Huso Dauricus Research Articles

Assessment of biological and productive parameters of female hybrids between the Volga sterlet (Acipenser ruthenus) and Amur kaluga (Huso dauricus). Part 2. Hybrids between kaluga females and sterlet males. Comparative characteristics of reciprocal hybrids

The second part (for the first part of the article, see No. 6, 2024) of the work describes the production indicators of fertile female hybrids between Kaluga females and sterlet males, and also provides a comparison with the previously described indicators of hybrids between sterlet females and Kaluga males. The study of the production parameters of reciprocal hybrids in the process of long-term formation of breeding stocks is of both scientific and practical interest. The purpose of the work is to evaluate the fish-breeding, biological and production characteristics of female hybrids, and the effectiveness of their use as promising objects for obtaining food caviar. The maturation periods, inter-spawning intervals, the weight of the eggs obtained and the weight of the eggs, fertility and oosomatic indices of 67 females of 5 age-related generations of reciprocal hybrids from the warmwater farm of the Primorsky Territory weighing from 17 to 35 kg, participating in 87 spawning campaigns from the age of 9 to 14–18 years, were studied. One of the generations is represented by real albinos of lemon-yellow color with red eyes and light caviar. The conducted studies have shown that the number of fertile females in different generations varies from 10 to 30%, but from 25% of females it was not possible to obtain eggs even once. Females begin to mature at the age of 9–12 years, the duration of maturation of all females of the same generation reaches 8–10 years. Most females skip 2–4 years between spawning or mature once. Caviar resorption in winter occurs in 17–42% of female hybrids. On average, during one spawning, females produce from 1,5 to 1,7 kg of eggs with an average weight of 23 mg of eggs. The production performance of hybrids is significantly lower compared to hybrids between beluga and sterlet (besters). Due to their biological characteristics and low productivity, reciprocal hybrids between Kaluga and sterlet are of greater scientific interest for genetic research than as producers of caviar. The cultivation of hybrids in order to obtain industrial volumes of caviar for food purposes is recognized as costly, ineffective and inexpedient.

Assessment of biological and productive parameters of female hybrids between the Volga sterlet (Acipenser ruthenus (Linnaeus, 1758)) and amur kaluga (Huso dauricus (Georgi, 1775)). Part 1

Some of the females of hybrids between sterlet and kaluga with different levels of ploidy turned out to be fertile, which came as a surprise to geneticists and fish farmers. The purpose of the work is to evaluate the fish-breeding, biological and production characteristics of female hybrids between a female sterlet and a male kaluga as possible objects for obtaining food caviar. The maturation periods, inter-spawning intervals, the weight of the eggs obtained and the weight of the eggs, fertility and oosomatic indices of 35 female sterlet×kaluga hybrids participating in 46 spawning campaigns from the age of 9 to 14–18 years were studied. The females are represented by the two most numerous generations in 2005 and 2007, weighing from 17 to 37 kg. The conducted studies have shown that the number of fertile females in these generations is low and amounts to 16–20% of the initial number of RВS. Females begin to mature at the age of 9–12 years, the duration of maturation of all females of the same generation reaches 8 years. Most females skip 2–4 years between spawning or mature once. In 17% of female hybrids, the resorption of mature eggs was noted in winter. On average, during one spawning, large females produce from 1.6 to 1.7 kg of eggs with an average weight of eggs of 18–23 mg with an output of eggs of 5–7% of body weight. The small number of females in the RВS, late and prolonged maturation, long inter-spawning intervals and low yield of eggs relative to body weight make the cultivation of hybrids between sterlet and Kaluga unprofitable and impractical for obtaining industrial volumes of food caviar.

