| influence of trophic position on organochlorine concentrations and compositional patterns in a marine food web. | the accumulation of polychlorinated biphenyls (pcbs), ddts (p,p'-ddt [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane], o,p'-ddt [1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane], p,p'-ddd [1,1,-dichloro-2,2-bis(4-chlorophenyl)ethane], o.p'-ddd [1,1-dichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane], and p,p'-dde [1,1-dichloro-2,2-bis(4-chlorophenyl)ethene]), chlordanes (trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor and oxychlordane), hexachlorocyclohexanes (alpha-, ... | 2002 | 12389914 |
| four-year monitoring of parasite communities in gobiid fishes of the south-western baltic. i. guild and component community. | the parasite communities of goby species (teleostei, percomorphi) from the south-western baltic sea were investigated from 1997 to 2000 in three different seasons. in total, 30 parasite species were found in the guild of four goby spp. from dahmeshöved (lübeck bight). the component community of pomatoschistus minutus comprised 22, pomatoschistus pictus 20, gobiusculus flavescens 18 and gobius niger 14 parasite species, whereas pomatoschistus microps from the salzhaff (mecklenburg bight) harboure ... | 2003 | 12827504 |
| four-year monitoring of parasite communities in gobiid fishes of the south-western balticii. infracommunity. | the parasite infracommunity of five goby species (pomatoschistus minutus, p. pictus, p.microps, gobiusculus flavescens, gobius niger) from the south-western baltic was investigated during spring, summer and autumn of the years 1997-2000. the mean parasite species number in single hosts was high, ranging between 1.1 (p. minutus), 2.1 (p. pictus) to even 3.3 (p. microps). gobius niger is the only host which lives longer than a year and is infested by almost identical parasites for longer times, i. ... | 2004 | 15034786 |
| four new species of gyrodactylus von nordmann, 1832 (monogenea, gyrodactylidae) on gobiid fishes: combined dna and morphological analyses. | four gyrodactylus species parasitising four closely related gobiid species in european coastal waters were studied and compared with g. arcuatus bychowsky sensu bychowsky & poljansky (1953) from gasterosteus aculatus . these were g. gondae n. sp. from pomatoschistus minutus and p. lozanoi , g. flavescensis n. sp. from gobiusculus flavescens , g. arcuatoides n. sp. from p. minutus and g. branchialis n. sp. from p. microps. combined molecular and morphological analyses, as well as morphometric and ... | 2004 | 15477751 |
| first record of a kabatana sp. microsporidium infecting fish in the atlantic ocean. | two-spotted goby gobiusculus flavescens from the swedish gullmarsfjord regularly present subcutaneous creamy-white patches in the body musculature, associated with kabatana sp. infection. analysis of the 16s rrna gene of the microsporidium showed 98.54% homology with kabatana newberryi infecting a marine goby from california, indicating that the swedish microsporidium is either a different strain of k. newberryi or a closely related species. this represents the first record of a kabatana species ... | 2009 | 19326795 |
| effect of sub-lethal exposure to ultraviolet radiation on the escape performance of atlantic cod larvae (gadus morhua). | the amount of ultraviolet (uv) radiation reaching the earth's surface has increased due to depletion of the ozone layer. several studies have reported that uv radiation reduces survival of fish larvae. however, indirect and sub-lethal impacts of uv radiation on fish behavior have been given little consideration. we observed the escape performance of larval cod (24 dph, sl: 7.6±0.2 mm; 29 dph, sl: 8.2±0.3 mm) that had been exposed to sub-lethal levels of uv radiation vs. unexposed controls. two p ... | 2012 | 22536406 |
| seasonal variation in male alternative reproductive tactics. | genetic parentage analyses reveal considerable diversity in alternative reproductive behaviours (e.g. sneaking) in many taxa. however, little is known about whether these behaviours vary seasonally and between populations. here, we investigate seasonal variation in male reproductive behaviours in a population of two-spotted gobies (gobiusculus flavescens) in norway. male two-spotted gobies guard nests, attract females and care for fertilized eggs. we collected clutches and nest-guarding males ea ... | 2016 | 27654134 |
| size dependent male reproductive tactic in the two-spotted goby (gobiusculus flavescens). | male investment in testes and sperm duct gland in the polygamous nest breeding two-spotted goby gobiusculus flavescens (fabricius) was investigated in relation to time in reproductive season and individual physical parameters. this small teleost fish is most likely the most abundant species found along the rocky shores of the north east atlantic. the two-spotted goby has a single reproductive season, during which nest-caring males can raise several clutches of offspring. according to the literat ... | 2015 | 26642324 |
| within-season variation in sexual selection in a fish with dynamic sex roles. | the strength of sexual selection may vary between species, among populations and within populations over time. while there is growing evidence that sexual selection may vary between years, less is known about variation in sexual selection within a season. here, we investigate within-season variation in sexual selection in male two-spotted gobies (gobiusculus flavescens). this marine fish experiences a seasonal change in the operational sex ratio from male- to female-biased, resulting in a dramat ... | 2014 | 24917383 |
