Objective The macula lagena in birds is located at the apical end of the cochlea and contains many tiny otoliths. The macula lagena is innervated and has neural projections to the brainstem, but its physiological func...Objective The macula lagena in birds is located at the apical end of the cochlea and contains many tiny otoliths. The macula lagena is innervated and has neural projections to the brainstem, but its physiological function is still unclear. It remains disputable that it is because otoliths in the lagena are rich in elements Fe and Zn that birds can obtain geomagnetic information for homing. To clarify this issue, we carried out a study to determine whether or not otoliths in the lagena of homing pigeons are richer in magnetic elements than those in the saccule and the utricle. Methods The contents of ferromagnetic elements （Fe, Co, Ni） and other metal elements in lagenal otoliths of adult homing pigeons were precisely analyzed with inductively coupled plasma mass spectrometry （ICP-MS） of high sensitivity, and then they were compared with those in saccular and utricular otoliths （all the contents were normalized to Ca）. Results In adult homing pigeons, the contents of ferromagnetic elements （Fe, Co, Ni） in lagenal otoliths were less than 0.7% （normalized to Ca element） and were the same order in magnitude as those in saccular and utricular otoliths. The content of Fe in lagenal otoliths was not significantly different from that in utricular otoliths and was even lower than that in saccular otoliths. The content of Co in lagenal otoliths was lower than that in saccular otoliths and higher than that in utricular otoliths. The content of Ni in lagenal otoliths was not significantly different from that in saccular otoliths and was higher than that in utricular otoliths. The contents of other metal elements Na, Mg, K, Al, Mn and Pb in lagenal otoliths were not significantly different from those in utricular and saccular otoliths. The contents of metal elements Zn, Ba and Cu in lagenal otoliths were lower than those in saccular otoliths. Conclusion The contents of magnetic elements in lagenal otoliths of homing pigeons are not much higher than those in utricular and saccular otoliths, which does not support the hypothesis that birds depend on high contents of Fe and Zn in lagenal otoliths for sensation of geomagnetic information. Similarities in morphology, element ingredient and element content between lagenal otoliths and utricular otoliths suggest that the two types of otolithic organs may play similar roles in sensing gravitational and acceleration signals.展开更多
Oxygen and carbon isotope ratios（δ^（18）O and δ^（13）C） in otoliths were used to identify the stock structure of small yellow croaker,Larimichthys polyactis.Otoliths were collected from fish at five locations ac...Oxygen and carbon isotope ratios（δ^（18）O and δ^（13）C） in otoliths were used to identify the stock structure of small yellow croaker,Larimichthys polyactis.Otoliths were collected from fish at five locations across the Yellow Sea and the Bohai Sea representing most of their distributional range and fisheries areas.The significant differences in the isotopic signatures showed that the five locations could be chemically distinguished and clearly separated,indicating stock subdivision.Correlation of δ^（18）O and δ^（13）C values suggested that population of L.polyactis could be divided into the Bohai Sea group,the southern Yellow Sea group and the central Yellow Sea group.Discriminant analysis of δ^（18）O and δ^（13）C values demonstrated a high significant difference with 85.7% classification accuracy.The spatial separation of L.polyactis indicated a complex stock structure across the Yellow Sea and the Bohai Sea.These results indicate that optimal fisheries management may require a comprehensive consideration on the current spatial arrangements.This study has provided further evidence that measurement of the stable isotopes ratios in otolith can be a valuable tool in the delineation of fishery management units.展开更多