Effects of ultrasound pretreatment on the enzymolysis of hybrid sturgeon (Huso dauricus × Acipenser schrenckii) protein and the structural, functional, and antioxidant properties of hydrolysates

In the current study, hybrid sturgeon hydrolysates were prepared using ultrasound (US) pretreatments for different periods (0, 15, 30, and 45 min) followed by an enzymolysis process using compound proteinase, and their structural, functional, and antioxidant properties were examined. The application of US pretreatments significantly increased the hydrolysis process. SDS-PAGE analysis revealed that as sonication time was increased, peptides with lower molecular weights were obtained. Based on US pretreatment time, hydrolysates demonstrated significant changes in free amino acids, solubility, emulsifying properties, surface hydrophobicity, and water-oil holding ability. Furthermore, US pretreatments had a significant impact on the antiradical activity (DPPH• and ABTS•+) at different hydrolysate concentrations. Partial least-squares regression (PLSR) analysis revealed a positive relationship between most hydrolysate properties and the degree of hydrolysis. These findings indicated that using US pretreatments would be a promising procedure for improving the functional, structural, and antioxidant properties of hybrid sturgeon hydrolysates, thereby expanding their application in the field of food processing.

InDel DNA Markers Potentially Unique to Kaluga Sturgeon Huso dauricus Based on Whole-Genome Resequencing Data

Sturgeons are ancient and endangered species whose populations have been greatly reduced over the past few centuries due to habitat destruction and overfishing for the production of expensive caviar. All sturgeon species are listed in CITES Appendix II to limit their trade; therefore, accurate species identification is crucial. In this study, we performed whole-genome resequencing of five sturgeon species, including Kaluga sturgeon (H. dauricus), Siberian sturgeon (A. baerii), Sterlet sturgeon (A. ruthenus), Russian sturgeon (A. gueldenstaedtii), and Amur sturgeon (A. schrenckii), to obtain species-specific InDel-based nucleotide sequences for Kaluga sturgeon. Through whole-genome screening within these five sturgeon species, we developed methods for the rapid identification of Kaluga sturgeon germplasm. Using dominant/co-dominant molecular markers designed for Huso dauricus, purebred or hybrid samples can be identified through a PCR reaction. These markers allow for the precise identification of Kaluga sturgeon lineages from at least seven sturgeon species (H. dauricus, A. schrenckii, A. ruthenus, A. baerii, A. gueldenstaedtii, A. stellatus, and H. huso) and their hybrids. This development is expected to have a positive effect on both the sturgeon trade and the conservation of sturgeon germplasm resources.

Consortiums «tumbleweeds» of the Amurskii liman

For the first time, the «tumbleweeds» – consortia of the Amur estuary were studied. The determinants of consortia are fragments of brown algae-macrophytes thalli and colonies of hydroid polyps, rolled up into a ball by currents, and the consorts are amphipods inhabiting it. It was show that the reason for the emergence of consortative relationships is the hydrological conditions of the estuary and features of it bottom landscape, under which amphipods are forced to seek shelter. In the diet of the kaluga Huso dauricus and Amur sturgeon Acipenser schrenckii in the Amur Estuary, amphipods were found together with plant remains, which indicates the feeding of sturgeons by consortia. Kaluga, in comparison with the Amur sturgeon, consumes such type food much more often and in greater quantities. Animals associated with the aggregation of dead algae and polyps play a significant role in the formation of the food base for sturgeons in the Amur Estuary.

Size and age structure and population of the kaluga Huso dauricus and the Amur sturgeon Acipenser schrenckii (Acipenseridae) in the Amur river

Based on research findings from 1963–2021 the analysis of size-age indicators, qualitative structure of populations and changes in the number of kaluga Huso dauricus and Amur sturgeon Acipenser schrenckii in the river was carried out. Amur. It is established that in the period from the 60s. last century to 2008–2011 in the kaluga and the Amur sturgeon in the Amur River, there was a reduction in the size range and number of age groups, the proportion of mature individuals, the level of replenishment of populations with juveniles and abundance. The main reason for these changes is INN fishing (illegal, unreported and unregulated). According to the results of research in 2021, it was revealed that the modern number of kaluga exceeded the figures of the 60s. last century. In the Amur sturgeon, the process of population growth has not yet reached the historical values noted in the 1960s–1970s, but exceeded the indicators of the 1980s and subsequent years. Despite the noted positive points, at present, the population of kaluga in the river. Amur is characterized by the smallest average size and age over 60 years of study. The situation is better for the Amur sturgeon, which is due to the lower interest of fishermen in this species and the large volume of release of its juveniles from sturgeon hatcheries (ORZ). The reason for the positive dynamics is the artificial reproduction that has been developing on the Amur over the past decade, as well as the introduced set of restrictions on the Pacific salmon fishery. To further increase the number of Kaluga and Amur sturgeon in the river. Amur, it is proposed to maintain the current volumes of artificial reproduction of sturgeons and extend the restrictive measures in the salmon fishery for at least the next 10 years.

