rss_2.0Oceanological and Hydrobiological Studies FeedSciendo RSS Feed for Oceanological and Hydrobiological Studies and Hydrobiological Studies 's Cover (Copepoda; Philichthyidae) – an interesting cranium parasite of the swordfish collected from the Baltic Sea<abstract> <title style='display:none'>Abstract</title> <p>The swordfish, <italic>Xiphias gladius</italic> Linnaeus, 1758, is a fish that sporadically enters the Baltic Sea. The present paper describes the identification of a very rarely recorded and poorly studied copepod of the family Philichthyidae – <italic>Philichthys xiphiae</italic> <xref ref-type="bibr" rid="j_oandhs-2021-0028_ref_032">Steenstrup, 1862</xref> – in a dead swordfish found on a sea beach in Dźwirzyno (Poland) in 2016. Philichthyidae are parasites inhabiting the sensory canals in the lateral line and skull bones of marine fish. In the present case, two <italic>P. xiphiae</italic> females were found, which constitutes the first record of the species in the Baltic area.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00Effects of seasonal changes and environmental factors on bioindicator bacteria levels in Çardak Lagoon, Çanakkale Strait, Turkey<abstract> <title style='display:none'>Abstract</title> <p>Çardak Lagoon is one of the most important marine environments in the Turkish Strait system, which is home to a variety of organisms. The lagoon is currently under stress and faces the risk of heavy pollution. For this reason, the present state of the lagoon was monitored in this study. During sampling from October 2018 to June 2019, the levels of indicator microorganisms fluctuated up to 4.04 Log<sub>10</sub> cfu 100 ml<sup>−1</sup> and their presence was found to be higher in warmer seasons. The highest positive correlations were observed for total coliform levels with salinity and chemical oxygen demand, whereas the highest negative correlations were found between the levels of fecal coliforms, pH and temperature. <italic>E. coli</italic> and fecal streptococci showed moderate correlations with the environmental factors in all seasons. Although nitrite and nitrate (NO<sub>2</sub> + NO<sub>3</sub>) were not significantly correlated with bacteria levels, they were present at elevated levels. Çardak Lagoon showed the lowest microbiological and chemical quality in the summer season, and this situation continued into the autumn season as a possible result of increased wastewater discharge and human activities. The lagoon should therefore be monitored regularly and precautions should be taken to prevent severe ecological deterioration.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00Effects of feed on fatty acid composition in muscles and gonads of the Chinese mitten crab ()<abstract> <title style='display:none'>Abstract</title> <p>In this study, the effects of different feeds on fatty acid composition in the Chinese mitten crab (<italic>Eriocheir sinensis</italic>) were investigated. The fatty acid composition in the Chinese mitten crab was significantly correlated with the type of feed source provided. Differences between the feed groups pertained mainly five fatty acids: oleic acid, linoleic acid, palmitic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The content of EPA and DHA was higher in the group of frozen trash fish than in the group of formulated feed. On the other hand, the content of oleic acid, linoleic acid and palmitic acid was higher in the formulated feed group than in the frozen trash fish group. There were significant differences in the nutritional value of the Chinese mitten crab reared under different feed sources, i.e. Chinese mitten crabs reared with the frozen trash fish feed were larger than those reared with the formulated feed, especially as regards the ω-3/ω-6 PUFA ratio and essential fatty acid levels.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00Growth parameters of (Lesueur, 1821) (Actinopterygii, Poeciilidae) – an introduced species in brackish water of Wadi Al-Bahayes (Oman)<abstract> <title style='display:none'>Abstract</title> <p>This work is one of the first studies on the growth of <italic>Poecilia latipinna</italic> outside its natural habitat. The objective of our study was to investigate the growth parameters of the population of <italic>P. latipinna</italic>, which is an alien species in Oman (Wadi Al-Bahayes). The population structure of <italic>P. latipinna</italic> in Wadi Al-Bahayes (Oman; 23°40′47″N; 58°11′36″E) was studied in June and August 2020, using 124 fish. In the course of this study, the number of individuals of each sex, age, weight and size composition were determined. In addition, the total length–weight relationship (LRW) was calculated, as well as the von Bertalanffy growth equation. The mean growth performance (phi prime) and the condition factor were calculated. Males accounted for 37.10% and females for 62.90% of the population. The length–weight relationship and the von Bertalanffy growth equation were W = 0.0214 × L <sup>2.7889</sup> R<sup>2</sup> = 0.9212, Lt = 11.46 (1 − e <sup>−0.127 (t + 2.71)</sup>) for males and Lt = 14.51 (1 − e<sup>−0.072 (t + 3.98)</sup>) for females. The mean growth performance and the condition factor were calculated as 1.22 for males and 1.18 for females and 1.54 for all specimens.