DOI: 10.5061/dryad.4tmpg4fm4
title: Data from: From spawn to survival: Decoding the hydraulic conditions for successful silver carp egg incubation

description: Natural rivers exhibit complex and dynamic flow conditions that
 significantly impact the survival and development of semi-buoyant fish
 eggs. This study investigated the effects of flow velocities and
 turbulence on the semi-buoyant fish eggs in running water, using silver
 carp eggs as a representative species. Experiments conducted in a
 race-track flume revealed that moderate flow conditions (0.5 m/s) yielded
 the highest hatching rates, while excessive velocities (1.1 m/s) led to
 complete mortality at the blastula stage. Mild turbulence benefited egg
 incubation, but extreme turbulence reduced hatching rates and increased
 larval deformation. These findings demonstrate a clear relationship
 between hydraulic conditions and successful egg development, suggesting
 that optimal spawning and hatching conditions are differ. The results
 provide a foundation for evaluating suitable hydraulic conditions for
 semi-buoyant fish egg hatching in river habitats and offer insights into
 the potential impacts of hydraulic structures on fish populations. This
 research contributes to river ecosystem management, conservation of
 semi-buoyant fish species, and the design of fish-friendly hydraulic
 structures.
description: <strong>Collection of silver carp
 eggs</strong> The Animal Care and Use Committee
 of Chongqing Jiaotong University granted us permission to possess silver
 carp (<em>Hypophthalmichthys molitrix</em>) eggs and larvae in
 a laboratory setting for research purposes only (Permit No.
 Wang-20220325-002). The silver carp eggs were obtained from Yongchuan
 Shuihua Fishery Association, a fishery farm located in Chongqing,
 (105.9°E, 29.263°N), from May to July in 2022 and 2023.
 <strong>Design of Race-track flume</strong>
 A Race-track Flume (RTF) was designed for this study to
 investigate silver carp egg development under controlled flow conditions.
 The FTR, depicted in Figure. 1, consists of three main components aligned
 at the top: an incubation channel, a buffer channel, and an overflowing
 weir. The incubation channel, serving as the primary
 experimental area, measures 0.20 m in width and 0.40 m in height, with an
 operational water depth of 0.30 m. Adjacent to this, the buffer channel
 has the same width but reduced height of 0.20 m. This design ensures
 stable flow transition between channels. Flow control
 was achieved through two inlet pipes, each followed by two inflows. The
 angles between these inflows and the flume wall were adjusted to either
 45° or 135°, allowing precise regulation of flow conditions in the
 incubation channel by modifying inlet pipe flow rates (Figure
 S1). To prevent fish egg loss, the system incorporates
 an overflowing weir (0.35 m in width and 0.10 m in height) equipped with a
 finely woven mesh featuring a 1 mm square grid. This design effectively
 contains the eggs while permitting water flow. 
 <strong>Characterization of flow
 conditions</strong> 1) Measurement of flow
 velocity A comprehensive three-dimensional flow
 velocity measurement was conducted in RFT using an acoustic Doppler
 velocimeter (ADV, Vector 300m, Nortek Engineering AS Vector. Norway;
 detailed specifications available in Text S1). The measurement setup
 comprised 72 strategically designed points distributed across the flume.