Modern Data on the Distribution, Abundance and Qualitative Structure of the Populations of the Kaluga Huso dauricus and the Amur Sturgeon Acipenser schrenckii (Acipenseridae) in the Amur River and the Amur Estuary

Modern Data on the Distribution, Abundance and Qualitative Structure of the Populations of the Kaluga Huso dauricus and the Amur Sturgeon Acipenser schrenckii (Acipenseridae) in the Amur River and the Amur Estuary

Antioxidant Activities of Optimized Enzymatic Protein Hydrolysates from Hybrid Sturgeon (Huso dauricus × Acipenser schrenckii) Prepared Using Two Proteases

ABSTRACT The objective of this work was to optimize the hydrolysis conditions of hybrid sturgeon (Huso dauricus × Acipenser schrenckii) protein using flavourzyme and compound proteinase, and to evaluate the antioxidant activity of hydrolysates. The lyophilized flavourzyme hydrolysate (FH) and compound proteinase hydrolysate (CPH) with degree of hydrolysis of 18.16% and 19.35% under optimal conditions had 85.36% and 87.24% protein content, 89.19 and 96.97 g/100 g protein total amino acid content, 92.86% and 95.12% protein solubility, and 902.47 nm and 1025.76 nm particle size, respectively. The CPH had the highest DPPH and ABTS radical scavenging activities, which were 71.04 and 66.84% with IC50 at 2.85 and 3.37 mg/mL, respectively; while the FH had higher metal-chelating activity, which was 58.37% with IC50 at 24.81 mg/mL. The obtained hydrolysates have excellent antioxidant properties and could be used as food additives and natural substitutes for synthetic antioxidants compounds, particularly in food and pharmaceuticals.

Phosphorus Absorption and Excretion in Hybrid Sturgeon (Huso dauricus♀ X Acipenser schrenckii♂) Intubated with Different Ca/P Ratios

To study the effect of Ca/P ratio on the P and Ca absorption and excretion in hybrid sturgeon (Huso dauricus♀ X Acipenser schrenckii♂), five groups of fish were intubated with 100 mg P·kg−1 BW with the Ca/P ratios of 0:1, 0.25:1, 0.5:1, 1:1, and 2:1. Plasma P concentrations were significantly elevated at Ca/P ratios below 2:1, and the highest value was obtained at Ca/P ratio of 0.5:1. Plasma Ca content was significantly increased at the highest Ca/P ratio. Urine P excretion rate in the fish intubated with Ca/P ratio of 0.5:1 was significantly higher than that of the groups with Ca/P ratios of 0:1 and 2:1. The highest urea excretion rates were observed at Ca/P ratio of 0.5:1 and 1:1. The total P excretion at 48 h post intubation reached about 30 mg·kg−1 BW, which was recorded for the group with Ca/P ratio of 0.5:1. The present study showed that P absorption efficiency was improved in hybrid sturgeon at Ca/P ratio of 0.5:1, indicating that P inclusion level in sturgeon feed can be further optimized to reduce dietary P input and lower the excessive undigested P discharge into the rearing water.

Rhipidocotyle husi n. sp. and three known species of Bucephalidae Poche, 1907 from the East Asian Region: morphological and molecular data.