| context consistency and seasonal variation in boldness of male two-spotted gobies. | in order to attribute the behaviour of an animal to its personality it is important to study whether certain behavioural traits show up consistently across a variety of contexts. the aim of this study was to investigate whether breeding state males of the two-spotted goby, gobiusculus flavescens, showed consistent degree of boldness when tested in four different behaviour assays. we also wanted to investigate whether boldness varied over the breeding season in accordance with changes in male-mal ... | 2014 | 24671255 |
| mate competition and resource competition are inter-related in sexual selection. | sexual selection can be affected by the competition for limited breeding resources and/or the competition for limited mates. although there is ample evidence for each type of competition by itself, little is known about their relative importance and interaction. to address these questions, we established 48 experimental breeding populations of the two-spotted goby (gobiusculus flavescens), a substrate-breeding fish with paternal care. in three experimental treatments, males were limited in the a ... | 2014 | 24443989 |
| elevated co2 affects embryonic development and larval phototaxis in a temperate marine fish. | as an effect of anthropogenic co2 emissions, the chemistry of the world's oceans is changing. understanding how this will affect marine organisms and ecosystems are critical in predicting the impacts of this ongoing ocean acidification. work on coral reef fishes has revealed dramatic effects of elevated oceanic co2 on sensory responses and behavior. such effects may be widespread but have almost exclusively been tested on tropical reef fishes. here we test the effects elevated co2 has on the rep ... | 2013 | 24198929 |
| operational sex ratio but not density affects sexual selection in a fish. | the operational sex ratio (osr) and density are considered important factors affecting the strength of sexual selection. although there is increasing evidence that osr and density affect the potential for sexual selection, few studies have addressed whether this is realized in phenotypic selection and how the two factors interact. we manipulated osr (three levels) and male density (two levels) in 36 experimental breeding populations of gobiusculus flavescens-a fish with paternal care. we measure ... | 2013 | 23815651 |
| large males fight and court more across a range of social environments: an experiment on the two spotted goby gobiusculus flavescens. | the present study explored how male size relates to mating competition across a natural range of male and female densities in the two-spotted goby gobiusculus flavescens. across this range of social environments, large males were more than twice as likely as small ones to chase other males, to become nest-holders, and to court females, but large males were not significantly more likely to engage in agonistic fin displays. overall, the study showed that large males court and fight more than small ... | 2012 | 22747802 |
| sex roles and mutual mate choice matter during mate sampling. | the roles of females and males in mating competition and mate choice have lately proven more variable, between and within species, than previously thought. in nature, mating competition occurs during mate search and is expected to be regulated by the numbers of potential mates and same-sex competitors. here, we present the first study to test how a temporal change in sex roles affects mating competition and mate choice during mate sampling. our model system (the marine fish gobiusculus flavescen ... | 2012 | 22617262 |
| female ornamentation and egg carotenoids of six sympatric gobies. | belly colouration, gonad carotenoid concentration and skin transparency were quantified in gravid gobiusculus flavescens, as well as in females of five sympatric gobies where belly ornamentation has not been described. although g. flavescens females did, indeed, have far more colourful bellies than the other species, this could only in part be explained by a high concentration of total gonad carotenoids. comparable, or occasionally higher, carotenoid levels were found in the gonads of other spec ... | 2009 | 20738523 |
| multiple mating and a low incidence of cuckoldry for nest-holding males in the two-spotted goby, gobiusculus flavescens. | a major question in behavioural ecology concerns the relationship between genetic mating systems and the strength of sexual selection. in this study, we investigated the genetic mating system of the two-spotted goby (gobiusculus flavescens), a useful fish model for the study of sexual selection whose genetic mating system remains uncharacterized. we developed four polymorphic microsatellite markers and used them to conduct parentage analyses on 21 nests collected during the breeding season to ex ... | 2009 | 19133131 |
