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Lynda D. Corkum - One of the best experts on this subject based on the ideXlab platform.
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olfactory sensory input increases gill ventilation in male round gobies Neogobius Melanostomus during exposure to steroids
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2006Co-Authors: Rachelle M Belanger, Lynda D. Corkum, Barbara S ZielinskiAbstract:In teleostean fish, ventilation increases have been observed in response to low dissolved oxygen levels, visual stimuli, and gustatory cues. However, olfactory sensory input may also stimulate gill ventilation rate. We investigated whether olfactory sensory input mediates gill ventilation responses, as suggested by the observation that steroidal compounds detected by the olfactory system elicited increases in opercular activity in the perciform teleost, the round goby (Neogobius Melanostomus). Close parallels between gill ventilation and olfactory responses, led us to conduct an empirical study that used two different olfactory sensory deprivation techniques to seek a causal relationship between olfactory epithelial activity and hyperventilation. Chemical lesion of olfactory sensory neurons or mechanical occlusion of the nasal cavities inhibited gill ventilation responses of reproductive male round gobies to estrone (1,3,5(10)-estratrien-3-ol-17-one) and to ovarian extracts. This direct evidence demonstrates the role of olfactory sensory input for the gill ventilation response to putative reproductive pheromones and may represent an important regulatory mechanism for odorant sampling during pheromone communication.
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behavioural responses of female Neogobius Melanostomus to odours of conspecifics
Journal of Fish Biology, 2005Co-Authors: Don B Gammon, A P Scott, Barbara S Zielinski, Lynda D. CorkumAbstract:The behavioural responses of reproductive and non-reproductive female round gobies Neogobius Melanostomus to water conditioned by reproductive and non-reproductive males and females were tested. The behavioural responses of reproductive female round gobies exposed to odour of reproductive males included increased time spent near the source of the odour, elevated swimming velocities and directed movement to and around the odour source when compared with their responses to control water. These results suggested that pheromones released from reproductive males may induce spawning behaviour in reproductive females. Non-reproductive females exposed to reproductive female odour spent significantly more time near the odour source of reproductive females compared with control water. Non-reproductive females also showed directed movement towards and around the odour source when exposed to reproductive female odour. These results suggested that round gobies use inter-sexual and intra-sexual pheromones and that both sex and reproductive status are important in the detection and release of these pheromones.
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Assessment of fish size on shelter choice and intraspecific interactions by round gobies Neogobius Melanostomus
Environmental Biology of Fishes, 2005Co-Authors: Katie L. Stammler, Lynda D. CorkumAbstract:We examined shelter occupancy and behavioural interactions in non-reproductive male round gobies, Neogobius Melanostomus ,an invasive fish, to determine if gobies can assess one another’s prowess effectively. Results of laboratory experiments revealed a significant, positive relationship between body size (total mass) and time for individual fish to occupy shelters. Shelter size selection did not vary with body size, but males that abandoned shelters were smaller than those that remained. Overall, the number of interactions between residents and intruders were low with most interactions occurring between large residents and large intruders. A size differential between residents and intruders of 3% was sufficient to predict the proportion of victories in conflicts between round gobies. This ability of the round goby to perceive size differences between themselves and potential opponents reduces the number of interactions and may account for the occurrence of high densities of round gobies observed in the field.
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comparison of methods needed to estimate population size of round gobies Neogobius Melanostomus in western lake erie
Journal of Great Lakes Research, 2005Co-Authors: Timothy B Johnson, Melissa Allen, Lynda D. CorkumAbstract:The round goby (Neogobius Melanostomus) is a small, demersal fish that was introduced into the Great Lakes basin in 1990. Since their arrival, the round goby has been implicated in many ecological changes—most notably changes in the flow of energy from the benthic to the pelagic food web through their consumption of dreissenid mussels. However, methods for evaluating the density and size of round gobies across different substrates are lacking, preventing the true quantification of the effects of round gobies on invaded ecosystems. In our study, we evaluated catch efficiency of numerous passive and active sampling methods for capturing round gobies. We then applied the best techniques to estimate the distribution, density, and biomass of round gobies in western Lake Erie. Visual census (underwater video transects) proved the best technique for assessing round goby size and density across a wide range of substrates. A combination of angling and bottom trawling proved most effective for obtaining biological samples. We estimated 9.9 billion round gobies in western Lake Erie in 2002. Continued efforts to describe abundance and demographics of round gobies in invaded ecosystems will enable scientists and managers to fully understand the impacts of this invading species.
