Siberian Taimen Research Articles

РЕТРОСПЕКТИВНЫЙ АНАЛИЗ ИХТИОФАУНЫ РЕКИ ТОМЬ В ПРЕДДВЕРИИ СТРОИТЕЛЬСТВА КРАПИВИНСКОГО ВОДОХРАНИЛИЩА

The resumption of design and survey work for the construction of the Krapivinsky Hydroelectric Power Plant on the Tom River has necessitated the assessment of the current state of its fish resources and called for making the prediction of their transformation in the event of the hydroelectric complex being put into operation. In the early 20th century, the Tom River was classified as a salmonid habitat. At that time, such valuable commercial species as the Siberian taimen Hucho taimen, blunt-snouted lenok Brachymystax tumensis , tugun Coregonus tugun, humpback whitefish Coregonus pidschian, Nickolsky’s grayling Thymallus nikolskyi , nelma Stenodus leucichthys nelma, muksun Coregonus muksun, and peled Coregonus peled were permanent residents. Sturgeons, such as the Siberian sturgeon Acipenser baerii and sterlet Acipenser ruthenus, were also abundant. Currently, out of these species, grayling, occasionally taimen and lenok are caught in the Tom River; the common roach Rutilus rutilus , European perch Perca fluviatilis, Siberian dace Leuciscus baicalensis and Eurasian ruffe Gymnocephalus cernuus comprise 95 % of all fish caught. If construction of the Krapivinsky Reservoir on the Tom River is completed and it is put into operation, a deep-water, slow-flowing “lake-type” water body will be created. The river bed will be blocked, so semi-anadromous fish species, many of which are listed in the Red Data Book-such as Siberian sturgeon, sterlet and nelma,-will disappear. A decrease in the abundance of grayling, taimen and lenok, already low in number, should also be expected. These fish species winter in the pits, some of them migrate to the Ob River, so, after passing the spillway, they will not be able to return upstream to the spawning grounds. The abundance of lake and lake-river species is expected to increase, among them the common roach, dace Leuciscus leuciscus , European perch, Prussian carp Carassius gibelio (introduced locally, subsequently self-dispersed), as well as common bleak Alburnus alburnus and sunbleak Leucaspius delineates (accidental invaders). In the future, it is possible to make an attempt to introduce peled to the upper basin of the Krapivinsky Reservoir. There is a prospective threat of the Chinese sleeper Perccottus glenii spreading in the upcoming reservoir, which can severely undermine its fish stocks.

Максимальная масса тайменя сибирского Hucho taimen (Pallas) в ареале

In most western regions, Siberian taimen has become a rarity in its range. At present, only a few refugiums of the Siberian and Far Eastern rivers still have groups of Siberian taimen, where fish of the maximum size are recorded. In the east of its range, the rivers that flow into the southern part of the Sea of Okhotsk: The Amur, Uda and Tugur, are the few areas where the Siberian taimen groups are still preserved in good condition in uninhabited places. On the example of p. Tugur (Tuguro-Chumikansky district of the Khabarovsk Territory, Sea of Okhotsk), where there are no roads and a small population, the authors studied the local grouping of Siberian taimen, where individuals of maximum size are still not uncommon. The remaining areas of the range are considered according to scientific publications. Fish of the maximum size are very rare, which is logical: the number of extreme values of the size-age range is minimal. In 2007-2018, in the Tugur River, individuals aged 6-10 years were the maximum (27.6%), and 31-35 years – the minimum (0.9%) of the age range. The archives of the sport fishing base in the Tugur River basin for 2008-2020 showed that the maximum body length of the Siberian taimen was 165 cm, and the maximum body weight was 51.12 kg. Neither in the era of black-and-white photography, nor in the era of video, there is no documentary evidence of the Siberian taimen with a body length of more than 170 cm.

