Research

14 pages, 4582 KiB

Open AccessArticle

Age, Growth, and Reproductive Biology of Euchiloglanis davidi in the Middle and Lower Yalong River, China

by Jie Chen, Xiangyun Zhu, Xin Yang, Xianqin Hu, Pengcheng Lin, Bin Xu, Kaijin Wei and Baoshan Ma

Fishes 2023, 8(9), 435; https://doi.org/10.3390/fishes8090435 - 25 Aug 2023

Viewed by 940

Abstract

In the present study, we investigated the age, growth, and reproductive characteristics of Euchiloglanis davidi, a species of Sisoridae fishes, from the Yalong River, China. Fish samples were collected from the tributaries of the middle and lower Yalong River in May 2013 [...] Read more.

In the present study, we investigated the age, growth, and reproductive characteristics of Euchiloglanis davidi, a species of Sisoridae fishes, from the Yalong River, China. Fish samples were collected from the tributaries of the middle and lower Yalong River in May 2013 and December 2015. Their standard length ranged from 67 to 190 mm, and the total weight ranged from 3.42 to 75.06 g. The age and growth pattern of E. davidi were determined using the vertebra. Furthermore, the sampled fish were categorized into 10 age groups (1–10 years old): the maximum age was 10 years and 9 years for male and female fish, respectively. The relationship between the standard length and weight was expressed as W = 6.744 × 10⁻⁵ L^2.653, and the t-test showed allometric growth. The growth of E. davidi was defined by the von Bertalanffy growth function, described as L_t = 260.8(1−e^{−0.104(t+1.942)}), W_t = 173.5(1−e^{−0.104(t+1.942)})^2.653, respectively. The growth inflection point was observed at 7.44 years, with corresponding length and weight values of 162.50 mm and 49.46 g. The fecundity ranged from 105 to 352 eggs, with an average of 205 eggs. The relative fecundity of weight (F_W) ranged from 2.90 to 8.98 eggs/g, and the relative fecundity of length (F_L) ranged from 0.71 to 2.11 eggs/mm. Altogether, these characteristics of slow growth and low fecundity demonstrated the vulnerability of E. davidi to exploitation in the middle and lower reaches of the Yalong River. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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12 pages, 1831 KiB

Open AccessArticle

Distribution and Abundance of the East Asian Finless Porpoise in the Coastal Waters of Shandong Peninsula, Yellow Sea, China

by Yongtao Li, Zhaolong Cheng, Tao Zuo, Mingxiang Niu, Ruisheng Chen and Jun Wang

Fishes 2023, 8(8), 410; https://doi.org/10.3390/fishes8080410 - 10 Aug 2023

Cited by 1 | Viewed by 945

Abstract

The baseline data pertaining to the population of the East Asian finless porpoise (Neophocaena asiaeorientalis sunameri) in Chinese waters are significantly deficient. Boat-based visual line transect surveys were conducted from 2018 to 2020 to evaluate the distribution and abundance of the [...] Read more.

The baseline data pertaining to the population of the East Asian finless porpoise (Neophocaena asiaeorientalis sunameri) in Chinese waters are significantly deficient. Boat-based visual line transect surveys were conducted from 2018 to 2020 to evaluate the distribution and abundance of the East Asian finless porpoise in the coastal waters (depth < 30 m) of the Yellow Sea, with a specific focus on the Shandong Peninsula. A total of 50 transects covering 2705 km were conducted, encompassing an area of 23,604 km² between 119°30′ E–123°15′ E and 35°25′ N–38° N. Throughout the surveys, a total of 117 East Asian finless porpoise groups were detected, with over 90% of these groups occurring within 15 km of the coast or adjacent islands. The estimated abundance of the East Asian finless porpoise in the study area was determined to be 3978 individuals (CV = 22.39%, 95%CI = 2561–6177), reflecting a low density of 0.169 individuals/km² (CV = 22.39%, 95%CI = 0.109–0.262) within the coastal waters of the Yellow Sea in the Shandong Peninsula. The findings highlight the need for conservation measures to address the threats faced by this species, including bycatch, habitat degradation, and pollution. The establishment of marine protected areas and the implementation of bycatch mitigation measures are crucial for the long-term survival of the East Asian finless porpoise population in the study area. By providing valuable data on the distribution and abundance of the East Asian finless porpoise, this study contributes to our understanding of the population dynamics and conservation status of this threatened species in the Yellow Sea of the Shandong Peninsula. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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12 pages, 917 KiB