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in vitro biosynthesis of novel 5β reduced steroids by the testis of the round goby Neogobius Melanostomus
General and Comparative Endocrinology, 2005Co-Authors: Wesley J Arbuckle, Lynda D. Corkum, Andrea J Belanger, Barbara S Zielinski, Sangseon Yun, Sadie Bachynski, A P ScottAbstract:Previous studies indicate that, in the round goby Neogobius Melanostomus, the reproductively mature male releases a pheromone that attracts ripe females. Furthermore, studies suggest that the pheromone may be a steroid (more specifically a 5beta-reduced androgen) produced by specialized glandular tissue in the testes. In the present study, it is shown that the testis of the male round goby contains such specialized glandular tissue. In vitro, the testes convert [3H]androstenedione into 3alpha-hydroxy-5beta-androstane-11,17-dione (i.e., 11-oxo-etiocholanolone, 11-oxo-ETIO); 11-oxo-ETIO sulfate (11-oxo-ETIO-s); 11-oxo-testosterone (i.e., 11-ketotestosterone), 3alpha-hydroxy-5beta-androstan-17-one (etiocholanolone, ETIO); 11beta-hydroxy-androstenedione; ETIO sulfate and testosterone. Glucuronidated steroids were not identified. Neither 11-oxo-ETIO nor 11-oxo-ETIO-s has previously been identified in teleost gonads. Both these steroids are formed in the round goby testis even when [3H]17-hydroxyprogesterone is used as a precursor. The fact that, for both steroids, the carbon A ring has a 5beta-configuration (already linked with olfactory sensitivity and behavior induction in two other species of gobies) makes them likely candidate pheromones in the round goby. However, their in vivo production and pheromonal activity remain to be proved.
Barbara S Zielinski - One of the best experts on this subject based on the ideXlab platform.
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invasive male round gobies Neogobius Melanostomus release pheromones in their urine to attract females
Canadian Journal of Fisheries and Aquatic Sciences, 2013Co-Authors: Keith B Tierney, A P Scott, Matthew Kereliuk, Yogesh Kumar Katare, Stephen J Loeb, Barbara S ZielinskiAbstract:The round goby (Neogobius Melanostomus) is an invasive fish in the Laurentian Great Lakes and beyond. Pheromones appear to be important for their reproductive success, as females are attracted to water in which reproductive males have resided (“conditioned water”). Previous investigation has shown conjugated and unconjugated forms of 3α-hydroxy-5β-androstane-11,17-dione (11-oxo-etiocholanolone; 11-O-ETIO) are released in the urine of these males. The goal of this study was to determine if the urine of reproductive males and fractionated extracts attract females. We found that reproductively active females were attracted to male urine and to isolates of male-conditioned water that contained conjugated 11-O-ETIO. The fractionated preparation that corresponded to unconjugated 11-O-ETIO (i.e., “free” steroid released via the gills of males) was not attractive to reproductive females, but curiously, it was attractive to nonreproductive females. Olfactory sensory deprivation confirmed that the behavioural respo...
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Responses of round goby (Neogobius Melanostomus) olfactory epithelium to steroids released by reproductive males
Journal of Comparative Physiology A, 2011Co-Authors: Alyson J. Laframboise, Barbara S ZielinskiAbstract:The wild perciform teleost Neogobius Melanostomus (the round goby) originated from the Ponto-Caspian region and is now a highly successful invasive species in the Laurentian Great Lakes. Males may attract females into their nests for spawning by releasing reproductive pheromones, and it has been previously shown that reproductive males synthesize and release the 5β-reduced and 3α-hydroxyl steroids 3α-hydroxy-5β-androstane-11,17-dione (11-oxo-etiocholanolone; 11-O-ETIO) and 3α-hydroxy-5β-androstane-11,17-dione 3-sulfate (11-oxo-etiocholanolone-3-sulfate; 11-O-ETIO-3-s) and 3α,17β-dihydroxy-5β-androstan-11-one 17-sulfate. In this study, we investigated properties of these released steroids by recording field potential responses from the olfactory epithelium (electro-olfactogram, EOG). The steroid 3α,17β-dihydroxy-5β-androstan-11-one 17-sulfate did not elicit olfactory responses while both 11-O-ETIO and 11-O-ETIO-3-s stimulated olfactory field potentials in the round goby, but not in the goldfish. Cross-adaptation analysis demonstrated that round gobies discriminated between11-O-ETIO and 11-O-ETIO-3-s (as well as etiocholanolone, ETIO) at the sensory level. Second messenger cascades depending on both cAMP and IP_3 were inferred for steroids from pharmacological inhibition studies, while the canonical teleost odors taurocholic acid (a bile acid) and l -alanine (an amino acid) used only cAMP and IP_3, respectively. The round goby presents itself as an excellent species for the study of olfactory function of fish in the wild, given its possible use of these released steroids as pheromones.
