Features of biology of the round goby <Emphasis Type="Italic">Neogobius melanostomus</Emphasis> (Perciformes,Gobiidae) in waters of Kuibyshev Reservoir

Based on materials of 2003–2005, the size-age composition, dates of reproduction, distribution, as well the qualitative and quantitative composition of the food of the round goby Neogobius melanostomus in the coastal part of Kuibyshev Reservoir are considered. It is shown that the round goby prefers coastal parts of the reservoir with depths to 10 m and rocky grounds and that its main food are mollusks of the genus Dreissena.     

Variation of food spectra of tube-nosed goby <Emphasis Type="Italic">Proterorhinus marmoratus</Emphasis> (Perciformes,Gobiidae)—a new species in the Rybinsk Reservoir

Size-age structure and food composition of tube-nosed goby Proterorhinus marmoratus in the Rybinsk Reservoir have been studied. It was shown that food spectra changed in the process of dispersal of this species over the water body and considerably vary during the season. In the period of naturalization, feeding of the tube-nosed goby is characterized by group specialization; the object of specialization is Gmelinoides. Having dispersed over the water body and naturalized, it manifested itself as a generalist; its food composition became diverse and was determined by the seasonal dynamics of the population and biomass of food items.     

Environmental factors influencing the gobiid assemblage of a Mediterranean Lagoon: Empirical evidence from a long-term study

A severe freshwater inflow during our long-term ichthyological study of the brackish Vaccarès lagoon (1993–1998) helped us to assess the impact of sudden environmental changes on the specific biomass composition of the gobiid population and the catches per unit effort of the black goby Gobius niger, the common goby Pomatoschistus microps and the sand goby P. minutus. In 1993, the composition of the Gobiid fish assemblage of the Vaccarès lagoon was dominated by the black goby (63%) and finally evolved to an assemblage dominated by the common goby (80%). The black goby disappeared from the Vaccarès lagoon 2 years after the inflow, whereas catches of the common goby increased significantly after the environmental changes and reached maximum values in 1998. Catches of sand goby did not seem to be affected by environmental changes and depended on the communication between sea and lagoon. This study showed that evolution of an ecosystem after environmental changes is linked to the reaction that species developed to face perturbations.     

Seasonal dynamics of growth and feeding of big-headed sculpin <Emphasis Type="Italic">Batrachocottus baicalensis</Emphasis> (Cottidae) in the Cape Berezovyi area (southern Baikal)

The seasonal features of the growth and feeding of one of the mass fish species of the littoral zone of Lake Baikal, big-headed sculpin Batrachocottus baicalensis, are investigated in the study area near the Cape Berezovyi (southern Baikal). It is found that the greatest increase of the linear parameters of the individuals of all age classes occurs in autumn, in the middle of the feeding period. Twenty-nine food objects, i.e., invertebrates and fishes, have been noted in the feeding spectrum of big-headed sculpin. It is found that the amphipods comprise the basic food year round. The transition of big-headed sculpin to predominant consumption of fish food is noted in the reproduction periods of other sculpins in the shallows. In general, the seasonal changing in species composition and food object ratio in the food are due to the fish life cycles, migrations of amphipods of different species, and, to a lesser extent, changing numbers of different groups of zoobenthos.     

Comparative Ecology of the Gobies <Emphasis Type="Italic">Nes longus</Emphasis> and <Emphasis Type="Italic">Ctenogobius saepepallens</Emphasis>, Both Symbiotic with the Snapping Shrimp <Emphasis Type="Italic">Alpheus floridanus</Emphasis>

