Search Results (6)

Schizothorax wangchiachii, as a cold-water fish, is a predominant or common species in high-altitude areas with large population sizes. It is among the main edible economic fish species in the production area. We used genotype sequencing (GBS) technology to analyze the genetic diversity and population structure of 10 wild populations in the Jinsha River and Yalong River basins of the upper Yangtze River. A total of 724,858 single-nucleotide polymorphisms (SNPs) were detected in these 10 wild populations. The population genetic diversity was low; however, the degree of genetic differentiation was not significant. The populations from the Jinsha River and Yalong River could not be clustered separately on the basis of the SNPs. The Panzhihua (PZH) and Wudongde (WDD) populations from the Jinsha River exhibited gene flow with the Yajiang (YJ) population from the Yalong River, and a secondary pulse of gene flow subsequently connected the PZH and WDD populations to the upper-Jinsha population Suwalong (SWL). The demographic history of S. wangchiachii, reflected in its effective population size (N_e), has been influenced by the uplift of the Qinghai–Tibet Plateau (QTP). Furthermore, the identified SNPs are functionally associated with key cellular processes, environmental adaptation, and metabolism. These findings provide critical genomic insights that can inform conservation strategies and support the sustainable utilization of wild S. wangchiachii resources. Full article

The mechanisms of nutritional niche differentiation among sympatric Schizothoracinae fishes play an important role in their adaptive evolution and should be considered in conservation strategies. To date, there have been no reports about the role of different feeding strategies in nutritional niche differentiation among five Schizothoracinae species (Ptychobarbus leptosomus, PL; Gymnodiptychus pachycheilus, GP; Schizothorax kozlovi, SK; Schizopygopsis malacanthus, SM; and S. wangchiachii, SW). This study explored the role of feeding strategy differences in nutritional niche differentiation among sympatric Schizothoracinae fishes. We analyzed feeding/digestive organ morphology, diet composition, intestinal digestive enzyme activity, and microbial diversity in five species from the middle Yalong River. The results revealed dietary divergence: PL consumed small fish, invertebrates, and algae; GP/SK fed on invertebrates and algae; and SM/SW primarily ate algae. Additionally, α-amylase activity was lower in PL/GP/SK than in SM/SW (p < 0.05), while lipase activity was lower in SM/SW than in PL/GP/SK (p < 0.05), and PL exhibited the highest trypsin activity (p < 0.05). The intestinal microbial composition/diversity also varied: the PL group differed significantly from the GP + SK and SM + SW groups (p < 0.05), with Cetobacterium being dominant in the PL group and Clostridium being dominant in the other groups; the α diversity was highest in the SM + SW group and lowest in the PL group. PICRUSt2 predictions revealed significant differences in nutrient metabolism pathways between the PL group and the other groups (p < 0.05). Overall, the morphological differences in feeding/digestive organs and recent food intake may drive the dietary divergence, inducing adaptive changes in digestive enzymes and microbial diversity and ultimately promoting nutritional niche differentiation among sympatric Schizothoracinae species. Full article

To investigate the group behavioral characteristics of Schizothorax wangchiachii during the spawning period, we used acoustic telemetry to track 10 mature individuals (4 females, 12 males) in a semi-controlled stream section (28.1 m × 5.8 m) simulating natural spawning microhabitats from 23 to 26 January 2024. By integrating trajectory similarity analysis and wavelet transform, we examined the aggregation patterns and activity rhythms during natural spawning events. The population formed two relatively stable subgroups, with significantly shorter inter-individual distances during the day (1.69 ± 0.72 m) than at night (2.54 ± 0.85 m, p < 0.01). Aggregation behavior exhibited a dominant ultradian rhythm of 16.5 h, with stable clustering between 09:00 and 16:00 (spawning window: 13:40–14:20) and dispersal from 19:00 to 00:00. Group activity followed a decreasing-then-increasing trend, with higher nighttime activity. Males were more active than females (F = 51.89, p < 0.01); female activity peaked on the spawning day and was influenced by reproductive progression, while male activity was mainly driven by diel rhythms (p < 0.01). A weak positive correlation was found between active time and inter-individual distance in both sexes (r = 0.32, p < 0.05), indicating reduced activity when aggregated. These findings provide insight into the temporal coordination and spatial regulation of reproductive behavior under semi-controlled conditions. However, due to the short monitoring period and experimental setup, caution is warranted when generalizing to the full reproductive season or fully natural habitats. Full article