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olfactory sensory input increases gill ventilation in male round gobies Neogobius Melanostomus during exposure to steroids
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2006Co-Authors: Rachelle M Belanger, Lynda D. Corkum, Barbara S ZielinskiAbstract:In teleostean fish, ventilation increases have been observed in response to low dissolved oxygen levels, visual stimuli, and gustatory cues. However, olfactory sensory input may also stimulate gill ventilation rate. We investigated whether olfactory sensory input mediates gill ventilation responses, as suggested by the observation that steroidal compounds detected by the olfactory system elicited increases in opercular activity in the perciform teleost, the round goby (Neogobius Melanostomus). Close parallels between gill ventilation and olfactory responses, led us to conduct an empirical study that used two different olfactory sensory deprivation techniques to seek a causal relationship between olfactory epithelial activity and hyperventilation. Chemical lesion of olfactory sensory neurons or mechanical occlusion of the nasal cavities inhibited gill ventilation responses of reproductive male round gobies to estrone (1,3,5(10)-estratrien-3-ol-17-one) and to ovarian extracts. This direct evidence demonstrates the role of olfactory sensory input for the gill ventilation response to putative reproductive pheromones and may represent an important regulatory mechanism for odorant sampling during pheromone communication.
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behavioural responses of female Neogobius Melanostomus to odours of conspecifics
Journal of Fish Biology, 2005Co-Authors: Don B Gammon, A P Scott, Barbara S Zielinski, Lynda D. CorkumAbstract:The behavioural responses of reproductive and non-reproductive female round gobies Neogobius Melanostomus to water conditioned by reproductive and non-reproductive males and females were tested. The behavioural responses of reproductive female round gobies exposed to odour of reproductive males included increased time spent near the source of the odour, elevated swimming velocities and directed movement to and around the odour source when compared with their responses to control water. These results suggested that pheromones released from reproductive males may induce spawning behaviour in reproductive females. Non-reproductive females exposed to reproductive female odour spent significantly more time near the odour source of reproductive females compared with control water. Non-reproductive females also showed directed movement towards and around the odour source when exposed to reproductive female odour. These results suggested that round gobies use inter-sexual and intra-sexual pheromones and that both sex and reproductive status are important in the detection and release of these pheromones.
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in vitro biosynthesis of novel 5β reduced steroids by the testis of the round goby Neogobius Melanostomus
General and Comparative Endocrinology, 2005Co-Authors: Wesley J Arbuckle, Lynda D. Corkum, Andrea J Belanger, Barbara S Zielinski, Sangseon Yun, Sadie Bachynski, A P ScottAbstract:Previous studies indicate that, in the round goby Neogobius Melanostomus, the reproductively mature male releases a pheromone that attracts ripe females. Furthermore, studies suggest that the pheromone may be a steroid (more specifically a 5beta-reduced androgen) produced by specialized glandular tissue in the testes. In the present study, it is shown that the testis of the male round goby contains such specialized glandular tissue. In vitro, the testes convert [3H]androstenedione into 3alpha-hydroxy-5beta-androstane-11,17-dione (i.e., 11-oxo-etiocholanolone, 11-oxo-ETIO); 11-oxo-ETIO sulfate (11-oxo-ETIO-s); 11-oxo-testosterone (i.e., 11-ketotestosterone), 3alpha-hydroxy-5beta-androstan-17-one (etiocholanolone, ETIO); 11beta-hydroxy-androstenedione; ETIO sulfate and testosterone. Glucuronidated steroids were not identified. Neither 11-oxo-ETIO nor 11-oxo-ETIO-s has previously been identified in teleost gonads. Both these steroids are formed in the round goby testis even when [3H]17-hydroxyprogesterone is used as a precursor. The fact that, for both steroids, the carbon A ring has a 5beta-configuration (already linked with olfactory sensitivity and behavior induction in two other species of gobies) makes them likely candidate pheromones in the round goby. However, their in vivo production and pheromonal activity remain to be proved.
Pavel Jurajda - One of the best experts on this subject based on the ideXlab platform.