</p> <p>The study shows that the population of the species is characterized by a wide age range. Consequently, monitoring of this alien species is highly recommended.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00First record of straight-needle pteropod Rang, 1828 bloom in the Çanakkale Strait (NE Aegean Sea, Turkey)<abstract> <title style='display:none'>Abstract</title> <p>Pteropods are marine pelagic calcifier mollusks sensitive to chemical changes in seawater due to their highly soluble aragonite shells. Increased acidity (reduced pH) of seawater causes difficulties in precipitating their shells and/or results in their dissolution, which is related to increased atmospheric CO<sub>2</sub> concentrations and warming of seawater. They are therefore indicators of environmental changes. In this paper, we present the first record of the straight-needle pteropod <italic>Creseis acicula</italic> Rang, 1828 bloom in the surface waters of the Ҫanakkale Strait, Turkey (NE Aegean Sea), encountered in July 2020, when the highest sea surface temperatures and pH levels since 2007 were recorded. In coastal zones, such as the Ҫanakkale Strait, anthropogenic activity contributes significantly to environmental changes. Consequently, the increase in pH at elevated temperatures indicates an auxiliary factor (i.e. anthropogenic activity) that triggered the <italic>C. acicula</italic> bloom, rather than global atmospheric CO<sub>2</sub> levels.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00A review of occurrence, distribution and alien status of and () (Mollusca: Heterobranchia) in the Mediterranean Sea<abstract> <title style='display:none'>Abstract</title> <p><italic>Notodiaphana atlantica</italic> and <italic>Liloa mongii</italic> are two cephalaspidean species described respectively from the Atlantic Ocean and the Red Sea, and considered widespread in their native ranges. Both species have also been recently recorded from the Mediterranean Sea, prompting some authors to consider them alien. Notwithstanding clear morphological differences in their shells, the two species have often been confused or misidentified in the literature, or specimens have been described with incorrect locality data. We hereby review the occurrence, distribution and status of both species in the Mediterranean Sea based on published data and examination of new material. <italic>Notodiaphana atlantica</italic> is considered a cryptogenic species with a range spanning from the western to eastern part of the basin. The presence of <italic>L. mongii</italic> in the Mediterranean is questioned until specimens that can be reliably assigned to this taxon or to any congeneric species are found in the area. Alien species inventories play an important role in regional policy and management decisions, thus requiring a high degree of confidence in the validity of species identification and their non-indigenous status. The present paper adds further evidence of the excess of “bibliographically introduced” alien records and reiterates the need for periodic re-evaluation of published data.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00Historical review of Dutch Pectinariidae with as a new taxon for the Netherlands (Annelida: Polychaeta: Pectinariidae)<abstract> <title style='display:none'>Abstract</title> <p>Two trumpet worms (Pectinariidae), which do not resemble the two known species: <italic>Lagis koreni</italic> <xref ref-type="bibr" rid="j_oandhs-2021-0024_ref_069">Malmgren, 1866</xref> and <italic>Amphictene auricoma</italic> (<xref ref-type="bibr" rid="j_oandhs-2021-0024_ref_078">Müller, 1776</xref>), have recently been collected in the Dutch North Sea (Oyster Grounds). Their characteristics match those of <italic>Pectinaria belgica</italic> (<xref ref-type="bibr" rid="j_oandhs-2021-0024_ref_084">Pallas, 1766</xref>), a species with a northern distribution. This paper summarizes the current state of knowledge of Dutch Pectinariidae and describes in detail the historical records of trumpet worms recorded in the Netherlands, along with the confusion around the species epithet <italic>belgica</italic>. <italic>Pectinaria belgica</italic> is reported here for the first time from the Dutch North Sea.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00First record of the rare crab (Crustacea: Brachyura: Varunidae) in the North Sea<abstract> <title style='display:none'>Abstract</title> <p>Several species new to the area were collected while monitoring Dutch marine waters using a dredge. The varunid crab <italic>Asthenognathus atlanticus</italic> <xref ref-type="bibr" rid="j_oandhs-2021-0030_ref_020">Monod, 1933</xref> was recorded for the first time in the North Sea. Until 2008, this relatively rare crab was known from the west coast of Africa and the western Mediterranean to northern Brittany in the north. In recent years, its distribution range has expanded, as indicated by records from the Bay of the Seine and the area around Dieppe-Le Tréport. Our finding from Brown Bank (southern North Sea) indicates a further, northward expansion of its distribution range. We list the hosts with which the crab is associated. Earlier arguments for climate change as an explanation for the northward range expansion are supported.