Pomatoschistus Microps Research Articles

New Light on the Evolutionary History of the Common Goby (Pomatoschistus microps) with an Emphasis on Colonization Processes in the Mediterranean Sea

Through the study of the phylogeographic structure and demographic history of the common goby, Pomatoschistus microps, the influence of Quaternary climatic changes on the evolutionary history of coastal and marine fishes is investigated. Because of its sedentary life cycle in Mediterranean lagoons, it is also a good model to study more specifically if the formation of lagoons during the Holocene had an impact on population structure and demography. Mitochondrial sequences of Northeastern Atlantic and Western Mediterranean specimens were used for phylogenetic reconstructions as well as divergence time estimates, demographic history and population structure analyses. Pomatoschistus microps was a highly supported monophyletic clade including four lineages. It may have appeared 77,000 yr ago, and the divergence of its lineages likely occured shortly thereafter (between 61,000 and 54,000 yr). Most lineages had polytomic topologies, low nucleotide diversity and demographic analyses providing evidence of population expansion. Each lineage was characterized by a large number of private haplotypes. Most haplotypes found in Mediterranean localities were endemic, and one was dominant. Complex reticulated relationships connecting North European, Atlantic and Mediterranean haplotypes were observed. Moderate to high population structure was underlined. Contrary to previous published studies, no significant differentiation was observed between Atlantic and Mediterranean populations, indicating that the Gibraltar Strait is not a phylogeographic break for P. microps. Indeed, molecular dating combined with the tree topologies, phylogeographic and demographic analyses as well as high haplotype diversity underline a recent and rapid population divergence during the last glacial. However, population structure indicates that differentiation is an ongoing process. From an ancestral population trapped in the Atlantic, this goby colonized first northern Europe and later the Mediterranean Sea. Shared haplotypes could have dispersed in the western Mediterranean basin before the lagoon formation, while most private haplotypes, evidencing a recent isolation, probably diverged in lagoons after their closure.

Are Estuarine Fish Opportunistic Feeders? The Case of a Low Anthropized Nursery Ground (the Canche Estuary, France)

Stomach contents of the main fish species (i.e. sprat Sprattus sprattus, sea-bass Dicentrarchus labrax, common goby Pomatoschistus microps and flounder Platichthys flesus) in the Canche nursery ground (France) were examined from May 2006 to March 2007 according to food availability (i.e. macrozoobenthos and zooplankton) to analyse diet composition, trophic competition and prey selection. Overall, 44 prey fish species were identified from the 684 stomach contents examined. Fish diet was characterized by a wide diversity of prey, a relatively high feeding activity (vacuity index ranged between 16.9 and 29.0 % according to species) and spatiotemporal changes, except for D. labrax which did not vary between periods or estuarine zones. Copepods Temora longicornis and Euterpina acutifrons were the most important items in the diet of S. sprattus; for D. labrax, the dominant prey was the amphipod Gammarus sp., while Platichthys flesus and Pomatoschistus microps showed a more similar trophic niche (similarity percentage = 39 %) with diets consisting of nematodes and amphipods. Spatiotemporal sharing of trophic resources by fish and high food resources in the Canche estuary was examined, and very limited diet overlap was observed, indicating that competition for food resources was limited. Differences between the available preys and fish diets demonstrated that fish do not select the most abundant food resources. S. sprattus showed a selection for Tachidius sp. and cladocerans; D. labrax for Gammarus sp., Hediste diversicolor and to a lesser extent nematodes and Corophium sp.; Pomatoschistus microps for nematodes and Gammarus sp.; and Platichthys flesus for nematodes, Gammarus sp., H. diversicolor and Corophium sp. It was concluded that the studied fish exhibit a specialist rather than opportunistic feeding strategy.