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no effect of round goby Neogobius Melanostomus colonisation on young of the year fish density or microhabitat use
Biological Invasions, 2016Co-Authors: Michal Janac, Kevin Roche, Zdenka Valova, Pavel JurajdaAbstract:The round goby Neogobius Melanostomus has recently invaded several major freshwater systems in Europe and North America. Despite numerous studies predicting an impact on native fish assemblages, few have attempted to demonstrate it. In this case study, we monitored the effect of N. Melanostomus colonisation on abundance and habitat utilisation of both young-of-the-year (YOY) native fish and YOY western tubenose goby Proterorhinus semilunaris in a typical, medium-sized European river. Colonisation by N. Melanostomus had no apparent effect on either native fish abundance and species richness or P. semilunaris abundance. Moreover, after colonisation, both native fish and P. semilunaris occupied similar niches (i.e. microhabitats) to those occupied before colonisation. While niche use of YOY N. Melanostomus and P. semilunaris overlapped significantly, YOY native fish utilised different habitats from the gobiids. We suggest that N. Melanostomus did not compete for resources with YOY fish in our study area due to lack of niche overlap and/or surplus resources. As N. Melanostomus rapidly dominated the fish assemblage at our site, we further suggest that utilisation of an empty niche, rather than competitive superiority, was the main factor facilitating its success.
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carcass feeding as a cryptic foraging mode in round goby Neogobius Melanostomus
Journal of Fish Biology, 2015Co-Authors: Matej Polacik, Pavel Jurajda, Radim Blažek, Michal JanacAbstract:Round gobies Neogobius Melanostomus were observed readily consuming soft tissue from carcasses of larger fishes under both laboratory and field conditions. Consumption normally progressed in a typical sequence, starting with soft and easily accessible tissues such as the eyes, followed by puncture of the abdominal cavity, gut consumption and then muscle consumption. Carcass feeding has not previously been seen in N. Melanostomus and has potential consequences for transfer of nutrients and contaminants.
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a newly established round goby Neogobius Melanostomus population in the upper stretch of the river elbe
Knowledge and Management of Aquatic Ecosystems, 2015Co-Authors: Kevin Roche, Michal Janac, Luděk Slapanský, Libor Mikl, Lukas Kopecek, Pavel JurajdaAbstract:The invasive round goby (Neogobius Melanostomus , Pallas, 1814) has increased its European range dramatically over recent decades, with international shipping suspected as the main vector. Here, we provide the first population and morphological data for a newly established round goby population in the upper Elbe (Usti nad Labem, Czech Republic). Surveys in 2013 along the same stretch found no evidence of gobies, indicating introduction within the past two years. Analysis of morphological similarity confirms the most likely source as the recently established population in the tidal Elbe near the port of Hamburg. Due to the species’ restricted range ( establishment of widely-separated populations through port-to-port transfer and rapid inter-site connection through downstream drift and natural migration.
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diet of two invading gobiid species proterorhinus semilunaris and Neogobius Melanostomus during the breeding and hatching season no field evidence of extensive predation on fish eggs and fry
Limnologica, 2014Co-Authors: Mojmir Vasek, Lucie Vsetickova, Kevin Roche, Pavel JurajdaAbstract:Abstract One of the potential impacts of invasive gobies on native fish fauna is predation on eggs and fry. Therefore, the diet composition of two invading gobiid species, the tubenose goby Proterorhinus semilunaris and round goby Neogobius Melanostomus, was examined in the Dyje river system (Danube basin, Central Europe) during the 2011 reproductive season to ascertain the extent of gobiid predation on heterospecific and conspecific eggs and juveniles. Consumption of fish eggs and juveniles by invading gobies was very low. The diets of both species consisted largely of benthic macroinvertebrates, and particularly insect larvae. These results indicate that invading gobies in the Dyje river system are likely to impact native fish fauna more through competitive effects than through direct predation on eggs and juveniles.