Variability of Siberian Taimen Hucho taimen (Salmonidae) of The Amur River

The morphological variability of nine characters in six samples of Siberian taimen Hucho taimen from the Amur River was studied. The differences in the level of fluctuating asymmetry of fish from different tributaries are small, which indicates the similarity of the conditions of embryonic and early postembryonic development; significant differences between the samples were noted only in six cases. The maximum fluctuations in the coefficient of variation are characteristic for the number of postorbital bones and channels of the seismosensory system on the 1st postorbital bone; the minimum, for the number of soft rays in the pectoral fins and channels of the seismosensory system on the preopercular bones. The largest sum of the variation coefficients values for individual characteristics differs in the sample from the Bikin River; the smallest, the Limuri River. These difference positively correlates with the length and area of ​​the basin of these tributaries. A regular decline in the mean values in the fish sampled at increasing distance from the mouth of the Amur River concerns only the number of postorbital bones. Clustering according to the mean values ​​of the features, revealed that the samples form three clusters: (1) the rivers Bol’shaya Ussurka and Tyrma (2nd order tributaries, the farthest from the Amur mouth), (2) the Limuri River (the least distant from the Amur mouth), 3) the rivers Anyui, Khor and Bikin (geographically close populations). Revealed features may indicate the similarity of the conditions of early development and the likelihood of gene exchange between the last three groups.

First results of acoustic tags using for studies of migrations of siberian taimen Huho taimen (Salmonidae) in the Tugur River basin (northwestern Okhotsk Sea)

Method of acoustic tagging of large-sized fish in a medium river is successfully tested for the case of siberian taimen Hucho taimen in the Tugur River. Algorithm of fish anesthesia and acoustic tag input into its body cavity is developed. For successful tagging, total duration of the process, including anesthesia, should not exceed 5 minutes. The best results of tagging are obtained for fish with a body length of 110–130 cm, which tolerate anesthesia easily. In 2017–2019, 25 out of 29 tagged fish were registered by acoustic equipment that indicates high efficiency of the method (86.2 %). Distance from the release point to the point of tag registration varied from 0.2 to 39.8 km. Some fish crossed almost completely the buoy-controlled section of the river that indicates a rather high migration potential of siberian taimen. On the background of high individual diversity of migration activity, two principally different behavioral strategies are distinguished — «residents» staying in one place up to 2 months and «nomads» migrating to a distance up to 30 km per day. The radius of taimen migration increases usually in May and September and decreases in August. The seasonal increasing is associated with feeding migrations: taimen feed on downstream juveniles of chum salmon Oncorhynchus keta and prespawning minnows Rhynchocypris lagowskii in May and on chum adults migrating to spawning grounds in September. During twilight and at night, the migrations are usually more active, but they are less visible and shorter in the morning and afternoon. Correspondingly, the main feeding of taimen is assumed in the twilight and dark time, whereas a supporting feeding in the daytime.

Some Features of Biology of the Siberian Taimen Hucho taimen (Salmonidae) from the Tugur River Basin

Data on the size-age and sex structure, as well as the magnitude, of Siberian taimen Hucho taimen population from the Tugur River basin are presented.

Invasiveness screening of non‐native fishes for the middle reach of the Yarlung Zangbo River, Tibetan Plateau, China

AbstractThe aim of this study was to identify potentially invasive non‐native freshwater fishes in the middle reach of the Yarlung Zangbo River, Tibetan Plateau (China), using the Aquatic Species Invasiveness Screening Kit (AS‐ISK), as decision‐support tool. Based on independent evaluations of 24 non‐native freshwater fishes, receiver operating curve analysis identified a threshold score of ≥29 for distinguishing species likely to pose a high risk of becoming invasive from species likely to pose low‐to‐medium risk (<29) in the risk assessment area. Nine species were categorized as “high risk”: goldfish Carassius auratus, topmouth gudgeon Pseudorasbora parva, brook trout Salvelinus fontinalis, Oriental weatherfish (a.k.a. dojo gudgeon) Misgurnus anguillicaudatus, Siberian taimen Hucho taimen, common carp Cyprinus carpio, peled Coregonus peled, western mosquitofish Gambusia affinis, and Chinese rice fish Oryzias sinensis. The three lowest scoring species were Arctic cisco Coregonus autumnalis, Wuchang bream Megalobrama amblycephala, and Chinese ice fish Neosalanx taihuensis, which are unlikely to be invasive because they are unable to complete their life cycle in the risk assessment area. Climate change assessments scores increased or remained the same for warm‐water species and decreased for coldwater species. This study was the first application of AS‐ISK in western China, and the results suggest that AS‐ISK is a useful and valid tool for identifying potentially invasive risk aquatic species in China.