The Chaenocephalus aceratus were sampled in summers between 1979 and 1990. Their otoliths show pattern of daily microincrements as otoliths of similar species--Pseudochaenichthys georgianus and fishes both temperate a...The Chaenocephalus aceratus were sampled in summers between 1979 and 1990. Their otoliths show pattern of daily microincrements as otoliths of similar species--Pseudochaenichthys georgianus and fishes both temperate and tropical waters. Changes of the microincrements growth pattern and otolith shape are described in relation to larval, hatching and metamorphosis stages have similar patterns for Ps. georgianus and Charnpsocephalus gunnari, reflecting similar habitats in their early life. Width of larvae-postlarvae daily increments are： （1.0-1.6）×10-3 SSI, （1.8-2.8）×10-3 SG1 and （1.5-2.4）×10-3 ANI. They were search and chosen automatically from density profiles of otolith tissues. Tissues were prepared by new saving time and materials way--one time up to 40 ones per microscopic glass. Age of fish estimated from microincrements was alike to that inferred from the body length distribution, otoliths mass （age （years） = 140.82 OM （g） ＋ 0.8546） and otolith shape changes--large in length and surface on medial plane. Those parameters create age groups of close neighbours. They have different environments. C. aceratus due to its adaptation to cold water, attain rapidly large body according to a growth equation： Lt= 75.1 ×10-3 （1-e-0.26（t-0.51）. Among large fishes there were only females.展开更多
Fish otolithδ^(15) N(δ^(15) N_(oto))is a demonstrated source of information of dietary history for marine fi sh as it is available iN_(oto)lith archives and sedimentary deposits unlike white muscle tissue(WMT).WMT a...Fish otolithδ^(15) N(δ^(15) N_(oto))is a demonstrated source of information of dietary history for marine fi sh as it is available iN_(oto)lith archives and sedimentary deposits unlike white muscle tissue(WMT).WMT and stomach content data are insufficient for trophic level(TL)data of past fi shes which is important for the changes of marine fi shery resources over long time scales.To determine the correlation betweenδ^(15) N_(oto) and fi sh WMTδ^(15) N(δ^(15) N_(wmt))and the feasibility of usingδ^(15) N_(oto) in characterizing the TLs of marine fi shes,we conducted nitrogen stable isotope analysis(SIA)in the otolith and WMT of 36 marine fi sh species sampled from the Yellow Sea and northern East China Sea in 2011-2014.Bothδ^(15) N_(oto) andδ^(15) N_(wmt) were analyzed using an elemental analyzer coupled with an isotope ratio mass spectrometer(EA-IRMS).Multiple otoliths were combined to make each otolith measurement and were analyzed as-is without a carbonate dissolution pre-processing step.δ^(15) N_(oto) andδ^(15) N_(wmt) comparisons for species in the Yellow Sea and northern East China Sea are currently lacking and would be helpful for both regional studies and for increasing the number of species for whichδ^(15) N_(oto) andδ^(15) N_(wmt) have been compared.Additionally,to determine the relative accuracy of trophic level calculated usingδ^(15) N_(oto),we compared TL calculated fromδ^(15) N_(oto) to traditional trophic level metrics calculated usingδ^(15) N_(wmt).The results showed a positive and highly signifi cant correlation(R=0.780,P<0.001)betweenδ^(15) N_(oto) andδ^(15) N_(wmt).Trophic level estimation using WMT(TL wmt)and otolith(TL oto)showed congruence in our study,which is not entirely surprising given thatδ^(15) N_(oto) was regressed againstδ^(15) N_(wmt) and the resulting regression coefficient was used to convertδ^(15) N_(oto) toδ^(15) N_(wmt) prior to calculating TL oto.This conversion was required in order to be consistent with previousδ^(15) N_(wmt)-based calculations of TL for comparison.TL oto calculations resulted in TL values that were largely within 5%-10%of TL values calculated withδ^(15) N_(wmt).Our fi ndings show thatδ^(15) N_(oto) is a feasible technique for characterizing the TLs of marine fi sh and can also assist in food web and marine ecosystem studies.展开更多
This study explored the morphological characteristics and differences of the otoliths in three native species,Schizothorax biddulphi,S.eurystomus and S.curvifrons,in the Yarkand River of the Tarim River,Xinjiang,China...This study explored the morphological characteristics and differences of the otoliths in three native species,Schizothorax biddulphi,S.eurystomus and S.curvifrons,in the Yarkand River of the Tarim River,Xinjiang,China.A total of 93 specimens(27 S.biddulphi,39 S.eurystomus,and 27 S.curvifrons)were analyzed using six basic otolith morphological parameters(OA,R_(max),R_(min),OP,OL,OW)to derive six factors(F_(1),F_(2),F_(3),F_(4),F_(5),F_(6))and seven indices(RO,FF,CI,RE,EL,RR,AR)for morphological assessment.A discriminant analysis incorporating 77 Fourier coefficients of the otoliths revealed distinct morphological differences among the species.A significant power function relationship between otolith morphology and standard length was observed across the species,with R2 values ranging from 0.409 to 0.749.Principal component analysis(PCA)of 7 traditional otolith morphological indicators explained 81.243%of the variance,yielding an overall species discrimination rate of 81.65%.Further PCA of 77 Fourier harmonic values enhanced the discrimination accuracy,with the first 3 components accounting for 77.49%of the total variation and an improved discrimination