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EN
Cyanobacteria can form blooms and pose a threat tothe functioning of freshwater ecosystems. Cyanobacterial invasions are expected to increase due to climate change. Alien species cause a decline in biodiversity by displacing native species, lead to extinctions, affect food webs,and produce cyanotoxins which potentially impact theenvironment and human health. Three species, Raphidiopsis raciborskii, Sphaerospermospis aphanizomenoides and Chrysosporum bergii, are considered non-native to European waters. Recently, they have expanded their native habitats and become established in temperate lakes. In this article, we provide a detailed overview of the countries where they are distributed and the occurrence of the blooms in Europe. We discuss the biotic and abiotic environmental factors that influence their establishment, as well as the characteristics of the species that make them so adaptable in non-native habitats. Understanding the interplay of these factors willallow us to better recognise patterns of invasiveness and predict their future threats to ecosystems.
EN
The paper reports on the first record of Sinelobus vanhaareni, a non-native tanaid, in the Polish coastal waters (Gulf of Gdansk, southern Baltic Sea). The species was found in the port of Gdynia in 2014, while in 2015–2017 it already colonized the western part of the Gulf of Gdansk, inhabiting mainly hard substrates, including both natural (e.g. boulders) and anthropogenic ones (e.g. vertical concrete piles or walls of offshore structures and breakwaters, horizontal PVC plates and oyster shells used as filling in habitat collectors). During the survey period, S. vanhaareni was found in different seasons of the year (from winter and early spring to autumn), which, combined with the presence of ovigerous females as well as high abundance (up to tens of thousands of individuals per square meter), allows us to assume that the species has already established a population in the Gulf of Gdansk.
EN
Pumpkinseed Lepomis gibbosus, Linnaeus (1758) is a non-native fish species, which the largest population in Poland inhabits warm canal of a “Dolna Odra” Power Plant. Until now, the growth in length and weight and changes the gonad’s maturity of adults individual of this species were carried out. The aim of this study was to evaluate the effect of high water temperature on the seasonal changes in the length, weight, condition, and the number of sclerites, with particular emphasis on length (S0) at which in this species the scales start forming. The research material included 341 pumpkinseed individuals in age 0+ (305 ind.) and 1+ (36 ind.) caught during monthly catches (electrofishing). The fish was weighted (W, g) to the nearest 0.1 g, measured (TL, SL, mm) and their conditions was determined by the coefficient Fulton (K). In addition, number of sclerites (S) on scales and the time of setting up the annual ring were determinated. The biggest monthly increases in mean length - SL (more than 0.5 cm/month) and increases of mean weight W (above 0.7 g / month) in the fish were recorded in the months of highest thermals water (July, August) (ANOVA, p <0.001). The decrease of water temperature in the warm channel in the autumn and winter months, resulted in reduction of monthly growth of fish. Analysis of regression between length (SL) and the length of the scale radius (Po) took the form of a linear function: SL = 1.5813 + 3.1424 * Po (R = 0.91029, p = 0.0000) and showed that the length at which in this species the scales start forming is 1,58cm. Number of sclerites (S) on scales of juvenile pumpkinseed has grown at an annual cycle of 8.20 ± 0.78 (in June) to 27.37 ± 5.18 (in May of the following year). In April and May the fish were recorded already formed on scales a year ring and respectively 1.38 ± 0.55 and 3.40 ± 1.02 sclerites of the second year of life. Moreover, the number of sclerites (S) on pumpkinseed’s scales proportionally increased to the length of this species according to the formula: S = -0.8441 + 5.0880 * SL (R = 0.95682, p <0.001).
