Grass Goby Zosterisessor Ophiocephalus Research Articles

Biochemical response of two fish species of Gobiidae (Gobiiformes) to Cryptocotyle (Opisthorchiida, Heterophyidae) metacercariae infection from the mouth of the river Chernaya (Black Sea)

Metacercariae of Cryptocotyle are among the most numerously recorded trematode parasites in the estuarine biocenoses of the Azov-Black Sea basin. These parasites can massively affect body surface, gills and fins of host fishes including gobiids. However, information on the influence of Cryptocotyle metacercariae on the physiological and biochemical status of gobies is extremely limited. Biochemical response of two fish species of Gobiidae - grass goby Zosterisessor ophiocephalus (Pallas, 1814) and mushroom goby Ponticola eurycephalus (Kessler, 1874) to Cryptocotyle spp. metacercariae infection at the mouth of River Chernaya (Black Sea) was investigated. Activities of superoxide dismutase, catalase, peroxidase, glutathione reductase, glutathione-S-transferase, alanine transaminase, aspartate transaminase, level of thiobarbituric acid-reactive substances were measured as parameters of biochemical response. The findings of this study demonstrate interspecific differences in fish response to parasite infections. High infection leads to an intensification of lipid peroxidation and a weakening of antioxidant protection in the muscles of mushroom goby but activation of the antioxidant enzyme system in the muscles of grass goby. The results show a greater resistance of grass goby to the infection when compared with mushroom goby.

Change of spatial distribution in the ichiotocenosis of the shabolat estuary in the process of its anthropogenic transformation

Consequences of Shabolat estuary natural ecosystems transformation under the influence of anthropogenic factors are reflected in the composition of ichthyocenosis, changes in the basic population characteristics of the most mass species.The purpose of the work was to find out the spatial distribution of the Shabolat estuary most massive representatives of the ichthyocenosis in terms of its anthropogenic transformation.Material and methods. The material for the study was selected from industrial fishing gear in the spring, summer and autumn periods of 2009-2012. A complete biological analysis of fish (goby round, goby grass, flounder, flounder, mullet pilengas, etc.) was carried out according to the conventional method.Result. The regularities of formation of ichthyocenosis largest masses populations were studied depending on: water salinity, connection with adjacent water areas, fish acclimatization and introduction, anthropogenic loading and peculiarities of spatial distribution of ichthyocenosis largest masses populations in aquatics.The most important Shabolat estuary ichthyocomplex components include representatives of the Gobiidae family, the Platichthys luscus population and the mullet family representatives.Of particular interest to the members of the goby family are the mass species of gobies: the round goby Neogobius melanostomus and the grass goby Zosterisessor ophiocephalus, which are able to hibernate and reproduce in the estuary. This is an important link in the food chains of the reservoir. By entering into competition with other representatives of ichthyocenosis, they significantly affect the state of the forage base and production capacity of the estuary.Representatives of the mullet family and gloss flounder are distributed in the estuary deep water areas and in areas with maximum salinity.Conclusions. It has been established, that in the conditions of anthropogenic transformation of the estuary, in the last 35-40 years, the round goby and grass goby numbers and distribution range have decreased. In bulk, they have survived only in reservoir small, local areas, due to the deterioration of reproduction conditions and the degradation of the zoster and reddest associations. The main reasons for the decline in the size and distribution range of gobies in the Shabolatsky estuary was their mass death as a result of a large-scale environmental catastrophe and reproduction conditions deterioration. The reason for the significant decrease in the flounder and mullet number and distribution range was the mass death in 1992, as well as changes in the salinity of the Shabolat estuary

Mercury and selenium in the grass goby Zosterisessor ophiocephalus (Pisces: Gobiidae) from a mercury contaminated Mediterranean lagoon

Mercury (Hg) and its bioaccumulation are important in evaluating the health risk through fish consumption. In the Marano and Grado Lagoon a historical contamination originating from both mining and industrial sources is present.In this study the Hg levels in the grass goby and the protective effect of selenium (Se) were determined as a function of size, sex, sampling sites and season.Mercury often exceeded the limit for commercialisation, whereas Se was mostly constant being homeostatically regulated.The mean Se/Hg molar ratio showed about 40% of data >1.0 and the HBVSe index was on average equal to 0.0. Thus, grass goby of this area is not a Se source food indicated for pregnant and/or breastfeeding women, but its occasional consumption would appear to have no contraindications if integrated with other Se rich foods: the ingestion of about 10 fish fillets per week can be safely consumed by adults.