Complete Mitochondrial Genomes of the Cherskii's Sculpin Cottus czerskii and Siberian Taimen Hucho taimen Reveal GenBank Entry Errors: Incorrect Species Identification and Recombinant Mitochondrial Genome.

The complete mitochondrial (mt) genome is sequenced in 2 individuals of the Cherskii’s sculpin Cottus czerskii. A surprisingly high level of sequence divergence (10.3%) has been detected between the 2 genomes of C czerskii studied here and the GenBank mt genome of C czerskii (KJ956027). At the same time, a surprisingly low level of divergence (1.4%) has been detected between the GenBank C czerskii (KJ956027) and the Amur sculpin Cottus szanaga (KX762049, KX762050). We argue that the observed discrepancies are due to incorrect taxonomic identification so that the GenBank accession number KJ956027 represents actually the mt genome of C szanaga erroneously identified as C czerskii. Our results are of consequence concerning the GenBank database quality, highlighting the potential negative consequences of entry errors, which once they are introduced tend to be propagated among databases and subsequent publications. We illustrate the premise with the data on recombinant mt genome of the Siberian taimen Hucho taimen (NCBI Reference Sequence Database NC_016426.1; GenBank accession number HQ897271.1), bearing 2 introgressed fragments (≈0.9 kb [kilobase]) from 2 lenok subspecies, Brachymystax lenok and Brachymystax lenok tsinlingensis, submitted to GenBank on June 12, 2011. Since the time of submission, the H taimen recombinant mt genome leading to incorrect phylogenetic inferences was propagated in multiple subsequent publications despite the fact that nonrecombinant H taimen genomes were also available (submitted to GenBank on August 2, 2014; KJ711549, KJ711550). Other examples of recombinant sequences persisting in GenBank are also considered. A GenBank Entry Error Depositary is urgently needed to monitor and avoid a progressive accumulation of wrong biological information.

Seasonal home range shifts of the Siberian taimen (Hucho taimenPallas 1773): Evidence from passive acoustic telemetry in the Onon River and Balj tributary (Amur River basin, Mongolia)

Hucho taimen, the world's largest salmonid, is a potadromous species that is listed as endangered in Mongolia. While mature individuals are known to have extended longitudinal movements of over 90 km along main river channels, details of the seasonal movements and residency of individuals within and between tributary habitats have been largely undocumented. Therefore, the current research aimed to detect and quantify the seasonal distances moved by adult taimen (65–96 cm; n = 10) within and between the Onon River (Amur River basin) and a major tributary (Balj) over 12 months using passive acoustic telemetry. The median distance moved by taimen in spring was 17.4 km (n = 6), in summer 9.1 km (n = 4), autumn 4.7 km (n = 9) and winter 0.4 km (n = 8). However, there were no statically significant differences amongst these median seasonal home range sizes. Two taimen traversed between the Onon River and the Balj tributary during the study period, recording overall home ranges of 44.5 km and 126.1 km. One of these individuals moved twice, exiting the tributary in autumn and returning again in spring where it remained for 36 days, while the second taimen moved only once into the tributary in spring and re-entered the main channel in late summer after 85 days. Another two taimen entered surrounding smaller tributaries and recorded home ranges of 26.1 km and 29.2 km, while all remaining individuals were detected moving only within the waterway where they were originally captured and released (0.8–20.1 km). Taimen movements within tributaries such as the Balj can be extensive (<60 km), as they provide access to important spawning, feeding and overwintering habitats as well as refuge from adverse thermal and hydrological conditions. Thus to enhance population recovery, it is essential that current and future management and conservation efforts include preserving or restoring the ecological integrity and hydrological connectivity of these critical tributaries and the main river channel throughout the Onon and Amur River basins and across the remaining distribution of this endangered species.