Open AccessArticle

Correlations between Environmental Factors and the Distribution of Juvenile Hucho bleekeri in the Taibai River, Shaanxi, China

by Jinming Wu, Jinping Wu, Huan Ye, Wei Xiong, Wanmin Qu, Xiaoqian Leng and Hao Du

Fishes 2023, 8(7), 379; https://doi.org/10.3390/fishes8070379 - 21 Jul 2023

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Abstract

Sichuan taimen (Hucho bleekeri) is a national highly protected wild animal that faces significant impacts from habitat degradation and loss. To study the habitat selection by H. bleekeri, data on the Taibai River and the distribution of juvenile H. bleekeri [...] Read more.

Sichuan taimen (Hucho bleekeri) is a national highly protected wild animal that faces significant impacts from habitat degradation and loss. To study the habitat selection by H. bleekeri, data on the Taibai River and the distribution of juvenile H. bleekeri were recorded seasonally between February 2017 and January 2018, and habitat selection was assessed using the suitability curve method. The results indicate that the average distribution density of juvenile H. bleekeri in the Taibai River is 0.08 ± 0.09 ind./m, with an optimal elevation range from 1200 to 1600 m, river sinuosity range from 1.0 to 1.2, and vegetation coverage between 0.7 and 1.0. When choosing a microhabitat, juvenile H. bleekeri individuals tend to inhabit water areas with a water depth of 0.65 ± 0.33 m, flow velocity of 0.50 ± 0.24 m/s, and offshore distance of 7.66 ± 4.25 m. Furthermore, smaller juvenile fish prefer nearshore habitats with lower flow velocities and shallower water depths. The results provide technical support for the protection and restoration of the habitat of H. bleekeri. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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12 pages, 1601 KiB

Open AccessFeature PaperArticle

Conservation Genetics of Clinch Dace Chrosomus sp. cf. saylori

by Rebecca Bourquin, Michael J. Moore, Donald J. Orth and Eric M. Hallerman

Fishes 2023, 8(7), 365; https://doi.org/10.3390/fishes8070365 - 13 Jul 2023

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Abstract

Clinch Dace (Chrosomus sp. cf. saylori) is a newly recognized and yet-undescribed species of minnow with a restricted and fragmented distribution in the upper Tennessee River basin in southwestern Virginia, USA. We collected Clinch Dace from seven streams and observed variations [...] Read more.

Clinch Dace (Chrosomus sp. cf. saylori) is a newly recognized and yet-undescribed species of minnow with a restricted and fragmented distribution in the upper Tennessee River basin in southwestern Virginia, USA. We collected Clinch Dace from seven streams and observed variations at nine selectively neutral microsatellite DNA loci to infer population genetic processes and identify units for conservation management. Bayesian cluster analysis showed that three of the seven surveyed populations were genetically distinct, while the other four populations showed signs of recent admixture. Estimated effective population sizes and m-ratios were low within most populations, suggesting loss of alleles due to recent genetic drift. Positive F_IS values, high average individual inbreeding coefficients, and high degrees of inferred relatedness among individuals suggested that inbreeding is taking place in some populations. F_ST values were high, and analysis of molecular variance indicated genetic divergence among populations. These indicators suggest that Clinch Dace populations are subject to the genetic processes that are characteristic of small and isolated populations. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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8 pages, 4118 KiB

Open AccessCommunication

Estimates of the Effective Population Size and Genetic Structure of the Critically Endangered Ship Sturgeon (Acipenser nudiventris) in the Chinese Section of the Ili River

by Guo Hu, Feng Chen, Ying Zhang, Peixian Luan, Zhiyuan Luo, Jiangong Niu, Peng Zheng, Sai Wang, Tao Zhang, Yongjun Shu and Feng Ji

Fishes 2023, 8(7), 354; https://doi.org/10.3390/fishes8070354 - 07 Jul 2023

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Abstract

Ship sturgeon (Acipenser nudiventris) is a critically endangered fish that is listed on the International Union for Conservation of Nature’s Red List of Threatened Species. Sixteen individuals from the Chinese section of the Ili River were genotyped using genome re-sequencing technology. [...] Read more.