Effect of pollution on the fluctuating asymmetry in the grass goby Zosterisessor ophiocephalus Pallas, 1811 as contamination indicator of Eastern Tunisia.

Effect of pollution on the fluctuating asymmetry in the grass goby Zosterisessor ophiocephalus Pallas, 1811 as contamination indicator of Eastern Tunisia.

Fluctuating asymmetry in grass goby Zosterisessor ophiocephalus Pallas, 1811 inhabiting polluted and unpolluted area in Tunisia

Fluctuating asymmetry, a random deviation of bilateral traits, is assessed on grass goby Zosterisessor ophiocephalus Pallas, 1811 living in one disturbed site and in one unpolluted site Gulf of Gabes (Tunisia). Statistical analysis showed that assessed asymmetries are fluctuating. FA of orbital diameter, sub-orbital distance, pectoral fin and post-orbital length are higher in polluted site compared to control. Chemical pollution seems to be responsible for this high FA.

Seasonal variations in proximate and fatty acid composition of muscle of Tunisian Grass goby Zosterisessor ophiocephalus

The present study focuses on the seasonal variation of the global chemical composition of Gradd goby, Zosterisessor ophiocephalus , of the coastal catch from the Gabes Gulf (Tunisia). The variations of moisture, protein fat and ash contents of the fresh muscle fish were examined as a function of sex. These variations are low for moisture and fat and medium for protein and ash. The highest moisture content was reached during July for males (82.25 ± 0.70 g/ 100 g of fresh muscle) and during November for females (73.68 ± 0.65 g/ 100 g of fresh muscle). Over the year, this fish present lower fat content. However, higher protein values were observed over the year (15.27-21.33 g/ 100g of fresh muscle). Interestingly, muscle of Zosterisessor ophiocephalus may constitute a source of protein with lower fat content suggesting the use of this fish as a flower of healthy diet for humans. Significant differences were also observed for fatty acids. Palmitic acid was the most abundant fatty acid ranging from 20.57 % to 34.90 %. Oleic acid was the main unsaturated fatty acid ranging from 24.12 % to 43.47 %. The muscle contained high rate of ω-3 polyunsaturated fatty acids (PUFA), ranging from 7.58 to 20.07 %.

The Parasite Fauna of the Gobiid Fish (Actinopterygii, Gobiidae) in the Sukhyi Lyman, Black Sea

Abstract The parasite fauna of gobiid fish of the Sukhyi Lyman, Black Sea, is described. Seventeen species of parasites are registered in the gobiids in the water body. The marine tubenose goby Proterorhinus marmoratus has the richest parasite fauna (12 species), the grass goby Zosterisessor ophiocephalus has the fewest number of parasite species (5 species). The microsporidian Loma sp. and ciliate Trichodina domerguei are recorded for the first time for gobiids in the north-western Black Sea. The core of the parasite fauna is formed by metacercariae Cryptocotyle spp. The core, secondary, satellite, and rare species in the parasite community of each host are described. Not only marine and brackish water parasites, but also limnetic species, namely metacercariae D. spathaceum, were registered in the Sukhyi Lyman that differentiates it from the many of localities in the north-western Black Sea.

Body size correlates with fertilization success but not gonad size in grass goby territorial males.

In fish species with alternative male mating tactics, sperm competition typically occurs when small males that are unsuccessful in direct contests steal fertilization opportunities from large dominant males. In the grass goby Zosterisessor ophiocephalus, large territorial males defend and court females from nest sites, while small sneaker males obtain matings by sneaking into nests. Parentage assignment of 688 eggs from 8 different nests sampled in the 2003–2004 breeding season revealed a high level of sperm competition. Fertilization success of territorial males was very high but in all nests sneakers also contributed to the progeny. In territorial males, fertilization success correlated positively with male body size. Gonadal investment was explored in a sample of 126 grass gobies collected during the period 1995–1996 in the same area (61 territorial males and 65 sneakers). Correlation between body weight and testis weight was positive and significant for sneaker males, while correlation was virtually equal to zero in territorial males. That body size in territorial males is correlated with fertilization success but not gonad size suggests that males allocate much more energy into growth and relatively little into sperm production once the needed size to become territorial is attained. The increased paternity of larger territorial males might be due to a more effective defense of the nest in comparison with smaller territorial males.

