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EN
The pond slider Trachemys scripta is one of the most widespread alien turtle species in the world. Its unregulated trade and the consequent uncontrolled releases into the wild led to negative impacts on the native turtles of the invaded areas. In Italy, alien pond sliders are widely spread, and the occurrence of hatchlings and well-established populations is known in some areas. However, to date in Sicily, only a single female of Trachemys scripta laying eggs was reported. Besides that, nothing is known about the actual reproduction success and establishment of self-sustaining T. scripta populations in Sicily. Therefore, based on 14 previously characterised highly polymorphic microsatellite loci, we aimed to unravel if the alien turtles successfully reproduce in Sicily, in both natural and semi-natural areas (i.e., lake “Biviere di Gela” and “Parco d’Orléans”, respectively). Our results show a clear structuring of the two studied populations. Several full-sibling relationships between the sampled turtles were found, suggesting actual reproduction in the wild of the pond sliders in Sicily. However, further sampling is desirable since no parent-offspring relationships were observed in the studied populations. Due to our results, systematic monitoring of alien pond sliders in the whole of Sicily is crucial for better planning of mitigation strategies in order to protect the native biota of Sicilian inland waters.
EN
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 a multi-deployment of baited traps in the growing season increases the diversity and abundance of collected mobile epifauna. Nineteen species of benthic mobile epifauna, including six non-indigenous species (NIS), were collected between May and October 2014 using all tested types of traps in the Port of Gdynia (southern Baltic Sea). Crustaceans, represented by 16 taxa, constituted the group with the highest diversity and abundance. Our study showed that HC1 and HC2 are more effective gear than BT1 and BT2, as both species richness (including NIS) and abundance were higher. Furthermore, the double deployment of BT1 and BT2 increased the diversity and abundance of the captured fauna. The use of artificial habitat collectors as an additional method to the already recommended baited traps for mobile epifauna monitoring in ports should be considered and the number of baited trap deployments should be increased during the growing season.
EN
Four Talitridae species have been recorded in the southern Baltic Sea, including two indigenous species – Talitrus saltator, Deshayesorchestia deshayesii, and two presumably non-indigenous ones – Cryptorchestia garbinii, Platorchestia platensis. It has been twelve years since Platorchestia platensis was recorded for the first time. The distribution and abundance of talitrids have not been studied since the 1990s. Therefore, the main objective of this research was to document the occurrence in Talitridae in the region in order to determine whether non-indigenous P. platensis has spread and whether it co-occurs with indigenous species. Talitrids were recorded at 20 out of 43 sampling sites. T. saltator occurred both along the coast of the open sea and in the Gulf of Gdańsk. The remaining species were found only around the gulf. P. platensis was more abundant than other species and its density was positively correlated with wrack biomass. Our studies have shown that the area of T. saltator occurrence has decreased during the last two decades. Non-indigenous species P. platensis co-occurred with all other Talitridae species, whereas C. garbinii co-occurred only with P. platensis.
EN
The present paper reports the first observation of the North American amphipod Melita nitida Smith, 1873 in the Gulf of Gdańsk (the southern Baltic Sea, Poland). In 2014, 13 adult specimens, including 3 males, were collected in the Port of Gdynia, which is located in the western part of this waterbody.
EN
The paper reports the range extension of the Ponto- Caspian gammarid Dikerogammarus villosus (Sowinsky, 1894) and the first occurrence of this species in new areas of the Polish part of the Baltic Sea basin: the Śmiała Vistula and the Vistula Lagoon. The studies additionally determine the osmoregulatory ability of the species under laboratory conditions within the salinity range of 2-22 PSU. Determination of the osmoregulation of the species shows that D. villosus is a hyperregulator at given experimental salinities and can function in a wide range of external salinities so it is potentially able to colonize various water bodies. Osmoregulatory capacity, which is an indicator of organism’s efforts to regulate the concentration of its body fluids, shows that for individuals from the Gulf of Gdańsk, 6 PSU is the best tolerated salinity. Osmoregulatory capacity is the lowest at this salinity value. The range extension and potential osmoregulatory abilities of the species to spread to other waters are discussed in the context of pollution levels given in the literature with reference to the habitat and sensitivity of the species to e.g. fluoride and cadmium toxicity.
