Journal of Applied Ichthyology最新文献

{"title":"Cellular, Physiological, and Biochemical Basis of Adaptive Response to Variable Osmotic Environments by the River Shad, Tenualosa ilisha","authors":"Wasim Akram, Maliha Tabassum, Md. Lifat Rahi","doi":"10.1155/2023/4910938","DOIUrl":"https://doi.org/10.1155/2023/4910938","url":null,"abstract":"The river shad, hilsa (Tenualosa ilisha), is an anadromous fish that migrates from marine to freshwater for spawning. This transition/migration poses severe osmotic stress that hilsa needs to successfully minimize. The present study was conducted to evaluate the cellular (ultrastructure of gill and kidney), physiological (hemocyte counts, blood, and water osmolality), and biochemical (free amino acids, free fatty acids, blood glucose, and cortisol levels) parameters of hilsa collected from four different environmental salinity levels (0‰, 10‰, 20‰, and 30‰ salinity levels; using 10 fish samples from each salinity). Results indicate that increased amount of fatty/mucus cells in the gill and lower number of glomerular capsules in kidney were observed at low (0‰ and 10‰) salinities compared to high (20‰ and 30‰) salinities. Water and blood osmolality (total ionic content) showed declining trends with lowering salinities. Total number of blood cells was also found to vary significantly <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\"> <mfenced open=\"(\" close=\")\" separators=\"|\"> <mrow> <mi>P</mi> <mtext> </mtext> <mo><</mo> <mtext> </mtext> <mn>0.05</mn> </mrow> </mfenced> </math> among salinities. Salinity-specific blood cortisol and glucose levels of hilsa were observed as 0‰ > 10‰ > 30‰ > 20‰. Total essential and free amino acids of hilsa blood showed significantly declining trends <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\"> <mfenced open=\"(\" close=\")\" separators=\"|\"> <mrow> <mi>P</mi> <mtext> </mtext> <mo><</mo> <mtext> </mtext> <mn>0.05</mn> </mrow> </mfenced> </math> with salinity reductions. No significant differences were observed between 10‰, 20‰, and 30‰ salinities for different types of fatty acids, while hilsa collected from 0‰ showed significantly higher <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M3\"> <mfenced open=\"(\" close=\")\" separators=\"|\"> <mrow> <mi>P</mi> <mtext> </mtext> <mo><</mo> <mtext> </mtext> <mn>0.05</mn> </mrow> </mfenced> </math> levels of fatty acids compared to the remaining three salinities. Findings indicate that hilsa rapidly alters cellular, physiological, and biochemical traits for successful transition between different salinity habitats.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":" 43","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135340494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Length-Weight Relationships of Four Fish Species from the Dongting Lake Basin, Central South China","authors":"Xiao Xie, Jiang Xie, Congqiang Luo, Jinlong Wang, Bolan Song, Ruisong Wang, Hongxing Yin, Liangguo Liu, Pinhong Yang","doi":"10.1155/2023/8441358","DOIUrl":"https://doi.org/10.1155/2023/8441358","url":null,"abstract":"Length-weight relationships (LWRs) were described for four fish species inhabiting the tributaries of the Dongting Lake, China. Fish were sampled using stationary gillnets (50 m long × 2.0 m high and mesh size: 2, 6, 10, and 14 cm) and lobster pots (18 m long × 0.33 m high × 0.45 m width and mesh size: 1 cm) twice a year from May 2021 to July 2023. All fishes were measured in the field immediately after collection for total length (L) to the nearest 0.1 cm and body weight (W) to the nearest 0.1 g. There was a strong correlation between total length and weight in all four species (r2 > 0.98). The values of parameter b in LWR ranged from 2.9709 to 3.4373. The LWR of Sinilabeo tungting, Acrossocheilus jishouensis, Onychostoma rara, and Onychostoma barbata provide new data for https://Fishbase.org and can be useful for establishing conservation measures of fish resources after fishing closure in the Dongting Lake basin, China.