Common Goby Pomatoschistus Microps Research Articles

Environmental factors structuring fish composition and assemblages in a small macrotidal estuary (eastern English Channel)

The fish assemblage structure was analyzed along an estuarine gradient of a small macrotidal estuary (the Canche, France). Fishes were collected every two months between May 2006 and July 2007 from 12 sampling stations using a 1.5-m beam trawl with a 5 mm mesh size in the cod end. To complement this information, sampling was also performed using 15-m fyke nets (8 mm mesh size in the cod end). For each sample, abiotic (temperature, salinity, pH, oxygen, turbidity, river flow, wind speed and depth) and biotic (macro crustacean species abundances) were recorded. Throughout the study, 28 fish species belonging to 20 families were collected. Fish catches were dominated by juveniles, especially Young-Of-the-Year (YOY) for the majority of the species. According to the Index of Relative Importance (IRI), common goby Pomatoschistus microps, flounder Platichtys flesus, sprat Sprattus sprattus, sea-bass Dicentrarchus labrax and plaice Pleuronectes platessa were the most abundant species, together accounting for 99.2% of the total IRI. Estuarine residents (ER = 66.2%) and marine juvenile migrants species (MJ = 31.4%) were the most important ecological guilds. The structure of the fish assemblage and its relationship to environmental variables was examined using multivariate techniques. Cluster and non-metric multidimensional scaling (nMDS) analysis defined six distinct groups in the Canche estuary, which are discriminated by specific species (SIMPER). Spatio-temporal variations in fish assemblage structure reflect the density peaks of the most abundant species. Spearman rank correlations and canonical correspondence analysis (CCA) showed that among the ten environmental variables examined, temperature, salinity and Crangon crangon (a potential predator for YOY fish or prey for older ones) are the three most important factors influencing fish species richness and abundances. Our observations reinforce the idea that certain fish species may have different life history styles in different geographic areas. The present study highlights the necessity of a better knowledge of the connectivity between estuaries and adjacent marine areas. The Canche constitutes an important ecosystem for fishes and as it is subject to little anthropogenic disturbance; its ichthyofauna can be viewed as a reference or normal assemblage for small temperate macrotidal estuaries.

Acute effects of Benzo[a]pyrene, anthracene and a fuel oil on biomarkers of the common goby Pomatoschistus microps (Teleostei, Gobiidae)

The objective of this study was to investigate the effects of two different PAHs and a complex petrochemical mixture on the common goby, Pomatoschistus microps, using selected biomarkers as effect criteria. Benzo[a]pyrene (BaP) and anthracene were used as reference substances, while the water accommodated fraction of #4 fuel-oil (#4 WAF) was used as an example of a petrochemical mixture. P. microps was used since it is both a suitable bioindicator and a good test organism. Groups of fish were exposed to different concentrations of each of the test substances for 96 h and the activities of several enzymes commonly used as biomarkers were determined at the end of the bioassays. All the substances inhibited P. microps acetylcholinesterase (AChE) indicating that they have at least one mechanism of neurotoxicity in common: the disruption of cholinergic transmission by inhibition of AChE. An induction of lactate dehydrogenase (LDH) activity was found in fish exposed to BaP or to anthracene, suggesting an increase of the anaerobic pathway of energy production. On the contrary, inhibition of LDH was found in fish exposed to #4 WAF, suggesting a distinct effect of the mixture. An induction of P. microps glutathione S-transferase (GST) activity was found in fish exposed to BaP or to #4 WAF, while an inhibition was observed after exposure to anthracene. These results suggest that GST is involved in the detoxification of BaP and #4 WAF, but not of anthracene. All the substances increased catalase activity and isolated PAHs also increased superoxide dismutase, glutathione reductase and glutathione peroxidase activities, while #4 WAF did not cause significant alterations on these enzymes. These results suggest that all the substances may induce oxidative stress on P. microps, with BaP and anthracene apparently having more oxidative stress potential than #4 WAF.