EN
We examined the claw strength, handling behavior, consumption rate, and size selective predation of the invasive Chinese mitten crab Eriocheir sinensis feeding on native Baltic Sea blue mussels Mytilus edulis trossulus during 24 h laboratory experiments. Single starved crabs were offered 15 mussels (five mussels in three length classes) at a time. The total number of mussels consumed by a single crab increased significantly (P < 0.05) with the experimental time from 1.7 ± 0.7 # mussels crab−1 h−1 after 4 h to 0.2 ± 0.7 # mussels crab−1 h−1 after 24 h. The highest consumption rate was observed within the first 4 h, and it decreased significantly (P < 0.05) during the experiment. This was most likely due to the crabs being starved before the start of the experiment. E. sinensis can also harm blue mussel shells by crushing them without further consumption. The mean daily damage, and not consumption, by a single crab was 0.9 ± 1.4 of 11–40 mm mussels. The claw strength of E. sinensis ranged from 1.50 to 20.43 N (mean 8.51 ± 5.93 N) and was significantly correlated (P < 0.05) with sex and both claw size and carapace size. The study showed that E. sinensis may be able to impact the native M. edulis trossulus population abundance in the coastal Baltic waters either through direct predation or indirect mortality by damaging (crushing) the shell.
EN
Within the framework of the possibility of using the Mediterranean pen shell Pinna nobilis in restoration and conservation plans of benthic habitats, an in situ experiment was conducted using empty P. nobilis shells. The latter were transplanted in a bare soft-bottomed area and their associated fauna were followed along 120 days and compared at different temporal points and with the assemblages living in the surrounding soft-sediment area. Compared to soft-sediment communities, an evidently increasing succession of species richness, abundance, and diversity descriptors (Shannon-Wiener H′ and Pielou's evenness J′) was observed with the community inhabiting empty Pinna shells. Among the forty-five (45) species found in association with the transplanted empty shells, seventeen (17) were found constantly in the three temporal points; the other twenty-eight (28) species appeared in the samples collected in the second and/or third sampling time. While motile and sessile species associated to Pinna shells showed an increasing pattern of appearance and abundance along the experiment time, those of soft sediment remained almost constant. The comparison between Pinna shells and soft-sediment associated communities showed that the species richness was slightly different between the two different sample types (49 for soft sediment versus 45 for empty Pinna shells); however the total abundance was found more important with empty Pinna shells. The results obtained herein argue in favor of the important engineering effect of P. nobilis in soft benthic habitats and therefore for the necessity of its conservation.
PL
Celem pracy jest określenie przydatności wskaźnika BPL (ang. biopollution level index) do oceny stanu biozanieczyszczenia polskiej części Zalewu Wiślanego. Na podstawie danych z lat 2010 i 2012 w akwenie odnotowano łącznie 15 gatunków makrozoobentosu, w tym 5 zaliczono do grupy gatunków nierodzimych: Marenzelleria neglecta, Rhitropanopeus harrissi, Potamopyrgus antipodarum, Dreissena polymorpha i Rangia cuneata. W oparciu o przyjęte kryteria i dane literaturowe dotyczące wpływu obcych gatunków na środowisko, stan biozanieczyszczenia Zalewu Wiślanego został oceniony jako średni.
EN
This paper presents biopollution assessment results with respect to macrozoobenthic non-indigenous species in the Polish part of the Vistula Lagoon. A biopollution level index (BPL) was applied and evaluated based on the studies on macrozoobenthos conducted in 2010 and 2012 within the frame of several individual projects. Overall 15 macrozoobenthic species were identified, 5 of which were aquatic alien species: Marenzelleria neglecta, Rhitropanopeus harrissi, Potamopyrgus antipodarum, Dreissena polymorpha and Rangia cuneata. According to the applied criteria the Vistula Lagoon was moderately influenced by invasive species.
EN
The present paper reports on the occurrence of the Atlantic rangia Rangia cuneata in the Wisła Śmiała River (coastal waters of the Gulf of Gdańsk, the southern Baltic Sea) from around 2012–2014.