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00Establishment and range expansion of non-native fish species facilitated by hot springs: the case study from the Upper Sakarya Basin (NW, Turkey)<abstract> <title style='display:none'>Abstract</title> <p>Non-native species can enter new habitats and ecosystems in a variety of ways. Suitable ecological conditions must exist for non-native species to reproduce in newly colonized habitats. Hot springs are suitable habitats for tropical, aquarium, and ornamental fish species. This paper presents the results of research on the distribution of non-native and native species in relation to environmental factors in the Upper Sakarya Basin, where several such springs are present. The fish fauna in the basin includes native (60% – 21 species, 14 of which are endemic) and non-native (40% – 14 species) fish species. Most of the non-native species (seven species) were found only in warm springs (minimum water temperature 16°C). In addition, 75 fish species belonging to 26 families were found throughout the Sakarya Basin. Hot springs were found to play an important role in the establishment of non-native species. The Kernel Density Estimation (KDE) results revealed that the non-native species density was high in the Upper Sakarya Basin where hot springs are common. This confirms that minimum and maximum temperatures are the main drivers of changes in the distribution of non-native fish species. Two aquarium fishes, <italic>Bujurguina vittata</italic> and <italic>Xiphophorus</italic> spp., are reported for the first time in the present study for inland waters of Turkey.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00Demographics of great sturgeon () in Iranian waters of the Caspian Sea (2008–2010)<abstract> <title style='display:none'>Abstract</title> <p>Demographic data of the great sturgeon, <italic>Huso huso</italic>, from the Iranian coastal waters of the Caspian Sea were derived from measurements of individuals with a fork length ranging from 84 to 255 cm, obtained from commercial fisheries. The maximum age of fish caught in the south Caspian Sea was 30 years. The estimates of the asymptotic length L<sub>∞</sub> and the growth coefficient (K) were 265.255 cm and 0.062 per year for males and 275.78 cm and 0.08 per year for females, respectively. Total mortality rates obtained by Gulland's method were larger for males (0.64) than for females (0.46). Annual mortality rates were calculated as 47% for males and 37% for females. Data obtained in this study and their comparison with data from previous studies indicate that the great sturgeon stock is definitely exploited in an unsustainable manner.</p> </abstract>ARTICLE2021-09-02T00:00:00.000+00:00Impact of waterbirds on chemical and biological features of water and sediments of a large, shallow dam reservoir<abstract> <title style='display:none'>Abstract</title> <p>Large numbers of Mallard Anas platyrhynchos (max. 10,490 ind.), Black-headed Gull Chroicocephalus ridibundus (max. 3,430 ind.) and Great Cormorant Phalacrocorax carbo (max. 1,449 ind.) were recorded on the Goczałkowice Reservoir, Poland (2,754 ha). Most of the waterbirds occurred in the backwater of this reservoir. The amount of phosphorus and nitrogen loaded by the most numerous waterbirds into Goczałkowice Reservoir was estimated at 958 kg and 2,621 kg, respectively in 2011 and 1,043 kg and 2,793 kg, respectively in 2012. In 2011 and 2012, the waterbirds introduced a considerable amount of phosphorus, nitrogen and a large number of coliforms into the backwater of the reservoir. The concentration of different forms of phosphorus and nitrogen, chlorophyll-a and bacteria coli in the water was not greater at the site of birds’ concentration (except dissolved organic nitrogen). The concentration of nitrates in the water at the site near the breeding colony of gulls in comparison with the reference site was not different. The amounts of P-tot and N-tot in the sediment were similar at the site affected by waterbirds and at the reference site. The dynamics of water masses was not the reason for the lack of differences between the studied sites.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00Freshwater green algal biofouling of boats in the Kabul River, Pakistan<abstract> <title style='display:none'>Abstract</title> <p>Freshwater green algal biofouling of boats refers to the accrual of freshwater green algae on boats immersed in water. The current research focused on the morphological characteristics of the isolates, species ecology, and the physicochemical properties of the water at the sampling sites. Two localities, Haji Zai and Sardaryab, were sampled at the Kabul River in the district of Charsadda, Pakistan. Freshwater green algae causing biofouling were isolated from the boats. A total of three genera: Cladophora, Rhizoclonium, and Spirogyra with fifteen species belonging to the families Cladophoraceae and Zygnemataceae were observed. Statistical analysis reveals significant stimulation of green algal species in the boats’ fouled communities by increases in water temperature, conductivity, and Total Suspended Solids (TSS). The algal growth at the Haji Zai site is suppressed by TDS in autumn (Pearson −0.56) and is stimulated by water temperature in spring (Pearson 0.44). At the Sardaryab site, algae were stimulated in spring by pH of water (Pearson 0.61), and suppressed by Total Dissolved Solids (TDS) in autumn (Pearson −0.43). Statistical analysis indicates that pH, conductivity, and temperature are the main factors determining the algal biofouling in the Kabul River.