| hormonal regulation of female nuptial coloration in a fish. | physiological color change in camouflage and mating is widespread among fishes, but little is known about the regulation of such temporal changes in nuptial coloration and particularly concerning female coloration. to better understand regulation of nuptial coloration we investigated physiological color change in female two-spotted gobies (gobiusculus flavescens). females of this species develop an orange belly that acts as an ornament. the orange color is caused by the color of the gonads combi ... | 2008 | 18586039 |
| spectral sensitivity of the two-spotted goby gobiusculus flavescens (fabricius): a physiological and behavioural study. | microspectrophotometry of gobiusculus flavescens photoreceptors revealed a single rod visual pigment (lambdamaxat 508 nm) and the three cone pigments (lambdamax 456, 531 and 553 nm). the cone population was dominated by identical double cones containing the middle-wave-sensitive (mws) pigment, but with a small number of non-identical mws/lws (long-wave-sensitive) and identical lws double cones. small populations of large single cones also contained either the mws or lws pigment. the short-wave-s ... | 2006 | 16709906 |
| chromatic interaction between egg pigmentation and skin chromatophores in the nuptial coloration of female two-spotted gobies. | in two-spotted gobies (gobiusculus flavescens fabricius 1779), females develop an orange belly as they approach sexual maturity. bright belly coloration is preferred by males and has been suggested to act as a female ornament. this coloration is unusual in that it originates partly from pigmentation of the abdominal skin but also from strongly pigmented gonads directly visible through the skin. in addition, females have been observed to temporarily become more colourful during courtship and comp ... | 2005 | 16339859 |
| comparative studies on goby (teleostei) parasite communities from the north and baltic sea. | the parasite communities of three goby species from the marine north and the brackish baltic sea were compared. the samples of summer 1992/93 from helgoland, lubeck and kiel bight comprised a parasite spectrum of 4-5 in pomatoschistus microps, 2-3 in p. pictus or 3-8 parasite species in gobiusculus flavescens. the highest numbers were found in kiel bight whereas those of helgoland and lubeck bight differed between 3 and 7, respectively. in comparing the species identity of the studied localities ... | 2005 | 15772865 |
| four-year monitoring of parasite communities in gobiid fishes of the southwest baltic: iii. parasite species diversity and applicability of monitoring. | the parasite infrapopulations of five goby species (pomatoschistus minutus, p. pictus, p.microps, gobiusculus flavescens and gobius niger) were investigated during spring, summer and autumn of the years 1997-2000. in total, 34 parasite species were found: 17 digenea, 6 nematoda, 5 cestoda, 3 acanthocephala, 2 protozoa, and 1 monogenea. the dominant parasites were the digeneans podocotyle atomon and cryptocotyle concavum, which represent different ecological groups in terms of their modes of tran ... | 2005 | 15609062 |
| unusually dynamic sex roles in a fish. | sex roles are typically thought of as being fixed for a given species. in most animals males compete for females, whereas the females are more reluctant to mate. therefore sexual selection usually acts most strongly on males. this is explained by males having a higher potential reproductive rate than females, leading to more males being sexually active (a male-biased operational sex ratio). however, what determines sex roles and the strength of sexual selection is a controversial and much debate ... | 2004 | 15175750 |
| male mate choice selects for female coloration in a fish. | although sexual selection theory has proved successful in explaining a wide array of male ornaments, the function of ornaments occurring in females is largely unknown. traditionally, female ornaments have been considered nonfunctional, being merely a genetically correlated response to selection for male ornamentation. however, this hypothesis is only relevant to species in which the ornament is basically the same in the two sexes. alternatively, female ornaments may be influenced by selection ac ... | 2001 | 11606720 |
| parental investment of male two-spotted goby, gobiusculus flavescens (fabricius). | the trade-off between parental care and feeding was studied in the male two-spotted goby (gobiusculus flavescens f.). two temperatures, 8.5 degrees c and 13.0 degrees c, were used, with five replicates at each temperature, in order to determine whether temperature influenced parental behaviour. in each replicate, two males and four females were introduced to an aquarium, where the males chose between two nests and courted the females. in each replicate, one male spawned. after spawning, the male ... | 2001 | 11399271 |
| colonization and seasonality of goby (gobiidae, teleostei) parasites from the southwestern baltic sea. | a comparative parasitology study of gobiid fishes from two sites on the western baltic sea was done to get information on the quality of the respective environments. the parameters used were the infracommunity, the species numbers and abundance with respect to the size classes of the hosts, and the abundance with respect to the seasons. the hosts, gobius niger, gobiusculus flavescens, pomatoschistus minutus, and p. pictus, were caught at blank eck (kiel bight) and dahmeshöved (lübeck bight) duri ... | 1998 | 9660135 |