Small Yellow Croaker Larimichthys Polyactis Research Articles

Functional Characterization of Three GnRH Isoforms in Small Yellow Croaker Larimichthys polyactis Maintained in Captivity: Special Emphasis on Reproductive Dysfunction.

Simple SummarySmall yellow croaker is a popular marine fish in southeast Asian countries. Due to a decline in production in the wild, marine aquaculture has been initiated in Korea. Seed production is performed using captive-reared broodstock, which is known to undergo reproductive dysfunction. Reproductive dysfunction is closely linked to endocrinological dysfunction in the brain-pituitary-gonad (BPG) axis. Gonadotropin-releasing hormone (GnRH) acts as a central regulator in the BPG-axis. To determine the possible involvement of GnRHs in reproductive dysfunction of small yellow croaker reared in captivity, three GnRH isoforms were cloned and functional characterization has been performed. The expression of GnRH1 in the brain was significantly higher at the ripen stage in both sexes during gonadal development. Gonadotropin subunits (GPα, FSHβ, LHβ) were simultaneously increased in the pituitary at the ripen stage in both sexes. Interestingly, females showed significantly lower expression of GnRH1 and GtHs than males. Both in vivo and in vitro administration of GnRH1 showed that GtHs were increased significantly in the pituitary at high concentration. However, sex-steroids (E2 and MT) significantly inhibited the GnRH1 expression in the brain in a dose-dependent manner. Altogether, GnRH1 plays a key role in gonadal maturation, and a low level of GnRH1 and GtHs might be responsible for reproductive dysfunction in the female small yellow croaker.Fish reproduction is regulated by the brain–pituitary–gonad (BPG) axis where the gonadotropin-releasing hormone (GnRH) plays a central role. Seed production of small yellow croaker (Larimichthys polyactis) is performed using captive-reared broodstock known to undergo reproductive dysfunction, which is connected to endocrinological dysfunction. To determine the endocrinological mechanism of GnRHs in the BPG axis of small yellow croaker, full-length sequences of three GnRH isoforms encoding sbGnRH (GnRH1), cGnRH-II (GnRH2), and sGnRH (GnRH3) were cloned and characterized from brain tissue. qRT-PCR, in vivo, and in vitro experiments were performed for functional characterization. The mRNA expression of GnRH1 in the brain and gonadotropin subunits (GPα, FSHβ, and LHβ) in the pituitary were significantly higher at the ripen stage during gonadal development and GnRH1 at spawning stage during spawning events. Expression of both GnRH1 and GtH subunits was significantly lower in females than males. GtH subunits were induced at higher concentrations of GnRH1 in vivo and in vitro. Sex-steroids significantly inhibited the GnRH1 expression in vitro in a dose-dependent manner. Taken together, results indicated that GnRH1 plays a key role in gonadal maturation and sex-steroids induced negative feedback in the regulation of GnRH. A lower level of GnRH1 and GtHs might be responsible for reproductive dysfunction in a female small yellow croaker.

A Preliminary Study on the Effects of Taurine-Enriched Rotifers on the Growth and Survival of the Small Yellow Croaker Larimichthys polyactis Larvae.

Simple SummaryRotifers may not meet the nutritional requirements of cultured marine fish species during seed production. Therefore, we evaluated the effect of feeding rotifers enriched with taurine on the growth performance and survival of the small yellow croaker Larimichtys polyactis larvae. The taurine content in the fish increased with the increase in the rotifer taurine levels. The growth and survival rates of the larvae fed taurine-enriched rotifers were higher than those fed control rotifers.The effect of feeding with taurine-enriched rotifers on larval growth and survival in the small yellow croaker Larimichthys polyactis was investigated. Rotifers, control (without taurine enrichment) or enriched with a commercial taurine supplement at two concentrations (400, and 800 mg/L), were used. The larvae (initial notochord length = 3.83 mm) were fed taurine-enriched rotifers in triplicate, from 3 days after hatching for 12 days. The average taurine contents of the rotifers were 0.31, 5.34, and 8.55 mg/g dry matter, respectively. The rotifers from all treatments had similar fatty acid composition. The growth and survival rates of the larvae fed rotifers enriched with 800 mg/L taurine supplementation were significantly higher than those of larvae fed rotifers without taurine enrichment (p = 0.005 and 0.002, respectively). The whole-body taurine content in the fish increased significantly with the increase in taurine level in the rotifers: 1.02, 3.48, and 4.11 mg/g in larvae fed control rotifers, and rotifers enriched with 400, and 800 mg/L taurine supplementation, respectively. The results of this study indicate that small yellow croaker larvae benefit from taurine concentrations above those typically reported in non-taurine-enriched rotifers.