The relationships between temperature changes and reproductive investment in a Mediterranean goby: Insights for the assessment of climate change effects

The relationships between changes in water temperature and the timing and level of reproductive investment were investigated in an estuarine fish, inhabiting the Venice lagoon: the grass goby Zosterisessor ophiocephalus. A time series of the mean monthly values of gonado-somatic index was coupled with thermal profiles of lagoon water temperatures over 14 years, from 1997 to 2010. Results showed that the reproductive investment was positively affected by water temperature changes, both in terms of monthly thermal anomalies and cumulative degree days.A predictive model was also developed to assess the temporal shift of reproductive peaks as a response to inter-annual thermal fluctuations. This model allowed the detection of deviations from the median level, indicating that during warmer years, the reproductive peak tended to occur earlier than during colder years. The model is therefore proposed as a tool to predict anticipated consequences of climate change on fish phenology in transitional waters, regarding recurrent biological phenomena, such as reproduction and recruitment.

Influence of seagrass meadows on predator–prey habitat segregation in an Adriatic lagoon

Seagrass meadows have been hypothesized to protect mobile macrofauna from preda- tion by providing structural complexity that interferes with predator movement and vision. However, if ambush predators are common in seagrass, they may exclude many prey species, resulting in lower total abundance and diversity in seagrass relative to neighboring bare substrates, and segregation of predators and their prey into different habitats. We tested these abundance and diversity predictions using visual censuses of fish and invertebrates employing georeferenced videography to quantify habitat and pinpoint every observation, and using bait stations and drop nets over 38 km of scuba transects in all 4 seasons and by day and night in an enclosed estuary of the northeast Adriatic (Novi- grad Sea, Croatia). The primary fish predators at our study site were the ambush or stalk-attack predators, grass goby Zosterisessor ophiocephalus and European eel Anguilla anguilla, and we found that these species strongly preferred seagrass habitat. In contrast, most other fish, including small juveniles, avoided seagrass and preferred bare sediment to vegetated habitats. Species strongly pre- ferring seagrass were primarily sessile invertebrates not preyed on by the goby or eel. Both total macrofaunal density and total taxon richness were greatest on bare sediment and lowest in dense seagrass habitats. The 3-dimensional aspect of habitat structure was as important in delineating the communities as the presence or absence of habitat structure. These results are consistent with the hypothesis that ambush predators reduce the value of seagrass habitat for their prey relative to neighboring bare sediment or rock; that structured habitat might carry a higher mortality risk for many prey species, and that neighboring unvegetated habitat, including bare sediment, can be at least as important as seagrass in harboring biodiversity.

Sperm‐duct gland secretion of the grass goby Zosterisessor ophiocephalus exhibits antimicrobial activity

The grass goby Zosterisessor ophiocephalus sperm‐duct gland extract displayed antimicrobial activity against gram‐positive and gram‐negative bacteria. This suggests that sperm‐duct gland mucins might be functional in protecting eggs and possibly parents from pathogens, an activity of great adaptive value for Z. ophiocephalus, which lays eggs in mud nests.

Comparative energy allocation in two sympatric, closely related gobies: the black goby Gobius niger and the grass goby Zosterisessor ophiocephalus

Seasonal energy allocation of lipid reserves into different body tissues was analysed comparatively in two sympatric, closely related gobies: the grass goby Zosterisessor ophiocephalus and the black goby Gobius niger. Lipid reserves were measured in liver, muscle and ovary and compared between the two species within a given sex and seasonal period (reproductive v. non‐reproductive). Furthermore, temporal patterns of lipid reserves were investigated in the two species in relation to gonado‐somatic and liver‐somatic indices, as well as the relationship between size and lipid content. Results showed that the grass goby allocated more lipid reserves in reproduction while the black goby accumulated more reserves in liver and muscle, at a given size, although the temporal patterns of lipid accumulation and depletion were basically similar. Results are discussed in the light of life‐history theories, taking into account both adaptation and evolutionary constraints.