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":"12 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135539645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acoustic Target Strength of Jellyfish, Nemopilema nomurai, Measured at Multi-Frequency and Multi-Orientation","authors":"Hang Yang, Jing Cheng, Taolin Tang, Jun Chen, Guodong Li","doi":"10.1155/2023/6650863","DOIUrl":"https://doi.org/10.1155/2023/6650863","url":null,"abstract":"The jellyfish Nemopilema nomurai occupies an important position in the Northwest Pacific ecosystem, and monitoring its biomass is necessary to ensure the protection of fishery resources and the safety of offshore industrial production. The acoustic method has been proposed for jellyfish flux estimation and bloom warning, in which the target strength (TS) of the jellyfish is a crucial parameter. However, varied swimming orientations of jellyfish aggregation result in different backscatter strengths. The acoustic echo characteristics in horizontal swimming orientations and multi-frequency broadband signals are yet to be revealed. This study aims to obtain the TS of jellyfish in various orientations and to comprehensively investigate the jellyfish acoustic echo features at various frequency broadband sounds. In an anechoic tank, we used wide-band echosounder and 70 kHz, 120 kHz, and 200 kHz split-beam transducers to measure the TS of jellyfish swimming omnidirectionally. The results show a difference of approximately 4 dB in the jellyfish’s normalized TS at 70 kHz (frequency range: 45 kHz to 95 kHz) and 200 kHz (frequency range: 160 kHz to 260 kHz) center frequency. The normalized TS of jellyfish varies by around 8 dB between horizontal and vertical swimming orientations. For jellyfish swimming horizontally, the TS and bell diameter have the following least squares fits: <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\"> <mi>T</mi> <msub> <mrow> <mi>S</mi> </mrow> <mrow> <mi>D</mi> <mn>70</mn> <mi>k</mi> <mi>H</mi> <mi>z</mi> </mrow> </msub> <mo>=</mo> <mn>20</mn> <mtext> </mtext> <mi mathvariant=\"normal\">log</mi> <mtext> </mtext> <mi>D</mi> <mo>−</mo> <mn>89.36</mn> <mfenced open=\"(\" close=\")\" separators=\"|\"> <mrow> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mn>0.83</mn> </mrow> </mfenced> </math> ; <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\"> <mi>T</mi> <msub> <mrow> <mi>S</mi> </mrow> <mrow> <mi>D</mi> <mn>200</mn> <mi>k</mi> <mi>H</mi> <mi>z</mi> </mrow> </msub> <mo>=</mo> <mn>20</mn> <mtext> </mtext> <mi mathvariant=\"normal\">log</mi> <mtext> </mtext> <mi>D</mi> <mo>−</mo> <mn>93.85</mn> <mfenced open=\"(\" close=\")\" separators=\"|\"> <mrow> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mn>0.83</mn> </mrow> </mfenced> </math> . The swimming orientation has significant effects on TS estimation and model construction.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135366902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical Patterns in Lake Sturgeon (Acipenser fulvescens) Larval Drift within Two Rivers Directly Connected to Green Bay, Lake Michigan","authors":"Patrick S. Forsythe, Dave A. Lawrence, Ashok Ragavendran, Kari McClellan, Miguel A. Ortiz, Tanna M. Dittmar, Robert F. Elliott, Michael C. Donofrio","doi":"10.1155/2023/6619373","DOIUrl":"https://doi.org/10.1155/2023/6619373","url":null,"abstract":"Fish larvae in riverine environments often disperse (e.g., drift) from areas of egg deposition at the time of hatch. Several components of drift can be important in terms of survival including timing, distribution in the water column, and body size. The longitudinal and cross-sectional aspects of larval lake sturgeon (Acipenser fulvescens) drift from upstream spawning sites have received considerable study. However, the vertical distribution of larval lake sturgeon in the water column has not been comprehensively evaluated with respect to river size, water depth, the size of larvae in drift over the entire drift period, and the effectiveness of traditional sampling gear (D-frame nets) designed to collect larvae along the river bottom. In 2013, we sampled larval lake sturgeon drifting from upstream spawning sites in the Menominee and Oconto Rivers (Wisconsin, USA) using traditional D-frame nets and custom fabricated sampling nets that vertically partitioned the water column. Drifting larval lake sturgeon were observed from the river bottom to the top of the water column in both systems. Vertical net section was a significant predictor of total larval catch with the highest catch occurring in nets towards the center of the water column but was dependent on net location within the rivers’ cross section and downstream distance from spawning locations. 