The Effects of Selective Harvest on Exploited Population and Economic Benefits

The composition of catch is affected by exploited fishing gear and its selectivity, and long-term selective harvest induces the change in biological characters and economic value of exploited population. Stow net is the main fishing gear to capture commercially important fish species small yellow croaker (Larimichthys polyactis) in Haizhou Bay, China. Long-term stow net selective harvest affects both the biological characters and economic benefits of small yellow croaker. Therefore, an appropriate harvest scenario that can achieve the high economic benefits and the sustainable use of resource needs to be explored. In this study, we develop a bio-economic model for small yellow croaker and focus on different harvest scenarios for obtaining maximum economic benefit and sustainable utilization of resource. Our results indicate that the increase in mesh size has positive effects on the protection of small yellow croaker population, and optimal harvest scenario achieves the short- or long-term economic benefits to different stakeholders. Fishing with small mesh size gets high economic value in short-term, while fishing with large mesh size achieves better economic value and effectively protect small yellow croaker resource under long-term fishing pressure. This study provides evidence to balance the long-term economic benefits and sustainable utilization of fishery resource, and it also offers a basis for the scientific formulation of fishery policy.

Evaluation of Spawning- and Natal-Site Fidelity of Larimichthys polyactis in the Southern Yellow Sea Using Otolith Microchemistry

Small yellow croaker Larimichthys polyactis is an important commercial fish species; however, industrial-scale fishing has largely contributed to the changes in its biological characteristics, such as individual miniaturization, faster growth, and younger average age. Robust understanding of the pivotal life history of L. polyactis, a typical oceanodromous species, is needed for its conservation and restoration. However, L. polyactis fidelity to natal or spawning sites is not well understood and, at present, there is no effective management strategy to guarantee the sustainable exploitation of L. polyactis. This study used laser ablation inductively coupled plasma-mass spectrometry to analyse the elemental composition of otoliths from 60 adult yellow croakers caught in the southern Yellow Sea, including two spawning groups with 1- and 2-year-old fish (S1 and S2, respectively) sampled close to China and one overwintering group including two-year-old fish (O2) sampled close to South Korea. The ratios of elements (Li, Na, Sr, and Ba) to Ca in the otolith core zones were significantly higher (P < 0.05) than in those of the year one (Y1) and year two (Y2) annual rings, but there were no significant differences in the elemental ratios between the Y1 and Y2 zones. Principal component analysis (PCA) of the elemental otolith signatures of the core, Y1, and Y2 zones in the three groups revealed two distinct clusters (cluster 1: S1-core, S2-core, and O2-core zones; cluster 2: S2–Y1, O2–Y1, S2–Y2, and O2–Y2 zones) and one zone (S1–Y1), suggesting spawning-site fidelity and natal-site fidelity uncertainty, especially considering the dispersal by current in prolonged period (50 h) from fertilized eggs to hatching and internal effect, such as yolk sac and maternal effect. Furthermore, these results indicated that the S2 and O2 groups could represent the same population, suggesting a stable migratory route for L. polyactis in Chinese and South Korean waters, whereas the S1 group could represent another population. This suggests the possibility a mixed L. polyactis population in the southern Yellow Sea. Characterization L. polyactis spawning-site fidelity is a crucial step toward linking spawning-site fidelity of this overexploited species with thorough conservation and management strategies.

Sub-acute exposure to nanoplastics via two-chain trophic transfer: From brine shrimp Artemia franciscana to small yellow croaker Larimichthys polyactis

This study investigated the trophic transfer of nanoplastics in marine food chains. We fed nanoplastic-exposed Artemia franciscana (brine shrimp) to Larimichthys polyactis (small yellow croaker) daily for eight days. Subsequently, the overall health condition, histopathological damage to the liver and digestive tract, and swimming ability of the fish were measured. After the sub-acute exposure to nanoplastics via trophic transfer, the fish showed inhibited growth, severe liver damage, as well as a poorer swimming ability compared to the control. The swimming ability was especially affected, in terms of the overall movement as well as thigmotaxis. The results thus clarified that even an indirect exposure to nanoplastics could induce neurotoxic effects and affect the swimming ability of the fish. As fish are well-known human food resources, the possibility of such trophic transfers affecting higher trophic level organisms, such as humans, cannot be ruled out.