On the catch of Siberian taimen in the Lower Kama reservoir

In May 2014 in the aft bay of Votkinsk Hydraulic Power Station in illegal catches, two specimens of taimen delivered for study were found. Measurements and description of one of specimens was performed. Catch of taimen can indicate that, in the Lower Kama reservoir, a small population of this species has retained.

First mtDNA sequencing of Volga and Ob basin taimen Hucho taimen: European populations stem from a late Pleistocene expansion of H. taimen out of western Siberia and are not intermediate to Hucho hucho.

New concatenated mtDNA sequences (three genes; n = 22) of Siberian taimen Hucho taimen primarily from west Siberian and European regions of the species' range were added to 12 previously published sequences to provide a phylogeographic overview of the species. European samples show only very minor divergence from west Siberian populations, supporting a late Pleistocene expansion from Siberia into the Urals, with no particular relation to the Danube River basin huchen Hucho hucho as once hypothesized. The disjunct distribution of the genus is most likely based on an early Pleistocene vicariant event.

Complete mitochondrial genome of Siberian taimen, Hucho taimen not introgressed by the lenok subspecies, Brachymystax lenok and B. lenok tsinlingensis

The complete mitochondrial genomes were sequenced in two individuals of Siberian taimen Hucho taimen. The sizes of the genomes were 16,833 and 16,914 in the two isolates, representing two haplotype groups previously detected. The gene arrangement, base composition, and size of the two sequenced genomes are very similar to the H. taimen genome previously published (HQ897271), but did not contain introgressed fragments from two subspecies of lenok, Brachymystax lenok and B. l. tsinlingensis.

Mitochondrial DNA Variation and Introgression in Siberian Taimen Hucho taimen

Siberian taimen Hucho taimen is the largest representative of the family Salmonidae inhabiting rivers of northern Eurasia. The species is under intensive aquaculture activity. To monitor natural taimen populations we have sequenced a portion (8,141 bp) of the mitochondrial (mt) genome in 28 specimens of H. taimen from six localities in the Amur River basin. Nucleotide variability is low (π = 0.0010), but structured in two divergent haplotype groups. A comparison of the data with the GenBank H. taimen mt genome (HQ897271) reveals significant differences between them in spite of the fact that the fish specimens come from neighboring geographical areas. The distribution of divergence is non-uniform with two highly pronounced divergent regions centered on two genes, ND3 and ND6. To clarify the pattern of divergence we sequenced the corresponding portion of the mt genome of lenok Brachymystax tumensis and analyzed the GenBank complete mt genomes of related species. We have found that the first and second divergent regions are identical between the GenBank H. taimen and two lenok subspecies, B. lenok and B. lenok tsinlingensis, respectively. Consequently, both divergent regions represent introgressed mtDNA resulting from intergeneric hybridization between the two lenok subspecies and H. taimen. Introgression is, however, not detected in our specimens. This plus the precise identity of the introgressed fragments between the donor and the recipient GenBank sequence suggests that the introgression is local and very recent, probably due to artificial manipulations involving taimen – lenok intergeneric hybridization. Human-mediated hybridization may become a major threat to aquatic biodiversity. Consequently we suggest that due attention needs to be given to this threat by means of responsible breeding program management, so as to prevent a potential spread of hybrid fishes that could jeopardize the resilience of locally adapted gene pools of the native H. taimen populations.