An abundant small sized fish as keystone species? The effect of Pomatoschistus microps on food webs and its trophic role in two intertidal benthic communities: A modeling approach

Ecological network analysis (ENA) was used to study the effects of Pomatoschistus microps on energy transport through the food web, its impact on other compartments and its possible role as a keystone species in the trophic webs of an Arenicola tidal flat ecosystem and a sparse Zostera noltii bed ecosystem. Three ENA models were constructed: (a) model 1 contains data of the original food web from prior research in the investigated area by Baird et al. (2007), (b) an updated model 2 which included biomass and diet data of P. microps from recent sampling, and (c) model 3 simulating a food web without P. microps. A comparison of energy transport between the different models revealed that more energy is transported from lower trophic levels up the food chain, in the presence of P. microps (models 1 and 2) than in its absence (model 3). Calculations of the keystone index (KSi) revealed the high overall impact (measured as εi) of this fish species on food webs. In model 1, P. microps was assigned a low KSi in the Arenicola flat and in the sparse Z. noltii bed. Calculations in model 2 ranked P. microps first for keystoneness and εi in both communities, the Arenicola flat and the sparse Z. noltii bed. Taken together, our results give insight into the role of P. microps when considering a whole food web and reveal direct and indirect trophic interactions of this small-sized fish species. These results might illustrate the impact and importance of abundant, widespread species in food webs and facilitate further investigations.

Modeling fish biological responses to contaminants and natural variability in estuaries

Understanding the factors that influence biological responses to contaminants has long been a major goal in marine environmental research. Seven estuarine sites along the Portuguese coast were sampled over a year, and different biological responses of Pomatoschistus microps and Atherina presbyter were determined: superoxide dismutase, catalase, ethoxyresorufin O-deethylase, glutathione S-transferase, metallothioneins, lipid peroxidation, RNA:DNA ratio and condition factor K. Generalized linear models (GLM) were developed for each biological variable per species in relation to sediment chemical characterization (metals and polycyclic aromatic hydrocarbons concentration) and environmental conditions (month, site, water temperature, salinity, depth and mud percentage in the sediment). GLM varied in explanatory power and in the set of predictor variables included in the models. Environmental factors were frequently selected as predictor variables. Individual metals concentration and sediment quality guidelines (integrating all metals) were the major contaminants explaining biological variability. Accordingly, models for metallothioneins and lipid peroxidation had highest explanatory power. Species-specific responses and dataset size were the basis of observed differences between GLM for the two species.

Effects of local and large-scale climate patterns on estuarine resident fishes: The example of Pomatoschistus microps and Pomatoschistus minutus

Large-scale and local climate patterns are known to influence several aspects of the life cycle of marine fish. In this paper, we used a 9-year database (2003–2011) to analyse the populations of two estuarine resident fishes, Pomatoschistus microps and Pomatoschistus minutus, in order to determine their relationships with varying environmental stressors operating over local and large scales. This study was performed in the Mondego estuary, Portugal. Firstly, the variations in abundance, growth, population structure and secondary production were evaluated. These species appeared in high densities in the beginning of the study period, with subsequent occasional high annual density peaks, while their secondary production was lower in dry years. The relationships between yearly fish abundance and the environmental variables were evaluated separately for both species using Spearman correlation analysis, considering the yearly abundance peaks for the whole population, juveniles and adults. Among the local climate patterns, precipitation, river runoff, salinity and temperature were used in the analyses, and North Atlantic Oscillation (NAO) index and sea surface temperature (SST) were tested as large-scale factors. For P. microps, precipitation and NAO were the significant factors explaining abundance of the whole population, the adults and the juveniles as well. Regarding P. minutus, for the whole population, juveniles and adults river runoff was the significant predictor. The results for both species suggest a differential influence of climate patterns on the various life cycle stages, confirming also the importance of estuarine resident fishes as indicators of changes in local and large-scale climate patterns, related to global climate change.

Structure, growth and production of a remarkably abundant population of the common goby, Pomatoschistus microps (Actinopterygii: Gobiidae)

The common goby, Pomatoschistus microps, is a relevant species from estuarine food webs, playing important roles as predator of polychaetes and crustaceans and as prey for larger fishes and crustaceans. The Minho estuary (NW Portugal) is a relatively well-preserved and productive system. To assess the population structure and production of P. microps in this estuary, monthly samples were undertaken in three different areas along an estuarine gradient in the lower estuary. The density of P. microps varied considerably among seasons and sampling stations, with higher densities occurring in summer and autumn. The lowest densities were found closer to the sea. In general, the density of females was higher than the density of males in all sampling stations, while juveniles were more abundant within a salt marsh area. Compared with other European estuaries, our data showed a remarkable higher density and production values of P. microps. This may be related to the high freshwater input and the low salinities found in this estuary. In addition, we hypothesize that the lower density of the sympatric species P. minutus and the high availability of bivalve shells observed in the Minho estuary may have also contributed to the present results, once P. minutus and P. microps often display a diet overlap and the bivalve shells are crucial for the common goby reproduction.