rate of 100.00%.Cluster analysis resulted in the grouping of S.biddulphi and S.curvifrons together and revealed their association with S.eurystomus,indicating notable morphological distinctions.Both otolith shape indices and elliptical Fourier analysis have been useful in distinguishing the phenotypic units of different fish species.In this study,otolith morphology was applied for the first time to identify Schizothorax species,providing an in-depth description of species distribution and evolutionary history.This study provides a reference for the identification and systematic classification of Schizothorax species and a scientific basis for formulating effective species protection measures,for promoting the sustainable management of species and important habitats.展开更多
The otolith nucleus captures a fish’s life history during egg and hatching stages,offering insights into species-specific differences in element types and concentrations as well as the endogenous and exogenous factor...The otolith nucleus captures a fish’s life history during egg and hatching stages,offering insights into species-specific differences in element types and concentrations as well as the endogenous and exogenous factors shaping these variations.This study aimed to investigate the variation in the types and concentrations of elements within the otolith nuclei of three Antarctic fish species,including Pagothenia borchgrevinki,Trematomus hansoni,and Trematomus bernacchii,collected from Prydz Bay,East Antarctica.Nine elements,^(23)Na,^(24)Mg,^(29)Si,^(31)P,^(39)K,^(57)Fe,^(66)Zn,^(88)Sr,and^(137)Ba,were selected for analyses because of their concentrations and ecological significance.Ratios of each element to Ca(Me/Ca)were used for analysis,and Me/Ca in the otolith nuclei of these species were analyzed to explore species-specific variations in element types.Significant differences in element composition,except for Fe/Ca and Ba/Ca,were found in different species.Temperature,salinity,reproduction,pelagic larval lifestyle,and diet composition were considered as key endogenous and exogenous factors influencing these differences.Decision tree discriminant analysis,based on the variation of the types and concentrations of elements,was used to identify P.borchgrevinki,T.hansoni,and T.bernacchii with accuracy rates of 86.54%,82.61%,and 73.33%,respectively.Principal component analysis showed overlapping 95%confidence el-lipses for the three species at 79.96%,67.31%,and 56.71%,respectively.As these species belong to the Nototheniidae family and share a similar hatching period,the accuracy of species discrimination is reduced.Considering the high probability of error in distin-guishing species using otolith nucleus elements,we recommend otolith shape should also be considered to improve identification ac-curacy.展开更多
Background:Vestibular assessments,such as the video ocular counter roll(vOCR)test,offer valuable insights into the interactions between age,otolith function,and vestibular performance.Objective:To analyze the relation...Background:Vestibular assessments,such as the video ocular counter roll(vOCR)test,offer valuable insights into the interactions between age,otolith function,and vestibular performance.Objective:To analyze the relation between age and vOCR gains as a potential marker of age-related otolith degeneration.Methods:A total of 107 participants underwent vOCR testing.Descriptive statistics and simple linear regression analyses were conducted to explore the association between age and vOCR gains.Results were presented using regression coefficients,95%confidence intervals,p-values,and R-squared values.Results:In the overall sample,statistically significant associations were observed between age and vOCR gains in both ears.For the right ear,vOCR gains decreased with increasing age(coefficient:-0.03;95%CI:-0.05 to-0.01;p<0.001;R^(2)=0.08),while the left ear showed a slightly stronger association(coefficient:-0.04;95%CI:-0.07 to-0.02;p<0.001;R²=0.12).These findings indicate a moderate age-related decline in otolith-mediated vestibular responses.Conclusion:vOCR gains appear to decline with age,reflecting potential age-related otolith degeneration.These results support the clinical value of vOCR as a non-invasive method to assess vestibular function and its changes across the lifespan.展开更多