Early life migration and population discrimination of the small yellow croaker Larimichthys polyactis from the Yellow Sea: inferences from otolith Sr/Ca ratios

Early life migration and population discrimination of the small yellow croaker Larimichthys polyactis from the Yellow Sea: inferences from otolith Sr/Ca ratios

The Effect of Frying Process on Lipids in Small Yellow Croaker (Larimichthys polyactis) and Frying Oil

ABSTRACT The effect of frying process on lipid oxidation in small yellow croaker and frying oil was evaluated in this study. Parameters including the proximate composition, the contents of phosphatidylcholine (PC) and phosphatidylethanolamine (PE), acid value (AV), peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), and fatty acid composition were measured. After frying, lipid content as well as triacylglycerol content in small yellow croaker was increased, and the profile of fatty acid in small yellow croaker was changed due to the exchange of moisture and the absorption of lipid with frying oils. However, the decrease of PC and PE contents during frying process proved the occurrence of lipid hydrolysis, while the increase of POV indicated that lipid oxidation occurred. In addition, the water-rich small yellow croaker also accelerates the exchange of moisture and free fatty acid between small yellow croaker and frying oil and further accelerates the hydrolysis and oxidation of palm oil and soybean oil. In conclusion, the lipid profile of small yellow croaker was significantly changed during frying, and the nutritional value of fried products was time-dependently reduced upon frying.

Developing an intermediate-complexity projection model for China’s fisheries: A case study of small yellow croaker (Larimichthys polyactis) in the Haizhou Bay, China

Developing an intermediate-complexity projection model for China’s fisheries: A case study of small yellow croaker (Larimichthys polyactis) in the Haizhou Bay, China

KIFC1 functions in nuclear reshaping and midpiece formation during the spermatogenesis of small yellow croaker Larimichthys polyactis

The C-terminal kinesin motor protein (KIFC1) has essential functions in spermatogenesis. To evaluate molecular mechanisms of KIFC1 during teleost fish spermatogenesis, there was cloning and sequencing the kifc1 cDNA in the testis of Larimichthys polyactis. Quantitative PCR results indicated there were Lp-kifc1 mRNA transcripts in the testes. Results from conducting fluorescence in situ hybridization and immunofluorescence procedures indicated there were trends in relative abundance changes in Lp-kifc1 mRNA transcripts that were associated with abundance of Lp-KIFC1 protein during spermatogenesis. The Lp-KIFC1 protein was detected at all stages of spermatogenesis. There was minimal Lp-KIFC1 in the cytoplasm of spermatogonia, with content being greater and concentrated in the perinuclear region in spermatocytes and during early/mid-stages of development of spermatids. There were large abundances of Lp-KIFC1 in spermatids at the mid-developmental stage. In late-developing spermatids, Lp-KIFC1 content was less and concentrated in the bottom of the nucleus, where the midpiece formed. There was a small Lp-KIFC1 in the midpiece of mature sperm. These findings indicate Lp-KIFC1 may have functions in L. polyactis spermatogenesis. Results from conducting immunofluorescence procedures indicated Lp-KIFC1 was co-localized microtubules and mitochondria throughout spermatogenesis. There were large abundances of Lp-KIFC1 and tubulin in spermatids during the mid-developmental stage, when there is a decrease in size and reshaping of the nucleus. During midpiece formation, there was co-localization of the Lp-KIFC1 and mitochondria in the spermatid perinuclear region to the midpiece. These findings indicate Lp-KIFC1 is involved in nuclear reshaping and midpiece formation during spermatogenesis in L. polyactis.