AbstractMorphological data and the first molecular data are provided for four species of the trematode family Bucephalidae Poche, 1907 from marine and freshwater teleost fish species of East Asia. A new species, Rhipidocotyle husi n. sp., was isolated from Huso dauricus from the Amur River, Russia. Adult worms of this species were distinguished from their congeners Rhipidocotyle illense and Rhipidocotyle kovalai by morphological analysis. Three other known species were identified: Bucephalus skrjabini and Prosorhynchus cf. squamatus were detected in Siniperca chuatsi from the Amur River and in Myoxocephalus spp. from the Okhotsk Sea, Russia, respectively, while Prosorynchoides karvei was extracted from Strongylura strongylura from Halong Bay, Vietnam. The 28S ribosomal DNA (rDNA)-based phylogenetic analysis showed that the new species formed a shared polytomy clade with Rhipidocotyle fennica. Phylogenetic analysis of all available molecular data showed that four genera, namely Rhipidocotyle, Bucephalus, Prosorynchoides and Prosorhynchus, are para- or polyphyletic. Molecular-based phylogenetic analysis of morphologically validated bucephalid species indicated that three genera – Rhipidocotyle, Bucephalus and Prosorynchoides – were monophyletic. The genus Prosorhynchus maintained paraphyly, and P. cf. squamatus was more closely related to Dollfustrema spp. than to other Prosorhynchus spp. These findings do not exclude the possibility that representatives of Dollfustrema and P. cf. squamatus belong to the same genus.

The full-length transcriptome sequencing of three sturgeons reveals the occurrence of whole genome duplication event.

Sturgeon is one of the ancient fish species with the fossil records over 200 million years ago. However, the sturgeon genomes are rather complicated, owing to several rounds of genome polyploidizations, which makes it difficult to assemble a high quality genome so that only a few studies analyze their whole genome evolutions (WGDs). This study applied the PacBio sequencing technology to sequence the full-length transcriptomes of blood samples of octoploid Huso dauricus, octoploid Acipenser schrenckii and tetraploid Acipenser stellatus. A total of non-redundant 33,407 transcript assemblies of the three sturgeons were finally generated and fully annotated with different gene function databases, as well as the predictions of simple sequence repeats, transcription factors and long non-coding RNAs. Data valuation exhibited that annotations of the three transcriptomes had the higher quality than those of the previously sequenced sturgeon genomes. A phylogeny of eight typical sturgeons was constructed using the low copy genes, which illustrated that Acipenser and Huso might share a single origin. The sturgeon WGDs were parallelly timed by calculating the divergence times of 2-member gene clusters and heterozygous-SNP-carried genes, which both suggested the occurrence of the WGDs later than 150 mya. The full-length transcriptome sequences were supposed to be the reliable reference data for the study of sturgeon.

Structural analysis and anti-cancer activity of low-molecular-weight chondroitin sulfate from hybrid sturgeon cartilage

Low-molecular-weight chondroitin sulfate (CS) has attracted widespread attention due to its better bioavailability and bioactivity than native CS. In this study, a low-molecular-weight CS (named SCS-F2) was prepared from hybrid sturgeon (Acipenser schrenckii × Huso dauricus) cartilage by enzymatic depolymerization with high in vitro absorption and anti-cancer activity. The structure of SCS-F2 was characterized and the in vivo biodistribution and colorectal cancer prevention effect was investigated. The results revealed that SCS-F2 consisted of 48.84% ΔDi-6S [GlcUAβ1-3GalNAc(6S)], 32.11% ΔDi-4S [GlcUAβ1-3GalNAc(4S)], 16.05% ΔDi-2S,6S [GlcUA(2S)β1-3GalNAc(6S)] and 3.0% ΔDi-0S [GlcUAβ1-3GalNAc]. Animal study showed that the SCS-F2 could be effectively absorbed and delivered to the tumor site and significantly prevented the growth of HT-29 xenograft by inhibiting cell proliferation and inducing apoptosis without showing any negative effect to normal tissues. Therefore, SCS-F2 could be developed as a potential nutraceutical to protect against colorectal cancer.