Synopsis We re-examined the symbiotic association of the western Atlantic gobiid fishes Nes longus and Ctenogobius saepepallens with the snapping shrimp Alpheus floridanus on the basis of a critical literature review and new data. Our research confirms that N. longus interacts closely with the shrimp and is dependent on it for the cover provided by the burrow that the shrimp constructs; the goby serves as the sentinel at the burrow entrance. Ctenogobius saepepallens is often seen occupying a burrow of the alpheid, and the shrimp will leave the burrow to deposit sediment with the goby at the entrance, even pushing the goby aside at times. However, the shrimp does not make contact with the goby with its antennae, nor does the goby communicate with caudal fin fluttering at the approach of danger. We suggest that their relationship is a first step in an evolutionary process that may lead to the very close mutualistic association exhibited by N. longus and the alpheid, as well as Indo-Pacific shrimp gobies of 13 different genera and their alpheid partners. Nes longus remains close to the burrow entrance; it feeds mainly on small gastropods, decapod crustaceans, ostracods, and isopods. By contrast, C. saepepallens makes longer excusions from the shelter of the burrow; its diet is dominated by benthic copepods, followed by ostracods and lesser amounts of foraminiferans, isopods, and decapod crustaceans. By virture of its greater mobility, it can be more selective in its prey.     

Morphological divergence and diagnostic characters of ginger goby <Emphasis Type="Italic">Neogobius eurycephalus</Emphasis> (Kessler, 1874) and surman goby <Emphasis Type="Italic">N. cephalargoides</Emphasis> Pinchuk, 1976 (Perciformes,Gobiidae)

Comparative analysis of morphometric characters of surman goby Neogobius cephalargoides and of two subspecies of ginger goby N. eurycephalus is made. Characteristics liable to size variation and sex dimorphism are revealed. Independence of the investigated species and the diagnostic value of characters previously suggested for classification are confirmed. The obtained data confirm isolation of north-western populations of ginger goby as a separate subspecies N. eurycephalus odessicus and suitability of three meristic characters for differentiation of the subspecies: the number of rays in the second dorsal fin and anal fin and the number of transverse rows of scales.     

Diet composition and consumption rate in round goby (<Emphasis Type="BoldItalic">Neogobius melanostomus</Emphasis>) in its expansion phase in the Trent River,Ontario

We assessed density, gut fullness and prey composition of round goby (Neogobius melanostomus) from three areas in the Trent River (Ontario) representing areas of initial introduction and subsequent expansion. Round goby had been present at the area of original introduction since 2003, and by 2007/2008, their range had expanded upstream and downstream into the outermost reaches sampled in the study. Catch per unit angling effort in nearshore sites indicated that round goby density in the area of original introduction was more than double their density in the upstream expansion area and nearly three times the density in the downstream expansion area. Gut fullness index was lower in gobies from the area of original introduction than for those at the upstream and downstream edges of their expanded range. The most dramatic difference in diet composition was with dreissenids, where large gobies (≥70 mm) occupying the area of original introduction had almost no dreissenid biomass in their guts, whereas dreissenids were the predominant prey type in gobies occupying the two expansion areas. Post-hoc zebra mussel density in the area of original introduction was an order of magnitude lower than in the two expansion areas which, combined with the differences in stomach fullness and prey composition, suggest that local, density-related reduction of this prey type was occurring in the river.     

Effect of anthropogenic pollution on the immunological and biochemical mechanisms of maintaining homeostasis in fish of the Black Sea

This paper examines several immuno-biochemical indices of the liver and blood serum of the Mediterranean horse mackerel Trachurus mediterraneus ponticus (Aleev, 1956) and the round goby Neogobius melanostomus (Pallas, 1814) that live in the coastal waters of the Black Sea in locations with different anthropogenic loads. The antimicrobial properties of blood serum, the lipid fraction composition and antioxidant activity of the fish tissues were investigated. Fish from the polluted location displayed weak humoral immunity, low antioxidant activity of tissues, and low triglyceride content, compared to individuals from relatively clean habitats. At the same time, the contents of total lipids, cholesterol, nonesterified fatty acids, and malonic dialdehyde in fish were higher in the polluted than in the relatively low-polluted location.     