Single and combined effects of microplastics and pyrene on juveniles (0+ group) of the common goby Pomatoschistus microps (Teleostei, Gobiidae)

Microplastic particles have increasingly been detected in aquatic biota, from zooplankton to fish, raising concern for potential effects on aquatic organisms. In addition, they may potentially influence the toxicity of other contaminants in the marine environment. The aim of this study was to clarify whether polyethylene microspheres (1–5μm) modulate short-term toxicity of the polycyclic aromatic hydrocarbon pyrene to juveniles (0+ group) of the common goby (Pomatoschistus microps). Fish were exposed for 96h to pyrene (20 and 200μgL−1) in the absence and presence of microplastics (0, 18.4 and 184μgL−1). Mortality, bile pyrene metabolites, and biomarkers involved in neurotransmission, aerobic energy production, biotransformation and oxidative stress were quantified. Microplastics delayed pyrene-induced fish mortality and increased the concentration of bile pyrene metabolites. Microplastics, alone or in combination with pyrene, significantly reduced acetylcholinesterase (AChE) activity, an effect also observed for pyrene alone. The mixture also decreased isocitrate dehydrogenase (IDH) activity. No significant effects were found for glutathione S-transferase activity or lipid peroxidation. Overall, results show that: (i) microplastics modulate either the bioavailability or biotransformation of pyrene; (ii) simultaneous exposure to microplastics and pyrene decrease the energy available through the aerobic pathway of energy production; and (iii) microplastics inhibit AChE activity. The mechanism for AChE inhibition appeared to be different for pyrene and microplastics, since simultaneous exposure to both did not increase significantly the inhibitory effect. The observed neurotoxic effects of microplastics per se and the effects on IDH activity of the two stressors combined are of concern because they may increase mortality in natural fish populations. More studies need to be carried out on possible combined effects of microplastics and polycyclic aromatic hydrocarbons on fish, particularly juveniles.

Trophic ecology of Pomatoschistus microps within an intertidal bay (Roscoff, France), investigated through gut content and stable isotope analyses

The diet of Pomatoschistus microps has been studied using both gut content and stable isotope analyses. In the Roscoff Aber Bay (Brittany, France), this fish is commonly found on sandy muddy intertidal flats. Gut content analyses were also interpreted using trophic indices. Owing to the large diversity of prey consumed, these indices emphasised the opportunistic feeding behaviour of P. microps. Here, this species fed mainly on endofauna with meiofauna being of high relative importance. The main biotic components of its trophic habitat, characterized by δ13C and δ15N, provided evidence of a major trophic pathway based on drift Enteromorpha sp. Trophic positions estimated by both diet analyses and isotopic analyses led to similar results. In this bay, P. microps is a first-order predator with a low degree of omnivory. Despite a preferential consumption of the amphipod Corophium arenarium, we assumed that this goby behaves as a generalist feeding on a uniform variety of endofauna taxa.

ON THE OCCURRENCE OF TENACIGOBIUS YONGEI (DAVIS & COHEN) IN THE GULF OF ELAT (RED SEA) (PISCES: GOBIIDAE)

The goby Tenacigobius yongei (Davis & Cohen, 1968) has been described from Borneo and Hawai. It lives on the antipatharian sea whip Cirhipathes sp., sharing this ecological niche with the palaemonid shrimp Pontonides unciger (Calman) (Davis & Cohen, 1968). Although the sea whip and associated shrimp have been known from the Red Sea for many years, this goby has surprisingly not been recorded from the Red Sea or the Western Indian Ocean. This small goby has probably been overlooked by scientists, as have many other common gobies recently discovered(Goren, 1983), due to its small size. During a redent study of the taxonomy and ecology of gobies living in association with sessile invertebrates, carried out in the northern Red Sea, specimens of T. yongei were collected and identified, and the species is reported here as being a new record for the Red Sea