Spoilage microbes’ effect on freshness and IMP degradation in sturgeon fillets during chilled storage

Bacterial spoilage is an important reason causing freshness deterioration of fish during postmortem storage. The aim of this study is mainly to investigate the role of bacteria in freshness and the degradation of inosine 5′-monophosphate (IMP) as well as nucleotide derived values in chilled sturgeon (hybrid, Acipenser schrenckiid × Huso dauricus) fillets using a microbial reduction pretreatment. During storage at 4 or -1 °C, lower total bacterial count and total volatile base nitrogen in the treated samples was observed when compared to the control samples. But very close K, Ki value and IMP was observed in both groups, although higher IMP was recorded at day 6 and 9 at 4 °C. In later storage period, accelerated decrease of inosine (Ino) and increment of hypoxanthine (Hx) occurred in two control groups, resulting in a rapid increase of G and H values, significant higher than the treated groups. Six predominant spoilage bacteria (Acinetobacter johnsonii, Acinetobacter lwoffii, Shewanella baltica, Pseudomonas Fragi, Pseudomonas koreensis and Pseudomonas antarctica) were isolated from the sturgeon fillets during storage. Based on the results of respective co-cultivation of IMP with the six species, only Acinetobacter johnsonii had ability to degrade IMP when reached a high density of 2.84 × 109 CFU/mL. Results suggested that microbial reduction pretreatment could better the freshness of chilled sturgeon fillet. Comparing to endogenous IMPase, spoilage bacteria probably played a small role in IMP degradation, but affected considerably the decomposition of Ino to Hx.

The Species Composition and Distribution of Fish and Prawn in the Bed of the Lower Amur River

The distribution of fish and prawn in the bed of the lower Amur River (within 40–960 km from the mouth) is described based on the results of a beam-trawl survey (57 trawl taw at depths of 1.5–23.0 m) conducted in September and October 2003. A total of 2584 ind. of 22 fish species and 1077 ind. of one invertebrate species (the prawn Palaemon modestus) were caught. The most frequently occurring fish species were members of the orders Cypriniformes (13 species) and Siluriformes (4 species). The total number of benthic and demersal fish was estimated at 32.161 million ind.; the total number of prawn was estimated at 4.887 million ind. The most abundant fish were two commercial catfish species: the Brazhnikov’s catfish Tachysurus brashnikowi (estimated at 16.26 million fish) and the Chinese catfish T. sinensis (4.32 million fish). The abundance of both fish and prawn increased by many times towards the mouth of the Amur, which correlated with the increasing biomass of the benthic food supply in the same direction. The total biomass of fish and prawn equaled 583.8 and 8.8 t, respectively. The fish biomass varied in the 0.012–2.572 g/m2 range (with an average of 0.450 ± 0.270 g/m2) and the prawn biomass varied within 0.005–0.044 g/m2 (0.021 ± 0.012 g/m2). The major portion of the fish biomass (82.4%) was recorded mainly from the lower reaches of the Amur River (40–400 km from the river mouth); the entire prawn biomass was concentrated in the lower reaches (50–150 km from the mouth). The following fish species were dominant in catches in terms of biomass: Chinese catfish (32.9%), Brazhnikov’s catfish (24.0%), Chinese lizard gudgeon Saurogobio dabryi (12.6%), Ussuri catfish T. ussuriensis (9.7%), Amur whitefin gudgeon Romanogobio tenuicorpus (7.8%), Amur sturgeon Acipenser schrenckii (5.6%), Siberian gudgeon Gobio cynocephalus (2.4%), and kaluga Huso dauricus (0.6%).

Species composition and distribution of fishes and prawns in the Amur River channel

