蒙古国鱼类地理分布简介

有关蒙古鱼类及其分布的文献很少,中文文献更少。本文依记载做了汇综简介。现知有43～44种(一种为引入外来鱼),另外尚可能有10～11种。在鱼类地理分布学内属全北区的环极亚区(西伯利亚分区)、黑龙江过渡亚区(黑龙江分区)及宁蒙高原亚区(西蒙古分区和内蒙古分区)。     

剑尾鱼线粒体细胞色素b基因的序列分析

目的　克隆和测定剑尾鱼 (Xiphophorushelleri)线粒体细胞色素b基因 (cytb)的全序列。方法　提取剑尾鱼肝脏的总DNA。设计合成特异引物进行PCR扩增。扩增产物经琼脂糖电泳检测、纯化后克隆到pGEM Teasyvectorsystem中的T载体上 ,筛选转化子 ,提取质粒 ,酶切鉴定。挑取重组质粒pGEM T xhcytb 11进行序列测定。结果　获得了剑尾鱼线粒体cytb基因的全序列 ,共 114 0bp。结论　用BLAST与GenBank中的线粒体DNA序列进行比较 ,显示剑尾鱼与其他鱼类的cytb基因具有较高的同源性 ;根据剑尾鱼与其他 13种鱼的cytb基因序列同源性所建立的进化树 ,与传统的分类地位基本吻合     

Polymorphisms of GA/GT Microsatellite Loci from Anguilla japonica

Six novel microsatellite loci, containing (GA)_15\N17 or (GT)_10\N19 perfect tandem repeats, were isolated and characterized for the catadromous eel Anguilla japonica. The allelic size of the 6 loci ranged from 79 to 226 bp in length. All loci were polymorphic with a mean number of 14.7 alleles per locus and a mean heterozygosity of 0.67, suggesting higher polymorphism than that of freshwater and anadromous fishes, but lower than that of marine fishes. Genotype diversity of the 6 loci ranged from 0.22 to 0.61 with a mean value of approximately 0.5. Cross-species amplification showed that 5 of the 6 microsatellite primers proved to be useful in addressing questions of population genetics for all Anguilla species. Received October 11, 2000; accepted December 29, 2000.     

Isotopic evidence of functional overlap amongst the resilient pelagic fishes

The Lake Victoria ecosystem once hosted a diverse fish community dominated by a large species flock of haplochromine cichlids. Today this fish assemblage is highly altered by anthropogenic activities, with at least half of the indigenous species either extinct or very rare. The fauna and flora of the tropic’s largest lake are still in flux, and little is known about even the most basic ecological questions, such as the source of carbon and nitrogen for its spectacular productivity. The actual food-web structure is difficult to determine with results based on traditional gut analysis. At the moment both scientists and conservationists are at odds as to whether there is any evidence of functional replacement or functional overlap amongst the resilient pelagic fishes of Lake Victoria. This study used a static stable isotope model to investigate the source of carbon and the extent of the trophic overlap amongst three pelagic fishes, Rastrineobola argentea, ssichromis laparogramma and Y. fusiformis in the Kenyan waters of Lake Victoria. The δ ¹³C of plants ranged from ?8.8 to ?24.6 $\permil$, while fishes ranged from ?18.6 to ?24.5 $\permil$, suggesting assimilation of mostly C₃ sources for the fish species. On the basis of the isotope model, it is evident that Yssichromis laparogramma, Yssichromis fusiformis , and Rastrineobola argentea obtained from 90 to 97.5$%$, with an average of 94.2$%$, of their food from the same trophic level. The very high degree of overlap in the effective trophic level of these three zooplanktivores has important ecological and conservation implications.     