Inter-season and interannual variations in fish and macrocrustacean community structure on a eastern English Channel sandy beach: Influence of environmental factors

The intertidal zone of an exposed sandy beach on the French coast of the English Channel was sampled with a 1.5 m beam-trawl over five years (2000 and 2003–2006) at weekly intervals. The fish and macrocrustacean catches were analysed to determine the inter-season and interannual variation in community structure and relate these variations to changes in the major environmental variables. Only six species (plaice Pleuronectes platessa, common goby Pomatoschistus microps, sprat Sprattus sprattus, sand eel Ammodytes tobianus, brown shrimp Crangon crangon and shore crab Carcinus maenas) from the 27 species captured can be considered as dominant species of the intertidal zone, and they accounted for >90% of total numbers. Most individuals caught were young-of-the-year or juvenile. Analysis of similarities (ANOSIM) and similarities percentage (SIMPER) indicated that inter-season variability of community structure (mean average similarity = 47%) was more pronounced than interannual variability (mean average similarity = 65%). Canonical correspondence analysis (CCA) indicates that a substantial component (32.2%) of the measured inter-season variation in community structure can be explained by environmental factors (mainly water temperature). The main inter-season changes in the abundance and community structure were due to the variation of the six key species and reflect the different times of their recruitment. During the five years of the study, the structure of the fish and macrocrustacean spring community persisted from year to year, with the dominant species reappearing consistently even though their abundances fluctuated from year to year. This interannual variation probably reflects variable recruitment success influenced by physico-chemical conditions. In spite of the considerable interannual variation (40 times) in the spring bloom of the prymnesiophyte alga Phaeocystis globosa we found no effect of this bloom on either fish and macrocrustacean species densities or diversity index.

The ecological role of overwintering fish in the food web of the Culbin Sands lagoon ecosystem, NE Scotland: Identifying major trophic links and testing effects of the fish <i>Pomatoschistus microps</i> (Pallas) on benthic invertebrates

The Culbin Sands lagoon ecosystem in NE Scotland was studied during a three-year period (1994-1996) to identify the major trophic links from benthic invertebrates to epibenthic predators, and to assess impacts of overwintering fish on their prey communities. Every 2-4 weeks, samples of mobile fauna were collected to study their diets. The major trophic links identified between benthic invertebrates and epibenthic predators were from benthic invertebrates to the shrimp Crangon crangon, and to the common goby Pomatoschistus microps and the plaice Pleuronectes platessa . The energy flow from benthic invertebrates to overwintering fish was estimated at 133 kJ m –2 yr –1 . A flow of 10 kJ m –2 yr –1 was also observed from eggs and larval stages of the overwintering shrimp Crangon crangon to the overwintering fish. Nevertheless, manipulative field experiments showed no significant impacts of the most abundant overwintering fish Pomatoschistus microps on prey community densities, despite an overall individual ingestion rate of 89 J day –1 .

Sublittoral abundance and food consumption of Baltic gobies

Two small demersal fishes, the sand goby Pomatoschistus minutus and the common goby Pomatoschistus microps, were quantified on soft bottoms at 20–40 m depth in the Baltic Sea, using a camera placed above the bottom. The largest numbers of gobies were seen following the settlement of young in late summer and autumn. Most recorded fishes were sand gobies. An annual average of 4·7 individuals m−2(0·24 g dry mass m−2) was recorded in 1983–1985 and 2·5 individuals m−2(0·13 g m−2) in 1997–1998. Using these densities, the annual goby food consumption was estimated to 100 kJ m−2 in 1983–1985 and 50 kJ m−2 in 1997–1998, corresponding to most of the annual macrobenthos production available to the gobies. The resulting goby production, assumed equal to 25% of the food consumed, must have been an important food source for the larger fishes occasionally recorded in the photographs.

Acute effects of 3,4-dichloroaniline on biomarkers and spleen histology of the common goby Pomatoschistus microps

The aromatic amine 3,4-dichloroaniline (DCA) is a model environmental contaminant, precursor for synthesis and degradation product of several herbicides, which is commonly found in European estuarine ecosystems. In this work, the possibility of using biochemical and histological markers to assess sub-lethal effects of DCA in natural populations of Pomatoschistus microps juveniles was investigated. Alterations on the activities of the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH) and glutathione S-transferase (GST) and histological alterations on spleen were investigated after 96 h of exposure to sublethal concentrations of DCA (0.50–1.49 mg/l). At the concentrations tested, DCA had no effect on AChE activity. LDH and GST activities were significant altered in treated animals when compared to control groups. As already described for mammals, DCA induced splenic histological alterations in P. microps, including expansion of red pulp and deposition of hemosiderin granules in a concentration-dependent manner. This suggests that DCA is a xenobiotic of concern in estuaries receiving agricultural effluents.