istribution of fishes and prawns in the Amur River (40–960 km from the mouth) is described on results of the beam-trawl survey conducted in September-October, 2003 (57 trawl stations at the depth of 1.5–23.0 m). In total, 2584 ind. of 22 fish species and 1077 ind. of 1 invertebrate species (prawn Palaemon modestus) were caught. The highest species richness was registered for orders Cypriniformes (13 species) and Siluriformes (4 species). The fish and prawn stocks were evaluated as 32.161 . 106 ind. (583.8 t) for bottom and near-bottom fish and 4.887 . 106 ind. (8.8 t) for prawns. Two commercial fish species were the most abundant: catfishes Tachysurus brashnikowi (16.26 . 106 ind. or 32.9 % of total biomass) and T. sinensis (4.32 . 106 ind. or 24.0 % of total biomass); other 6 fish species with considerable biomass were lizard gudgeon Saurogobio dabryi (12.6 %), ussuri catfish T. ussuriensis (9.7 %), amur white-pinned gudgeon Romanogobio tenuicorpus (7.8 %), amur sturgeon Acipenser schrenckii (5.6 %), amur gudgeon Gobio cynocephalus (2.4 %), and kaluga Huso dauricus (0.6 %). Distribution density varied in the range of 0.01–2.57 g/m2 (on average 0.45 ± 0.27 g/m2) for fish and 0.005–0.044 g/m2 (0.021 ± 0.012 g/m2) for prawns. Abundance of both fish and prawns increased multifold towards the Amur mouth that correlated with increasing of forage benthos biomass in the same direction. So, the main portion of fish biomass (82.4 %) was distributed in the Amur River downstream (40–400 km from the mouth) and the prawn stock was concentrated completely in its lowermost part (50–150 km from the mouth).

P.683 First episode psychosis outcome trajectories: The role of functioning and neurocognition

China has recently become the leader country for sturgeon aquaculture and caviar production, deeply changing the traditional geography of this market in few years. As a consequence, some species originating from the Far East Asia increased their economic relevance, joining the ones traditionally harvested for caviar. In this context, the possibility to reliably and promptly identify these species on the market has increasing importance for the enforcement of control actions against illegal trade or commercial frauds. The present study focuses on two commercially relevant species, massively reared in China not only as pure species but also as reciprocal hybrids: the Amur (Acipenser schrenckii) and Kaluga (Huso dauricus) sturgeons. We assess the identification power of two putatively diagnostic markers isolated from two predicted introns of the nuclear coding gene Ribosomal Protein L8. The markers were tested on tissue or caviar of 508 individuals of the two species and 31 hybrids. In order to compare results across loci, most individuals were also checked at two already published microsatellite markers, with a good, even if incomplete, identification efficiency for the two species. No marker showed fixed alternative alleles between Amur and Kaluga sturgeons, confirming the difficulty of distinguishing these two sympatric species in spite of the marked morphological differences and the consequent classification into different genera. So far, the multi-locus panel here used represents the more effective tool for the genetic identification of pure Amur and Kaluga sturgeons and resulted to be fully efficient to validate caviar and tissues obtained from hybrids between the two species.

Olfactory flow in the sturgeon is externally driven

Fluid dynamics plays an important part in olfaction. Using the complementary techniques of dye visualisation and computational fluid dynamics (CFD), we investigated the hydrodynamics of the nasal region of the sturgeon Huso dauricus. H. dauricus offers several experimental advantages, including a well-developed, well-supported, radial array (rosette) of visible-by-eye olfactory sensory channels. We represented these features in an anatomically accurate rigid model derived from an X-ray scan of the head of a preserved museum specimen. We validated the results from the CFD simulation by comparing them with data from the dye visualisation experiments. We found that flow through both the nasal chamber and, crucially, the sensory channels could be induced by an external flow (caused by swimming in vivo) at a physiologically relevant Reynolds number. Flow through the nasal chamber arises from the anatomical arrangement of the incurrent and excurrent nostrils, and is assisted by the broad, cartilage-supported, inner wall of the incurrent nostril. Flow through the sensory channels arises when relatively high speed flow passing through the incurrent nostril encounters the circular central support of the olfactory rosette, decelerates, and is dispersed amongst the sensory channels. Vortices within the olfactory flow may assist odorant transport to the sensory surfaces. We conclude that swimming alone is sufficient to drive olfactory flow in H. dauricus, and consider the implications of our results for the three other extant genera of sturgeons (Acipenser, Pseudoscaphirhynchus and Scaphirhynchus), and for other fishes with olfactory rosettes.