雅砻江河口区产漂流性卵鱼类早期资源现状

为了解雅砻江河口区产漂流性卵鱼类的早期资源现状,2016-2018年6-7月在攀枝花市盐边县雅砻江河口开展了鱼类早期资源调查工作。共采集产漂流性卵鱼类5种,分属1目2科,其中长江上游特有鱼类3种,分别为长薄鳅(Leptobotia elongata)、中华金沙鳅(Jinshaia sinensis)和短身金沙鳅(Jinshaia abbreviata);2016-2018年流经雅砻江河口断面的鱼卵径流量分别为3.5×10^6、13.78×10^6和3.87×10^6ind;调查期间累计出现8次产卵高峰(2016和2018年各2次,2017年4次),鱼类的繁殖盛期在6月中下旬;通过推算,攀枝花盐边县和攀枝花米易县得石镇是河口区产漂流性卵鱼类的主要产卵场。     

Prehistoric fisheries in the Caribbean

We studied faunal remains from archaeological sites on five Caribbean islands, each with an early (1,850-1,280 years B.P.) and late (1,415-560 years B.P.) occupation. On each of these islands (Puerto Rico, St. Thomas, St. Martin, Saba, and Nevis), the mean size of reef fishes in the faunal remains declined from the early to the late occupation. The large samples from sites on St. Thomas and Nevis allowed examination of the size distribution of individual taxa. Samples of obligate reef fishes (Scaridae, Acanthuridae, Lutjanidae, and Serranidae) showed large reductions in size between the early and late occupations. Samples of facultative reef fishes (Carangidae and Clupeidae) showed little change in size frequency distribution. The percentage of estimated reef fish biomass in the total aquatic faunal record sharply declined in the samples from four of the islands, while on Nevis there was a slight increase. The mean trophic level of reef fishes declined from the early to the late occupations on each island. Together these patterns suggest that populations of reef fishes adjacent to occupation sites on these islands were heavily exploited in prehistoric times. Such exploitation resulted in shifts in size structure and species composition among the reef fish fauna. On some islands the decline in reef fish resources corresponded with a shift towards greater exploitation of pelagic species.     

Habitat and resource use by larval and juvenile fishes in an arid-land river (Rio Grande, New Mexico)

1. Studies of mesic temperate and tropical rivers suggest an important role for floodplain habitats as nursery areas for larval and juvenile fishes. In arid‐land rivers the extent and duration of flooding is diminished and habitats and resources used by larval fishes are poorly known. Our study documented habitat and resource use of larval fishes in the Rio Grande, New Mexico, an arid‐land river. 2. Spatial and temporal distribution of larval and juvenile fishes and their inferred microhabitat preferences were studied during spring, summer and autumn, 2003. Stable carbon (¹³C : ¹²C) and nitrogen (¹⁵N : ¹⁴N) isotope ratios were measured to identify nutrient sources and characterise trophic positions of young‐of‐year fishes in this system. 3. Some fishes recruited during high flows (in spring), whereas others recruited during low‐flow periods in late summer. Regardless of the timing of reproduction, microhabitats with lower current velocity and higher temperature appeared to serve as vital nursery grounds for Rio Grande fishes. Ephemeral backwaters and disconnected side channels held the highest abundance and diversity of larvae and juveniles. 4. Stable isotope analyses revealed that fish larvae obtained carbon predominately from algal production in early summer, but used organic carbon derived from emergent macrophytes as river discharge decreased in mid‐summer. This shift may have been facilitated by microinvertebrate prey that grazed down edible algae and then switched to macrophytes in mid‐summer. Nitrogen isotope ratios did not differ among species or early life stages, suggesting that larval and juvenile fishes use similar food resources, especially when restricted to isolated pools in summer.     

A novel pharyngeal expansion mechanism in the yellow-spotted fanray, Platyrhina tangi (Elasmobranchii: Batoidea), with special reference to the function of the fifth ceratobranchial cartilage in batoids

Expansion of the ‘pharynx’ during breathing or capturing prey in fishes generally involves posteroventral retraction of the hyoid arch. However, the hyoid arch structure of batoid fishes (skates, rays, guitarfishes, and sawfishes) is unique, and how they expand the pharyngeal cavity is poorly understood. To investigate the mechanism of pharyngeal expansion during breathing in the yellow-spotted fanray, Platyrhina tangi, we conducted anatomical and kinematic investigations of the pharyngeal region. Our study revealed that the yellow-spotted fanray and sharks have different skeletal linkage systems for pharyngeal expansion. During pharyngeal expansion in the yellow-spotted fanray, the hyoid bar and branchial apparatus rotate ventrally around the hinge joint between the fifth ceratobranchial cartilage and the pectoral girdle. This pharyngeal expansion mechanism appears to be widespread among batoid fishes and is unique among cartilaginous fishes (sharks, batoids, and holocephalans). Batoid fishes possibly developed this pharyngeal expansion mechanism during early batoid evolution.     