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00Latitudinal pattern of abundance and composition of ciliate communities in the surface waters of the Atlantic Ocean<abstract> <title style='display:none'>Abstract</title> <p>Abundance, biomass, and taxonomic composition of the ciliate community were studied in the surface waters along a transect between 50°S 61°W and 48°N 5°W (Atlantic Ocean, March-April 2011). The abundance of heterotrophic ciliates was low in the equatorial zone (280–320 cells l−1, 0.11–0.12 μg C l−1), but it increased toward both the northern and southern temperate zones with the maximum abundance observed at 44°S (2667 cells l−1, 0.82 μg C l−1). This pattern resembles the global distribution of oceanic primary production, which is low at lower latitudes and high in temperate zones. In temperate zones ciliate abundance peaks during spring and fall. Thus, because the present study was carried out during spring in the northern hemisphere and austral fall in the southern hemisphere, the ciliate abundance at higher latitudes was additionally elevated. Functionally autotrophic Mesodinium rubrum was only observed in the northern hemisphere and tropical waters. Its maximum abundance was observed at 48°N (1080 cells l−1, 1.14 μg C l−1). The most frequently observed ciliates were oligotrichs and choreotrichs. Other important ciliates were haptorids (including M. rubrum) and hypotrichs.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00New localities of rare species Kobayasiella okadae (Skvortzov) Lange-Bert. and K. tintinnus Buczkó, Wojtal & Jahn in Europe — morphological and ecological characteristics<abstract> <title style='display:none'>Abstract</title> <p>The aim of the present work conducted in the area of Międzyrzeki Strict Nature Reserve in the Roztocze National Park was to show new sites of rare and species new to Poland from the Kobayasiella genus (K. okadae (Skvortzov) Lange-Bert., K. tintinnus Buczkó, Wojtal &amp; Jahn) with regard to morphological and ecological characteristics. Chemical parameters show that investigated habitats are poor and oligotrophic with a low content of chlorides, sulfates and nitrates. K. okadae, K. subtilissima (Cleve) Lange-Bert. and K. tintinnus were found in the studied area. The authors suggest the use of synonym Navicula hoeflerii Cholnoky for the Kobayasiella okadae. LM and SEM images were used in the analysis of the material.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00Predation of adult large diving beetles Dytiscus marginalis (Linnaeus, 1758), Dytiscus circumcinctus (Ahrens, 1811) and Cybister lateralimarginalis (De Geer, 1774) (Coleoptera: Dytiscidae) on fish fry<abstract> <title style='display:none'>Abstract</title> <p>The presented study describes the presence of fish fry in the diet of imagines of large Dytiscidae. The study was conducted between March and September in 2012 and 2013. A total of 163 large, aquatic, diving beetles were caught, which represented the following species: Dytiscus marginalis, Dytiscus circumcinctus, Cybister lateralimarginalis. Fish were identified by scales, bones, vertebrae, pharyngeal teeth. Insects were identified by epicrania, mandibles, hooks, limbs, body segments, eyes and wings. Crustaceans were identified by limbs and Oligochaeta by bristles. Seeds and eggs of invertebrates were found whole and intact. Fragments of fish fry were found in the digestive tracts of all three species collected in three studied ponds. The alimentary canals of the studied beetles contained also fragments of insects, detritus, plant tissue, Crustacea, Arachnida, other invertebrates, Oligochaeta, and Gastropoda.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00Occurrence of potentially human pathogenic bacteria in the seawater and in the sand of the recreational coastal beach in the southern Baltic Sea<abstract> <title style='display:none'>Abstract</title> <p>The occurrence and the distribution of potentially human pathogenic bacteria such as Aeromonas, Pseudomonas aeruoginosa, Staphylococcus and Vibrio-like organisms in the sand and the adjacent seawater of the recreational coastal beach were studied. The highest mean number among these four studied groups of bacteria was represented by Aeromonas-like organisms and the lowest one by Staphylococcus-like organisms. Dry sand was inhabited by the highest number of all studied potentially pathogenic bacteria. Within a year, the number of the studied bacteria inhabiting the sand and the seawater showed considerable monthly changes. There were differences in the abundance of potentially pathogenic bacteria between the surface and the subsurface sand layers with a clear decrease in their number toward the deeper layers of the sand.