Otoliths are biogenic carbonate minerals whose microstructure and microchemistry have been used for age determination, stock identification, life history and environmental tracing. Using X-ray diffraction （XRD） and ...Otoliths are biogenic carbonate minerals whose microstructure and microchemistry have been used for age determination, stock identification, life history and environmental tracing. Using X-ray diffraction （XRD） and Fourier transform infrared （FTIR） spectroscopy, we have determined the mineral types and crystalline characteristics of three pairs of otoliths from naked carp Gymnocypris przewalskii, the predominant fish in Lake Qinghai. The results indicate that the mineral of both lapillus and sagitta of the naked carp is aragonite, and that of asteriscus is vaterite. The aragonite of lapillus has prefect crystallization. Given the shape of lapillus and the sensitivity of its aragonite to water chemistry, lapillus was used to analyze temporal Sr/Ca ratios along the maximal growth axis by an electron probe microanalyzer （EPMA）. Consistent variations of Sr/Ca ratios with a range of 1.0x10-3-5.0~10-3 on the long and short radii indicate that Sr/Ca ratios of lapillus potentially respond to the chemical compositions of the host waters during the period of the naked carp＇s growth and migration. Discontinuous （dark） zones of lapillus were formed during fall and winter when the naked carp grows slowly in Lake Qinghai, resulting in similar low Sr/Ca ratios to lake water, whereas incremental zones with higher St/Ca ratios respond to its migratory river waters during spring and summer. Various Sr/Ca ratios of incremental zones suggest that the migratory pattern of the naked carp may be much more flexible, rather than in a single river. Therefore, high-resolution otolith microchemistry of the naked carp can be used to trace its migratory behavior, which is of significance for determining its migratory pattern and life history of this precious species inhabiting the Tibetan Plateau.展开更多
Two basic questions must be solved in age determination of the early life stage of the eel, Anguilla japonica, in daily precision: (i) recognizing the initial increment in otolith and determining the timing of the ini...Two basic questions must be solved in age determination of the early life stage of the eel, Anguilla japonica, in daily precision: (i) recognizing the initial increment in otolith and determining the timing of the initial increment formation; (ii) confirming the deposition rate of the increment. A clear understanding of the first question in the otolith of larvae and glass eel, Anguilla japonica, has not been got, such as how to confirm the initial increment in age determination of glass eel, determine the timing of hatch check formation and validate the microstructure in the otolith of the early life stage of Anguilla japonica.展开更多
Atlantic halibut(Hippoglossus hippoglossus,Linnaeus,1758)are a data-poor stock within the waters of the United States.This study evaluated the use of otolith measurements to back-calculate lengths of Atlantic halibut ...Atlantic halibut(Hippoglossus hippoglossus,Linnaeus,1758)are a data-poor stock within the waters of the United States.This study evaluated the use of otolith measurements to back-calculate lengths of Atlantic halibut at previous ages.Back-calculations have proven useful for estimating length at age and growth rates of other species.To the best knowledge of the authors,this study is the first to document the use of this method for Atlantic halibut.Otolith back-calculations rely on a few key assumptions,such as proportionality of fish length and otolith length,which are not always met.This study shows that backcalculations using the Fraser-Lee method can provide reasonable estimates of Atlantic halibut length at previous ages,especially when samples from young halibut are included to improve estimates of the intercept of the linear regressions.Based on back-calculated estimates,female and male halibut in the Gulf of Maine showed different growth rates after age five.There was no evidence of changes in growth rates over an approximately 15 year time period.Halibut caught in the Gulf of Maine and on the neighboring Scotian Shelf showed some differences in growth rates;however,the results did not support strong conclusions about differences between the two regions as the direction of the differences was not consistent between the sexes and previous tagging studies have shown extensive movement between the two areas.The finding of reasonably accurate back-calculated lengths at previous ages is important for this data-poor species,as back-calculations increase the amount of information that can be obtained from otoliths.展开更多