Scales and Dermal Skeletal Histology of an Early Bony Fish Psarolepis romeri and Their Bearing on the Evolution of Rhombic Scales and Hard Tissues

Recent discoveries of early bony fishes from the Silurian and earliest Devonian of South China (e.g. Psarolepis, Achoania, Meemannia, Styloichthys and Guiyu) have been crucial in understanding the origin and early diversification of the osteichthyans (bony fishes and tetrapods). All these early fishes, except Guiyu, have their dermal skeletal surface punctured by relatively large pore openings. However, among these early fishes little is known about scale morphology and dermal skeletal histology. Here we report new data about the scales and dermal skeletal histology of Psarolepis romeri, a taxon with important implications for studying the phylogeny of early gnathostomes and early osteichthyans. Seven subtypes of rhombic scales with similar histological composition and surface sculpture are referred to Psarolepis romeri. They are generally thick and show a faint antero-dorsal process and a broad peg-and-socket structure. In contrast to previously reported rhombic scales of osteichthyans, these scales bear a neck between crown and base as in acanthodian scales. Histologically, the crown is composed of several generations of odontodes and an irregular canal system connecting cylindrical pore cavities. Younger odontodes are deposited on older ones both superpositionally and areally. The bony tissues forming the keel of the scale are shown to be lamellar bone with plywood-like structure, whereas the other parts of the base are composed of pseudo-lamellar bone with parallel collagen fibers. The unique tissue combination in the keel (i.e., extrinsic Sharpey''s fibers orthogonal to the intrinsic orthogonal sets of collagen fibers) has rarely been reported in the keel of other rhombic scales. The new data provide insights into the early evolution of rhombic (ganoid and cosmoid) scales in osteichthyans, and add to our knowledge of hard tissues of early vertebrates.     

The effects of seaweed harvesting on fishes: a response

References Rangeley (1994) has argued that sampling biases, errors in experimental design and low statistical power make the conclusion by Black & Miller (1991), that there was no large impact of an experimental harvest of the seaweedAscophyllum nodosum on fishes, unmerited and misleading. Our study was conducted mainly at two sites close to Lower Argyle, southern Nova Scotia, Canada where harvesting ofAscophyllum nodosum has been carried out continuously for 30 years along-side intense and productive shellfish and finfish fisheries. In southern Nova Scotia, on-going removal ofAscophyllum nodosum with mechanical harvesters is about 17% (Sharpe & Semple 1991); planned annual removal in New Brunswick where Rangeley has worked will be only about 5% (Anon. 1993). The context of our investigation was a small-scale (400 m²) but extreme, experimental removal (100%) of the seaweed. Our focus was on fishes that moved into the intertidal zone as the tide rose in the evening and early morning and were caught in trammel nets, and on the fishes that were retained in a fixed seine that was set at high tide in early morning and the fishes removed at the next low tide. Thus, subject to the constraint on the size of the fishes imposed by the nature of our fishing gear with its stretch mesh of 25 mm, we were concerned with the identity and abundance of fishes that moved in and out of the intertidal zone and their behavioural response to the 400 m² patches of habitat that formed our experimental units. The most striking result was the unexpected, low abundance of fishes caught in our gear.     

Do early life history characteristics determine species ranges and dispersal of coral reef fishes in the Indo‐Pacific?

The Indo‐Pacific consists of extensive continuous coastlines and many island groups of varying sizes and isolation. The species ranges of coral reef fishes vary enormously from Indo‐Pacific wide to highly endemic. There is also great variation in the early life history characteristics of coral reef fishes ( e.g . pelagic larval durations, spawning strategies and swimming abilities). We use individual‐based models (IBMs) to simulate the dispersal of coral reef fishes in the Indo‐Pacific. The development of dispersal strategies is explored based on ecological and geographical constraints. Simulations are presented for climatic and anthropogenically‐induced events.     

