rss_2.0Oceanological and Hydrobiological Studies FeedSciendo RSS Feed for Oceanological and Hydrobiological Studieshttps://sciendo.com/journal/OANDHShttps://www.sciendo.comOceanological and Hydrobiological Studies 's Coverhttps://sciendo-parsed-data-feed.s3.eu-central-1.amazonaws.com/61a9a0c332fa2f51bbc1e76f/cover-image.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20220129T105247Z&X-Amz-SignedHeaders=host&X-Amz-Expires=604799&X-Amz-Credential=AKIA6AP2G7AKDOZOEZ7H%2F20220129%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Signature=433bbbbde11060f8efdfe602ac9cec59d7e766eaf341f94acfe8b560261098cd200300Determination of functional structure of soft-bottom marine macrobenthic communities of the Samsun Shelf Area using biological traits analysishttps://sciendo.com/article/10.2478/oandhs-2021-0040<abstract> <title style='display:none'>Abstract</title> <p>Biological Traits Analysis (BTA) was used to investigate the functional structure of marine macrobenthic communities along the Samsun Shelf Area (SSA). Benthic samples were collected seasonally from five different locations and at four different depths using a Van Veen grab sampler. Macrofaunal communities distributed in the SSA were assessed using 10 biological traits to identify characteristic traits for each depth and location. It was found that variability of benthic ecosystem functions in the SSA was driven by biological traits such as maximum size, living habit, sediment position, feeding mode and type of reproductive behavior. Bivalves, polychaetes and crustaceans of small to medium size, biodepositing, burying themselves in the sediment (burrowers) and feeding in suspension were relatively more abundant at depths of 0–60 m. However, the biomass of <italic>Amphiura</italic>, <italic>Abra</italic>, <italic>Papillicardium</italic> and some polychaetes characterized by medium to large sizes, diffusive mixing, free living and feeding on deposit and subsurface deposit showed higher values at depths below 60 m. In general, it is concluded that the functional structure of the benthic infauna in the SSA has adapted to physical disturbance, and communities distributed in this area consist mainly of taxa resistant to mechanical pressure.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Otolith phenotypic analysis for the endemic Anatolian fish species, Caucasian bleak Steindachner, 1897 (Teleostei, Leuciscidae), from Selevir Reservoir, Akarçay Basin, Turkeyhttps://sciendo.com/article/10.2478/oandhs-2021-0037<abstract> <title style='display:none'>Abstract</title> <p>Otolith phenotypic variability was analyzed in the Caucasian bleak (<italic>Alburnus escherichii</italic>) from the Selevir Reservoir in Turkey. Utricular (lapillus) and lagenar (asteriscus) otoliths were removed, while distinguishing between left and right otoliths. All otoliths were photographed on the distal (for asterisci) and dorsal surface (for lapilli) using a Leica DF295 digital camera. Otolith morphometrics were measured to the nearest 0.001 mm using Leica Imaging Software. Linear and nonlinear (power) models were applied to determine the relationships between otolith measurements and total length of fish individuals. Two length classes (Class I: 6.7–10.9 cm <italic>L<sub>t</sub></italic>; Class II: 11.0–15.0 cm <italic>L<sub>t</sub></italic>) were established to analyze the shape of otoliths. The Form Factor, Circularity, Roundness, Rectangularity, Aspect Ratio and Ellipticity were used to analyze the shape of otoliths. A standardized model was used to remove the effect of size on otolith measurements. Multivariate analysis was performed to detect differences in otolith shape variation. The results of discriminant function analysis showed that 79.9% of <italic>A. escherichii</italic> specimens were correctly classified by length classes. In this study, intraspecific variation of asteriscus and lapillus otoliths in <italic>A. escherichii</italic> is reported for the first time. The results of this study provide the first comprehensive data on otolith shape analysis and the relationship between otolith morphometrics and total length in the Caucasian bleak.