Feeding ecology and growth of age 0 yearPlatichthys flesus(L.) in a vegetated and a bare sand habitat in a nutrient rich fjord

A study was carried out to investigate the diet and feeding strategies of age 0 year juvenile flounderPlatichthys flesusin two different micro‐tidal habitats in the nutrient enriched Mariager Fjord on the Danish east coast. Juvenile flounder and benthic macrofauna were sampled monthly from June to October 1999 in a bare sand habitat and a habitat covered by filamentous and mat forming macroalgae. The presence of the ‘opportunistic’ macroalgae created a shift in the dominance of surface dwelling prey such as epifaunal amphipods to more infaunal groups such as oligochaetes and polychaetes. The diet of the flounder varied considerably between the two habitats mainly reflecting prey availability relative to their abundance, prey spatial distribution, habitat structure and ontogenetic prey shifts as a function of total length. Flounder in the vegetated site fed on a diverse diet of copepods, polychaetes and oligochaetes, whereas those caught in the bare sand site fed primarily on the amphipodCorophium volutatorwhich was numerically dominant at this site. During the growth season, two diet shifts were observed: from copepods early in the season to macrofauna organisms and, later in the season, the inclusion of more hyperbenthic prey such asMysideaspp;Idoteaspp. and the common gobyPomatoschistus microps.

Feeding ecology of the gobies <i>Pomatoschistus minutes</i> (Pallas, 1770) and <i>Pomatoschistus microps</i> (Krøyer, 1838) in the upper Tagus estuary, Portugal

The sand goby Pomatoschistus minutus (Pallas, 1770) and the common goby Pomatoschistusmicrops (Kroyer, 1838) are among the most abundant fish species in estuaries, lagoons and along the Atlantic shores of Europe. In the Tagus estuary these species are particularly important in the food web. Fish samples were taken monthly in the upper estuary, and the gut contents of a total of 431 P.minutus and 382 P. microps were analysed in order to study preferences and seasonal changes in their diets and to understand intra- and interspecific relations between these two congeneric gobies. The sand goby had no dominant prey, although mysids were particularly important in the diet of this species. Shrimps and polychaetes were also common prey. P.microps preferentially ingested polychaetes, with isopods, amphipods, bivalves and copepods as secondary prey items. Significant seasonal variations in the ingestion of the main prey groups of both species were obtained, which reflect variations in prey availability. During the reproductive season there were differences in the food consumed by males and females, mainly for P.minutus, reflecting the different activity pattern exhibited by males and females during the breeding season, since parental care is supported by the former. The smallest classes from P.minutus increased their niche widths as they grew. Due to the different length reached by each species, the degree of interspecific overlap decreased with increasing body size.

Ellipsomyxa gobii (Myxozoa: Ceratomyxidae) in the common goby Pomatoschistus microps (Teleostei: Gobiidae) uses Nereis spp. (Annelida: Polychaeta) as invertebrate hosts.

Nereis diversicolor O.F. Müller and N. succinea Frey et Leuckart (Polychaeta, Nereidae) living in brackish shallow areas in Denmark are naturally infected with tetractinomyxon actinospores. Infected Nereis spp. were experimentally fed to various potential fish hosts, and the actinosporean stages developed into myxosporean stages of Ellipsomyxa gobii Køie, 2003 (Ceratomyxidae) in the gallbladder of the common goby Pomatoschistus microps (Krøyer) (Gobiidae). The European eel Anguilla anguilla (L.), three-spined stickleback Gasterosteus aculeatus L., small sand eel Ammodytes tobianus L., flounder Platichthys flesus (L.), European plaice Pleuronectes platessa L. and common sole Solea solea (L.) did not become experimentally infected. In Danish shallow brackish areas P. microps is naturally infected with E. gobii, in some areas with a prevalence >90%. We compared small subunit ribosomal DNA sequences of the actinosporean with E. gobii from P. microps. Sequences were identical, which further verifies that both forms belong to the same organism. This is the first myxozoan two-host life cycle in the marine environment.

Ellipsomyxa gobii gen. et sp. n. (Myxozoa: Ceratomyxidae) in the common goby Pomatoschistus microps (Teleostei: Gobiidae) from Denmark

A new myxosporean species Ellipsomyxa gobii gen. et sp. n. is described from the common goby Pomatoschistus microps (Krøyer) (Perciformes, Gobiidae). Plasmodia with long branched pseudopodia in the gallbladder develop to subspherical bisporous plasmodia. The myxospores were found in the gallbladder, and the hepatic and bile ducts. The new genus is characterised by the morphology of the myxospores. The myxospores have smooth thin valves elongated in the direction perpendicular to the plane of the straight central transverse indistinct sutural line. The two spherical polar capsules open some distance from the sutural line on opposite sides. The new genus thereby differs from Leptotheca Thélohan, 1895. Ellipsomyxa gobii is tentatively placed in the Ceratomyxidae.