Discrimination between invasive Ponto‐Caspian gobies using a PCR‐RFLP method

Accurate identification of invaders, and especially their juveniles and eggs, is a difficult task if several morphologically similar species co‐occur. The aim of the study was to develop and test a rapid and cost‐effective procedure for identification of five species of invasive gobies occurring in the middle Danube basin, namely round goby Neogobius melanostomus, bighead goby Ponticola kessleri, monkey goby Neogobius fluviatilis, racer goby Babka gymnotrachelus and tubenose goby Proterorhinus semilunaris. First, a 708 bp fragment of the cytochrome oxidase I gene was amplified and sequenced for representative samples of these five species. Appropriate sequences of the five species available in public databases were used for in silico analysis. A digestion of the amplified fragment with the BfaI enzyme was found to be suitable for the species identification, as it showed unique restriction patterns for each species. The technique was also successfully applied for fish remains from burbot Lota lota stomachs. Thus the technique could be a useful tool in monitoring biological invasions, especially by identifying specimens that could not be determined on the basis of morphological features. The results demonstrate that the PCR‐RFLP method may in some cases be more reliable for species identification than a standard DNA sequencing.     

Genetic analysis reveals the diversity of larval Gobiidae in a temperate estuary

Using molecular tools to examine Gobiidae, the second most abundant taxon in ichthyoplankton samples in the Gulf of Riga (Baltic Sea), the sand goby Pomatoschistus minutus was the most abundant taxon (82% of all individuals analysed), the common goby Pomatoschistus microps constituted 12% and the black goby Gobius niger 6%. The spatiotemporal distribution of P. microps and G. niger indicated a preference for habitats closer to the river inlet and their abundances increased slightly towards the end of the sampling period in summer. The species composition was interpreted in the context of the prevailing habitat conditions, characterized by extremely low water transparency, low salinity, limited spread of vegetated area and dominance of sandy–muddy substrata.     

On the finding of round goby <Emphasis Type="Italic">Neogobius melanostomus</Emphasis> (Pallas) (Gobiidae) in the food of burbot <Emphasis Type="Italic">Lota lota</Emphasis> (L.) of the Rybinskoe water reservoir

The fish swallowed by the burbot caught with gill nets in the Volzhskii reach of the Rybinskoe water reservoir in 2007 are investigated. Based on the teretial body shape, the absence of a swim bladder, the presence of a pelvic disc, the dimensions of the skull, the body length, the body weight, and the age, the specimens found in the gut of the burbot are identified as round goby Neogobius melanostomus (Pallas). The round goby should be regarded as an adventive (invasive) species because it is not distributed in different biotopes of the Rybinskoe water reservoir.     

Predator and prey: the role of the round goby Neogobius melanostomus in the western Baltic

Different studies on the position of the non-indigenous species Neogobius melanostomus within the coastal food web of the Pomeranian Bay (western Baltic) were performed, resulting in a quantitative and qualitative species list of prey organisms found in the stomachs of the invader and an estimation concerning the importance of round goby as prey for different resident predators. It seems that the colonization process is not fully completed yet, but the results reveal that the species is already established in the food web 16 years after the first observation within the study area. The results show that N. melanostomus feed upon a wide range of different resident organisms. While a direct predation effect on native fish species appears rather unlikely, indirect effects such as competition cannot yet be excluded. In addition, our results reveal an ontogenetic diet shift and that the round goby itself already serves as an important prey for piscivorous fish and seabirds. Finally, we formulate different hypotheses based on our results which will require further research.     

Evidence for predatory control of the invasive round goby

We coupled bioenergetics modeling with bottom trawl survey results to evaluate the capacity of piscivorous fish in eastern Lake Erie to exert predatory control of the invading population of round goby Neogobius melanostomus. In the offshore (>20 m deep) waters of eastern Lake Erie, burbot Lota lota is a native top predator, feeding on a suite of prey fishes. The round goby invaded eastern Lake Erie during the late 1990s, and round goby population size increased dramatically during 1999–2004. According to annual bottom trawl survey results, round goby abundance in offshore waters peaked in 2004, but then declined during 2004–2008. Coincidentally, round goby became an important component of burbot diet beginning in 2003. Using bottom trawling and gill netting, we estimated adult burbot abundance and age structure in eastern Lake Erie during 2007. Diet composition and energy density of eastern Lake Erie burbot were also determined during 2007. This information, along with estimates of burbot growth, burbot mortality, burbot water temperature regime, and energy densities of prey fish from the literature, were incorporated into a bioenergetics model application to estimate annual consumption of round goby by the adult burbot population. Results indicated that the adult burbot population in eastern Lake Erie annually consumed 1,361 metric tons of round goby. Based on the results of bottom trawling, we estimated the biomass of yearling and older round goby in offshore waters eastern Lake Erie during 2007–2008 to be 2,232 metric tons. Thus, the adult burbot population was feeding on round goby at an annual rate equal to 61% of the estimated round goby standing stock. We concluded that the burbot population had high potential to exert predatory control on round goby in offshore waters of eastern Lake Erie.     

