Avilés Canyon Systems (Central Cantabrian Sea). We provide a detailed description and illustration of the species, as well as brief notes on

Abstract Although well represented in the fossil diatom flora throughout Europe and Asia, from the early-middle Miocene to the Quaternary, Stauroneis balatonis is considered a very rare diatom with a contemporary distribution limited to two ancient lakes – Ohrid and Prespa. The objective of this study was to describe the first finding of S. balatonis in Serbia in Lake Savsko and to update information

Abstract The presence of chironomids and/or oligochaetes is generally considered to be an indication of poor status of freshwater. Non-chironomid dipterans show unclear trends. The abundance and percentage of these groups are rarely used as potential indicators. We attempted to determine whether these metrics reveal freshwater quality in lowland streams and lake littoral (Northern Europe, Baltic ecoregion

Abstract Planktothrix rubescens is a filamentous cyanobacterium with a worldwide distribution in lakes and reservoirs of varying size and morphology. The objective of this study was to identify the population dynamics and the major drivers of P. rubescens blooms. Samples for qualitative and quantitative analysis of phytoplankton were collected every month in 2014 and 2015 from stationary depths, while

Abstract In 1996–2008, macrozoobenthos of the Small Aral Sea was investigated. A total of 320 macrozoobenthos samples were collected. Statistical analysis and statistical mapping were performed using Statistica and Photoshop software. Ten taxa of macrozoobenthos were identified, with an average water salinity of the Small Aral Sea ranging from 6.3 to 19.0 PSU. Average annual community abundance reached

Abstract The paper presents the first record of a Chara connivens (Characeae) stand from Fuerteventura (Canary Islands, Spain). The species was previously recorded only on Tenerife and Lanzarote, mostly in marine and artificial habitats. Physicochemical parameters of water and morphological features of the thalli and plant community were analyzed. General habitat requirements of C. connivens populations

Abstract The solitary ascidian Phallusia nigra is commonly found on hard substrates along the Jeddah coastal waters of the central Red Sea. In this study, the recruitment pattern of P. nigra on artificial substrates was assessed in relation to their type, surface color and orientation. The results showed a higher recruitment rate of the ascidian species on concrete and dark panels. The abundance of

Abstract This study explores the activity of total superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR), biomass accumulation and chlorophyll a content in Scenedesmus ellipsoideus Chodat grown under conditions of varying zinc (Zn) concentrations. In addition, the activity of different SOD isozymes (MnSOD, FeSOD and CuZnSOD) was measured separately to determine the intracellular