Journal of Applied Ichthyology最新文献

Thiamine is a crucial nutrient in larval stage of fish, and thus, the present study aimed at evaluating the effects of dietary thiamine supplementation on survival, growth performance, and biochemical parameters of beluga, Huso huso, larvae. The fish larvae (50 ± 4.5 mg) were fed diets containing 0 (control), 5, 10, and 20 mg/kg thiamine for 26 days from 18 days after hatching to 44 days after hatching. Thiamine significantly increased the larvae survival, growth rate, digestive enzymes activity, and whole body protein and ash but decreased the whole body lipid and moisture (P < 0.001). Also, alanine amino transferase (ALT) and alkaline phosphatase (ALP) were decreased significantly in thiamine-treated groups (P < 0.05). The highest survival and whole body ash were observed in 20 mg/kg thiamine treatment; the highest whole body protein and lipase activity were observed in 10 mg/kg thiamine treatment. The highest growth rate, amylase, and lowest whole body lipid, alanine amino transferase (ALT), and alkaline phosphatase (ALP) were observed in 10 and 20 mg/kg thiamine treatments. All thiamine-treated fish exhibited similar pepsin and chymotrypsin activities, all above the control fish. There were no significant effects of dietary thiamine supplementation on trypsin, whole body lysozyme, alternative complement (ACH50), lactate dehydrogenase (LDH) activities, and IgM levels. According to the results, 10–20 mg/kg dietary thiamine supplementation can increase the performance of beluga larvae by improving the health of liver and the activity of digestive system.

During multiple annual spawning runs from 2013 to 2021, over 9,000 mature anadromous alewife (Alosa pseudoharengus A. Wilson, 1811) were monitored with passive integrated transponders (PITs) in four rivers of the Chignecto Isthmus, Bay of Fundy, Canada. A subsample of 384 individuals tagged during 2016–2019 were aged from 3 to 6 years (mean ± SD; 4.2 ± 0.7 years, n = 232, males; 4.5 ± 0.7 years, n = 152, females). Biotelemetry revealed that one unsexed individual survived seven years post tagging, possibly making it 10–13 years old. Return rates varied among the rivers, with the lowest rates in the most anthropogenically impacted river. Biotelemetry and ageing data were used to estimate apparent annual survival rates ranging from 0.25 to 0.50 depending on the river and the year. Based on capture-mark-recapture (CMR) analysis of biotelemetry data from the three less impacted rivers, the estimated overall annual survival was 0.396, total instantaneous mortality (Z) was 0.93, and future life expectancy from time of release was 1.08 years. Frequency distribution of ages 4–6 for alewife pooled from all four study rivers estimated a lower annual survival rate of 0.301, Z = 1.20, and a future life expectancy of 0.83 years. The biotelemetry detection rates were 0.89–0.98 but varied depending on the river and the year, with the lowest rates in one river during 2017-2018 possibly related to a malfunctioning tide gate preventing upstream fish passage and subsequent detection. Based on CMR, males had a higher survival rate compared to females, which translated into an overall mean survival increase of 0.05. Alewife survivorship in our study highlighted that a limited ecosystem-based management period is required to mitigate river connectivity and mortality issues to avoid loss of population cohorts and decrease the risk of extirpation.

Body colors are an important trait for the survival and reproduction of animals. In this study, transcriptomes and related single nucleotide polymorphisms (SNPs) of black- and red-colored Plectropomus leopardus (Lacépède) were identified to investigate important molecules and SNP markers associated with body color formation. In the comparison of red- and black-colored groups, 489 differential expressed genes (DEGs) were detected and among them, 236 up- and 253 down-regulated genes were found in the red-colored group. Gene ontology (GO) analysis of DEGs showed that pigmentation associated terms including pigment granule, pigmentation, melanin metabolic process, tyrosine metabolic process, pigment metabolic process, and pigmentation cell differentiation were enriched. Kyoto encyclopedia of genes and genomes (KEGG) analysis of DEGs presented that melanin related pathways (tyrosine metabolism and melanogenesis) were enriched. Furthermore, lipid metabolism and immune-related metabolism were also enriched. A total of 1,048,575 SNPs were detected from the transcriptome, and among them, 627,172 SNPs were located in the gene region. A total of 1323 SNPs were identified as differential SNPs in the comparison of black- and red-colored groups and were located in 1127 genes. Among the 1127 genes, 20 genes were identified as DEGs and were comprised of 9 SNPs with a potential role in body color selective breeding in fish farming.

Acentrogobius virgatulus (Jordan & Snyder, 1901) is a small coastal species of goby found along the Western Pacific. It is commonly found in Maizuru bay along the muddy sediment between the intertidal zone and depths of 10 m. In June and July of 2022, two independent agonistic interactions between male A. virgatulus were observed and recorded during its spawning season. One interaction, lasting over 4 minutes, included certain aggressive behaviors such as jaw locking, mouth gaping, fin extensions, rapid color changes, and fast strikes to the head and body. Another interaction exhibited similar mouth gaping, fin extension, and rapid color changes but did not lead to further escalation. These behaviors coincide with those found in similar species and provides in situ evidence of these uncommon interactions. This is the first record of agonistic behavior by an Acentrogobius species. Accumulating findings such as these can contextualize intraspecific interactions, reveal differences across multiple species, and guide future experiments.