EN
The round goby was noted for the first time in the Gulf of Gdańsk in 1990. After a few years, the round goby had invaded all suitable areas in the west part of the Gulf of Gdańsk. Generally, the sandy bottom was the factor that do not prevent the fish invasion. The effectiveness of reproduction is one of the most important factors in deciding the success of an introduction into a new area. The round goby needs a hard bottom for egg laying and subsequent embryo development in nests guarded by males. We observed the round goby nests in the Gulf of Gdańsk during three subsequent years. Distances between nests, nest size, number of eggs per nest, and depth of nest locations were investigated by underwater survey, from May till September, throughout the round goby spawning season. Our investigation led us to confirm that any solid elements on the bottom may be utilized as nest substrate when nesting areas are limited. Distances between nests decrease noticeably in comparison with native round goby areas. Taking into account these findings, we conclude that shallow water areas, of almost any type of bottom, might be invaded by the round goby.
EN
Evadne anonyx, a new invasive Ponto-Caspian species, was detected for the first time in the Gulf of Gdańsk in the summer of 2006. Seven years probably elapsed from the first record of E. anonyx in the Baltic Sea (Gulf of Finland) to the first one in the Gulf of Gdańsk. Although the species was found at 10 out of 13 stations in rather low densities (not exceeding 6 indiv. m-3), all the developmental stages of E. anonyx were present (juveniles as well as adults - parthenogenetic females, gamogenetic females and males) in the plankton material investigated.
EN
To date 11 non-indigenous benthic taxa have been reported in Puck Bay (southern Baltic Sea). Five of the 34 taxa forming the soft bottom communities are regarded as non-indigenous to this area. They are Marenzelleria spp., Mya arenaria, Potamopyrgus antipodarum, Gammarus tigrinus and Amphibalanus improvisus. Non-indigenous species comprised up to 33% of the total number of identified macrofaunal taxa (mean 17%). The average proportion of aliens was 6% (max 46%) in the total abundance of macrofauna, and 10% (max 65%) in the biomass. A significant positive relationship was found between the numbers of native taxa and non-indigenous species. The number of native taxa was significantly higher on a sea bed covered with vascular plants than on an unvegetated one, but no such relationship was found for their abundance. No significant differences were found in the number and abundance of non-indigenous species between sea beds devoid of vegetation and those covered with vascular plants, Chara spp. or mats of filamentous algae. G. tigrinus preferred a sea bed with vegetation, whereas Marenzelleria spp. decidedly preferred one without vegetation.
EN
Non-indigenous gammarid species: Pontogammarus robustoides (G.O.Sars, 1894), Obesogammarus crassus (G.O. Sars, 1894), Dikerogammarus haemobaphes (Eichwald, 1841) and Dikerogammarus villosus (Sowinsky, 1894) are present in the Gulf of Gdańsk (southern Baltic Sea). These species reached the Gulf of Gdańsk by 2010 near the point where the River Vistula flows into the Baltic Sea, and become constituents of the amphipods in shallow bottom. All the gammarid species found are of Ponto-Caspian origin. They have been able to move across Europe along rivers and canals, and inhabit reservoirs and drainage systems in the vicinity of such waterways. D. villosus is the latest gammarid species to have colonized Poland. The floods that afflicted Poland in May and June 2010 could have had a significant influence, intensifying as they did the inflow of water from the Vistula into the Gulf of Gdańsk. This could have accelerated the arrival of individuals of these species. The water salinity at the sampling stations was 5.8 – 6.1 PSU. The possible invasion of non-native gammarids may have important consequences for the benthic fauna communities in the Gulf of Gdańsk.
PL
Nierodzime gatunki kiełży: Pontogammarus robustoides (G.O.Sars, 1894), Obesogammarus crassus (G.O. Sars, 1894), Dikerogammarus haemobaphes (Eichwald, 1841) and Dikerogammarus villosus (Sowinsky, 1894) obecne są już w Zatoce Gdańskiej (Bałtyk Południowy). Gatunki te pojawiły się w Zatoce Gdańskiej w 2010 roku, niedaleko ujścia Wisły do Bałtyku i stały się składnikiem obunogów płytkiego dna. Wszystkie wymienione gatunki są pochodzenia ponto-kaspisjkiego. Przedostały się do Europy rzekami i kanałami, i zasiedlają zlewnie tych rzek. D. villosus jest najnowszym przybyszem, który skolonizował Polskę. Najprawdopodobniej powódź, która dotknęła Polskę w maju i czerwcu 2010 roku zintensyfikowała napływ wód Wisły do Zatoki Gdańskiej. Przyśpieszyło to przedostanie się osobników wymienionych gatunków do Zatoki Gdańskiej. Zasolenie wody na stacjach zbioru materiału wynosiło od 5.8 do 6.1 PSU. Inwazja nierodzimych gatunków kiełży może znacznie wpłynąć na zespoły bentosowe Zatoki Gdańskiej.