 As illustrated in Figure.1 (c), these points were organized into 8
 cross-sections along the flume length. On each cross-section, 3 vertical
 perpendiculars were set with an interval of 0.05 m. For every vertical
 perpendicular, measurements were taken at three relative heights: 0.2,
 0.6, and 0.8 times the water depth. This systematic arrangement ensured a
 thorough capture of the flow dynamics throughout the RTF, providing a
 comprehensive dataset for analysis. 2) 2-D cloud map of
 flow velocity and turbulent intensity To enhance the
 visualization and understanding of the flow field within the incubation
 channel, we employed Surfer V.15.0 software to generate 2-D cloud maps
 depicting flow velocity and turbulent intensity. The spatial interpolation
 of our data was accomplished using Shepard's method, a sophisticated
 three-dimensional interpolation technique integrated into the Surfer
 software package. This approach involved a two-step process: first, we
 plotted the in-situ average flow velocities derived from equation (2), and
 then estimated velocities in unmeasured areas through above interpolation
 method. For the 2-D cloud map illustrating turbulent intensity, we
 exclusively utilized data from equation (3), which specifically
 represented turbulence intensity in the x-direction. This focus on the
 x-direction was justified by the observation that turbulence intensity
 differences in the y-direction and z-direction were not statistically
 significant. <strong>Selection of experimental
 parameters</strong> High-speed turbulent streams
 are commonly found in mountain rivers such as the upper reaches of the
 Yangtze River (Alvarez et al., 2017; Beechie et al., 2006; Constantinescu
 et al., 2011; Li et al., 2023). These flows are crucial for the spawning
 of certain fish species, including the four major Chinese carps, which
 require a flow velocity of approximately 1.1 m/s to release their eggs
 (Chen et al., 2021). Additionally, a specific flow velocity is needed to
 keep semi-buoyant fish eggs suspended and alive (Prada et al., 2021).
 Therefore, flow velocities ranging from 0.3–1.1 m/s were utilized in the
 current study. This comprehensive study investigated
 the effects of both flow velocity and turbulent intensity on silver carp
 egg incubation through two interconnected experimental series. This first
 series comprised six experiments examining flow velocity impacts. Five
 primary experiments (L1-L5, Table 1) utilized distinct average flow
 velocities (0.3, 0.5, 0.7, 0.9, and 1.1 m/s) in the incubation channel,
 while a control experiment (L0) employed a separate zero-velocity
 incubator with aerator-induced agitation for oxygenation. All experiments
 maintained a 0.3 m average water depth, with temperature continuously
 monitored in the buffer channel using a thermometer (model 1621A,
 manufactured by Hefei Zhice Electronic Co., Ltd., Hefei, China).
 The second experimental series focused on turbulent intensity
 effects, consisting of four primary experiments (W1–W4, Table 2) and a
 control (W0). The primary experiments maintained a consistent 0.7 m/s mean
 flow velocity while varying turbulent intensities (0.0968, 0.1044, 0.1297,
 and 0.1439 m/s) in x-direction. As before, a separate zero-velocity
 incubator serves as the control (W0). 
 <strong>Experimental procedure</strong>
 All experiments were conducted at the fishery farm. Prior to each
 experiment, flow conditions in the incubation channel were carefully
 adjusted to achieve the desired flow velocity and turbulence intensity,
 ensuring a stable environment. For every experimental run, 60 fertilized
 silver carp eggs at the 1-cell stage were carefully selected and
 transferred from the fishpond to the prepared channel. To ensure
 statistical robustness and reproducibility, each experiment was replicated
 three times, resulting in comprehensive study involving 1080 fertilized
 silver carp eggs. Throughout the incubation period, water quality was
 rigorously monitored to maintain dissolved oxygen level at a minimum of 7
 mg/L, thereby providing optimal conditions for egg development.
 Throughout the experiment, meticulous observation of silver carp
 eggs development was conducted at regular intervals. During the initial
 stages, eggs were examined every 30 to 60 minutes using a high-resolution
 portable microscope (SHOCREX DM9, 1000X magnification, Shenzhen
 Shu'an Technology Development Co., Ltd., Shenzhen, China). Once the
 organ differentiation stage was reached, observation intervals were
 extended to every 2 to 3 hours until hatching. The morphology and health
 status of silver carp eggs and larvae exposed to high-speed stream and
 turbulence were observed. Particular attention was paid
 to the morphology and health status of eggs and larvae exposed to
 high-speed streams and intense turbulence. Water temperature was strictly
 controlled at 28±0.5°C and continuously monitored throughout the
 experiment. The onset of each developmental stage was defined as the point
 when over 50% of the fertilized eggs reached that specific stage. The
 total incubation duration, which varied between 21 and 23 hours depending
 on specific conditions, was recorded along with egg mortality rates at
 each stage. <strong>Calculation of hatching rate
 and deformity rate</strong> The hatching rate (%)
 of silver carp eggs and the deformity rate (%) of hatched larvae was
 calculated using the following equations. 