Male mating success in relation to food availability in the common goby

In a feeding experiment with the common goby Pomatoschistus microps, there was no female preference for well‐fed males, although these males had a higher mating success. This suggests that care should be taken about drawing conclusions regarding mate choice and mating success based on mate preference tests alone.

Parasite populations and communities from the shallow littoral of the Orther Bight (Fehmarn, SW Baltic Sea).

Parasites of host guilds, such as mud snails (five species), benthic crustaceans (six species) and small-sized fishes ( Pomatoschistus microps, Gasterosteus aculeatus, Pungitius pungitius, young Pleuronectes flesus), were investigated in the Other Bight off West Fehmarn (Kiel Bight, German Baltic Sea). The hosts, especially the herbivorous Hydrobia spp, Gammarus spp and Idothea chelipes, attained extremely high densities in three habitats ( Enteromorpha belt, Fucus belt, sandy bottom), which may be a consequence of high eutrophication. Fish as carnivores and several helminths as parasites can profit from these massive appearances - more than 5,000 Hydrobia mud snails/m(2) or 282 I. chelipes/m(2). Prevalences of mud snails peaked in summer, by up to 30% extra, whereas species of benthic crustaceans attained increases of 47-100%, fish 57-100%. The most abundant helminths were the digeneans Maritrema subdolum, Microphallus claviformis and Asymphylodora demeli in Hydrobia spp, Maritrema subdolum, Microphallus papillorobustum, Levinseniella brachysoma and Podocotyle atomon in benthic crustaceans and Cryptocotyle concavum, Podocotyle atomon and Brachyphallus crenatus in fish. The copepod Thersitina gasterostei was also abundant in sticklebacks. The density of parasites (number/m(2)) peaked in summer, with more than 10,000 Maritrema subdolum metacercariae in I. chelipes from the Fucus belt and more than 1,000 in I. chelipes from the Enteromorpha belt or the sandy bottom. There was a clear seasonality in the appearance of digeneans in G. locusta, G. salinus and I. chelipes infected by M. subdolum and Gammarus spp infected by L. brachysoma and P. atomon. Therefore, the Orther Bight may be a epizootiotope for M. subdolum and C. concavum, i.e. a habitat with an extreme infection rate which can endanger the population of the host. Idothea chelipes also has a high infection potential to the final hosts of M. subdolum, crustacean-feeding birds. Similar relationships were found between the bird digenean C. concavum and the common goby Pomatoschistus microps. The infection mechanisms of both benthic crustaceans and small-sized fish follow the rule of predation in two steps: dispersion and accumulation.

Fitness consequences of prey depletion for the common goby Pomatoschistus microps

Pomatoschistus microps (Pisces: Gobiidae), a predatory, benthic feeder, occurs in high densities in variable, shallow, muddy coastal waters where prey availability can be unpredictable. Here, we investigate the effect and consequences of prey depletion on the body condition and nest building of adult male fish using manipulative mesocosm experiments in which the comparative value of meiofaunal and macrofaunal prey was investigated. Fish maintained in mesocosms from which macrofauna had been removed from the sediment had a significantly reduced hepatosomatic index (HSI), and were less likely to build nests than fish in mesocosms containing macrofauna and meiofauna, suggesting an indirect link between prey availability and nest quality. Reduced resource availability, in the form of scarcity of macrofauna, appears to have profound implications for the fitness of natural field populations.

The life cycle of Dichelyne (Cucullanellus) minutus (Nematoda: Cucullanidae)

Mature specimens of the nematode Dichelyne (Cucullanellus) minutus (Rudolphi, 1819) (Ascaridida, Cucullanidae, Seuratoidea) were obtained from the intestine of flounder Platichthys flesus (L.) caught in the Oresund, Denmark. Plaice Pleuronectes platessa L. and common goby Pomatoschistus microps (Kröyer) also harbour this species. The eggs embryonate on the seabottom. Larvae about 440 microm long, and believed to be in their third stage, hatch from the eggs. These larvae are not directly infective to flounders or gobies. The polychaete Nereis diversicolor O.F. Muller acts as obligatory intermediate host. Experimental infections showed that larvae >600 microm long and provided with achitinous tooth survived in flounder and common goby. The third-stage larvae moult to fourth-stage larvae in the fish gut wall. Mature worms occur in the lumen of the anterior part of the intestine. All developmental stages may be transferred from one flounder to another; thus the flounder may acquire the parasite also by devouring infected gobies.