This study examined the right and left otoliths of 174 individuals of Pseudotolithus senegalensis from the Porto-Novo lagoon, Lake Nokoué and the Atlantic coast. The results show a significant variation in the po...This study examined the right and left otoliths of 174 individuals of Pseudotolithus senegalensis from the Porto-Novo lagoon, Lake Nokoué and the Atlantic coast. The results show a significant variation in the population according to geographic location. Mixed-effects linear analysis showed no significant variation by site, side or sex (p > 0.05). Analysis of otolith shape using ANOVA showed significant differences for length, width and area (p 0.05). Canonical discriminant analysis revealed significant differences between sites (p < 0.05). Finally, shape analyses showed significant differences between sites (p = 0.0001) and between right and left sides (p = 0.007), but no difference by sex (p = 0.395). The study of otolith morphology is therefore proving to be a valuable tool for differentiating stocks and understanding ecological variations.展开更多
The lanternfishes are mesopelagic fish that are highly productive as common bycatch of deep-sea shrimp trawlers,but they are often neglected or discarded.Despite being one of the dominant lanternfish species in the Ar...The lanternfishes are mesopelagic fish that are highly productive as common bycatch of deep-sea shrimp trawlers,but they are often neglected or discarded.Despite being one of the dominant lanternfish species in the Arabian Sea,little is known about the life history of Diaphus thiollierei and its role in marine ecosystems.In this study,103 D.thiollierei were collected in the Arabian Sea during October-November 2020 to study population growth based on sagittal otolith daily ages;and 10 fish collected during April–May 2021 were subjected to otolith microchemistry analysis to reconstruct the vertical migration in their life history using LA-ICP-MS technique.The standard length–dry weight(SL-DW)relationships for D.thiollierei revealed both negative allometric growth and a significant difference between the sexes.Using daily growth annuli counts on the sagittal section of otoliths,the von Bertalanffy growth equation for D.thiollierei was determined.The pattern of four elemental ratios(Sr to Ca,Mg to Ca,Li to Ca,and Ba to Ca)in sagittal otolith suggested that,in general,D.thiollierei descended continually after hatching until the post-larval(PL)stage when they reached a depth of approximately 200 m.Subsequently,from the PL stage to the post-metamorphosisⅡ(PMⅡ)stage,D.thiollierei likely further sank from 200 m to a depth of approximately 300 m,and then in the daytime they were at a depth of approximately 300–800 m to take refuge from predators.This pilot study explored to unravel the vertical migration during life history in D.thiollierei from sagittal otoliths,whereas further investigation on otolith is needed to better delineate the population ecology in detail,and thus to provide basic information for the exploitation of the lanternfish resource and the understanding of their ecological roles.展开更多
Black rockfish Sebastes schlegelii juveniles （30-40 mm total length） were immersed in a range of calcein （CAL） solutions at concentrations ranging from 50 to 250 mg/L and alizarin red S （ARS） solutions at concen...Black rockfish Sebastes schlegelii juveniles （30-40 mm total length） were immersed in a range of calcein （CAL） solutions at concentrations ranging from 50 to 250 mg/L and alizarin red S （ARS） solutions at concentrations ranging from 100 to 500 mg/L in filtered seawater （salinity 30） for 24 h. Fluorescent marks were detected in otoliths （sagittae, asteriscus）, scales, fin rays （dorsal, pectoral, ventral, anal, and caudal fin rays）, and fin spines （dorsal, ventral, and anal fin spines） after a 60-d growth experiment. With the exception of 50-100 rng/L CAL, acceptable marks were produced in the otoliths and fin spines by all concentrations of CAL and ARS. In particular, marks were clearly visible under normal light in the sagittae, asteriscus, and fin spines offish immersed in 200 500 mg/L, 300-500 rag/L, and 200-500 mg/LARS, respectively. Scales and fin rays had acceptable marks at much higher concentrations （≥50 mg/L CAL, ≥300 mg/L ARS for scales and ≥50 mg/L CAL,≥200 mg/L ARS for fin rays）. The mark quality was highest （i.e., acceptable marks were observed in all sampled structures after immersion marking） in fish immersed in 150-250 mg/L CAL or 300-500 mg/LARS. In addition, there was no significant difference in survival and growth of marked fish compared with controls 60 d post-marking （P〉0.05）.展开更多