Reproductive biology of the black goby, Gobius niger (Teleostei: Gobiidae), in the Gulf of Gabès (Tunisia, Central Mediterranean)

The black goby Gobius niger (Linnaeus, 1758) (Gobiidae) is one of the most common gobies in southern Tunisian waters. This study provides the first detailed information on the reproductive biology of the G. niger in these areas. Samples of G. niger were collected by trawl from the Gulf of Gabès (Tunisia) between February 2009 and January 2010. A total of 1055 specimens were examined, ranging from 6.4 to 15.7 cm total length. The sex-ratio was in favour of males, especially in larger size-classes. The macroscopic analysis of the gonads and the progression of the monthly values of the gonadosomatic index (GSI) indicated that the reproductive season extended from March to June, with GSI peaking in May, and that spawning occurred from April to June. The utilization of lipid reserves, stored predominantly in the liver as well as in muscles, was important during the reproduction season. Monthly changes of the seminal vesicle somatic index showed that during the pre-spawning period they had a proliferation phase, followed by a regressive phase during the post-spawning period. Total fecundity of mature females ranged from 4280 to 14000 eggs per fish, showing a significant increase with size, with an average of 8522 ± 689 eggs per fish. The total length at 50% maturity was 10.13 ± 0.3 cm and 9.69 ± 0.18 cm for males and females, respectively.

Salinity as the main factor structuring small-bodied fish assemblages in hydrologically altered Mediterranean coastal lagoons

SUMMARY: In the Ebro Delta coastal lagoons, one of the main anthropogenic pressures is the artificial freshwater input. Each coastal lagoon has different water management schemes causing profound changes in its physicochemical characteristics. The main objective of this water management is to favour some bird species with interest either for conservation or hunting activities. The present study assesses the influence of hydrological alteration on the fish assemblages of three coastal lagoons in the Ebro Delta. The small-bodied fish fauna was mainly composed of five families: Gobiidae, Poecilidae, Cyprinodontidae, Atherinidae and Mugilidae. Salinity was found to be the main factor structuring fish community in the lagoons. The dominant species was the common goby (Pomatochistus microps) when the lagoons reached higher salinity values, whereas the invasive eastern mosquitofish (Gambusia holbrooki) dominated during the period of higher freshwater inputs. The juveniles of the family Mugilidae showed low catch per unit effort, especially during the period of lower salinity. This same pattern was found for the endangered Spanish toothcarp (Aphanius iberus). Overall, introduced species were favoured by low salinity, which highlights the importance of changing the present water management by reducing the freshwater inputs in order to maintain suitable levels of salinity to favour native species that are important for both commercial and conservation purposes.

Differential investment in acoustic communication during social interactions in two closely-related sand goby species

Communication signals provide key information for conspecific recognition, mate choice and rival assessment. The painted goby Pomatoschistus pictus and the common goby P. microps are two closely-related sand goby species, often sympatric and with an overlapping breeding season. In this study we staged male–male and male–female interactions and compared visual, tactile and acoustic behaviour in both species. Sound production in the common goby is here accounted for the first time. We observed some differences in visual behaviour and a striking divergence in the use of tactile and acoustic communication during courtship and agonistic interactions. We further describe differences in drumming signals with social context in the painted goby. This study suggests a divergence in communication in two closely-related sand goby species and emphasizes the importance of further research concerning the role of multimodal communication in closely-related species.

吉野川におけるオオヨシノボリ個体群の遺伝的分化および陸封化

吉野川におけるオオヨシノボリ個体群の遺伝的分化および陸封化

PCBs in the fish assemblage of a southern European estuary

The Mondego estuary fish assemblage was studied for the accumulation of PCBs. Three sampling stations were visited along an estuarine salinity gradient, and, in total, 15 species were collected. Analysis of PCBs revealed no significant differences among the sampling stations, although differences were observed among the fish assemblages. Fish assemblages could be divided into three groups. The first group comprised those with higher concentration (more than 10ngg−1, dw), included the species Gobius niger, Sardina pilchardus, Anguilla anguilla, Pomatoschistus microps, Chelidonichthys lucerna and Liza ramada; the second group with medium concentration (5–10ngg−1, dw), included the species Pomatoschistus minutus, Dicentrarchus labrax, Atherina presbyter, Chelon labrosus, Diplodus vulgaris, Platichthys flesus and Cilata mustela; and a third group with low concentration (less than 5ngg−1, dw), included the species Solea solea and Callionymus lyra. A positive correlation was found between lipid content and PCB concentrations. To evaluate the influence of the residence time of species on the accumulation of PCBs, species were divided into two groups: species that spend more than 3years in the estuary, and species that spend less than 3years in the estuary. Species that spend more than 3years in the estuary presented higher concentrations than species that spend less than 3years in the estuary. CBs 138 and 153 had higher concentration, and tended to increase with time spent in the estuary.