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00Resistance of riverine macroinvertebrate assemblages to hydrological extremes<abstract> <title style='display:none'>Abstract</title> <p>Macroinvertebrates were sampled in the lowland Drzewiczka River downstream from a dam reservoir and just below a whitewater slalom canoeing track. For over 20 years, pulse flow fluctuations of moderate intensity, an effect of two-three hour long releases of water per day to enable training of canoeists, induced a patchy mosaic in the tailwater riverbed compared to a natural site. After these regular disturbances, three accidental events of increased discharge of different magnitudes (three, five and sixteen times higher compared to a long-term median) occurred in two following years and we were able to investigate their impact on the habitat-specific processes.</p> <p>Two of the three events (in September 2000 and March 2001) had a minor effect on abiotic and biotic variables, while the third one (in February 2002, over 40 m3 s−1 discharge) destabilized the bed habitat, washing away the flood-sensitive macroinvertebrates of Ephemeroptera and Trichoptera. In the dominant benthic group, i.e. Chironomidae, varied resistance patterns were observed, depending on their mode of life and patch occupancy. In conclusion, biota in the Drzewiczka River have adapted their life history to long-term moderate flow disturbance, but the largest flood mobilized bed sediments together with most of their dwellers.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00Temporal fluctuations of the phytoplankton community in an isolated floodplain lake (North Mollaköy Lake) of the Sakarya River (Northern Turkey)<abstract> <title style='display:none'>Abstract</title> <p>The aim of this study was to determine the spatial and temporal variation of phytoplankton and water quality in response to the hydrological regime in an isolated floodplain lake (North Mollaköy Lake) of the Sakarya River. Variations in the composition, biomass and functional groups of phytoplankton and environmental parameters were monthly analyzed in sub-surface samples collected from the pelagic zone at four stations from July 2012 to June 2013. A total of 109 taxa were identified, and the species which contributed the most to the phytoplankton biomass were grouped into 14 functional groups (FGs). The distribution of FGs was linked to the transition (T1 and T2), high (HW) and low (LW) water periods in North Mollaköy Lake. FGs J, MP, N, G, X1, X2, Y, W1, W2, S1, H1, B and C were the contributors to the phytoplankton biomass during the low-water period (LW) and the transition periods (T1 and T2), while Lo contributed the most during the high-water period (HW). RDA revealed that the most important factor affecting the temporal distribution of FGs was the water discharge and that there are some differences between stations in terms of Si, pH values and the distribution of FGs.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00Morphology, ecology and distribution of the diatom (Bacillariophyceae) species Simonsenia delognei (Grunow) Lange-Bertalot<abstract> <title style='display:none'>Abstract</title> <p>Simonsenia delognei is a diatom species which is relatively rarely recorded, but apparently widespread in Europe and other continents. This taxon has recently been discovered for the first time in springs of Central Poland, where it was found to occur abundantly. Somewhat later this species has also been identified and photographed in samples from the Eagean Region in Turkey. Light and electron microscopic studies were carried out on S. delognei populations from the Quaternary spring located near Łódź (Central Poland) and from the Porsuk and Felent Rivers and a spring in the Türkmen Mountains in Kütahya and Havuzdere Stream in Yalova (NW Turkey). Morphological studies were accompanied by environmental measurements and determination of changes in the seasonal distribution of S. delognei in a key area, i.e. the Porzeczkowe spring in Central Poland, which are included in the present study. Identification of S. delognei under a light microscope is difficult and hence an electron microscope is required for accurate taxonomic identification.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00Cylindrospermopsin: cyanobacterial secondary metabolite. Biological aspects and potential risk for human health and life<abstract> <title style='display:none'>Abstract</title> <p>Cylindrospermopsin (CYN) is a cytotoxin produced by several species of cyanobacteria, which occur all over the world. It was demonstrated that CYN has a wide spectrum of biological activity in animal cells, involving hepatotoxicity, genotoxicity, cytotoxicity and carcinogenic potential, and is considered as one of the factors that caused human poisoning in Palm Island (Australia) and in Caruaru (Brazil). This compound may be introduced into organism by several ways, including consumption of water, fishes and seafood as well as accidental swallowing or aerosol spray inhalation during recreational using of reservoirs covered by cyanobacterial blooms. The information about the CYN impact on environment and its degradation processes under natural conditions is scant. Taking this into consideration CYN should be regarded as a potential threat to human health and life. This review presents physicochemical characteristic and biological activity of CYN, occurrence in freshwaters and its sensitivity to the influence of some environmental factors.</p> </abstract>ARTICLE2015-01-04T00:00:00.000+00:00en-us-1