42% of larvae captured across both rivers were outside of the sampling capability of the traditional D-frame nets (i.e., fish would have drifted over the top). Studies seeking to describe larval production for lake sturgeon, as well as other fish species that exhibit drift in larval dispersal, need to consider a balance between net design and sampling the vertical/cross sectional profiles of rivers. Size-based vertical drift may also have consequences for studies seeking to estimate genetic parameters (e.g., diversity and parentage).","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135511093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishment of SYBR Green I Real-Time PCR for Detection of Streptococcus agalactiae in Aquaculture Waters","authors":"Zaiyong Si, Zhenhua Ma, Fuguang Luo, Jingu Shi, Jie Huang, Zhiqiang Wang, Yanhong Wen, Yi Yi, Shuyu Han","doi":"10.1155/2023/9199300","DOIUrl":"https://doi.org/10.1155/2023/9199300","url":null,"abstract":"Streptococcus agalactiae has a serious negative impact on tilapia aquaculture, and rapid detection of trace S. agalactiae in aquaculture waters and timely and effective sterilization measures could significantly reduce the probability of its outbreak in tilapia farming. Here, we established a fluorescence quantitative detection method of S. agalactiae in tilapia aquaculture waters based on the Streptococcus agalactiae CAMP factor (cfb) (GU217532.1) sequence of its CAMP factor. The results showed that the Ct value and logarithm of plasmid copy number presented a good linear relationship (y = −3.49x + 38.78; R2 = 0.997) in the plasmid concentration range of 1.57 × 102−1.57 × 109 copies/μL, and the lowest concentration for sensitive detection of the established method was 1.57 × 102 copies/μL. The method exhibited high specificity for the detection of S. agalactiae and generated negative results when using the DNA of Aeromonas veronii, Staphylococcus epidermidis, Aeromonas hydrophila, and Edwardsiella tarda as templates for qPCR. Intra- and inter-group repeated experiments produced variation coefficients lower than 2%, indicating high stability and specificity of the method. The method was then used to detect S. agalactiae in two tilapia aquaculture waters. The results showed that the concentration of S. agalactiae was 12 copies/mL and 2 copies/mL in the two water samples, respectively. The method can directly detect trace S. agalactiae in the aquaculture water and facilitate the diagnosis, prevention, and control of S. agalactiae in tilapia aquaculture, which will greatly reduce the probability of large-scale outbreak of S. agalactiae and economic loss.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":"14 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135568058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Length-Weight Relationships and Condition Factor of Four Threatened Riverine Catfish Species in the Meghna River Estuary, Bangladesh","authors":"Jannatul Ferdous Jerin, Shanaz Akther, Joyoti Debnath, Debasish Saha","doi":"10.1155/2023/6651843","DOIUrl":"https://doi.org/10.1155/2023/6651843","url":null,"abstract":"The current study examined the length-weight relationships (LWRs), length-length relationships (LLRs), and condition factor (K) of four threatened riverine catfish species (Pangasius pangasius, Rita rita, Sperata aor, and Bagarius bagarius) sampled from the Meghna River Estuary (MRE), Bangladesh. A total of 578 individuals were collected from contracted fishermen between January and October 2022. The length and weight of each species exhibited a highly positive correlation. The regression coefficient was 2.24 for P. pangasius, 2.90 for R. rita, 2.91 for S. aor, and 3.25 for B. bagarius. Furthermore, all species demonstrated a highly positive correlation between total length and standard length (r &gt; 0.90). The calculated condition factor (K) values were 0.87 for P. pangasius, 1.18 for R. rita, 0.66 for S. aor, and 0.99 for B. bagarius indicating variations among the species. This study provides the first comprehensive documentation of all four major catfish species found in the MRE.