New species of grayling <Emphasis Type="Italic">Thymallus tugarinae</Emphasis> sp. nova (Thymallidae) from the Amur River Basin

Data on a new species, low Amur grayling Thymallus tugarinae sp. nova, inhabiting tributaries of the lower and middle current of the Amur River, are presented. This species has been earlier equated with the Amur grayling T. grubii, described by Dybowski (1869) from the rivers Onon and Ingoda (the Upper Amur Basin). The new species differs from other representatives of the genus in the body coloration, the pattern on the upper fin, and certain morphological characters. On most of the Amur Basin, the grayling from the Lower Amur is sympatric with T. grubii and in its tributary Bureya River, also with the Bureya grayling T. burejensis. Individuals with intermediate traits are unknown, pointing to reproductive isolation. These data are supported by the results of molecular-genetic analysis (Froufe et al., 2003, 2005; Knizhin et al., 2004).     

The food of the grayling Thymallus thymallus (L.) of the River Lugg, Herefordshire

The examination of the stomach contents of 253 grayling from the River Lugg has provided some evidence of a possible depression of feeding activity during the summer months. The diet was varied but bottom food predominated, especially insect larvae, Crustacea and molluscs. Some surface foods were taken but plant material was rarely eaten. Substrate material, detritus and debris and even large pebbles were eaten, mainly in summer. Most seasonal variations in the diet could be related to variations in availability. Fish were not eaten but cyprinid and salmonid eggs were eaten at the appropriate season. In general, increasing amounts of larger food items were eaten by the older grayling.     

Identification of reproductively isolated lineages of Amur grayling (Thymallus grubii Dybowski 1869): concordance between phenotypic and genetic variation

We analysed variation at maternally (mitochondrial DNA control region sequences) and bi-parentally (10 microsatellites) inherited genetic markers, as well as across 12 meristic characters in 7 populations of Amur grayling, Thymallus grubii, from eastern Siberia. All three data sets were concordant in supporting the existence of three diagnosable, reciprocally monophyletic, and most probably reproductively isolated, lineages of grayling within the Amur drainage. There was a significant correlation between genetic and phenotypic divergence, both within and among lineages. Two phenotypically distinct forms (with and without an orange spot on the posterior portion of the dorsal fin), found in sympatry in the lower Amur, most likely result from secondary contact, as they demonstrate 4.6% sequence divergence at the mitochondrial DNA control region. This divergence, together with the existence of at least one nearby population of orange spot grayling outside the Amur drainage (0.8% divergence) underscore the palaeo-hydrological complexity of the system, which presumably promoted genetic divergence in a shifting allopatric framework throughout the Pleistocene. Grayling from the upper Amur, corresponding to the type locality for the species, formed a sister group (1.4-1.6% divergent) to the orange spot lineage perhaps diverging in the early Pleistocene (1.4-1.6 Ma).     

Demography of spawning grayling (Thymallus arcticus) in the Beaverlodge River,Alberta

Changes in a grayling spawning population are described that occurred in relation to both natural and man-induced events. The spawning population was monitored from 1982 to 1987 with a trap on a fishway on the Beaverlodge River, Alberta. Most of the spawning run in each year was tagged with recaptures noted in subsequent years. Male grayling grew slightly faster than females. Growth rates were variable and appeared to be quite low in years of low water flow. Grayling first spawned at 2 to 6 years of age. The majority of tagged grayling would have returned to spawn a second time after a delay of one to two years were it not for the high adult mortality. It is hypothesized that the variable time to first maturity and the delay in the second spawning is a response to highly variable juvenile recruitment. Annual mortality rates increased with age, suggesting an increased vulnerability of larger fish to angling. The population appears highly sensitive to over-exploitation, because of the high mortality rates and the delayed time to spawning of the adults.Deceased.Deceased.     