First Report on the Occurrence of Eggs of the Small Yellow Croaker Larimichthys polyactis from Chilsan-do Island, Jeollanam-do, Korea

First Report on the Occurrence of Eggs of the Small Yellow Croaker Larimichthys polyactis from Chilsan-do Island, Jeollanam-do, Korea

Profile and Development of microsatellite markers for the small yellow croaker Larimichthys polyactis based on High-throughput Sequencing technology

Larimichthys polyactis is an economically important species in the Northwestern Pacific. In this study, characters of candidate microsatellite markers for L. polyactis were profiled and 24 polymorphic loci were developed using high-throughput sequencing method. A total of 6.085G raw data was obtained, and 7490 microsatellite-rich fragments were examined. Among them, 4199 dinucleotide, 2519 trinucleotide, 625 tetranucleotide, 121 pentanucleotide and 26 hexanucleotide repeats were detected. Besides, 24 candidate polymorphic microsatellite primers were isolated and characterized. The polymorphism information content of these microsatellite markers was 0.582 to 0.796, and all loci were highly polymorphic (PIC>0.50). The results of this study can not only provide abundant markers for the further genetic research of L. polyactis, but also provide basic information for understanding its distribution characteristics of microsatellites.

Estimating Length at Sexual Maturity of the Small Yellow Croaker Larimichthys polyactis in the Yellow Sea of Korea Using Visual and GSI Methods

Estimating Length at Sexual Maturity of the Small Yellow Croaker Larimichthys polyactis in the Yellow Sea of Korea Using Visual and GSI Methods

A dynamic energy budget model for small yellow croaker Larimichthys polyactis: Parameterisation and application in its main geographic distribution waters

Global fishery resources have generally declined, although the rapidity has decreased, and trends have reversed in specific instances following judiciously well-informed intervention. Appropriate management is necessary for the optimum utilisation of fish stocks. Small yellow croaker Larimichthys polyactis is an important fisheries species in the northwest Pacific Ocean, and a major decline in its abundance has been attributed to overfishing and environmental changes. For understanding energetics of small yellow croaker in responses to varying environmental conditions, a dynamic energy budget (DEB) model was applied to this species in the Yellow and East China Seas. The model was parameterised with the observed data including age-at-birth, age-since-birth-at-puberty, life span, fecundity, age-length and length-weight relationship. The model parameterisation has achieved an acceptable goodness of fit, with both low mean relative error and symmetric mean squared error of 0.083. Applications of the model have shown that it can reasonably reproduce the energetics of small yellow croaker in its main biogeographic distribution. Growth simulations in both length and weight were within the range of observations. The simulated fecundity matched the observation reasonably well. We discuss the need for further improvement of the model and additional collection of environmental data.

Analyses of egg size, otolith shape, and growth revealed two components of small yellow croaker in Haizhou Bay spawning stock

The geographical variations in life history characteristics of small yellow croaker Larimichthys polyactis, caused by experienced different environmental conditions, have been observed in China seas. Previous studies based on spatial distribution, migration route, and body morphometrics suggested a complex stock structure. In this study, to clarify the source of a spawning stock, we investigated the reproduction strategy and inter-structure of the Haizhou Bay (HZB) spawning stock in the middle Yellow Sea from both egg survey and adult otolith increment analysis. Egg and adult samples were collected from three surveys during spawning season in 2013. Distinct spatial and temporal variations were detected in egg distribution and size, and otolith shape analysis of adult fishes revealed two morphotypes with different increment growth using random forest cluster. The results indicate the existence of two components within the same spawning stock in HZB from different wintering grounds, and accordingly special protection should be required for this stock given the significance to maintain connectivity between adjacent subpopulations.

Application of a catch-based method for stock assessment of three important fisheries in the East China Sea

Most fisheries in China do not have maximum sustainable yield (MSY) estimates due to limited and poor data. Therefore, finding a common method to estimate MSY or total allowable catch (TAC) for fishery management is necessary. MSYs of three important fisheries in the East China Sea were evaluated through a catch-based model. Estimates for intrinsic rate of increase (r) and five levels of process error were considered. Results showed hairtail Trichiurus japonicas (Temminck and Schlegel) and small yellow croaker Larimichthys polyactis (Bleeker) fisheries experienced overfishing from the mid-1990s to the early 2000s, and the suggested TACs were 55.8×104 t and 9.06×104 t, respectively. Decades of overfishing in wintering and spawning grounds of large yellow croaker Larimichthys crocea (Richardson) caused the fishery’s collapse in the 1980s, and it has not recovered until today. The Catch–MSY model generated similar estimated MSYs with other methods and may be a useful choice for the assessment of regional stocks in China.