PL
Bass słoneczny Lepomis gibbosus, Linnaeus (1758) jest gatunkiem nierodzimym, którego najliczniejsza populacja w Polsce zasiedla kanał ciepły elektrowni "Dolna Odra". Dotychczas na osobnikach dorosłych tego gatunku przeprowadzono analizy wzrostu długości i masy oraz zmian dojrzałości gonad. Celem niniejszej pracy była ocena wpływu podwyższonej termiki wody na wielkość sezonowych zmian długości, masy i kondycji oraz liczby sklerytów, ze szczególnym uwzględnieniem długości (S0) przy której zakłada się łuska. Materiał do badań stanowiły osobniki młodociane w wieku 0+ (305 szt.) i 1+ (36 sztuk.) złowione podczas prowadzenia comiesięcznych elektropołowów. Ryby ważono (W, g) z dokładnością do 0,1g, zmierzono (TL, SL, mm) oraz określano ich kondycje za pomocą współczynnika Fultona (K). Ponadto na łuskach oszacowano liczbę sklerytów oraz termin zawiązywania się pierścienia rocznego. Największe miesięczne przyrosty długości SL (powyżej 0,5cm/miesiąc) oraz masy jednostkowej W (powyżej 0,7 g/miesiąc) u badanych ryb zanotowano w miesiącach o najwyższej termice wody (lipiec, sierpień) (ANOVA, p<0,001). Spadek temperatury wody w kanale ciepłym, w miesiącach jesienno- zimowych, powodował zmniejszanie się przyrostów miesięcznych ryb. Analiza regresji pomiędzy długością (SL) a długością promienia oralnego łuski (Po) przybrała postać funkcji liniowej: SL = 1,5813 + 3,1424*Po (R = 0,91029, p = 0,0000) i wykazała, iż długość przy której zakłada sie łuska u tego gatunku wynosi 1,58cm. Liczba sklerytów (S) na łuskach młodocianego bassa slonecznego wzrastała w cyklu rocznym od 8,20 szt. ±0,78 (w czerwcu) do 27,37 szt. ±5,18 (w maju następnego roku). W kwietniu i w maju u ryb zanotowano założony już pierścień roczny i odpowiednio średnio 1,38 szt. ±0,55 oraz 3,40 szt. ±1,02 sklerytów drugiego roku życia. Ponadto stwierdzono, że liczba sklerytów (S) na łusce bassa słonecznego rośnie proporcjonalnie do wzrostu długości tego gatunku zgodnie ze wzorem: S = -0,8441 + 5,0880*SL (R = 0,95682, p<0,001).
EN
The presence of exotic fish species in the Baltic Sea and its tributaries poses a serious threat for native ichthyofauna, mainly due to the spread of new pathogens. As the accurate identification of species is essential for an effective assessment of changes related to the appearance of non-native species in an aquatic environment, in this paper we tested the usefulness of biometrics and molecular markers in identifying a specimen from the Mugilidae family found in the Odra estuary. The results demonstrated that unambiguous identification of the specimen using biometric features was impossible due to high morphological similarities shared by grey mullets. Unambiguous identification was possible only due to molecular markers, e.g. rhodopsin gene, which helped to identify the collected fish specimen as Liza ramada (Risso, 1827), the first specimen of this species found in the Odra River estuary. The presence of an L. ramada specimen in the Odra River – which could signal the expansion of non-native species into wider ranges – may be linked to climate change or human activity.
EN
The present paper reports for the first time on the occurrence of the oriental shrimp Palaemon macrodactylus M. J. Rathbun, 1902 in the coastal waters of the Baltic Sea in 2014. Ovigerous females and young individuals were found, indicating a possible establishment of this species in the Baltic Sea.
EN
The aim of this study was to determine the occurrence, spatial distribution and abundance pattern of the Harris mud crab Rhithropanopeus harrisii in the Gulf of Gdańsk (southern Baltic Sea). Between 2006 and 2010, this species was found at 69 out of 129 sampling stations, at depths from 0 to 20 m. Two main aggregations of the Harris mud crab were established: (1) in Puck Bay (max. density 19 indiv. 100 m-2) and (2) in the Gdynia and Sopot area (max. density 5 indiv. 100 m-2). 920 specimens were collected during the whole sampling period: 150 juveniles, 370 females and 400 males. The minimum measured carapace width was 1.96 mm, the maximum 21.40 mm (mean 9.03 ±4.11 mm).
EN
This paper describes for the first time the gonad maturity stage of Eriocheir sinensis females (carapace width 55.20-78.10 mm) collected in the autumns and winters of 2005–2012 in the Gulf of Gdańsk and Vistula Lagoon (southern Baltic Sea). Seventeen females had gonads in the penultimate stage, which indicates that spawning would shortly take place. Four other females had gonads in the last stage, which means they were already carrying eggs. These accounted, on average, for 17.9± 2.9% of female weight and were in the 3rd and 4th embryo developmental stage. The results show that the low salinity of southern Baltic Sea (≤7 PSU) permits mating and fertilization as well as embryo development in E. sinensis. It is still not clear, whether such a salinity level will enable hatching and the complete larval cycle.