   
 
 <em>Z</em><sub>1</sub>=<em>Y</em><sub>1</sub>/<em>Y</em>×100% (1)   <em>Z</em><sub>1</sub>=<em>Y</em><sub>2</sub>/<em>Y</em>×100% (2) Here, <em>Z</em><sub>1</sub> is the hatching rate, <em>Z</em><sub>2</sub> is the deformity rate, <em>Y</em><sub>1</sub> is the hatched larvae, <em>Y</em><sub>2</sub> is the deformed fish larvae, and <em>Y</em> represents the initial number of silver carp eggs.
description: # From spawn to survival: Decoding the hydraulic conditions for successful
 silver carp egg incubation **Dataset Description** This dataset contains
 experimental data examining the effects of flow velocities and turbulence
 on the development and survival of silver carp (*Hypophthalmichthys
 molitrix*) eggs. The experiments were conducted in an annular flume to
 investigate how different hydraulic conditions impact egg incubation,
 hatching rates, and larval development. **Experimental Methods** *
 Experiments conducted in a custom-designed annular flume * Flow velocities
 ranging from 0.3 to 1.1 m/s * Turbulence intensities varied at constant
 flow velocity (0.7 m/s) * Water temperature maintained at 28±0.5°C *
 Continuous monitoring of dissolved oxygen (minimum 7 mg/L) **Data Files
 and Structure** The dataset (data.xlsx) contains 8 worksheets: 1. **Fig
 2**: Measurement results of flow characteristics in the annual incubation
 channel 2. **Fig 3**: Flow turbulence intensity calculation results 3.
 **Fig 4**: Impacts of mean flow velocities on the hatching rates of silver
 carp 4. **Fig 5(a)**: Dead eggs observed at different developmental stagea
 within different flow velocities 5. **Fig 5(b)**: Dead eggs observed at
 different developmental stagea within different turbulence intensities,
 operting at the same mean flow velocity of 0.7 m/s. 6. **FigS2**:
 Measurement results of turbulent intensity Note: (1) Contents highlighted
 in yellow were used to improve readability.            (2) Text in red
 font indicates flow values - the fundamental parameters for working
 condition control. **Data Collection Methods** * Egg development monitored
 using high-resolution portable microscope (SHOCREX DM9, 1000X) * Flow
 velocities measured using Acoustic Doppler Velocimeter (ADV, Vector 300m)
 * 72 measurement points distributed across 8 cross-sections * Sampling
 frequency: 25 Hz with 100s sampling time per point **Variables and Units**
 **Flow Parameters**: * Mean flow velocity: meters per second (m/s) * Water
 depth: meters (m) * Hydraulic radius: meters (m) * Kinematic viscosity:
 square meters per second (m²/s) * Reynolds number: dimensionless * Froude
 number: dimensionless **Biological Parameters**: * Hatching rate:
 percentage (%) * Deformity rate: percentage (%) * Development stages:
 according to Amy E. George's method **Usage Notes** * Data quality
 for ADV measurements ensured by correlation coefficients &gt;80% and SNR
 &gt;15db * Development stages defined when &gt;50% of fertilized eggs
 reached specific stage * Total incubation duration: 21-23 hours
 post-fertilization **Acknowledgments** This study was supported by
 National Natural Science Foundation of China (No. 42007213) **Citation**
 When using this dataset, please
 cite: [https://doi.org/10.5061/dryad.4tmpg4fm4](https://doi.org/10.5061/dryad.4tmpg4fm4) **Contact Information** For questions about the dataset, please contact: * Xian-bing Zhang * Email: [zhangxb@cqjtu.edu.cn](mailto:zhangxb@cqjtu.edu.cn) * Chongqing Jiaotong University, Chongqing, China