Post‐release growth and dispersal of pond and hatchery‐reared European grayling Thymallus thymallus compared with their wild conspecifics in a small stream

The growth, and dispersal of stocked European grayling Thymallus thymallus, reared in a hatchery (fed dry food pellets) or in a pond (fed natural food), compared with their wild conspecifics was assessed from the recapture of individually tagged fish 168 days after their release into the Blanice River, Czech Republic. Recapture rates and site fidelity were higher for wild T. thymallus than for artificially reared fish. Specific growth rate and upstream or downstream dispersal did not significantly differ between any of the groups of fish. An influence of rearing conditions (pond v. hatchery) on the overall performance of stocked fish was not demonstrated. Initially, lower condition factors of reared T. thymallus were equal to wild fish after recapture, suggesting adaptation of artificially reared fish that remained in the sections studied.     

Genetic assessment of spatiotemporal evolutionary relationships and stocking effects in grayling (Thymallus thymallus, Salmonidae)

Domestically reared introduced (or escaped) individuals can have detrimental genetic effects on the indigenous populations into which they are released. Consequently, numerous studies have attempted to estimate whether non-native specimens have contributed to the gene pool of wild populations. So far, the key limiting factor of such studies has been their lack of appropriate baseline genetic material. Here, microsatellite DNA analyses of historical scale samples and contemporary wild and introduced populations were used to assess spatiotemporal population structure and stocking effects among endangered Lake Saimaa (eastern Finland) grayling ( Thymallus thymallus , Salmonidae). Significant decreases in genetic differentiation were detected between wild and introduced populations since the commencement of stocking in 1986. Accordingly, up to 15% of the contemporary wild grayling were confidently identified to be of pure hatchery origin, and recent hybridization between the hatchery and indigenous individuals appeared likely. Despite these clear genetic imprints of stocking, the contemporary populations exhibited evolutionary relationships congruent with the sampling locations, and up to 73% of contemporary individuals were identified to be of pure indigenous origin. The use of historical baseline material should prove efficient for monitoring gene flow between domesticated and wild populations in other species also, e.g. salmonids, game animals and plants.     

New data about distribution of lower Amur grayling <Emphasis Type="Italic">Thymallus tugarinae</Emphasis> and Baikal-Lena grayling <Emphasis Type="Italic">Thymallus</Emphasis> sp. (Thymallidae) in the basins of the upper Amur River and Zeya River

New findings of lower Amur grayling (Lower Amur grayling) Thymallus tugarinae and Baikal-Lena grayling Th. sp. (Th. baicalolenensis) in the basins of the upper Amur River and Zeya River are reported for 2010?2014. Lower Amur grayling has been registered in the tributaries of Argun River and in the middle stream of Ingoda River. Baikal-Lena grayling has been found for the first time in the headstream of Ingoda River. New data about the distribution of this species in the basin of upper stream of Zeya River are reported; particularly, Baikal-Lena grayling has been found in Okonon Lake; this is the first finding of a representative of Thymallidae family in the alpine lakes of the watershed area of Amur River. In the basins of upper Amur River and Zeya River, the summer ranges of upper Amur grayling Th. grubii grubii and lower Amur grayling overlap to some extent; on the other hand, the ranges of Baikal-Lena grayling and lower Amur grayling are disjoint. During the summer period, upper Amur grayling and Baikal-Lena grayling together inhabit the basin of upper stream of Zeya River, but only Baikal-Lena grayling has been found in the headstream of Zeya River. In the basin of upper Amur River (the headstream of Ingoda River), the joint range of these species is still unknown; the sympatric zone is located in Dzhermoltai River (the basin of Onon River).     

Characterization of 12 highly variable tetranucleotide microsatellite loci for Arctic grayling (Thymallus arcticus) and cross amplification in other Thymallus species

We describe the isolation and development of 12 polymorphic tetranucleotide microsatellite loci for Arctic grayling (Thymallus arcticus). In a sample of 46 fish, we observed between three and 20 alleles per locus. All 12 of these loci were also polymorphic in at least one of the following Thymallus species and subspecies: T. burejensis, T. amurensis, T. thymallus, T. brevirostris, T. grubii, T. arcticus baicalensis and T. arcticus pallasi. These loci will aid in our understanding of the population genetics, behaviour and conservation of grayling species throughout the northern hemisphere.     

Length‐weight relationships for 11 fish species from the tributary of Amur River (Fuyuan,NE China)

Length‐weight relationships were determined for 11 fish species from the tributary of Amur River in Fuyuan, northeastern China. This is the first record of length‐weight relationships for six of these species.     