Adaptive radiation in labrid fishes: A central role for functional innovations during 65 My of relentless diversification

Early burst patterns of diversification have become closely linked with concepts of adaptive radiation, reflecting interest in the role of ecological opportunity in modulating diversification. But, this model has not been widely explored on coral reefs, where biodiversity is exceptional, but many lineages have high dispersal capabilities and a pan‐tropical distribution. We analyze adaptive radiation in labrid fishes, arguably the most ecologically dominant and diverse radiation of fishes on coral reefs. We test for time‐dependent speciation, trophic diversification, and origination of 15 functional innovations, and early bursts in a series of functional morphological traits associated with feeding and locomotion. We find no evidence of time‐dependent or early burst evolution. Instead, the pace of speciation, ecological diversification, and trait evolution has been relatively constant. The origination of functional innovations has slowed over time, although few arose early. The labrid radiation seems to have occurred in response to extensive and still increasing ecological opportunity, but within a rich community of antagonists that may have prevented abrupt diversification. Labrid diversification is closely tied to a series of substantial functional innovations that individually broadened ecological diversity, ultimately allowing them to invade virtually every trophic niche held by fishes on coral reefs.     

Exploring the evolutionary history of melanin-concentrating and melanin-stimulating hormone receptors on melanophores: neopterygian (holostean) and chondrostean fishes

The occurrence of melanin-concentrating hormone (MCH) receptors on integumental melanophores was found to extend back in the evolutionary line of ray-finned bony fishes (Actinopterygii) to the group ancestral to modern teleosts, the Holostei. The two species of holosteans studied, Amia calva and Lepisosteus platyrhincus, exhibited changes of melanophore index (melanosome aggregation), indicating responses to MCH and to melatonin but no response to norepinephrine (NE). Polyodon spathula, a species of chondrostean (an older group of bony fishes ancestral to holosteans), failed to respond to MCH, to melatonin, or to NE. Nevertheless, Polyodon skin darkened (melanosome dispersion) in response to melanocyte-stimulating hormone (MSH). The preliminary implication of these observations is that the mechanism of physiological color change involving MCH and its melanophore receptors evolved near the end of the Paleozoic or during the early Mesozoic, just before or early in the evolution of neopterygian (holostean and teleostean) fishes.     

Larval spatial distributions and other early life-history characteristics predict genetic differentiation in eastern Pacific blennioid fishes

In marine organisms, a pelagic larval stage increases the opportunities for long-distance dispersal and is often associated with little genetic differentiation over large geographical distances. Here we test the hypothesis that early life-history characteristics, including larval spatial distributions, affect the rates of dispersal and, therefore, the levels of genetic partitioning among three Gulf of California reef fishes: Axoclinus nigricaudus, Malacoctenus hubbsi and Ophioblennius steindachneri. These three blennioid fishes have markedly different early life histories: A. nigricaudus has a short larval duration (18 days) and develops inshore, M. hubbsi has an intermediate larval duration (24 days) and most individuals develop inshore and O. steindachneri has a long larval life (50 days) and disperses offshore. Estimates of genetic partitioning from mtDNA control region sequences differed greatly between these species and were in the same rank order as predicted by their early life-history characteristics (A. nigricaudus N(ST)=0.536, M. hubbsi N(ST)=0.261 and O. steindachneri N(ST)=0.000). These results indicate that larval strategies may be good predictors of population genetic structure in some marine fishes.     

Evolution of gastrulation in the ray-finned (actinopterygian) fishes

Sometime before or during the early Mesozoic era, new lineages of actinopterygian (ray-finned) fishes radically transformed their mode of gastrulation. During this evolutionary transformation, yolky endoderm was a hotspot for ontogenetic change. As holoblastic cleavage patterns were modified into meroblastic cleavage patterns, major changes in cell identity specification occurred within the mesendodermal marginal zone, as well as in the superficial epithelium of the embryo. These cellular identity changes resulted in the appearance of two novel extra-embryonic tissues within the embryos of teleostean fishes: the enveloping layer (EVL) and the yolk syncytial layer (YSL). The generation of these extra-embryonic tissues prompted major morphogenetic changes within the Organizer Region. As these evolutionary changes occurred, the outermost cell layer of the Organizer (the Organizer Epithelium) was apparently retained as a signaling center necessary for the establishment of left-right embryonic asymmetry in the embryo. Conserved and derived features of Organizer morphogenesis and gastrulation within ancient lineages of ray-finned fishes provide important insights into how the genetically encoded cell behaviors of early morphogenesis can be altered during the course of evolution. In particular, a highly divergent form of actinopterygian gastrulation, which is found in the annual fishes of South America, demonstrates that no aspect of vertebrate gastrulation is inherently immutable to evolutionary change.     