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downstream drift of round goby Neogobius Melanostomus and tubenose goby proterorhinus semilunaris in their non native area
Ecology of Freshwater Fish, 2013Co-Authors: Michal Janac, Luděk Slapanský, Zdenka Valova, Pavel JurajdaAbstract:Several Ponto-Caspian gobiid species have recently expanded their ranges in Europe and North America. This is the first study to demonstrate passive downstream dispersal (drift) of the round goby (Neogobius Melanostomus) and tubenose goby (Proterorhinus semilunaris) in newly colonised areas (River Dyje, Danube basin), a factor that could play an important role in their dispersal. Drift duration (i.e. number of dates on which the species was caught) in round goby was longer than that of both native species and tubenose goby, providing a possible advantage. Size of drifting fish was restricted to a narrow range of 6-8 mm and 5-8 mm for round and tubenose goby, respectively. Drift in both species occurred almost completely during hours of darkness (<1 lux) and fish size did not vary throughout the night. In both species, drift density increased significantly during the first hour after dusk. Round goby density gradually decreased up to dawn, while tubenose goby density varied throughout the night with no clear pattern. Drift of early life stages appears to be an important phenomenon that has not received adequate attention in studies of round and tubenose goby ecology and dispersal.
Ulrich K. Schliewen - One of the best experts on this subject based on the ideXlab platform.
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Cryptic alternative male mating strategies in invasive alien round goby (Neogobius Melanostomus) of the upper Danube River
Biological Invasions, 2020Co-Authors: Alexander F. Cerwenka, Joerg Brandner, Juergen Geist, Ulrich K. SchliewenAbstract:Male alternative mating strategies are a widespread life history choice, yet they have hardly been assessed in the context of fish invasions. As established proxies for alternative life-history strategies, body length and sexual maturity of Ponto–Caspian round goby ( Neogobius Melanostomus ) from the recently invaded upper Danube River were contrasted and differential trophic niche occupation was assessed. Only about 4% of analyzed gobies qualified as potential sneakers which may be explained by the recent and ongoing invasion process. This study provides evidence for the occurrence of sneaking behavior of invasive round goby in the upper Danube River.
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invasion strategies in round goby Neogobius Melanostomus is bigger really better
PLOS ONE, 2018Co-Authors: Joerg Brandner, Alexander F. Cerwenka, Ulrich K. Schliewen, Juergen GeistAbstract:Few studies have systematically investigated mid- or long-term temporal changes of biological characteristics in invasive alien species considering the different phases of an invasion. We studied the invasion performance of one of the most invasive species worldwide, the round goby Neogobius Melanostomus, from total absence over first occurrence until establishment from 2010 to 2015 in the upper Danube River. After an upstream movement of the invasion front of about 30 river km within four years, the pattern that round goby pioneering populations significantly differ from longer established ones has been confirmed: Pioneering populations at the invasion front comprised more females than males, and adult specimens with a larger body size compared to those at longer inhabited areas. On the population-level, the proportion of juveniles increased with time since invasion. The results of this study provide support for the previously postulated ´bigger is better´ and ´individual trait utility´ hypotheses explaining invasion success in round goby. Pioneering invaders with their greater exploratory behavior, highly adaptive phenotypic plasticity and increased competitive ability seem to act as prime emperors of new habitats, strongly following and benefiting from man-made river-bank structures.
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Little association of biological trait values with environmental variables in invasive alien round goby (Neogobius Melanostomus)
Ecology and evolution, 2017Co-Authors: Alexander F. Cerwenka, Alfredo Pagnotta, Carolin Böker, Joerg Brandner, Juergen Geist, Ulrich K. SchliewenAbstract:The relative importance of species-specific biological trait characteristics and environmental factors in invasions of nonindigenous species remains controversial because both have mostly been studied independently. Thus, the main objective of this study was to examine the correlation of biological traits with environmental variation in the globally invasive round goby Neogobius Melanostomus from the upper Danube River. Based on a sample of 653 specimens along a continuous 200 km river pathway, links between nine environmental factors (substrate-type, six water measurements, and the communities of fishes and macroinvertebrates) and seven biological traits (nutritional and energetic status, trade-offs of parasite resistance and resource allocation, and three growth proxies) were analyzed. Biological trait values of N. Melanostomus hardly correlated with the environment, could not explain invasion progress and imply a general low overall importance for invasion success. Instead, alternative individual life-history trajectories appear to determine invasion success. This is in line with up to 15% of all specimens having outlying biological trait values of potential adaptive value, suggesting a considerable importance of adaptive trait variation among single individuals for the whole invasion progress. This “individual trait utility hypothesis” gives an alternative explanation for success of invasive species by single individuals carrying particular traits, and it should be specifically targeted and analyzed at currently invaded sites.
Alexander F. Cerwenka - One of the best experts on this subject based on the ideXlab platform.