Current status and catch of Siberian taimen (Hucho taimen) in the lower Amur River

Siberian taimen, Hucho taimen (Pall.), is a common species in the Khabarovsk region, and it occurs nearly throughout the Amur River watershed (Pacific Ocean basin) and the upper tributaries of the Lena River (Arctic Ocean basin). Taimen only inhabits two coastal rivers - the Uda and Tugur. Commercial fishing for taimen has never been prohibited in the lower and central Amur River drainage basin. This species is a valuable food fish, and is especially attractive to recreational and sport fishing. Before the Second World War, taimen catches in the lower part of the Amur River were as high as 20 tons per year, but during the war, all bans on fishing were lifted, and the taimen catch increased to 100 tons per year. The period that is probably the most revealing for estimating the taimen population in the lower Amur River watershed is 1946-1969 when harvests ranged from 15 to 35 tons. In the 1970s, taimen catches declined probably because water temperatures in the Amur River increased. In the 1980-2005 period, illegal fishing increased, commercial fishing decreased, and catch statistics became unreliable. The best taimen rivers now are located in unpopulated areas in the Amur River drainage basin and inaccessible upper regions of the Lena River drainage basin.

Spawning behaviour of Sakhalin taimen, Parahucho perryi, from northern Hokkaido, Japan

A video camera mounted in an underwater housing and remotely operated was used to monitor the behaviour of five different Sakhalin taimen (Parahucho perryi), females and attendant males spawning in three coastal tributary streams in Northern Hokkaido, Japan. Based on three complete and two incomplete spawnings, we describe in detail for the first time the complete spawning behavioural repertoire of this species. The Sakhalin taimen was originally placed within Hucho, then removed from that genus based on morphological, life history and molecular data. Our study supports that removal—none of the behavioural traits we recorded clustered Parahucho with Hucho uniquely. Similarities between the two genera were all plesiomorphic traits that are widespread throughout the salmonines. The immediate behaviour right after spawning was found to be a major difference between Hucho and Parahucho. Like female Oncorhynchus and Salmo, Sakhalin taimen females cover their eggs by beats of their tails immediately after spawning. This is different from the “rest, then cover” behaviour shown by Siberian taimen (Hucho taimen) as well as lenok (Brachymystax lenok), supporting again that the Sakhalin taimen be removed from Hucho and placed in its own genus.

Ecology of Siberian Taimen Hucho taimen in the Lake Baikal Basin

Taimen Hucho taimen historically inhabited most tributaries and littoral areas of Lake Baikal, in south central Siberia, where they supported subsistence and commercial fisheries. Logging, pollution, and overfishing have caused dramatic population declines or local extinction of most stocks. Most of what is known about this species has been published in eastern journals and therefore is not readily available to western scientists. New data collected during the 1980s and 1990s have been combined with other reports to provide an overview of the biology and life history of this species. Taimen are long-lived fish and can reach ages of 29 years and sizes up to 60 kg. Populations can either be strictly riverine or anadromous. Adults from both life histories ascend rivers in spring to spawn and feed, and less extensive migrations occur in fall to prey on spawning omul ( Coregonus autumnalis migratorius). Principal food items for age 1 and 2 taimen are macroinvertebrates, but young taimen quickly become piscivorous at age 2 when they consume mainly black Baikal grayling ( Thymallus arcticus baicalensis), and sculpins ( Taracottus kneri, Cottus kesslerij). Males reach sexual maturity at ages 7 to 8 and later for females at ages 8 to 9. Average egg production per female was about 22,000 eggs. Parasite burdens are heavy but composed of few species and mediated by prey items consumed. This fish is a highly-specialized predator and plays an indispensable role in the structure of fish communities in mountains and foothills. Taimen conservation in the Baikal region is impossible without adoption and implementation of a dedicated rehabilitation program that includes the protection of remaining populations and habitat, and possibly introduction of hatchery-reared fish in selected areas where habitat remains, but parental stocks are low.