Ship sturgeon (Acipenser nudiventris) is a critically endangered fish that is listed on the International Union for Conservation of Nature’s Red List of Threatened Species. Sixteen individuals from the Chinese section of the Ili River were genotyped using genome re-sequencing technology. By applying a genomic relatedness estimation with 1,527,694 genome-wide SNP markers, we found that the coancestry coefficients showed a high level of relatedness between individuals. The effective population sizes over 500 generations were estimated, and this showed that the effective population sizes began to dramatically decline from about 14,840 to 171 individuals when going back four generations from the current population. Artificial reproduction techniques guided by genomic relatedness may be a valuable approach to the conservation of this critically endangered fish species. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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9 pages, 3940 KiB

Open AccessCommunication

Successful Ultrasonography-Assisted Artificial Reproduction of Critically Endangered Sichuan taimen (Hucho bleekeri)

by Xiaoqian Leng, Hao Du, Wei Xiong, Peilin Cheng, Jiang Luo and Jinming Wu

Fishes 2023, 8(3), 152; https://doi.org/10.3390/fishes8030152 - 03 Mar 2023

Cited by 1 | Viewed by 1434

Abstract

Sichuan taimen (Hucho bleekeri), a critically endangered species, is listed as a first-class protected species in China. The natural population has been missing from most of its known distribution areas for many years but was rediscovered in the Taibai River in [...] Read more.

Sichuan taimen (Hucho bleekeri), a critically endangered species, is listed as a first-class protected species in China. The natural population has been missing from most of its known distribution areas for many years but was rediscovered in the Taibai River in 2012, providing an important resource for the conservation stocking of the Sichuan taimen. In this study, 43 wild adult Sichuan taimen collected from the Taibai River were determined for gamete maturity for artificial reproduction using ultrasonography. The echogenicity of the gonads before and after hormonal induction was described to determine broodstock identification, injection dose of hormones, and spawning time. Four batches of artificial breeding were successfully achieved in 2013, 2014, and 2016. Broodstock (19 females and 16 males) spawned with average fertilization and hatching rates reaching 80.2% and 61.0%, respectively. This study demonstrates that ultrasonic imaging is a convenient and efficient method to track the state of gonads of mature Sichuan taimen during artificial reproduction, which will assist in broodstock cultivation, and further large-scale proliferation and effective resource restoration of the Sichuan taimen. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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Graphical abstract

20 pages, 5900 KiB

Open AccessArticle

Changes in Fish Assemblage Structure after Pen Culture Removal in Gehu Lake, China

by Xiaoliang Ren, Shulun Jiang, Long Ren, Yidong Liang, Di’an Fang and Dongpo Xu

Fishes 2022, 7(6), 382; https://doi.org/10.3390/fishes7060382 - 09 Dec 2022

Cited by 2 | Viewed by 1639

Abstract

The removal of the net enclosure has been used as a lake management strategy in various regions of China as ecological development is given more attention. Nevertheless, little is known about the substantive impact of this measure on fish communities in inland lakes. [...] Read more.

The removal of the net enclosure has been used as a lake management strategy in various regions of China as ecological development is given more attention. Nevertheless, little is known about the substantive impact of this measure on fish communities in inland lakes. To this end, the fish community composition and structural features after the removal of the net enclosure in Gehu Lake were explored and evaluated in this study from 2021 to 2022 and compared to the investigation before the net enclosure removal from 2017 to 2018. Belonging to 7 orders, 10 families, and 46 species, a total of 17,151 fish were collected, with pelagic, sedentary, and omnivorous species dominating. In comparison, the number of species increased by 10 after removal, and fish alpha diversity increased. The Index of Relative Importance (IRI) revealed that the composition of dominating species remained constant, including Coilia nasus, Hypophthalmichthys molitrix, and Hypophthalmichthys nobilis; Parabramis pekinensis, Megalobrama amblycephal, and Culter mongolicus were upgraded from common species to general species. Culter alburnus, Hemiculter bleekeri, and Pseudobrama simoni were downgraded from general species to common species. Elopichthys bambusa had become a common species (IRI = 109.35), which was not discovered before removal. According to the hierarchical clustering (HC) and non-metric multidimensional sequencing (NMDS), the fish community of the northern reserve was highly aggregated. As the Abundance Biomass Comparison (ABC) curve and biodiversity index indicated, the fish community structure of the whole lake was in a state of moderate anthropogenic disturbance with reduced stability, while that of the northern reserve was in a state of light anthropogenic disturbance with greater stability. The number of fish species increased in this survey compared to the period before removal, species and dominant species composition altered dramatically, and total lake stability declined. This study demonstrates that the fish diversity in Gehu Lake increased after the removal of the net enclosure. Meanwhile, the stability of the fish community structure was decreased temporarily. Lake restoration is a long-term process, and the underlying impact of the removal of the net enclosure still requires continuous monitoring and further studies. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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12 pages, 1825 KiB