We tested the utility of chemical marking techniques in the juvenile black rockfish Sebastes schlegelii. Juveniles （30-40 mm total length） were immersed in a range of tetracycline hydrochloride （TC） solutions at c...We tested the utility of chemical marking techniques in the juvenile black rockfish Sebastes schlegelii. Juveniles （30-40 mm total length） were immersed in a range of tetracycline hydrochloride （TC） solutions at concentrations ranging from 300 to 500 mg/L, and alizarin complexone （ALC） solutions at concentrations ranging from 200 to 400 mg/L in filtered sea water （salinity of 30） for 24 h, respectively. Otoliths （sagittae, asteriscus）, scales, fin rays （dorsal, pectoral, ventral, anal, and caudal fin rays）, and fin spines （dorsal, ventral, and anal fin spines） were sampled and used to detect fluorescent marks after a 60-day growth experiment. With the exception of 300 mg/L TC, acceptable marks were produced in the otoliths and fin spines by all concentrations of TC and ALC. In particular, we observed clearly visible marks in the sagittae, asteriscus, and fin spines under normal light at concentrations of200~00 mg/L, 250-400 mg/L, and 250-400 mg/L ALC, respectively. Scales and fin rays had acceptable marks at much higher concentrations （_〉350 mg/L TC, 〉250 mg/L ALC for scales and _〉350 mg/L TC, 〉300 mg/L ALC for fin rays）. The best mark quality （i.e., acceptable marks were observed in all sampled structures after immersion marking） were obtained following immersion in TC at between 350-500 rag/L, and ALC between 300-400 mg/L. In addition, there was no significant difference in survival and growth of TC and ALC marked fish compared to their controls up to 60 days post-marking （P〉0.05）.展开更多
Objective:To study the potential role of subjective visual vertical(SVV)as a prognostic marker for canalith repositioning maneuver(CRM)in patients with posterior canal benign paroxysmal positional vertigo(PC-BPPV)for ...Objective:To study the potential role of subjective visual vertical(SVV)as a prognostic marker for canalith repositioning maneuver(CRM)in patients with posterior canal benign paroxysmal positional vertigo(PC-BPPV)for the Indian population.Methods:SVV was examined in 30 patients with PC-BPPV before and after canalith repositioning maneuver and after complete resolution of PC-BPPV.Study parameters included the mean of 10 angular tilt readings and direction of deviation,which were compared before and after CRM and following complete resolution of PC-BPPV.Results:The angle of SVV tilt was greater and deviated towards the affected ear before CRM in all patients,which decreased significantly shortly after CRM and continued to decrease after complete resolution of PC-BPPV(p<0.0001).Conclusions:SVV can be used to test utricular dysfunction in PC-BPPV.The angle of tilt improves in response to CRM,which may be used as a prognostic marker in patients with PC-BPPV receiving CRM.展开更多
The migratory history of the engraulid fish Coilia nasus in the Rokkaku and Chikugo River estuaries of the Ariake Sea, Japan was assessed using otolith strontium（Sr） X-ray intensity maps and strontium：calcium（Sr...The migratory history of the engraulid fish Coilia nasus in the Rokkaku and Chikugo River estuaries of the Ariake Sea, Japan was assessed using otolith strontium（Sr） X-ray intensity maps and strontium：calcium（Sr：Ca） ratio life history transects by an electron probe microanalyzer（EPMA）. The results showed that seven of the ten specimens from the Rokkaku River Estuary（LJC） and all 15 specimens collected in the Chikugo River Estuary（ZHC） had low Sr：Ca ratios（≤3） at the central otolith area, indicating their riverine origin and initial freshwater residence. After the first regime shift adjacent to natal regions, the Sr level mapping displayed a wide variety of color patterns, and the Sr：Ca ratios obtained by the line transect analysis could be divided into one to six significantly different phases indicative of gradual life history transition. The other three specimens from the Rokkaku River Estuary had high Sr：Ca ratios（3–6.7） at the central otolith area but showed alternating changes between low and high values outside the natal region, suggesting that estuarine-origin individuals occurred in the Rokkaku River Estuary. The two-dimensional maps of the Sr level and average of the otolith Sr：Ca ratios along the life-history transects could be used as effective tools for reconstruction of past habitat use of the tapertail anchovy in estuaries of the Ariake Sea, Japan.展开更多
Although chub mackerel （Scomberjaponicus） is a primary pelagic fish species, we have only limited knowledge on its key life history processes. The present work studied the age and growth of chub mackerel in the East...Although chub mackerel （Scomberjaponicus） is a primary pelagic fish species, we have only limited knowledge on its key life history processes. The present work studied the age and growth of chub mackerel in the East China and Yellow Seas. Age was determined by interpreting and counting growth rings on the sagitta otoliths of 252 adult fish caught by the Chinese commercial purse seine fleet during the period from November 2006 to January 2007 and 150 juveniles from bottom trawl surveys on the spawning ground in May 2006. The difference between the assumed birth date of 1st April and date of capture was used to adjust the age determined from counting the number of complete translucent rings. The parameters of three commonly used growth models, the von Bertalanffy, Logistic and Gompertz models, were estimated using the maximum likelihood method. Based on the Akaike Information Criterion （AIC）, the yon Bertalanffy growth model was found to be the most appropriate model. The size-at-age and size-at-maturity values were also found to decrease greatly compared with the results achieved in the 1950s, which was caused by heavy exploitation over the last few decades.展开更多