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":"529 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135766003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Length-Weight Relationships and Relative Condition Factor of 53 Species of Shallow-Water Fish in the Colombian Caribbean Sea","authors":"Alfredo Rodriguez, Katherine Mendoza, Jorge Paramo","doi":"10.1155/2023/6632464","DOIUrl":"https://doi.org/10.1155/2023/6632464","url":null,"abstract":"Length-weight relationships (LWR) were described for 53 species of shallow-water fish caught with bottom trawls in a depth range between 7.3 and 108.1 m during September 2013 in the Colombian Caribbean Sea (fishing area 31 of the FAO). A linear regression was performed using the logarithmically transformed data to calculate a and b coefficients and their 95% confidence interval of the LWR for 53 fish species corresponding to 28 families and 44 genera. Six fish species showed a maximum total length greater than that reported in FishBase: Astrapogon alutus (102.00 mm), Eucinostomus harengulus (162.00 mm), Haemulopsis corvinaeformis (293.00 mm), Cyclopsetta chittendeni (390.00 mm), Etropus crossotus (224.00 mm), and Bairdiella ronchus (415.00 mm). A total of 24 species (45.3%) exhibited isometric growth, 21 species (39.6%) negative allometric, and 8 species (15.1%) positive allometric. This study shows the first estimates of LWR for 25 species of shallow-water fish in the Colombian Caribbean Sea. We found interdependence of growth parameters as a function of fish body shape. The analysis of the relative condition factor indicated that 21 fish species (39.6%) showed poor growth conditions. The results obtained from this study contribute to fill information gaps on shallow-water fish populations and also help fisheries scientists in future population assessment studies in the Colombian Caribbean Sea.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135346888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Different Feeding Rates for the Growth and Body Composition of Manchurian Trout, Brachymystax lenok","authors":"Enhui Liu, Tianqing Huang, Wei Gu, Gaochao Wang, Bingqian Wang, Xiulan Shi, Gefeng Xu","doi":"10.1155/2023/3485493","DOIUrl":"https://doi.org/10.1155/2023/3485493","url":null,"abstract":"A 50-day feeding trial was conducted to investigate the effects of feeding rates (FRs) on the growth, feed utilisation, and body composition of Brachymystax lenok. Juveniles of B. lenok (initial body weight of 7.6 ± 0.2 g) were fed a commercial diet at the different FRs of 1, 2, 3, 4, and 5% of their body weight. The results indicated that weight gain (WG) and specific growth rate (SGR) were first increased and then decreased with an increase in the FR. The WG and SGR of the 4% group were 299.78% and 3.96%, respectively. The feed conversion ratio (FCR) and protein efficiency ratio (PER) were also significantly affected by the FR ( <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\"> <mi>P</mi> <mo><</mo> <mn>0.05</mn> </math> ). Furthermore, the condition factor (CF) did not differ significantly among the treatment groups ( <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\"> <mi>P</mi> <mo>></mo> <mn>0.05</mn> </math> ). However, the FR significantly affected the hepatosomatic index (HSI) and visceral somatic index (VSI) ( <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M3\"> <mi>P</mi> <mo><</mo> <mn>0.05</mn> </math> ). With an increase in the FR, the moisture content of the fish decreased, but the ash content changed irregularly. The protein content increased significantly with increasing FR ( <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M4\"> <mi>P</mi> <mo><</mo> <mn>0.05</mn> </math> ). The lipid content showed a trend similar to protein in the body. Based on the SGR and FCR data, the optimal FR range was 2.4 to 3.1% for B. lenok (7−30 g body weight) at a water temperature of 16°C.