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Cryptic alternative male mating strategies in invasive alien round goby (Neogobius Melanostomus) of the upper Danube River
Biological Invasions, 2020Co-Authors: Alexander F. Cerwenka, Joerg Brandner, Juergen Geist, Ulrich K. SchliewenAbstract:Male alternative mating strategies are a widespread life history choice, yet they have hardly been assessed in the context of fish invasions. As established proxies for alternative life-history strategies, body length and sexual maturity of Ponto–Caspian round goby ( Neogobius Melanostomus ) from the recently invaded upper Danube River were contrasted and differential trophic niche occupation was assessed. Only about 4% of analyzed gobies qualified as potential sneakers which may be explained by the recent and ongoing invasion process. This study provides evidence for the occurrence of sneaking behavior of invasive round goby in the upper Danube River.
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invasion strategies in round goby Neogobius Melanostomus is bigger really better
PLOS ONE, 2018Co-Authors: Joerg Brandner, Alexander F. Cerwenka, Ulrich K. Schliewen, Juergen GeistAbstract:Few studies have systematically investigated mid- or long-term temporal changes of biological characteristics in invasive alien species considering the different phases of an invasion. We studied the invasion performance of one of the most invasive species worldwide, the round goby Neogobius Melanostomus, from total absence over first occurrence until establishment from 2010 to 2015 in the upper Danube River. After an upstream movement of the invasion front of about 30 river km within four years, the pattern that round goby pioneering populations significantly differ from longer established ones has been confirmed: Pioneering populations at the invasion front comprised more females than males, and adult specimens with a larger body size compared to those at longer inhabited areas. On the population-level, the proportion of juveniles increased with time since invasion. The results of this study provide support for the previously postulated ´bigger is better´ and ´individual trait utility´ hypotheses explaining invasion success in round goby. Pioneering invaders with their greater exploratory behavior, highly adaptive phenotypic plasticity and increased competitive ability seem to act as prime emperors of new habitats, strongly following and benefiting from man-made river-bank structures.
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Little association of biological trait values with environmental variables in invasive alien round goby (Neogobius Melanostomus)
Ecology and evolution, 2017Co-Authors: Alexander F. Cerwenka, Alfredo Pagnotta, Carolin Böker, Joerg Brandner, Juergen Geist, Ulrich K. SchliewenAbstract:The relative importance of species-specific biological trait characteristics and environmental factors in invasions of nonindigenous species remains controversial because both have mostly been studied independently. Thus, the main objective of this study was to examine the correlation of biological traits with environmental variation in the globally invasive round goby Neogobius Melanostomus from the upper Danube River. Based on a sample of 653 specimens along a continuous 200 km river pathway, links between nine environmental factors (substrate-type, six water measurements, and the communities of fishes and macroinvertebrates) and seven biological traits (nutritional and energetic status, trade-offs of parasite resistance and resource allocation, and three growth proxies) were analyzed. Biological trait values of N. Melanostomus hardly correlated with the environment, could not explain invasion progress and imply a general low overall importance for invasion success. Instead, alternative individual life-history trajectories appear to determine invasion success. This is in line with up to 15% of all specimens having outlying biological trait values of potential adaptive value, suggesting a considerable importance of adaptive trait variation among single individuals for the whole invasion progress. This “individual trait utility hypothesis” gives an alternative explanation for success of invasive species by single individuals carrying particular traits, and it should be specifically targeted and analyzed at currently invaded sites.
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effects of sampling techniques on population assessment of invasive round goby Neogobius Melanostomus
Journal of Fish Biology, 2013Co-Authors: Joerg Brandner, Alexander F. Cerwenka, Joachim Pander, Melanie Mueller, Juergen GeistAbstract:In this study, a comparison of point abundance sampling (PAS) electrofishing, angling with two different hook sizes and trap-based fishing was performed in a non-wadeable river to analyse their effects on catch per unit effort (CPUE) and population characteristics of invasive round goby Neogobius Melanostomus. PAS electrofishing was identified as the most effective (mean ± s.e. CPUE = 57 ± 4 N. Melanostomus min(-1) ) and least selective method in terms of size, feeding status and species composition. Angling had the second highest CPUE, but was more size selective and resulted in a higher proportion of males compared to electrofishing [overall sex ratio angling (female:male) = 1:0.92, electrofishing 1:0.65]. Owing to low CPUE (0.012 ± 0.004) and low frequency of occurrence, minnow traps were least suitable for N. Melanostomus population assessment. The results of this study suggest that a higher degree of standardization and inter-calibration is useful to achieve better comparability of population data of invasive N. Melanostomus and other benthic fish species.