Otolith shape is species specific and is an ideal marker of fish population affiliation. In this study, otolith shape of spottedtail goby Synechogobius ommaturus is used to identify stocks in different spawning locati...Otolith shape is species specific and is an ideal marker of fish population affiliation. In this study, otolith shape of spottedtail goby Synechogobius ommaturus is used to identify stocks in different spawning locations in the Yellow Sea. The main objectives of this study are to explore the potential existence of local stocks of spottedtail goby in the Yellow Sea by analysis of otolith shape, and to investigate ambient impacts on otolith shape. Spottedtail goby was sampled in five locations in the Yellow Sea in 2007 and 2008. Otoliths are described using variables correlated to size (otolith area, perimeter, length, width, and weight) and shape (rectangularity, circularity, and 20 Fourier harmonics). Only standardized otolith variables are used so that the effect of otolith size on the shape variables could be eliminated. There is no significant difference among variables of sex, year, and side (left and right). However, the otolith shapes of the spring stocks and the autumn stocks differ significantly. Otolith shape differences are greater among locations than between years. Correct classification rate of spottedtail goby with the otolith shape at different sampling locations range from 29.7%–77.4%.展开更多
基金supported by the National Natural Science Foundation of China(No.30470560 and 30730041)the National Basic Research Program of China (No.2007CB512306)the Knowledge Innovation Project of Chinese Academy of Sciences (No.KSCX1-YW-R-36)
文摘Objective The macula lagena in birds is located at the apical end of the cochlea and contains many tiny otoliths. The macula lagena is innervated and has neural projections to the brainstem, but its physiological function is still unclear. It remains disputable that it is because otoliths in the lagena are rich in elements Fe and Zn that birds can obtain geomagnetic information for homing. To clarify this issue, we carried out a study to determine whether or not otoliths in the lagena of homing pigeons are richer in magnetic elements than those in the saccule and the utricle. Methods The contents of ferromagnetic elements （Fe, Co, Ni） and other metal elements in lagenal otoliths of adult homing pigeons were precisely analyzed with inductively coupled plasma mass spectrometry （ICP-MS） of high sensitivity, and then they were compared with those in saccular and utricular otoliths （all the contents were normalized to Ca）. Results In adult homing pigeons, the contents of ferromagnetic elements （Fe, Co, Ni） in lagenal otoliths were less than 0.7% （normalized to Ca element） and were the same order in magnitude as those in saccular and utricular otoliths. The content of Fe in lagenal otoliths was not significantly different from that in utricular otoliths and was even lower than that in saccular otoliths. The content of Co in lagenal otoliths was lower than that in saccular otoliths and higher than that in utricular otoliths. The content of Ni in lagenal otoliths was not significantly different from that in saccular otoliths and was higher than that in utricular otoliths. The contents of other metal elements Na, Mg, K, Al, Mn and Pb in lagenal otoliths were not significantly different from those in utricular and saccular otoliths. The contents of metal elements Zn, Ba and Cu in lagenal otoliths were lower than those in saccular otoliths. Conclusion The contents of magnetic elements in lagenal otoliths of homing pigeons are not much higher than those in utricular and saccular otoliths, which does not support the hypothesis that birds depend on high contents of Fe and Zn in lagenal otoliths for sensation of geomagnetic information. Similarities in morphology, element ingredient and element content between lagenal otoliths and utricular otoliths suggest that the two types of otolithic organs may play similar roles in sensing gravitational and acceleration signals.