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Tunisian inland water microflora as a source of phycobiliproteins and biological activity with beneficial effects on human healthhttps://sciendo.com/article/10.2478/oandhs-2021-0033<abstract> <title style='display:none'>Abstract</title> <p>Ten monoclonal microalgal cultures were obtained from several Tunisian inland water bodies, and their dichloromethane and methanolic extracts were screened for antibacterial, antileishmanial, and antioxidant properties, as well as phycobiliprotein production capacity. <italic>Cylindrospermopsis raciborskii</italic> has been shown to synthesize high levels of phycocyanin and may be an effective alternative source to other sources used for commercial production of phycocyanin. <italic>Chroococcus</italic> sp. and <italic>Leptolyngbya</italic> sp1. exhibited the strongest radical scavenging activity against DPPH (IC<sub>50</sub> = 212.15 and 263.91 μg ml<sup>−1</sup>, respectively), indicating their promising potential for use as new effective and non-toxic antioxidants. Furthermore, <italic>Dunaliella</italic> sp. showed an interesting antileishmanial activity against the pathogens <italic>Leishmania infantum</italic> and <italic>Leishmania major</italic> (IC<sub>50</sub> = 151 and 284 μg ml<sup>−1</sup>, respectively), thus representing a good candidate for use against cutaneous and visceral leishmaniasis in Tunisia, a country endemic to these diseases where thousands of new cases are registered every year. These results suggest that the strains of microalgae featured in this work have the potential to serve as natural alternative, safe and sustainable sources of high value-added products that could be used to improve the final biomass value.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Effects of seasonal changes and depth on growth parameters of the Mediterranean mussel () on a shipwreck in the Eastern Mediterranean Seahttps://sciendo.com/article/10.2478/oandhs-2021-0038<abstract> <title style='display:none'>Abstract</title> <p>The study was conducted between July 2018 and May 2020 to compare seasonal changes in growth parameters of the Mediterranean mussel (<italic>Mytilus galloprovincialis</italic>) at different depths in two different areas of the Northeastern Mediterranean Sea (Aegean Sea). In a preliminary study, mussels were placed in cages at different depths of an artificial reef (AR – shipwreck) and natural reef (NR). Temperature, salinity, pH, and dissolved oxygen were determined seasonally at both sites at a depth of 37 m (deepwater) and 25 m (midwater). Linear increases in length and width of mussels at the AR site were recorded, while no consistent changes were observed for mussels at the NR. There was negative correlation between the specific growth rate (SGR) and salinity (r<sup>2</sup> = 0.5098) and temperature (r<sup>2</sup> = 0.1470) at the AR site. Negative correlations were also recorded between pH and the commercial condition index (<italic>CCI</italic>) at both the AR (r<sup>2</sup> = 0.3869) and NR (r<sup>2</sup> = 0.3600) sites. Our findings show that depth had a significant effect (<italic>p</italic> &lt; 0.05) on the <italic>CCI</italic> of mussels at the NR site, while its effect was insignificant for this index at the AR site (<italic>p</italic> &gt; 0.05). This study indicates that natural reefs provide more suitable conditions for the growth of Mediterranean mussels than shipwrecks used as artificial reefs.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Biodiversity of freshwater macroinvertebrates on Gökçeada Island (North Aegean Sea, Turkey)https://sciendo.com/article/10.2478/oandhs-2021-0036<abstract> <title style='display:none'>Abstract</title> <p>Island ecosystems have attracted the attention of scientists since the early days of science because of their formation and biodiversity. Despite their abundant freshwater resources, data on freshwater diversity of Gökçeada are incomplete, especially for macroinvertebrates. This study was conducted in a wide range of freshwater ecosystems on Gökçeada between May 2016 and September 2018. Sampling of macroinvertebrates was performed using a hand net from 34 pre-selected sampling sites on the island. A total of 78 aquatic macroinvertebrate taxa were found, 46 of which are new records for the island. The most common species during the study were <italic>Gammarus komareki</italic> and <italic>Bythinella gokceadaensis</italic> with a frequency of 25.93%, followed by <italic>Tubifex tubifex</italic>, <italic>Gammarus</italic> sp. and <italic>Caenis</italic> sp. with a frequency of 22.22%. Endemic and invasive species on the island were assessed according to their presence and frequency values. Based on the results of the current study and previous data, it can be concluded that Gökçeada is characterized by a remarkable species diversity compared to aquatic macroinvertebrates on other Aegean islands.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Empirical approach to risk management strategies of Mediterranean mussel farmers in Greecehttps://sciendo.com/article/10.2478/oandhs-2021-0039<abstract> <title style='display:none'>Abstract</title> <p>Risk perception and risk responses of Greek mussel farmers are important for understanding their risk behavior and the likely success of different risk mitigation strategies. This allows policy makers and actuarial companies to decide what risk management products to offer to address specific types of risks.