Evidence of genetic damage in grass gobies and mussels from the Venice lagoon

The presence of genetic damage has been investigated in two native species of the Venice lagoon: the common mussel Mytilus galloprovincialis and the grass goby Zosterisessor ophiocephalus. Two sampling campaigns were performed in summer 1998 and 1999. Aromatic-like DNA adducts were analysed in selected tissues of gobies and mussels by using the 32P-postlabelling assay. In 1999, micronuclei and other nuclear abnormalities were additionally scored on gill cells and haemocytes of individual mussels whereas inorganic (As, Cd, Cr, Hg, Ni, Pb, Sn) as well as organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls and other chlorinated compounds) were measured in the total mussel pulp. Compared to the lagoon inlet area, gobies and mussels from the industrial district (Marghera) showed significant DNA adduct levels and increased frequencies of cytogenetic alterations (evidence of genetic damage was absent or inconsistent in other sites). The substantial levels of aromatic and chlorinated contaminants detected in mussels from Marghera also support the exposure of native organisms to genotoxic agents.

Changes along the male reproductive axis in response to social context in a gonochoristic gobiid, Zosterisessor ophiocephalus (Teleostei, Gobiidae), with alternative mating tactics

Sexual selection has given rise, in several taxa, to intrasexual variation in male phenotype. While evolutionary studies have provided explanations of the adaptive function of this dramatic male phenotypic diversity, the proximate control of its expression has still to be completely understood. Several observations, primarily from sex-changing species, indicated a major role of social interactions in reproductive axis regulation and consequently in the expression of alternative male phenotypes. Here we documented changes along the male reproductive axis in response to social context in a gonochoristic species, the grass goby Zosterisessor ophiocephalus, where fully functional alternative male mating tactics appear to be expressed as an ontogenetic gradient. In the grass goby, larger and older males dig a nest and perform parental care, while smaller males sneak fertilization during territorial male spawning. Territorial males are characterized by a higher number of gonadotropin-releasing hormone (GnRH) neurons in forebrain preoptic area, smaller testes, larger seminal vesicles, and viscous ejaculates that last longer and contain fewer sperm than those of sneakers. To experimentally investigate the role of social factors in inducing changes along the male reproductive axis, sneakers were tested in two different situations: nesting alone or with ripe females. Sneakers that mated and performed parental care showed dramatic changes in brain, reproductive apparatus morphology, and ejaculate traits. GnRH-immunoreactive cells in forebrain preoptic area increased in number, reaching values typical of wild-caught parental males. Testes size decreased while seminal vesicle size increased and ejaculates showed lower sperm densities. These results were discussed within the framework of the social transduction hypothesis, which predicts that social experience should mediate, through a cascade of internal processes, shifts between morphs throughout life.

Somatic energy storage and reproductive investment in the grass goby Zosterisessor ophiocephalus

The pattern of somatic energy storage, measured as body lipid proportion, was investigated in the grass goby Zosterisessor ophiocephalus, by comparing the per cent lipids across three reproductive groups—large males (territory holding, caring for eggs, males), small males (sneaker males) and females—and across a seasonal phase including the entire breeding season and a post-reproductive period. Furthermore, the pattern of some indicators of somatic and reproductive investment, such as gonadosomatic index (GSI) and liversomatic index (LSI), was investigated, as well as the relationship between lipid content and fish body size was studied over time in both sexes. Results showed that the amount of somatic lipids depends largely on the different levels of reproductive investment shown by the breeding individuals. Females had the lowest levels of somatic lipids at the beginning of the breeding season when large males reached, by contrast, the highest levels. Large males showed a strong decrease in their reserves as the breeding season proceeded, and their replenishment was significantly slower than that of smaller males, which had relatively high levels already in September. Analysis of the trends of GSI and LSI revealed that the difference between females and males in the primary reproductive investment (gonadic mass) can explain most of the differences in the levels of somatic energy storage. The relationship between body size and lipid content changed over time, being positive and statistically significant at the beginning of the breeding season for each reproductive group, indicating that during these phases all the breeding individuals had accumulated energy in their tissues and that the breeding season reduced their somatic energy storage although with different intensity.