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136108075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cloning, Expression Analysis, and Detection of the Vitellogenin in the Chinese Black Sleeper Bostrychus sinensis","authors":"Yangyang Zhang, K. Meng, Tingting Zhou, Lei Chen, Tiansheng Chen, Min Long, Kefu Zhou","doi":"10.1155/2023/2172611","DOIUrl":"https://doi.org/10.1155/2023/2172611","url":null,"abstract":"Endocrine disruptors in marine environments represented by estrogens lead to reverse health phenomena. To obtain a more effective way to reflect and detect environmental estrogens pollution, a method was developed to obtain the full-length cDNA coding vitellogenin gene in B. sinensis, induced by 17β-estradiol (E2) solution. We have downloaded 16 fish gene sequences from the NCBI database and designed PCR primers accordingly. Based on the quantitative real-time PCR method (qRT-PCR), we analyze the differences in gene expression under the conditions of different E2 exposure times in the low, middle, and high-dose groups. The full-length cDNA consists of 4738 nucleotides with a reading frame encoding 1540 amino acid residues. In vitro recombinant plasmids were constructed and transferred to E. coli BL21 for vitellogenin expression. Efficient fusion expression was obtained by IPTG at 16°C, and the expressed target protein (680 amino acids, 75 kDa) existed in a soluble state, accounting for more than 25% of the total soluble protein. We prepared monoclonal antibodies using established immunohistochemistry to detect vitellogenin expression sites in sexually mature female fish. Our study shows that the expression sites of Vg in sexually mature female fish are mainly distributed in the fishtail, hepatopancreas, intestine, muscle, ovary, and pronephric kidney. In conclusion, the vitellogenin from B. sinensis could be used as a biomarker of environmental estrogens to achieve rapid detection in the marine environment and the subsequent experiments of development in colloidal gold strips after this research would be established to provide a highly efficient and convenient detection method for environment pollution.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48122370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Young Allis Shad Alosa alosa (Clupeidae) Would Not Be Euryphagous: An Assessment of Juvenile Diet and Prey Selectivity under Riverine-Type Conditions","authors":"L. Baumann, Adrien Aries, Jacky Vedrenne, J. Philip, S. Moreira, William Bouyssonnié, A. Bardonnet, M. Acolas","doi":"10.1155/2023/2499126","DOIUrl":"https://doi.org/10.1155/2023/2499126","url":null,"abstract":"Allis shad Alosa alosa hatches and develops in freshwater before migrating to the sea during its first months of life. Some field research works dedicated to the diet of the species in freshwater put forward that young stages of allis shad feed mainly on zooplankton, being opportunistic and euryphagous; their diet would diversify through ontogeny in relation to growth. However, these assumptions have never been confronted to the availability of prey, and the exact age of fish was unknown. In this work, we reared young allis shad under seminatural conditions, from 6 to 10 days posthatching until nearly 3 months old, in a trophic environment representative of a natural river. The rearing structures were designed as artificial rivers, supplied continuously by natural riverine water and zooplankton prey. Additional zooplankton was produced in separate basins and added daily in the structures. One artificial river was used to rear allis shad in 2018, and the experiment was conducted on two allis shad batches in 2019 (one batch per river). We described the nekton communities of potential prey available for allis shad in the rearing structures by sampling the water every week, and we compared these data with the stomach contents of fish captured at one and two months old posthatching to describe their diet and prey selectivity. Our results suggest that young allis shad should not be considered as opportunistic in their feeding, since clear selectivity was observed at both ages. One-month-old allis shad highly selected cladocerans, probably because they are easy to catch for fish at this age, when their swimming abilities are limited. Feeding selection at two months old drifted towards other prey taxa (dipteran larvae, ostracods, and/or copepods), whereas cladocerans were no longer preferred. Our results suggest that fish density and competition may entice two-month-old allis shad to enlarge their diet to other taxa, including benthic organisms, while one-month-old fish do not seem able to shift their diet and would fast in the absence of cladocerans. Thus, this highlights that the feeding of young allis shad may be highly challenging during their first month of growth.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48565599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}