Component communities of parasites in the grayling Thymallus thymallus (L.) (Salmoniformes, Thymallidae) and the minnow Phoxinus phoxinus (L.) (Cypriniformes, Cyprinidae) from the Pechora River

Component communities of parasites of Thymallus thymallus and Phoxinus phoxinus are described. The communities differ in the number of species and in the number of dominate species, which is one in P. phoxinus and usually two in T. thymallus. In the first case the dominate species is allogenic, while in the second case dominate species are autogenic. Values of the species diversity indexes are also different for these communities. The differences between parasite communities of T. thymallus and P. phoxinus underline positions of these hosts in hydrobiocenose. Species specialists take first place in the parasite communities both of the hosts, that is characteristic for the parasite communities of the fishes from the boreal submountain faunistic complex. Parasite communities in both of the hosts consist of three groups of species discriminated by the ratio of their biomasses, that suggests forming of the groups by a coordination of the species biomasses.     

Genetic lineages and postglacial colonization of grayling (Thymallus thymallus, Salmonidae) in Europe, as revealed by mitochondrial DNA analyses

In stark contrast to other species within the Salmonidae family, phylogeographic information on European grayling, Thymallus thymallus, is virtually nonexistent. In this paper, we utilized mitochondrial DNA polymerase chain reaction-restriction fragment length polymorphism (mtDNA PCR-RFLP) and sequence variation to infer the postglacial dispersal routes of T. thymallus into and within northern Europe, and to locate geographically, potential evolutionarily distinct populations. Mitochondrial analyses revealed a total of 27 T. thymallus haplotypes which clustered into three distinct lineages. Average pairwise interlineage divergence was four and nine times higher than average intralineage divergence for RFLP and sequence data, respectively. Two European grayling individuals from the easternmost sample in Russia exhibited haplotypes more genetically diverged from any T. thymallus haplotype than T. arcticus haplotype, and suggested that hybridization/introgression zone of these two sister species may extend much further west than previously thought. Geographic division of the lineages was generally very clear with northern Europe comprising of two genetically differentiated areas: (i) Finland, Estonia and north-western Russia; and (ii) central Germany, Poland and western Fennoscandia. Average interpopulation divergence in North European T. thymallus was 10 times higher than that observed in a recent mtDNA study of North American T. arcticus. We conclude that (i) North European T. thymallus populations have survived dramatic Pleistocene temperature oscillations and originate from ancient eastern and central European refugia; (ii) genetic divergence of population groups within northern Europe is substantial and geographically distinct; and (iii) the remainder of Europe harbours additional differentiated assemblages that likely descend from a Danubian refugium. These findings should provide useful information for developing appropriate conservation strategies for European grayling and exemplify a case with a clear need for multinational co-operation for managing and conserving biodiversity.     

汉江支流堵河鱼类群落结构及多样性

基于堵河2018年6月-2019年5月渔获物,分析了鱼类群落组成及变化、优势种以及群落多样性时空分布特征,讨论了外界环境扰动作用对鱼类群落结构和生物多样性的影响.结果 表明:调查期间共采集鱼类38种,分属4目8科,其中鲤形目鱼类最多(26种),占总种数的68.4％.群落优势种为鳙(Aristichthys nobili...     

长江上游支流南广河的鱼类多样性及资源现状

南广河是长江上游一级支流, 为全面了解该河流的鱼类多样性, 作者于2017年11月至2018年9月在南广河干流及支流28个采样点进行了6次调查, 共采集鱼类64种, 隶属于5目13科48属, 其中四川省重点保护鱼类有鲈鲤(Percocypris pingi)和岩原鲤(Procypris rabaudi) 2种, 长江上游特有鱼类17种, 列入《中国脊椎动物红色名录》的濒危和易危的鱼类有9种。南广河现有分布鱼类以小型种类为主, 宽鳍鱲(Zacco platypus)和鲤(Cyprinus carpio)为优势种。南广河鱼类多样性总体较高, Margalef丰富度指数、Shannon-Wiener多样性指数、Simpson优势度指数及Pielou均匀度指数分别为6.57、3.10、0.93、0.74; 中游河段的鱼类种类和数量较丰富, 分别占渔获物总种类和总数量的65.63%和28.98%; 支流镇舟河的鱼类种类和数量也较丰富, 分别占37.50%和20.48%。南广河不同河段的鱼类种类组成具有明显差异, 大坝建设和过度捕捞可能影响了鱼类分布并导致其资源量下降。     