EN
Seven epibiotic halacarid mites (Caspihalacarus hyrcanus, two species of Copidognathus, Halacarellus petiti, Porohalacarus alpinus, Soldanellonyx monardi and S. chappuisi), two oribatid mites (Hydrozetes lacustris and Trhypochthoniellus longisetus) and one water mite (Piona pusilla) were found on the setae-covered claws of eighteen Chinese mitten crabs (Eriocheir sinensis) collected from fresh and brackish waters in Poland and Germany. The most abundant of the 111 mite individuals recorded was one of the Copidognathus species (N = 52); this was followed by H. petiti (N = 38) and C. hyrcanus (N = 13). This is the first record of H. petiti and of the genus Copidognathus from Polish waters. The possibility of migrating over long distances assisted by catadromous mitten crabs enhances mite dispersal, as well as their introduction to new environments.
EN
We conducted a snapshot study to check the importance of non-native Ponto-Caspian gobies (monkey and racer goby) in the diet of native obligate (northern pike, pikeperch) and facultative (Eurasian perch) predators in the Vistula River 3-4 years after the appearance of aliens. In total 71 fish with non-empty stomachs, taken randomly from net catches from various parts of the river were analyzed, including 32 pike, 20 pikeperch and 19 perch specimens. We found that gobiids prevailed in the diet of smaller (<30 cm standard length, SL) individuals of pike and pikeperch, as well as larger (>15 cm SL) specimens of perch, although the effect of predator size on the presence of gobiids in the diet was not significant in the case of perch. Our results indicate that gobiids as a prey fish can stimulate considerable changes in local food webs, which require further studies.
EN
This is the first comprehensive review to examine the role of the central European invasion corridor on fish introductions into Belarusian and Polish inland waters (Dnieper-Bug-Vistula-Oder-Elbe-Spree-Havel). Historical and recent data were assessed, including the results of a 2003 - 2008 survey along the Belarusian and Polish sections of the corridor. Since the eighteenth century, at least six fish species of Ponto-Caspian origin have spread via the corridor and migrated westwards to the Baltic basin, with five species found in recent surveys, namely the monkey goby Neogobius fluviatilis, round goby N. melanostomus, racer goby N. gymnotrachelus, tubenose goby Proterorhinus marmoratus and the white eye-bream Abramis sapa. Four other non-native species were also found within the corridor - the Amur sleeper Perccottus glenii, gibel carp Carassius gibelio, brown bullhead Ameiurus nebulosus and the topmouth gudgeon Pseudorasbora parva. Their presence is related to numerous accidental introductions to many localities in Belarus and Poland, rather than from using the corridor as an invasion route. One species, the ninespine stickleback, Pungitius pungitius, has migrated from the Baltic basin to the Black Sea drainage systems.
EN
Eriocheir sinensis H. Milne-Edwards, 1853 is a non-native species found in European waters. Analyses of mitten crabs caught in brackish waters (Gulf of Gdańsk, Poland) and in freshwater (Havel River, Germany) have indicated that numerous epibionts (possibly temporary) inhabit the dense setal mats that cover the chelipeds. Of the 950 associates found on 22 crabs collected from brackish water, the most abundant were Nematoda (82.3%), followed by Bivalvia (10.3%), Crustacea (5.6%), Oligochaeta (1.2%) and Gastropoda (0.6%). In comparison, 1280 specimens (Chironomidae - 67.6% and Halacaridae - 32.4%), were identified from 13 crabs collected in freshwater. As this crab can migrate long distances, it is capable of transporting native and non-native species via its mittened claws to new habitats.
EN
This study deals with the occurrence and migration of Gammarus tigrinus Sexton 1939 into the Puck Bay (western part of the Gulf of Gdansk, Baltic Sea). The material was collected in September 2002 at nine stations (approximate depth – 0.4 m). The only Gammarus species found at five sampling stations was G. tigrinus. The species found at other stations located along the inner part of the Puck Bay were G. salinus, G. zaddachi, and G. duebeni. The sex ratio for G. tigrinus was close to 1. Almost 50% of the females were carrying eggs. The males were larger (6.0 š 0.8 mm) than females (4.7 š 0.8 mm). The average male dry weight was 2.5 š 1.2 mg and that of females was 2.1 š 0.7 mg. The relation between length (L) and dry weight (DW) was DW = 0.095źL1.76 (R2 = 0.76). This study indicates that G. tigrinus is spreading rapidly in the Baltic Sea.
EN
The present paper reports for the first time on the occurrence of the parasite Maritrema subdolum in the amphipod Gammarus tigrinus, a non-native species in the Gulf of Gdańsk.
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