Naturalization of the Pacific <Emphasis Type="Italic">Chameleon Goby Tridentiger trigonocephalus</Emphasis> (Perciformes,Gobiidae) in the Black Sea (Crimea,Sevastopol Gulf)

In summer 2008, colonies of the Pacific chameleon goby Tridentiger trigonocephalus were found in the Black Sea in two sites of the Sevastopol Gulf. Data are presented on size-age composition of the caught specimens, morphometric characteristics of females, males, and of immature specimens, and on variants of body coloration depending on physiological state. The number of yolk oocytes of different size and of unfertilized eggs in a clutch is determined. Early ontogenetic stages are described, as well as of behavior of males in the period of care of the egg clutch. Chameleon Goby is naturalized in Sevastopol Gulf and formed a self-reproducing population.     

Energy flow to two abundant consumers in a subtropical oyster reef food web

Oyster reefs are among the most threatened coastal habitat types, but still provide critical habitat and food resources for many estuarine species. The structure of oyster reef food webs is an important framework from which to examine the role of these reefs in supporting high densities of associated fishes. We identified major trophic pathways to two abundant consumers, gray snapper (Lutjanus griseus) and crested goby (Lophogobius cyprinoides), from a subtropical oyster reef using stomach content and stable isotope analysis. The diet of gray snapper was dominated by crabs, with shrimp and fishes also important. Juvenile gray snapper fed almost entirely on oyster reef-associated prey items, while subadults fed on both oyster reef- and mangrove-associated prey. Based on trophic guilds of the gray snapper prey, as well as relative δ¹³C values, microphytobenthos is the most likely basal resource pool supporting gray snapper production on oyster reefs. Crested goby had omnivorous diets dominated by bivalves, small crabs, detritus, and algae, and thus were able to take advantage of prey relying on production from sestonic, as well as microphytobenthos, source pools. In this way, crested goby represent a critical link of sestonic production to higher trophic levels. These results highlight major trophic pathways supporting secondary production in oyster reef habitat, thereby elucidating the feeding relationships that render oyster reef critical habitat for many ecologically and economically important fish species.     

The forgotten feeding ground: patterns in seasonal and depth-specific food intake of adult cod Gadus morhua in the western Baltic Sea

This study presents the diet composition of western Baltic cod Gadus morhua based on 3150 stomachs sampled year-round between 2016 and 2017 using angling, gillnetting and bottom trawling, which enhanced the spatio-temporal coverage of cod habitats. Cod diet composition in shallow areas (<20 m depth) was dominated by benthic invertebrate species, mainly the common shore crab Carcinus maneas. Compared to historic diet data from the 1960s and 1980s (limited to depth >20 m), the contribution of herring Clupea harengus decreased and round goby Neogobius melanostomus occurred as a new prey species. Statistical modelling revealed significant relationships between diet composition, catch depth, fish length and season. Generalized additive modelling identified a negative relationship between catch depth and stomach content weight, suggesting reduced food intake in winter when cod use deeper areas for spawning and during peak summer when cod tend to avoid high water temperatures. The results of this study highlight the importance of shallow coastal areas as major feeding habitats of adult cod in the western Baltic Sea, which were previously unknown because samples were restricted to deeper trawlable areas. The results strongly suggest that historic stomach analyses overestimated the role of forage fish and underestimated the role of invertebrate prey. Eventually, this study shows the importance of a comprehensive habitat coverage for unbiased stomach sampling programmes to provide a more reliable estimation of top predator diet, a key information for food web analyses and multispecies models.     