Finding a new form of the grayling Thymallus arcticus (thymallidae) in the basin of lake baikal

A dwarf form of the Arctic grayling Thymallus arcticus, inhabiting a group of small lakes at the origin of the Yakchii stream, which flows into the Verkhnyaya Angara River (basin of Lake Baikal), has been found in the northeastern watershed of the Baikal and Lena basins. The form is similar to upper Lena populations in body coloration and the pattern of dorsal fin. Our comparison by meristic characters indicated that the grayling of the Yakchii Lakes is more similar to the fish from Kutima River (basin of the upper courses of the Lena River) than to the black Baikal grayling T. arcticus baicalensis. The presence in Lake Baikal of a population similar to upper Lena graylings may have three causes: (1) possible drainage from Baikal to the pra-Lena via ancient valleys of the Barguzin and the Upper Angara; (2) appearance of transit zones as a result of glacial or tectonic events during the periods of watershed development between the Baikal and Lena basins; (3) the upper Lena grayling could be an endemic of the Baikal basin which was replaced by graylings penetrating from the Yenisei basin and remained in the form of relic populations in the upper courses of certain tributaries of the northern and northeastern parts of Lake Baikal.     

Late Pleistocene and Holocene development of the felid fauna (Felidae) of Europe: a review

In the fossil deposits of the Late Pleistocene ( c . 115 000–11 500 years ago), five felid species are recorded in Europe: the wildcat Felis silvestris , Eurasian lynx Lynx lynx , Iberian lynx Lynx pardinus , leopard Panthera pardus and cave lion Panthera leo spelaea . In the Holocene, Europe was colonized by F. silvestris , L. lynx and L. pardinus as well as the lion Panthera leo . The status of P. pardus in post-glacial Europe is unknown. So far, only sparse records indicate that P. pardus survived into the early Holocene. During the Late Glacial, both L. lynx and L. pardinus occurred on the Iberian Peninsula. However, from the Holocene, only the Iberian lynx is recorded in this region. There are subfossil records that indicate that L. pardinus also occurred in central and western France until c . 3000 years ago. Surprisingly, with reservations on the determination of the bones (by J. Altuna), both lions and cave lions seem to be recorded in the Iberian Peninsula in the Late Glacial. There are published records of the lion P. leo in the northern Iberian Peninsula from the early Holocene. However, its presence in Europe on the basis of subfossil records was proven initially from the Atlantic period. In Ponto-Mediterranean regions of Europe, the lion is recorded from the Atlantic to the younger sub-Atlantic.     

Rapid formation of distinct hybrid lineages after secondary contact of two fish species (Cottus sp.)

Homoploid hybridization after secondary contact between related species can lead to mixtures of genotypes which have the potential for rapid adaptation to new environmental conditions. Here, we focus on a case where anthropogenic changes within the past 200 years have allowed the hybridization between two fish species (Cottus rhenanus and Cottus perifretum) in the Netherlands. Specifically, we address the question of the dynamics of the emergence of these hybrids and invasion of the river systems. Using a set of 81 mostly ancestry-informative SNP markers, as well as broad sample coverage in and around the area of the initial contact, we find a structured hybrid swarm with at least three distinct hybrid lineages that have emerged out of this secondary contact situation. We show that genetically coherent groups can occur at geographically distant locations, while geographically adjacent groups can be genetically different, indicating that some form of reproductive isolation between the lineages is already effective. Using a newly developed modelling approach, we test the relative influence of founding admixture, drift and migration on the allele compositions of the sampling sites. We find that the allele frequency distributions can best be explained if continued gene flow between the parental species and the hybrid lineages is invoked. Genome mapping of the invasive lineage in the Rhine shows that major chromosomal rearrangements were not involved in creating this distinct lineage. Our results show that hybridization after secondary contact can quickly lead to multiple independent new lineages that have the capacity to form hybrid species.