EN
Palaemon elegans is a species of prawn new (since 2000) to the southern Baltic. The aim of this study was to find out whether there are differences in the sizes of individuals and in the reproductive traits of P. elegans inhabiting different areas of the southern Baltic Sea and to compare the data obtained with existing data for populations from other coastal areas. The present study was carried out in the summers of 2005 and 2007 in three areas differing in their hydrological conditions (primarily in salinity): Puck Bay (PB), the Vistula Delta (VD) and the Vistula Lagoon (VL), Poland. The maximum body lengths of these prawns (females = 60 mm, males = 41 mm), and body masses (1201 mg and 533 mg respectively) found in the southern Baltic were less than those reported from many other parts of the geographical range of this species. The increase in body mass with length was the smallest in the prawns inhabiting VL, and the maximum lengths they grew to were also shorter (females – 52 mm and males – 39 mm) than in PB. The numbers of eggs carried by P. elegans in the southern Baltic were smaller than those found in females in its native regions. Differences were also found in the numbers and sizes of eggs between prawns inhabiting different locations in the southern Baltic. It was concluded that the low salinity of the southern Baltic Sea (even below 7 PSU), while not preventing this prawn from reproducing, caused a shift to the production of fewer but larger eggs. The reproductive strategy that Baltic populations of P. elegans has adopted is one of the factors responsible for its very rapid and large-scale colonization of the southern Baltic Sea.
EN
The paper reports the first records of non-indigenous Ponto-Caspian gammarid species: Pontogammarus robustoides (G. O. Sars, 1894), Obesogammarus crassus (G. O. Sars, 1894), Dikerogammarus haemobaphes (Eichwald, 1841) and the latest colonizer - Dikerogammarus villosus (Sowinsky, 1894) - in the Gulf of Gdańsk (southern Baltic Sea).
EN
Until recently only two palaemonid species inhabited the southern Baltic: Palaemon adspersus and Palaemonetes varians. Soon after the year 2000 a new species - Palaemon elegans - arrived and quickly established itself as a new component in the trophic web. The objects of this research were to define the energy value and energy resources of P. elegans and to compare them with the corresponding values for the native P. adspersus. These parameters will supply information about this new link in the trophic web and may help to explain the part played by the new prawn and its population in the energy flow. This work demonstrated that the energy values of both prawn species were very much the same: the average energy value of P. elegans was 16.5š2.1 J mg-1 DW (19.3š2.5 J mg-1AFDW) (N = 150), that of P. adspersus was 16.7š2.1 J mg-1 DW (19.5š 2.5 J mg-1 AFDW) (N = 71). No statistically significant differences in energy value were found between the two species with respect to sex, size or season. The results show that P. elegans is an energetically valuable food item for predators. Its energy resources in Polish brackish coastal waters can be as high as 150 kJ m-2; the highest among the palaemonid species in this habitat, they constitute a rich supply of food for other organisms.
EN
Palaemon elegans, a new component of the Gulf of Gdańsk macrozoobenthos, colonised the southern Baltic coastal zone in the late 20th and early 21st century. Analysis of the stomach contents of P. elegans revealed 16 plant and animal taxa that these prawns had fed on. The principal dietary component was detritus, with a mean frequency of occurrence in stomachs of > 80%. The most frequently occurring plant components in the diet were algae from the genus Cladophora and the family Ectocarpaceae, while the most significant animal components were Harpacticoida, Chironomidae, Ostracoda and Gammarus spp. The results of the study show that the dietary composition of P. elegans differed significantly between stations and months. The foraging area consisted of two distinctive regions - the Inner Puck Bay, and the Outer Puck Bay together with the Dead Vistula River; two of the stations - Gdynia and Sopot - were distinct from all the others. However, no obvious seasonality in the food composition could be demonstrated.
EN
This communication reports on the occurrence of non-indigenous gammarid species of Ponto-Caspian and of North American origin - in the lower course of the River Vistula, in its Delta and in the Vistula Lagoon.
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