</p> <p>Results from an empirical survey showed that ex-farm prices and health/disability status of farmers are perceived as the most important sources of risk.</p> <p>Risk management decisions were strongly influenced by the attitudes of mussel farmers rather than their socioeconomic status or perception of risk sources.</p> <p>Financial reserves and an alternative source of stable income are both preferred by mussel farmers as risk management strategies, while optimizing farm management to produce at the lowest possible cost is commonly practiced to eliminate losses. Farmers recommend that for certain types of risks that lead to total losses, e.g. anoxia, tsunamis, harmful algal blooms (HABs), insurance contracts should be provided by the public sector, as in similar situations in agriculture. For other needs, customized insurance contracts should be provided by the actuarial market.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Distribution of oil, grease and polycyclic aromatic hydrocarbons in coastal water and sediments of Suez Bayhttps://sciendo.com/article/10.2478/oandhs-2021-0032<abstract> <title style='display:none'>Abstract</title> <p>The permanganate index (PI), oil and grease (O&amp;G), and 17 polycyclic aromatic hydrocarbons (PAHs) were analyzed in surface sediment and water samples collected at 13 sites along the western coast of Suez Bay (SB). PI and O&amp;G in the SB coastal seawater ranged from 9.6 mg O<sub>2</sub> l<sup>−1</sup> and 17.0 mg l<sup>−1</sup> to 16.0 mg O<sub>2</sub> l<sup>−1</sup> and 37.0 mg l<sup>−1</sup>, respectively. The level of polycyclic aromatic hydrocarbons (PAH) in water and sediment in the SB offshore area was determined by gas chromatography/flame ionization detection. The concentration ranged from 0.574 to 16873.2 ng g<sup>−1</sup> in the sediment and 0.502 to 43.540 ng l<sup>−1</sup> in water. The collected data were compared with values reported in the literature. The possible source and origin of pollution was also assessed based on the determined relative PAH levels at the study sites, the ratio of low molecular mass PAHs (LPAHs) to high molecular mass PAHs (HPAHs), and molecular indices of samples.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Analysis of heavy metal contamination in surface sediments of Iskenderun Bay, Turkeyhttps://sciendo.com/article/10.2478/oandhs-2021-0035<abstract> <title style='display:none'>Abstract</title> <p>The ecological risk resulting from the accumulation of some heavy metals in the sediments of Iskenderun Bay was assessed using the following measures: enrichment and contamination factor, pollution load index (<italic>PLI</italic>), and potential ecological risk index (<italic>RI</italic>). The concentrations of the studied heavy metals were in the following order: Fe &gt; Ni &gt; Mn &gt; Cr &gt; Zn &gt; Cu &gt; As &gt; Pb &gt; Cd &gt; Hg. Ni and As had the highest <italic>EF</italic> values. This situation is most likely due to the presence of iron, pesticide, and fertilizer plants in the region. According to the United States Environmental Protection Agency, Ni, As, Mn, and Cr may have harmful effects on faunal communities in sediments. According to the <italic>RI</italic>, Site 4 was more contaminated and toxic than the other seven study sites, with “moderate” ecological risk. Pearson’s correlation coefficient was determined by multivariate methods – cluster and principal component analysis. As can be inferred from the <italic>RI</italic> values, the potential toxic effect of As and Ni in the sediments is moderate.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Effect of water quality on the spatial distribution of charophytes in the Peshawar Valley, Khyber Pakhtunkhwa, Pakistanhttps://sciendo.com/article/10.2478/oandhs-2021-0031<abstract> <title style='display:none'>Abstract</title> <p>The presented research was conducted in 2018–2019 in the Peshawar Valley, Pakistan, to study for the first time the effect of water quality on the spatial distribution of charophytes. A total of six taxa of charophytes were found at 41 sites in the Peshawar Valley along the banks of seven rivers, 16 streams and two wetlands: <italic>Chara braunii</italic> C.C.Gmelin, <italic>C. connivens</italic> Salzmann ex A. Braun, <italic>C. contraria</italic> A. Braun ex Kützing, <italic>C. globularis</italic> Thuiller, <italic>C. vulgaris</italic> Linnaeus, and <italic>Nitellopsis obtusa</italic> (Desvaux) J. Groves. <italic>Chara vulgaris</italic> was the most abundant species, followed by <italic>C. globularis</italic>, and <italic>C. contraria</italic>. Water pH, electrical conductivity (EC), total dissolved solids (TDS), salinity and dissolved oxygen (DO) were within the permissible limits for Pakistan, while water temperature, oxidation reduction potential (ORP) and resistivity showed deviations. Canonical Correspondence Analysis (CCA) revealed that DO affected <italic>Chara vulgaris,</italic> pH and resistivity affected <italic>C. braunii, C. connivens</italic> and <italic>C. globularis</italic>, temperature and ORP affected <italic>C. contraria</italic> and <italic>Nitellopsis obtusa.