Demographic structure and life history traits of the common goby Pomatoschistus microps (Teleostei, Gobiidae) in a Mediterranean coastal lagoon (Rhône River delta, France)

Demographic structure and life history traits of the common goby Pomatoschistus microps were investigated in a brackish water lagoon of the Rhône River delta (Mediterranean Sea, southern France). The size frequency distribution and gonadosomatic index indicated that three different age groups occurred and reproduced successively in the lagoon, resulting in a long spawning period from March to September and a high investment in reproduction. This high investment in reproduction, which contrasts with that found in other mostly northern European populations, probably relates to the unpredictability of the gobyˈs environmental conditions.

Nest use by the common goby Pomatoschistus microps in Camargue (France)

Nest site use by the common goby, Pomatoschistus microps was investigated in the Malagroy lagoon (France, Camargue) during a complete breeding season. Male common gobies seemed to select their nests in relation to their size, as a positive relationship between male total length and nest area was found. No significant relationship was found between the number of eggs in a nest and the size of nesting male, suggesting that female common goby did not show a preference for larger males. Nests containing two distinct eggs clutches were observed for the first time. The percentage of double clutched nests was relatively high in June-July, when only young-of-the-year common gobies were observed to reproduce. Large nesting males reproduced first in the season (in February- March), but they were not observed to reproduce again in July. Instead they were replaced by small males born early in spring.

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 Vaccares 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 Vaccares 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 Vaccares 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.

Annual variations in the reproductive traits of Pomatoschistus microps in a Mediterranean lagoon undergoing environmental changes: evidence of phenotypic plasticity

The spawning period of the common goby Pomatoschistus microps from 1993 to 1997 in the Vaccarès lagoon did not vary, except in 1997 when it was longer due to the reproduction of the young‐of‐the‐year. Egg size and number, and reproductive allocation varied greatly with one year to another. Female common gobies increased both their fecundity per spawning act and their egg size from 1993 to 1995. The annual variation in the reproductive effort suggests a high phenotypic plasticity of reproductive traits in P. microps, in the face of environmental perturbations. In winter 1993–1994, a centennial flood of the Rhône River caused major hydrological changes in the lagoon in less than 1 week, affecting many invertebrates and fish for several years. The reproductive investment of the common goby increased, possibly as a consequence of those environmental changes.

Spatial and temporal variations in fish populations in the upper Thames estuary

Between February 1989 and August 1990, the upper Thames estuary contained 23 species of fish. Fish numbers were higher and relatively constant in the uppermost part of the estuary. Number of species was augmented in summer from fresh water and from downstream, coinciding with high temperature, low flow and high salinity. The eight most abundant species contributed to 98·5% of the total number. Flounder Pleuronectes flesus, dace Leuciscus leuciscus and perch Perca fluviatilis, recruited from May to August, and common goby Pomatoschistus microps, roach Rutilus rutilus and chub Leuciscus cephalus, from August to November. The upper estuary (salinity 0·34–2·96 p.s.u.) formed a species transition area between the freshwater but salinity‐resistant roach, chub, and gudgeon Gobio gobio upstream, and the estuarine eurhyhaline common goby and flounder downstream. The three‐spined stickleback Gasterosteus aculeatus and cyprinids were more abundant at upstream while perch was more abundant at downstream sites. High abundances of gudgeon, chub and roach were associated with high transparency and dissolved oxygen and low salinity, while high abundances of perch were associated with high salinity and low transparency. Dace and three‐spined stickleback were associated with high dissolved oxygen and low pH, and common goby with high pH. Flounder showed no clear preferences.

Spatial and temporal variations in fish populations in the upper Thames estuary

Between February 1989 and August 1990, the upper Thames estuary contained 23 species of fish. Fish numbers were higher and relatively constant in the uppermost part of the estuary. Number of species was augmented in summer from fresh water and from downstream, coinciding with high temperature, low flow and high salinity. The eight most abundant species contributed to 98·5% of the total number. Flounder Pleuronectes flesus, dace Leuciscus leuciscus and perch Perca fluviatilis, recruited from May to August, and common goby Pomatoschistus microps, roach Rutilus rutilus and chub Leuciscus cephalus, from August to November. The upper estuary (salinity 0·34–2·96 p.s.u.) formed a species transition area between the freshwater but salinity-resistant roach, chub, and gudgeon Gobio gobio upstream, and the estuarine eurhyhaline common goby and flounder downstream. The three-spined stickleback Gasterosteus aculeatus and cyprinids were more abundant at upstream while perch was more abundant at downstream sites. High abundances of gudgeon, chub and roach were associated with high transparency and dissolved oxygen and low salinity, while high abundances of perch were associated with high salinity and low transparency. Dace and three-spined stickleback were associated with high dissolved oxygen and low pH, and common goby with high pH. Flounder showed no clear preferences.