Permutation of the DNA in small-headed virions of coliphage P1

Summary Use of restriction endonucleases BglII, EcoRI, BamHI, and HindIII, has established that in small-headed (PIS) virions of coliphage P1, as a population, the entire genome found in big-headed (P1B) virions is represented. In addition, the origin and direction of DNA packaging are identical in P1S and P1B virions.     

Relative abundance of Ponto‐Caspian gobiids in the lower Vistula River (Poland) 3‐ to 4 years after first appearance

In the years 2000–2001, specimens of two Ponto‐Caspian gobiids (racer goby Neogobius gymnotrachelus and monkey goby Apollonia fluviatilis) were recorded for the first time in the lower Vistula River, which is a part of the central inland corridor used by Ponto‐Caspian species to migrate in Europe. In 2004, seine net surveys were made in the river course to examine relative abundance of the non‐indigenous gobiids in the local small‐fish community. Altogether 4420 specimens with total lengths ranging from 10 to 340 mm (mostly <100 mm) belonging to 18 species were recorded in 70 hauls. Monkey goby was one of the subdominant species (18.1% of total number of fish captured; 64.3% frequency of occurrence in hauls) together with bleak Alburnus alburnus (21.0, 54.3), roach Rutilus rutilus (18.2, 67.1) and three‐spined stickleback Gasterosteus aculaetus (17.3, 37.1). Racer goby was less abundant but quite common (2.5, 32.9), similar to common bream/white bream Abramis brama/Blicca bjoerkna (6.4, 47.1), Eurasian perch Perca fluviatilis (5.7, 57.1), dace Leuciscus leuciscus (4.2, 40.0) and European bitterling Rhodeus sericeus amarus (3.4, 27.1). The study shows that Ponto‐Caspian gobiids dispersed successfully in the lower Vistula, becoming species common to its nearshore zone 3‐ to 4 years after their first appearance.     

The phylogeny of a reduced ‘sand goby’ group based on behavioural and life history characters

Phylogenetic analysis of 27 behavioural and life history traits for five Mediterranean sand goby species (Perciformes, Gobiidae) produced one tree with a consistency index (excluding uninformative characters) of 0.756. This tree agreed with previous molecular analyses in providing strong support for the monophyly of the sand gobies, indicating that Pomatoschistus and Knipowitschia are paraphyletic and helping to resolve the ambiguous position of Economidichthys pygmaeus, placing it as the basal member of the reduced data set. Although the tree was completely resolved, the branches above E. pygmaeus were only moderately supported in the bootstrap analysis. Overall, the behavioural data provide information that may eventually help clarify the speciation bursts within the Mediterranean sand goby clade as much as is possible. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 916–924.     

Spread of alien (non-indigenous) fish species <Emphasis Type="Italic">Neogobius melanostomus</Emphasis> in the Gulf of Gdansk (south Baltic)

The round goby (Neogobius melanostomus) was first noticed in the Gulf of Gdansk in 1990. This Ponto-Caspian fish was most likely introduced to the Baltic environment from ships ballast water. During the first years of invasion, slow population growth was observed in the initially colonized regions. From 1994, round goby gradually spread in all shallow water zones of the Gulf of Gdansk. The area occupied by the population and the number of fish grew rapidly. By the end of the nineties, round goby became a dominant fish in shallow waters of the western part of the Gulf of Gdansk, where the fish used all solid substrates on the bottom, including concrete piers, big stones or even dumped waste for spawning and refuge. The presence of round goby in the Vistula Lagoon and shallow waters near Rugia (Western Baltic) was noticed for the first time in 1999. The present state, size and condition of the round goby population in the Gulf of Gdansk led us to predict a continual spread of this species into new regions of the Baltic. In addition, the population of round goby is so large that the species has started playing a part in commercial fishing in the Gulf of Gdansk.