Open AccessArticle

Population Structure of Wild Schizothorax kozlovi in the Upper Yangtze River Based on mtDNA and Stable Isotopes, and Their Relationship with Ambient Temperature

by Yongfeng He, Jinling Gong, Xingbing Wu, Yongjiu Zhu and Deguo Yang

Fishes 2022, 7(5), 292; https://doi.org/10.3390/fishes7050292 - 19 Oct 2022

Cited by 1 | Viewed by 1259

Abstract

Schizothorax kozlovi, as an endemic and vulnerable fish of the upper Yangtze River in China, faces many threats. In order to expose the population structure of wild S. kozlovi, the carbon and oxygen isotopic ratios in the otoliths, and the gene [...] Read more.

Schizothorax kozlovi, as an endemic and vulnerable fish of the upper Yangtze River in China, faces many threats. In order to expose the population structure of wild S. kozlovi, the carbon and oxygen isotopic ratios in the otoliths, and the gene sequences of two common mitochondrial markers (Cytb and COI) were investigated in four sampling locations, and then their relationship with ambient temperature was further investigated. In general, it exhibits limited geographic population structuring of S. kozlovi in the upper Yangtze River by both mtDNA and stable isotopes. The values of otolith stable isotope ratios varied from −15.30‰ to −12.37‰ for δ¹⁸O and from −10.10‰ to −6.13‰ for δ¹³C. Significant relationships were revealed between stable isotope ratios and specific mean monthly water temperature variables (from November to March), indicating low temperature effect on otolith stable isotope ratios. Haplotype diversity and nucleotide diversity were 0.928 and 0.00778, both exhibiting high levels. A median-joining haplotype network indicated a mixture of geographical distribution but exhibited two distinct haplotype lineages (Clade I and Clade II). AMOVA detected that the higher percentage of genetic variance was within sampling locations (96.94%) and between two haplotype lineages (72.82%). Most F_ST values between sampling locations showed small levels of genetic differentiation except the differentiation between population SJ (Sanjiangkou) and JP (Jinping). Therefore, two haplotype lineages and population JP of S. kozlovi in the upper Yangtze River are suggested as three management units for conservation due to their moderate-to-great genetic differentiation and isolated habitat. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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16 pages, 4228 KiB

Open AccessArticle

Macro-Habitat Suitability for Threespine Stickleback (Gasterosteus aculeatus L.) Near the Southern Limit of Its Global Distribution: Implications for Species Management and Conservation

by Andre Moreira, Joana Boavida-Portugal, Pedro R. Almeida, Sara Silva and Carlos M. Alexandre

Fishes 2022, 7(5), 271; https://doi.org/10.3390/fishes7050271 - 02 Oct 2022

Viewed by 1590

Abstract

The threespine stickleback is a freshwater fish listed as endangered in Portugal, near the southern limit of the species global distribution. However, few measures have been proposed aiming at the conservation of this species in suboptimal environments. From existing databases and specific sampling [...] Read more.

The threespine stickleback is a freshwater fish listed as endangered in Portugal, near the southern limit of the species global distribution. However, few measures have been proposed aiming at the conservation of this species in suboptimal environments. From existing databases and specific sampling campaigns, we obtained occurrence data of threespine stickleback for a total of 646 sites. The occurrence data, together with 15 environmental macrohabitat predictors, were used to model the potential distribution of the species using an ensemble of species distribution models. Through the results of our final ensemble, we project that the threespine stickleback occurs predominantly at lower stretches of river systems, where sandy substrate is dominant and flow is higher. Within this region, sticklebacks are also more likely to occur in sites with high levels of rainfall in the driest month, thus avoiding locations with high potential for drying during summer. The species also tends to avoid steep slope areas with high levels of annual precipitation. Based on our results, a map of the species probability of occurrence was generated and river sections were categorized into levels according to their importance for the species’ conservation. Full article

(This article belongs to the Special Issue Advances in Endangered Aquatic Animals Protection)

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