Improved method to investigate natal homing in marine fish with otolith chemistry

Dispersal is a critical process in marine ecology, with profound implications for population conservation and fisheries management. Previous research has predominantly focused on reef-associated species, but studying the dispersal of more mobile fish species in nearshore environments is exceptionally challenging due to the complex coastal hydrography similar to reefs, and therefore dispersal knowledge of some coastal migratory behavior fish remains preliminary. In this study, we investigated the dispersal of a coastal fish species (small yellow croaker Larimichthys polyactis) in its juvenile life stage using otolith elemental fingerprints. We aimed to investigate the dispersal patterns of juveniles with otolith chemistry and identify potential natal sources. Results indicated that (1) significant geographical variations in the otolith elemental signatures can be considered as natural markers for assessing fish dispersal; (2) although small yellow croakers in the juvenile life stage are capable of settlement, a significant proportion of individuals continue subsequent passive dispersal; (3) juveniles may have originated from 2 natal sources in the sampling areas based on the differences in the near-core chemistry fingerprints. Results demonstrate the applicability of otolith chemistry fingerprints as natural tags in coastal waters and suggest that juveniles with the ability to settle will still employ dispersal strategies. This study contributes to research on fish dispersal in the early life stage and has significant implications for the marine fishery management of small yellow croaker.

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.

Monthly fishery survey data of the small yellow croaker Larimichthys polyactis in the southern Yellow Sea from 2003 and 2013 were employed to evaluate the variation in the resource distribution and biological characteristics (especially body length and sex ratio) in the population on a decadal scale. The results indicated that the small yellow croaker migrated from the Shawai fishing ground to the Dasha fishing ground in spring and was mainly distributed in the central and western parts of the Dasha fishing ground in April and May. Larimichthys polyactis in the Dasha fishing ground migrated eastward to offshore wintering grounds in autumn and reached the central Dasha fishing ground in October and November. The small yellow croaker entered the western waters of the Shawai fishing ground in winter. A large number of age 0+ fish occurred in the Shawai and Jiangwai fishing grounds in October of 2003 and 2013. The body lengths of the spawning stock and wintering stock in 2013 were larger than those in 2003, and the monthly sex ratios (female to male) were significantly less than 1 in both years. The monthly distribution of this fish in the southern Yellow Sea was consistent with a previous finding that “the stock migrated between the wintering grounds in the west of Jeju Island and the Lusi spawning grounds” but tended to move more northward, with the spawning grounds extending outward. In the past decade, body length variation experienced a decline after an increase, rather than a steady decrease. The sex ratio in the single-stick stow net showed a tendency to increase over the decade, but was either less than or more than 1 depending on the fishing gear; therefore, further studies should be conducted to determine the sex structure.

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.

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

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

Mixed-stock analysis of small yellow croaker Larimichthys polyactis providing implications for stock conservation and management

Diving into the deep-end: investigating tropical deep-reef fish assemblages

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 population genetic structure of small yellow croaker Larimichthys polyactis in the Yellow Sea and East China Sea was analyzed using amplified fragment length polymorphism (AFLP). A total of 304 loci were detected by four primer combinations among 53 individuals collected from four locations representing three stocks of small yellow croaker, 231 of which were polymorphic (75.99%). The proportion of polymorphic loci and Nei’s genetic distances for four populations ranged from 58.11% to 69.43% and from 0.1076 to 0.1331. AMOVA analysis and pairwise FST revealed significant genetic differentiation among four samples, supporting separate stocks in this species and endemic branch tribes in South Yellow Sea stock. The UPGMA tree also revealed the significant geographic structure in this species. Pattern of isolation by distance was observed in this species, indicating that significant genetic differentiation among localities of small yellow croaker was mainly due to the geographic distance. Besides geographic distance, the migratory behavior might be another factor, which influences the genetic structure of this species. Key words: Larimichthys polyactis, small yellow croaker, genetic structure, AFLP.

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.

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.

Set-nets are common alongshore fishing gear used in Haizhou Bay, which rely on flow to catch fish. The catch per unit effort (CPUE) of set-net is affected by spatial-temporal and environmental factors but no research has been conducted on this subject. In this study, we used generalized additive models (GAMs) to explore the influence of spatial-temporal and environmental factors on CPUEs of species aggregated, small yellow croaker (Larimichthys polyactis), and octopus (Octopus variabilis) based on logbooks investigations conducted at 4 stations in an alongshore area of Haizhou Bay from 2011 to 2012. The results showed that all CPUEs exhibited significant spatial-temporal differences at various scales. Aggregated CPUE was high when the sea surface temperature (SST) was 15–18°C and 20–23°C, which was mainly determined by life history traits of the octopus and small yellow croaker (optimal SSTs 14–17°C and 19–24°C, respectively). Chlorophyll-a concentration had significant influences on the aggregated, small yellow croaker and octopus CPUEs at optimal ranges of 3.8–6.2 mg m−3, 4.2–4.8 mg m−3 and 4.5–5.5 mg m−3, respectively. Flow through the net had positive relationships with CPUEs. The approximate logarithmic trends in regression curves had a critical point of 2.5 Mm3 d−1, which was the dividing point that differentiated whether the major factor affecting CPUEs was the flow velocity or the fishery resource. Our results from this study will help guide fishery production and improve catch rate of set-net fishing in Haizhou Bay.

The delta-generalized additive model (Delta_GAM) is commonly used for analyzing zero-inflated continuous data, and has been widely applied in egg production methods (EPMs). It consists of two GAMs: one with a binomial distribution to estimate the probability of non-zero values, and the other with a log-normal distribution (Delta_LN model) or a gamma distribution (Delta_LG model) to model the continuous non-zero values. However, the rather restrictive distribution assumptions are not fulfilled for egg production data. In this study, we modified the Delta_GAMs using two machine learning techniques: random forest (Delta_RF) and support vector machines (Delta_SVM). We applied the tenfold cross-validation procedure to compare the performance of these four models using root mean square error (RMSE) and the EPM survey data of small yellow croaker Larimichthys polyactis, mullet Liza haematocheilus and gizzard shad Konosirus punctatus from Haizhou Bay, China. Both the Delta_RF and Delta_SVM models showed superior performance to that of the Delta_LN and Delta_LG models. Predicted spatial and temporal distributions varied among the models, although predictive performance varied little. The annual egg production was predicted and estimated with large uncertainty. We propose that machine learning techniques such as RFs and SVMs be used to model zero-inflated continuous data from EPM surveys, which tend to provide a more reliable estimation of annual egg production (AEP).