Weight-length relationships for five fish species from a temperate coastal lagoon of southern Europe

Summary The weight-length relationships (WLR) were estimated for five fish species of Ria Formosa, a coastal lagoon in southern Portugal. WLRs for Gobius couchi, Pomatoschistus microps and Parablennius pilicornis were determined for the first time ever and for Gobius cruentatus for the first time for the southern European Atlantic coast.

Effects of aniline on marine organisms: Comparison of biomarkers responses in the common goby (Pomatoschistus microps) and the common prawn (Palaemon serratus)

Effects of aniline on marine organisms: Comparison of biomarkers responses in the common goby (Pomatoschistus microps) and the common prawn (Palaemon serratus)

Genetic diversity ofPomatoschistus microps(Perciformes: Gobiidae) in ecologically differentiated estuarine systems

A landscape genetics approach was applied to common goby (Pomatoschistus microps) sampled from three estuaries (six sites) of the Portuguese coast. Individuals of each site were genotyped for eight microsatellite loci and levels of genetic diversity and differentiation were correlated to present-day estuarine characteristics and historical events. A general ecological state for each sampling site was obtained from a principal component analysis (PCA) applied to estuarine geomorphologic characteristics and levels of heavy metals and total polycyclic aromatic hydrocarbons contamination. Genetic diversity was higher than that previously reported for common goby in the Atlantic and Mediterranean. F-ST were generally very low (0.000-0.049), as well as Nei's genetic distances (0.000-0.167), although the later were statistically significant. Estuarine geomorphology and heavy metal contamination contributed the most to estuarine ecological differentiation but no trend was detected in the relationship between these characteristics and samples' genetic diversity. Mantel tests also revealed no significant relationships between geographic, genetic and ecological distances. Null alleles only contributed to explain significant Hardy-Weinberg departures in two of the eight loci scored, although disequilibria were detected in at least two loci per sample. Notwithstanding its exploratory character, results suggest an important role for historical factors in the timing and direction of P. microps colonization of the Portuguese estuaries. Environmental variation and P. microps ability to cope with it are also structuring factors in establishing and maintaining the patchy genetic diversity detected in the studied estuaries. (Less)

Isotopes reveal fluctuation in trophic levels of estuarine organisms, in space and time

The estimation of the trophic level (TL) occupied by organisms in estuarine food webs, based on isotopic analysis, is generally done only for one season or averaged among seasons and sites. This does not allow the observation of possible alterations of TL in time and space. As estuaries are highly dynamic environments, it is plausible that the TLs of many of its organisms are not static, like usually portrayed in food web diagrams, but fluctuate in space and time. The TLs of marine juvenile fish, resident fish, shrimp, polychaetes, bivalves and amphipods were determined isotopically, in the Tagus estuary. Sampling was carried out in two nursery areas at each season. Significant changes in TL were observed, in space and time, for the vast majority of the organisms. A drop in TL in summer was observed for various species. The high availability of microalgae and macroalgae in summer may be the cause for this drop, which mainly affects low TL omnivores. These omnivores may opportunistically increase the proportion of primary producers in their diet, thus lowering their mean TL. Such an effect seems to cascade to secondary consumers, like Solea senegalensis and Pomatoschistus microps, which also presented a drop in TL in summer. This study also revealed that organisms that have been considered to be mainly primary consumers, like Liza ramada, and Scrobicularia plana, can actually assume considerably higher TLs seasonally, placing them as secondary consumers.