Hydropower infrastructure has profoundly altered riverine connectivity, posing challenges to the migratory behavior of aquatic species. This study examined the post-passage migration efficiency of Schizothorax wangchiachii in a regulated river system, focusing on upstream and downstream reaches of the Songxin Hydropower Station on the Heishui River, a tributary of the Jinsha River. We used radio-frequency identification (RFID) tagging to track individuals after fishway passage and coupled this with environmental monitoring data. A Cox proportional hazards model was applied to identify key abiotic drivers of migration success and to develop a predictive framework. The upstream success rate was notably low (15.6%), with a mean passage time of 438 h, while downstream success reached 81.1%, with an average of 142 h. Fish exhibited distinct diel migration patterns; upstream movements were largely nocturnal, whereas downstream migration mainly occurred during daylight. Water temperature (HR = 0.535, p = 0.028), discharge (HR = 0.801, p = 0.050), water level (HR = 0.922, p = 0.040), and diel timing (HR = 0.445, p = 0.088) emerged as significant factors shaping the upstream movement. Our findings highlight that fishways alone may not ensure functional connectivity restoration. Instead, coordinated habitat interventions in upstream tributaries, alongside improved passage infrastructure, are crucial. A combined telemetry and modeling approach offers valuable insights for river management in fragmented systems. Full article

To explore the differences in the growth characteristics and population dynamics of Schizothorax wangchiachii populations in the Jinsha River (JSR) and the Yalong River (YLR), samples were collected in the upper reaches of the JSR (n = 230) from 2019 to 2020 and the middle reaches of the YLR (n = 187) from 2017 to 2018. In the JSR and YLR populations, the age range was 11 and 12 years old, respectively, and the best growth equation was the Von Bertalanffy equation. The comparative analysis of the two populations showed that the growth coefficient, initial sexual maturity age and age at first capture of the YLR population were greater than those of the JSR population. Comparing the mortality rates of the two groups, we found that the YLR population had the higher female mortality rate (0.658 years⁻¹) and the lower male mortality rate (0.453 years⁻¹). Our assessment of the three natural mortality rates showed that the F_cur of both male and female populations was greater than F_25%, indicating that both populations were in an overexploited state. Therefore, we suggest considering the two groups as separate protection units and implementing management measures such as ecological regulation, restoration of tributary habitat and strengthening of fishing ban monitoring to protect their resources. Full article

To understand the characteristics of the fish community structure and biomass particle-size spectrum in the upper reaches of the Jinsha River, fish and environmental surveys were conducted in 21 segments of the upper reaches of the Jinsha River in September 2019 and June 2020. A total of 4062 fish belonging to 2 orders, 5 families, 18 genera, and 28 species were collected. Among them, Cyprinidae fish were the most abundant (14 species), accounting for 50.00%. The Shannon index and Pielou evenness index values varied from 0.402–1.770 and 0.254–0.680, respectively. The dominant species of fish were Triplophysa stenura, Schizothorax wangchiachii, and Schizopygopsis malacanthus. Redundancy analysis (RDA) was used to analyse the relationship between the fish community and environmental factors. Velocity, altitude, and dissolved oxygen were the main influencing factors of fish community structure differences in the upper reaches of the Jinsha River. The abundance/biomass curves showed that the fish communities in the upper reaches of the Jinsha River were moderately or severely disturbed. The standardized biomass particle-size spectrum of fish showed that the degree of disturbance of fish in tributaries was much lower than that in the main stream. Compared with the historical data, the fish community structure in the Jinsha River has changed significantly, with the number of exotic species increasing, and the individual fish showing miniaturization and younger ages. It is suggested that habitat conservation strategies be adopted in the upper tributaries of the Jinsha River to provide a reference for the restoration of fishery resources and the conservation of fish diversity in the Yangtze River. Full article