Twenty-nine native freshwater fish species belonging to the four orders and eight families were collected from the Hongshui River, which belongs to the upper reaches of the Pearl River, to analyze their length-weight relationships (LWRs). Twenty-nine freshwater native fish were sourced using cages (0.2 m in height, 0.25 m in width, and 8 m in length, with a mesh size of 5 mm) and triple gillnets (20–40 m long, 1–3 m high, and mesh size, 2−3 cm) between December 2021 and July 2022. For each freshwater fish, the total length (TL) and weight were measured to the nearest 1.0 mm and 0.1 g. All LWR parameters of the twenty-nine species were statistically significant (P < 0.001). The length-weight relationships for the nine species were new to the FishBase and new maximum lengths were recorded for the twenty species. The LWR values provided for the first time will help to validate the accuracy and predictability of the Bayesian models for estimating the species-specific growth parameters of the data-poor species.

In this study, the length-weight relationships were determined for four fish species of the upper Yangtze River, Sichuan province, China. The fish were collected by drift net (mesh size: 4 cm × 4 cm) and ground bamboo cages (1 cm × 1 cm) from Yalong River, Laixi River, Pingtung River, and Baoxing River. Samples were collected from March 2017 to December 2022. According to the length-weight function equation (W = aL^b), r² values ranged from 0.960 to 0.991 and the b values of LWRs ranged from 2.916 (Megalobrama pellegrini) to 3.095 (Claea dabryi).

This study used gas chromatograph-mass spectrometer (GC-MS) to determine three kinds of halogenated organic pollutants (HOPs) in the edible muscles of nine fish species in the Laibin section of the Hongshui River of Xijiang River in the Pearl River system. The results showed that the sum of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in fish muscle was 8.94∼43.32 ng/g ww, 1.22∼4.09 ng/g ww, and ND∼0.13 ng/g ww, respectively. Evaluation indicators include analysis of the composition of homologous compounds, residues in different diets and habitats, and estimated daily intake (EDI) calculations. The analysis of the composition characteristics of homologous compounds showed that endrin was the most dominant in OCPs; hexachlorobenzene was the most dominant in PCBs; and BDE 154 was the most dominant PBDEs. Calculations of the levels of the HOPs in fish of different diets and habitats showed that OCPs and PCBs had the highest residues in carnivorous fish, and PBDEs had the highest residues in herbivorous fish. The residual OCPs, PCBs, and PBDEs in demersal fishes were the most. The estimated daily intake (EDI) results showed that daily fish consumption in the Laibin section of the Hongshui River would not cause HOPs health risks to the local residents. However, there is still a need for continuous monitoring of HOPs to reduce pollutant emissions and prevent pollution conditions from arising.

The long rough dab (Hippoglossoides platessoides) is one of the most common bottom dwelling fish species in the Barents Sea with a limited commercial value, even though it is regularly caught as bycatch. Adult H. platessoides can be found in large numbers along the west coast of Svalbard, but nothing is known about the spawning area of this species or the distribution of their eggs and larvae within Svalbard fjords. Recent findings of H. platessoides eggs in Kongsfjorden indicate that a spawning population exists either within the fjord or on the west Spitsbergen shelf.

In this study, we report, for the first time, mitochondrial genome of Narcine timlei (Bloch & Schneider, 1801) and its phylogenetic relationships within the order Torpediniformes. Narcine timlei is a medium-sized ray that occurs in nearshore waters of the Indo-Pacific and is classified as “‘vulnerable” category on the IUCN Red List. The mitogenome is assembled from short Illumina reads (150 bp paired end reads). It is 17,964 bp long and includes 13 protein-coding genes (PCGs), 22 tRNA genes, and 2 rRNA genes. The gene order, size, and nucleotide composition are largely consistent with mitogenomic characteristics of previously reported other Narcine spp. The slightly larger mitogenome length of N. timlei than other Narcine spp. may be due to the presence of a putative control region of 1,916 bp with three tandem repeats. Phylogenetic reconstruction using concatenated PCGs (n = 13) of 9 Torpediniformes based on maximum likelihood and Bayesian inference analysis revealed identical topologies. The tree showed two main clades: one clade containing members of the family Narcinidae and the second sister clade consisting of the families Narkidae and Torpedinidae. Our result supports the monophyletic nature of Narcinidae based on mtDNA. The information obtained in this study will contribute to a better understanding of the population genetics, phylogenetic analysis, conservation, and evolutionary biology research of N. timlei.

Aquaculture has tremendous economic significance in distinguishing males and females in the juvenile Silurus asotus (Linnaeus, 1758) to obtain a female population with tremendous growth potential. To investigate the potential biological markers between young males and females S. asotus, we analyzed the characteristics of sexual dimorphism by measuring the 14 length traits and 9 weight indicators in an artificial insemination population at 3, 5, and 7 months. In addition, quantitative real-time PCR (qRT-PCR) was performed to determine the sexually dimorphic expression of the growth hormone-1 gene (GH-1), growth hormone receptor gene (GHR), and insulin-like growth factor gene (IGF-1) in the hypothalamus, pituitary, gonad, and liver, at 3, 5, and 7 months. The results showed that in morphology, except for eye diameter and the distance between the pelvic and anal fins in 3-month fish, all other morphological indicators were significantly (P < 0.05) or very significantly (P < 0.01) different between juvenile males and females. The visceral weight, eviscerated weight, and intestine weight in females were significantly (P < 0.05) or very significantly (P < 0.01) higher than in males at 5 and 7 months. Joint static allometric analyses on 14 length indicators relative to weight showed different sex growth patterns in 3-month, 5-month, and 7-month fish. In gene expression patterns, GH-1, IGF-1, and GHR were highly expressed in the pituitary, with higher levels in females (P < 0.05 or P < 0.01). In contrast, the three genes were all more highly expressed in the testis than in the ovary (P < 0.01), indicating their essential roles in testis development. Our results demonstrate that S. asotus has female-biased sexual dimorphism. The length traits related to head shapes could be the potential phenotype marker to distinguish females and males in 7-month juveniles.