Fish assemblages of shallow intertidal habitats of the Ria Formosa lagoon (South Portugal): influence of habitat and season

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 446:259-273 (2012) - DOI: https://doi.org/10.3354/meps09455 Fish assemblages of shallow intertidal habitats of the Ria Formosa lagoon (South Portugal): influence of habitat and season Joaquim Ribeiro*, Gonçalo M. Carvalho, Jorge M. S. Gonçalves, Karim Erzini Centro de Ciências do Mar (CCMAR), Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal *Email: jmnribeiro@sapo.pt ABSTRACT: Fish assemblages in seagrass and unvegetated habitats located in shallow intertidal creeks within the saltmarsh area of the Ria Formosa coastal lagoon were sampled with a Riley push net at 3 sites on a monthly basis over a 1 yr period. The objective was to test if both habitats support similar fish assemblages in terms of abundance, diversity, assemblage structure, and size distribution, and to investigate how site and season affect the assemblages. Fish assemblages associated with these habitats were significantly different in terms of diversity, abundance, and assemblage structure. Seagrass supported a larger number of species and greater diversity, while unvegetated habitat supported greater fish numbers but only of a few species. The habitats were dominated by different groups of resident species that were responsible for major differences in fish assemblage structure between habitats. Pomatoschistus microps and young-of-the-year (YOY) Atherina presbyter dominated the unvegetated habitat, while seagrass was dominated by a diverse group of species, in particular syngnathids and small labrids, revealing different habitat preferences. Site and season were determinant factors conditioning the role of habitat in structuring fish assemblages. Distance between habitats, site elevation, and the amount of marsh drained affected fish assemblages in both habitats. Seasonal fluctuations in the presence and abundance of YOY from marine migrant and resident species were responsible for comparable changes in fish assemblage structure in both habitats. Both habitats provide a distinctive nursery area for different species, while common species reveal ontogenic distributional changes between habitats, where smaller fish appear first in unvegetated creeks. KEY WORDS: Fish fauna · Coastal lagoon · Saltmarsh · Intertidal habitats · Seasonal variations · Habitat association · Ria Formosa · South Portugal Full text in pdf format PreviousNextCite this article as: Ribeiro J, Carvalho GM, Gonçalves JMS, Erzini K (2012) Fish assemblages of shallow intertidal habitats of the Ria Formosa lagoon (South Portugal): influence of habitat and season. Mar Ecol Prog Ser 446:259-273. https://doi.org/10.3354/meps09455 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 446. Online publication date: February 02, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

愛媛県加茂川・中山川におけるヨシノボリ類個体群のダム隔離による遺伝的影響

河川人工構造物は，水生生物個体群の分断化を引き起こす．本研究では，貯水ダムが設置されている愛媛県の加茂川と中山川においてヨシノボリ類の遺伝的集団構造の解析および回遊履歴の判定を行い，ダムによる分断の程度を評価することを目的とした．加茂川および中山川の 6 地点からシマヨシノボリ，オオヨシノボリ，トウヨシノボリ，カワヨシノボリを 20～39 個体採集し，各個体の胸鰭から DNA を抽出した．マイクロサテライト領域の増幅には Rhi-5*, -7*, -11* の3 種のマーカー座を用い，アリルサイズを決定し遺伝的解析に用いた．耳石による回遊履歴の判定は加茂川の黒瀬ダム上流域の中奥，黒瀬ダム下流域の大久保，中山川下流域の大頭堰からそれぞれシマヨシノボリを 1 から 2 個体の耳石を採取し，Sr/Ca 濃度を測定した．遺伝的多様性を示すヘテロ接合体率 (期待値) の平均値は，シマヨシノボリ (0. 900～0. 921) で最も高く，続いてオオヨシノボリ (0. 869, 0. 889)，トウヨシノボリ (0. 7779 の順となり，カワヨシノボリ (0. 192～0. 271) で最も低く，種により遺伝的多様度に違いが見られた．各個体群間の遺伝的分化を示す異質性検定では，種間で有意差が見られた．耳石 Sr/Ca 解析により，加茂川の黒瀬ダム上流のシマヨシノボリ個体群の陸封化が確認されたが，遺伝的異質性検定では，黒瀬ダムの上流域と下流域のシマヨシノボリ個体群において有意な差は見られなかった．また，中山川のカワヨシノボリでも中山川逆調整池堰堤の上流域と下流域の個体群において有意な差が見られなかった．