Distribution of early life history stages of fishes in selected pools of the Upper Mississippi River

Effective management of the fishery resources of the Upper Mississippi River and successful mitigation of the loss of critical habitat depend in part on an understanding of the reproductive and early life history requirements of the affected fishes. However, little is known about the use of nursery areas by fishes in the river. Of the nearly 130 species identified in the adult ichthyofauna, only a few are represented proportionally in the available data on early life stages because study designs have not included consideration of the early stages, collection gears have not adequately sampled the young, and eggs and larvae of some species are difficult to sample by conventional approaches. For the species collected, information is available on seasonal variations in total densities, composition, and catch among different habitat types. However, the data are most accurate for species with buoyant early life stages, such as freshwater drum (Aplodinotus grunniens) and gizzard shad (Dorosoma cepedianum). Eggs and larvae of freshwater drum dominate collections made in the main channel, whereas other larval fishes are usually most abundant in backwater habitats. The species found there usually deposit eggs on the substrate or on vegetation. Habitat preferences (as indicated by relative abundance) often shift as development proceeds and physical and behavioral changes occur in the larvae. Only limited information is available on the distribution of larvae within habitats, but it is clear that variations within habitats are significant.     

Patterns of variation in life history among South American fishes in seasonal environments

Summary Ten traits related to life history theory were measured or estimated for 71 freshwater fish species from two locations in the Venezuelan llanos. Multivariate statistics and cluster analysis revealed three basic endpoint patterns bounding a two-dimensional continuum. A suite of attributes associated with parental care and aseasonal reproduction appeared to correspond to an equilibrium strategy. A second group of small fishes was distinguished by traits associated with rapid colonizing ability: early maturation, continuous reproduction, and small clutches. The third basic pattern was associated with synchronized reproduction during the early wet season, high fecundity, absence of parental care, and breeding migrations. A subset of mostly small fishes exhibiting little or no parental care, small clutches, and two to four month reproductive seasons was intermediate between the opportunistic (rapidly colonizing) and seasonal strategies. All ten life history variables showed significant effects of phylogeny. The cluster of species corresponding to the equilibrium group was dominated by siluriform fishes and perciforms of the Cichlidae. The opportunistic cluster was dominated by cyprinodontiform and characiform fishes, whereas the seasonal cluster contained primarily characiform and siluriform fishes. Seven of nine traits were significantly correlated with body length. The three reproductive patterns are interpreted as being adaptative with respect to relative intensity and predictability of temporal and spatial variation in abiotic environmental parameters, food availability, and predation pressure.     

Comparative study on pattern recognition receptors in non-teleost ray-finned fishes and their evolutionary significance in primitive vertebrates

Pattern recognition receptors(PRRs) play important roles in innate immunity system and trigger the specific pathogen recognition by detecting the pathogen-associated molecular patterns. The main four PRRs components including Toll-like receptors(TLRs), RIG-I-like receptors(RLRs), NOD-like receptors(NLRs) and C-type lectin receptors(CLRs) were surveyed in the five genomes of non-teleost ray-finned fishes(NTR) including bichir(Polypterus senegalus), American paddlefish(Polyodon spathula), alligator gar(Atractosteus spatula), spotted gar(Lepisosteus oculatus) and bowfin(Amia calva), representing all the four major basal groups of ray-finned fishes. The result indicates that all the four PRRs components have been well established in these NTR fishes. In the RLR-MAVS signal pathway, which detects intracellular RNA ligands to induce production of type I interferons(IFNs), the MAVS was lost in bichir particularly. Also, the essential genes of recognition of Lipopolysaccharide(LPS) commonly in mammals like MD2, LY96 and LBP could not be identified in NTR fishes. It is speculated that TLR4 in NTR fishes may act as a cooperator with other PRRs and has a different pathway of recognizing LPS compared with that in mammals. In addition, we provide a survey of NLR and CLR in NTR fishes. The CLRs results suggest that Group V receptors are absent in fishes and Group II and VI receptors are well established in the early vertebrate evolution. Our comprehensive research of PRRs involving NTR fishes provides a new insight into PRR evolution in primitive vertebrate.