Distribution of the early life stages of small yellow croaker in the Yangtze River estuary and adjacent waters

The horizontal distribution of the early life stages of small yellow croaker Larimichthys polyactis in the Yangtze River estuary and its adjacent area was investigated through six ichthyoplankton surveys conducted during the period of mid-April to mid-July 2015. A total of seven eggs and 2461 larvae and juveniles of small yellow croaker were collected. Abundance of the specimens was highest in mid-May and lowest in mid-July. The composition of the different development stages of small yellow croaker varied among the six cruises, although post-flexion larvae and juveniles dominated the ichthyoplankton collection in each cruise. Specimens at different development stages showed different distribution patterns in the study area. The eggs, yolk-sac and pre-flexion larvae were mainly collected at stations with depth exceeding 30 m, while post-flexion larvae and juveniles were mainly distributed in the relatively shallow waters near to the mouth of the Yangtze River. In conclusion, the study suggested that the study area had largely lost the ecological function to support small yellow croaker spawning, although it could still serve as nursery ground for the species.

Feeding habits of small yellow croaker Larimichthys polyactis in the Bohai Sea

PDF HTML阅读 XML下载 导出引用 引用提醒 渤海小黄鱼摄食习性 DOI: 作者: 作者单位: 1. 中国海洋大学水产学院, 山东 青岛 266003;2. 农业部海洋渔业可持续发展重点实验室, 山东省渔业资源与生态环境重点实验室, 中国水产科学研究院黄海水产研究所, 山东 青岛 266071;3. 青岛海洋科学与技术国家实验室海洋渔业科学与食物产出过程功能实验室, 山东 青岛 266237 作者简介: 魏秀锦(1993-),女,硕士研究生,主要从事鱼类摄食生态学研究.E-mail:w_xj4185@126.com 通讯作者: 中图分类号: S932 基金项目: 国家重点基础研究发展计划项目（2015CB453303）；中央级公益性科研院所基本科研业务费资助项目（20603022016003）；山东省泰山学者专项. Feeding habits of small yellow croaker Larimichthys polyactis in the Bohai Sea Author: Affiliation: 1. College of Fisheries, Ocean University of China, Qingdao 266003, China;2. Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture;Shandong Provincial Key Laboratory of Fishery Resources and Eco-Environment, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China;3. Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:根据2009年8月至2011年5月4个航次渤海底拖网调查所获得的样品，采用胃含物分析法、K-W检验和聚类分析等方法，对38~218 mm体长范围小黄鱼（）的摄食习性及其随体长、季节的变化进行了研究，并探讨了小黄鱼摄食随海域和年际的时空变化。结果表明：渤海小黄鱼摄食的饵料有40余种，主要以鱼类、虾类和浮游动物为食，优势饵料种类为六丝钝尾虾虎鱼（Euphausia pacifica）、长额刺糠虾（）。渤海小黄鱼在春夏秋这三个季节中，春季的摄食强度最低，夏季和秋季的摄食强度都较高，不同的是夏季摄食率更高，而秋季的摄食量更高。随着体长的增大，渤海小黄鱼的摄食策略发生了相应的变化。从摄食强度分析，在体长较小时，胃饱满指数低，小黄鱼通过高摄食率来提高摄食强度；随着体长的增加，通过高胃饱满指数来提高摄食强度。从摄食的饵料个体分析，小黄鱼采取了随着体长增加摄食饵料个数减少，饵料个体增大的摄食策略。从摄食的饵料组成分析，小黄鱼随着体长增加发生了显著的食性转换现象：体长小于60 mm属浮游动物食性；体长60~99 mm时，属混合动物食性；体长100~119 mm时，属虾食性；体长超过120 mm，包括了虾/鱼食性和鱼食性。小黄鱼摄食的时空变化与环境中优势饵料生物的数量波动密切相关。 Abstract:Based on four bottom trawl surveys conducted in the Bohai Sea from August 2009 to May 2011, 2979 stomach samples of small yellow croaker with body lengths of 38-218 mm were collected. Stomach contents analysis, the Kruskal-Wallis test and the cluster analysis were used to study their feeding habits and ontogenetic, temporal and spatial variations. The results indicated that small yellow croaker fed on more than 40 prey species. Euphausia pacifica, were the dominant prey item. With the increase of fish size, there is a corresponding change in the feeding strategy of the Bohai Sea small yellow croaker. According to the feeding intensity, as indicated by the percentage of empty stomachs (PES) and mean stomach fullness index (MSFI), MSFI was low at the smaller fish size, resulting in the small yellow croaker increasing the feeding intensity as observed by the low PES. With the increase of fish size, the feeding intensity was enhanced by increasing MSFI. According to the prey items, the mean number of prey per fish decreased significantly with the increased fish size, while the mean weight of prey items per fish increased. According to diet compositions, the feeding habits of small yellow croaker had significant ontogenetic variations. Small yellow croaker less than 60 mm in body length mainly fed on the zooplanktivores copepoda, euphausiacea and mysidacea. At 60-99 mm long, it mainly fed on demersal shrimps and copepoda. The frequency of demersal shrimps in the food increased gradually with the increasing fish size, whereas the frequency of copepod decreased. Thus, fish with a 60-99 mm body length belonged to the generalist predators group. At 100-119 mm long, it belonged to shrimp predators group, mainly feeding on demersal shrimps at a frequency of more than 60%, and fish. It still mainly fed on demersal shrimps and fish at greater than 120 mm in body length with the frequency of fish in the food increasing gradually, and ultimately more than the frequency of demersal shrimps (beyond 60%). Thus, fish greater than 120 mm long included shrimp/fish predators and piscivores. The feeding intensity varied significantly across seasons. The feeding intensity of spring was lowest and the feeding intensity of summer and autumn were higher. The difference in the feeding rate was higher (PES was lower) in summer and the feeding amount (MSFI) was higher in autumn. Seasonal variations were also discovered in diet composition. were the dominant preys in spring, were the dominant preys in summer, whereas was the dominant prey in autumn. By analyzing historical data, we found that the feeding habits of small yellow croaker in the Bohai Sea were closely related to the composition and abundance of dominant prey organisms. The temporal and spatial variations in the feeding habits of small yellow croaker is closely related to the fluctuation of dominant prey species in the environment. 参考文献 相似文献 引证文献