</italic> Furthermore, CCA showed that TDS, EC, and salinity had no effect on the spatial distribution of <italic>Chara contraria</italic>, <italic>C. vulgaris</italic> and <italic>Nitellopsis obtusa</italic>. <italic>Chara contraria</italic> and <italic>Nitellopsis obtusa</italic> should be protected under VU (Vulnerable) status (IUCN) along with their habitats.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Growth pattern, mortality and reproductive biology of common sole, (Linneaus, 1758), in the Sea of Marmara, Turkeyhttps://sciendo.com/article/10.2478/oandhs-2021-0034<abstract> <title style='display:none'>Abstract</title> <p>The study deals with the growth pattern, mortality, and reproduction of common sole, <italic>Solea solea</italic> (Linneaus, 1758), from the Sea of Marmara (Turkey). A total of 580 fish specimens were sampled monthly from October 2017 to September 2018. The total length of all sampled individuals ranged from 11.1 to 29.5 cm, corresponding to ages from 1 to 3 years. The length–weight relationship was expressed as W = 0.022 TL<sup>2.6838</sup>, where the slope indicated negative allometric growth. Growth parameters were <italic>L</italic><sub>∞</sub> = 33.7 cm, <italic>k</italic> = 0.48, and <italic>t</italic><sub>0</sub> = −0.18 for all samples. A seasonally oscillating growth model, indicating the amplitude of oscillations, revealed an important seasonal growth pattern. Total, natural, and fishing mortality rates were calculated as 1.42, 0.47, and 1.01, respectively. The exploitation ratio (E = 0.68) indicates that the fishing pressure on the common sole in the Sea of Marmara was high. The sex ratio (♀/♂) was 1.18. The gonadosomatic index (GSI) for females showed that two main spawning seasons were observed: one in spring (May) and one in autumn (September–October). Sizes at the onset of sexual maturity were estimated for both females and males at 21.6 and 18.6 cm, respectively.</p> </abstract>ARTICLE2021-12-03T00:00:00.000+00:00Effects of feed on fatty acid composition in muscles and gonads of the Chinese mitten crab ()https://sciendo.com/article/10.2478/oandhs-2021-0029<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+00:00Establishment and range expansion of non-native fish species facilitated by hot springs: the case study from the Upper Sakarya Basin (NW, Turkey)https://sciendo.com/article/10.2478/oandhs-2021-0021<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+00:00 (Copepoda; Philichthyidae) – an interesting cranium parasite of the swordfish collected from the Baltic Seahttps://sciendo.com/article/10.2478/oandhs-2021-0028<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+00:00First record of straight-needle pteropod Rang, 1828 bloom in the Çanakkale Strait (NE Aegean Sea, Turkey)https://sciendo.com/article/10.2478/oandhs-2021-0026<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+00:00First record of the rare crab (Crustacea: Brachyura: Varunidae) in the North Seahttps://sciendo.com/article/10.2478/oandhs-2021-0030<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+00:00Effects of seasonal changes and environmental factors on bioindicator bacteria levels in Çardak Lagoon, Çanakkale Strait, Turkeyhttps://sciendo.com/article/10.2478/oandhs-2021-0025<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+00:00Demographics of great sturgeon () in Iranian waters of the Caspian Sea (2008–2010)https://sciendo.com/article/10.2478/oandhs-2021-0027<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+00:00A review of occurrence, distribution and alien status of and () (Mollusca: Heterobranchia) in the Mediterranean Seahttps://sciendo.com/article/10.2478/oandhs-2021-0022<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+00:00Growth parameters of (Lesueur, 1821) (Actinopterygii, Poeciilidae) – an introduced species in brackish water of Wadi Al-Bahayes (Oman)https://sciendo.com/article/10.2478/oandhs-2021-0023<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+00:00Historical review of Dutch Pectinariidae with as a new taxon for the Netherlands (Annelida: Polychaeta: Pectinariidae)https://sciendo.com/article/10.2478/oandhs-2021-0024<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+00:00en-us-1