‘Birthday effect’ on the adoption of alternative mating tactics in Zosterisessor ophiocephalus: evidence from a growth model

The present study aims to apply a growth model to a species with a conditional reproductive strategy, the grass goby Zosterisessor ophiocephalus (Pisces: Gobiidae), in order to evaluate the adoption of alternative tactics by this species under the constraints of different dates of birth. The model describes the growth pattern (based on age, weight and gonadosomatic index data) of an individual, assumed to be representative of a given cohort, while also taking into account the energetic loss due to parental care. The most important parameters have been calibrated by comparing the results with a set of data collected in the lagoon of Venice. The comparison between the growth pattern of a parental male and that of a late-born male suggests that the birthday could be one of the major constraints affecting the adoption of an alternative tactic during the first breeding season.

Can goby spermatozoa pass through the filament adhesion apparatus of laid eggs?

SEM observations of the egg adhesion of grass goby Zosterisessor ophiocephalus show perforations between filament insertions on the basal plate. These are adequate in size to let through spermatozoa which eventually reach the micropyle. This accounts for post‐attachment egg fertilization occurring naturally and in artificial fertilization experiments.

Can goby spermatozoa pass through the filament adhesion apparatus of laid eggs?

SEM observations of the egg adhesion of grass goby Zosterisessor ophiocephalus show perforations between filament insertions on the basal plate. These are adequate in size to let through spermatozoa which eventually reach the micropyle. This accounts for post-attachment egg fertilization occurring naturally and in artificial fertilization experiments.

Ultrastructural aspects of the ovarian follicle and egg envelope of the sea‐grass goby Zosterisessor ophiocephalus (Osteichthyes, Gobiidae)

The development of the ovarian follicle, the chorion, the attaching filaments apparatus, and the egg surface are described in the grass goby Zosterisessor ophiocephalus by transmission and scanning electron microscopy. The first appearance of the zona radiata externa is followed by the apposition of a canalicular layer in the outer zona radiata interna, and then of a fibrous tangential network in the inner zona radiata interna, reaching an overall thickness of 5.6 μm in mature eggs. Both zona radiata interna components are likely secreted by the oocyte, whereas the apparently mucopolysaccharidic zona radiata externa is produced early by flattened granulosa cells. During maturation, granulosa cells become cubic in cross section and elongate from the animal pole, marked by the prospective micropyle and oriented along the oocyte meridians. Their cytoplasm is markedly engulfed with enlarged cisternae of the rough endoplasmic reticulum involved, together with mitochondria and well‐developed Golgi complexes, in adhesive filaments protein matrix secretion and the making of the basal plate. Filament matrix aggregates in the granulosa cells intercellular spaces, where it is confined by intercellular junctions. The basal plate is hollow in the centre surrounding the micropylar pit and supports a cribriform column of netted filaments eventually fraying off and becoming the egg adhesive apparatus. The comparative functional and systematic relevance of these features among teleosts is discussed and related to environmental and life style adaptations.

Mating system and alternative male mating tactics in the grass goby Zosterisessor ophiocephalus (Teleostei: Gobiidae)

Peculiar fertilization dynamics, with males releasing sperm in mucous trails lasting several hours, characterize some demersal spawning fish. The mating system was investigated in a natural population of one of these species: the grass goby Zosterisessor ophiocephalus (Pallas, 1814), a large coastal goby inhabiting seagrass meadows in shallow brackish water. Adult males ranged in size from 7.4 to 23 cm total length, but only larger ones were observed to dig and defend a burrow, where they performed parental care on eggs laid by one to several females. Field observations together with analyses of age, sperm production, trail sperm content and sperm competition tests indicated the occurrence of alternative male mating tactics, likely the expression of an ontogenetic gradient. Larger males are older than smaller ones, and while the former are territorial, the latter “sneak” territorial male spawns. The ejaculate characteristics indicate that grass goby males have functionally polymorphic spawns: in fact sperm trails of larger males last longer and release fewer sperm than those of smaller males. Sperm production over several days is more constant in larger than in smaller males, but the total number of sperm released is higher in the latter. The influence of seminal fluid in the functional intraspecific variability in sperm release in this species is discussed.