Age structure of juvenile Amur sturgeon Acipenser schrenckii and kaluga Huso dauricus in the Fuyuan reach of the Amur River, Northeast China

Amur sturgeon Acipenser schrenckiii Brandt 1869 and kaluga Huso dauricus (Georgi 1775) are critically endangered species with populations showing significant decline from historical levels due to overexploitation, yet little is known about their population structure. Adults are not often captured in the Fuyuan reach of the Amur River, Heilongjiang Province, Northeast China, and the government prioritizes juvenile sturgeon management. This study was conducted to determine the age and length/weight relationships of juvenile Amur sturgeon and kaluga in the Fuyuan reach of the Amur River. We estimated age using pectoral fin spine sections obtained from 65 juvenile Amur sturgeon and 50 juvenile kaluga. We compared the age estimates from two readers, and found 100% between-reader agreement in 67.7% of the Amur sturgeon and 64.0% of the kaluga. The majority of differences in estimated age were within 1 year. Length/weight relationships (LWR) were calculated, and the LWR of the Amur sturgeon and kaluga were W = 0.0025L3.106 (r2 = 0.966）and W = 0.0022L3.175 (r2 = 0.989), respectively. Our study provides the age structure and LWR in juveniles of two sturgeon species.

Diet of farm‐escaped sturgeon in the Yangtze River

The diet of farm-escaped sturgeon accidentally introduced into the Yangtze River ecosystem was investigated from samples collected over 10 days. The fish had consumed adequate quantities of natural food, with prey type related to fish body size. The fish were categorized according to their primary dietary component: demersal fish were most common prey of kaluga Huso dauricus and H. dauricus × Acipenser schrenckii hybrids of total length 120.3–188.7 cm. Shrimp Macrobrachium nipponensis made up the major portion of the diet of H. dauricus × A. schrenckii and Acipenser baerii × A. schrenckii of total length 91.1–106.8 cm. Gammarid amphipods were consumed by A. baerii × A. schrenckii of total length 35.0–81.2 cm. The body length of prey was proportional to the fork length of the sturgeon, Y = 0.19X-9.46, R2 = 0.997. Escaped sturgeon had travelled at least 898 km downstream from the point of escape in the Yangtze River and were feeding on native macrobenthos and demersal fish.

Sturgeon meat and caviar production: Global update 2017

This paper presents an update on the global sturgeon and caviar production until 2017, attempting to continue previous efforts on summarizing the global trends in these markets. For the current update, an expanded data base was derived from questionnaires sent to 86 regional contacts in 46 countries, mostly farmers or scientists, and personal interviews. A total of 2,329 commercial sturgeon farms were recorded by 2017 globally, which represented an increase by 7% compared to 2016. Of these farms 54% were located in China, followed by Russia (24%), the Middle East (8%), the Far East (7%) and Europe (6%). Among the rearing technologies flow-through (FT) systems (36%) were most common, followed by recirculation aquaculture systems (RAS) (21%), cages (18%), mix FT/RAS (11%), and ponds (6%). In total the aquaculture sturgeon biomass production peaked at about 129,608 t in the year 2015, with a decline to 119,979 t in 2016, and to 102,327 t in 2017. China contributed about 79,638 t to the overall production in 2017, followed by Russia (6,800 t), Armenia (6,000 t), Iran (2,514 t), and 52 other countries with less than 1,000 t each. This production exceeded the fishery harvest during the 1970–1980s by more than four times. Of the 25 species of Acipenseridae, 13 pure species and four hybrids were farmed for meat with Acipenser baerii dominating production in 2016 with a share of 39.5%, followed by the two hybrids, Huso dauricus × Acipenser schrenckii and A. baerii × A. schrenckii (35.6%), as well as A. schrenckii (10.2%). Global caviar production increased during the last years and the production for the year 2017 amounted to approximately 364 t. China contributed more than 100 t to the overall production in 2017, followed by Russia (49 t), Italy (43 t), France (37 t) and diverse other countries. The species composition in caviar production in 2016 was dominated by A. baerii (31% of the total volume), followed by Acipenser gueldenstaedtii (20%), the hybrid H. dauricus × A. schrenckii (13%), and Acipenser transmontanus (12%), while other species jointly contributed 24% to the overall yield. The trends of sturgeon meat and caviar productions of the last 5 years and the forecasts for the future suggest a short-term scenario in which the demand remains lower than the supply. In order to absorb the growing production, the market will have to be expanded by targeting new market segments.