Bottom-temperature distribution characteristics of small yellow croaker ( Larimichthys polyactis ) in the East China Sea and comparison of analysis methods

Bottom-temperature distribution characteristics of small yellow croaker ( <i>Larimichthys polyactis</i> ) in the East China Sea and comparison of analysis methods

Biological responses of small yellow croaker (Larimichthys polyactis) to multiple stressors: a case study in the Yellow Sea, China

Temporal changes in biological characteristics of small yellow croaker Larimichthys polyactis in the Yellow Sea were examined for the period of 1960–2008. The body size and age of small yellow croaker decreased substantially, in particular, average length of fish in 2008 was reduced by ~85% than those occurring in 1985, and at that time ~93% of the total catch was dominated by one-year-old individuals. Correspondingly, growth parameters also varied significantly over the years, i.e., k (growth coefficient) and t 0 (zero-length age) gradually increased from 0.26 and–0.58 year in 1960 to 0.56 and–0.25 year in 2008, respectively. Although, L∞ (body length) sharply decreased from 34.21 cm in 1960 to 24.06 cm in 2008, and t r (inflexion age) decreased from 3.78 year in 1960 to 1.61 year in 2008. There was a great increase both in natural mortality coefficient and fishing mortality coefficient. However, according to the gray correlation analysis, changes in the biological characteristics of small yellow croaker were induced by different stressors ranked as: fishing vessel power>feeding grade>sea surface temperature. This study suggests that the active fishery management measures for biological characters of fish populations should be considered.

Early life history of the small yellow croaker (Larimichthys polyactis) in sandy ridges of the South Yellow Sea

ABSTRACTThe early life history of the small yellow croaker Larimichthys polyactis was studied using the otolith microchemistry of juvenile fish and a recruitment survey in the sandy ridges of the South Yellow Sea. The otolith Sr/Ca ratio regime shifted markedly at the age of 5–7 days (early April) and 37–41 days (around early May). Subsequently, the Sr/Ca ratio was almost constant until late June, indicating an aggregation of L. polyactis juveniles in the relatively stable habitat of the sandy ridges, which was supported by a recruitment survey that showed a rapid increase in the number of juveniles in the same area between early May and the end of June. Variations in the Sr/Ca ratio between early April and early May might reflect a habitat adaptive strategy of L. polyactis in the pelagic stage to hydrodynamic processes of the sandy ridges. Based on the aforementioned habitat shifts and recruitment phenology, it was hypothesised that L. polyactis juveniles disperse between early April and early May, inhabit sandy ridges to feed, and migrate offshore in late June.