基金The National Basic Research Program(973 Program)of China under contract Nos 2015CB453300 and 2010CB428900
文摘Oxygen and carbon isotope ratios（δ^（18）O and δ^（13）C） in otoliths were used to identify the stock structure of small yellow croaker,Larimichthys polyactis.Otoliths were collected from fish at five locations across the Yellow Sea and the Bohai Sea representing most of their distributional range and fisheries areas.The significant differences in the isotopic signatures showed that the five locations could be chemically distinguished and clearly separated,indicating stock subdivision.Correlation of δ^（18）O and δ^（13）C values suggested that population of L.polyactis could be divided into the Bohai Sea group,the southern Yellow Sea group and the central Yellow Sea group.Discriminant analysis of δ^（18）O and δ^（13）C values demonstrated a high significant difference with 85.7% classification accuracy.The spatial separation of L.polyactis indicated a complex stock structure across the Yellow Sea and the Bohai Sea.These results indicate that optimal fisheries management may require a comprehensive consideration on the current spatial arrangements.This study has provided further evidence that measurement of the stable isotopes ratios in otolith can be a valuable tool in the delineation of fishery management units.
文摘The Chaenocephalus aceratus were sampled in summers between 1979 and 1990. Their otoliths show pattern of daily microincrements as otoliths of similar species--Pseudochaenichthys georgianus and fishes both temperate and tropical waters. Changes of the microincrements growth pattern and otolith shape are described in relation to larval, hatching and metamorphosis stages have similar patterns for Ps. georgianus and Charnpsocephalus gunnari, reflecting similar habitats in their early life. Width of larvae-postlarvae daily increments are： （1.0-1.6）×10-3 SSI, （1.8-2.8）×10-3 SG1 and （1.5-2.4）×10-3 ANI. They were search and chosen automatically from density profiles of otolith tissues. Tissues were prepared by new saving time and materials way--one time up to 40 ones per microscopic glass. Age of fish estimated from microincrements was alike to that inferred from the body length distribution, otoliths mass （age （years） = 140.82 OM （g） ＋ 0.8546） and otolith shape changes--large in length and surface on medial plane. Those parameters create age groups of close neighbours. They have different environments. C. aceratus due to its adaptation to cold water, attain rapidly large body according to a growth equation： Lt= 75.1 ×10-3 （1-e-0.26（t-0.51）. Among large fishes there were only females.
基金Supported by the National Key Basic Research Development Program of China(973 Program)(No.2015CB453303)the National Science Foundation for Young Scientists of China(No.41606195)。
文摘Fish otolithδ^(15) N(δ^(15) N_(oto))is a demonstrated source of information of dietary history for marine fi sh as it is available iN_(oto)lith archives and sedimentary deposits unlike white muscle tissue(WMT).WMT and stomach content data are insufficient for trophic level(TL)data of past fi shes which is important for the changes of marine fi shery resources over long time scales.To determine the correlation betweenδ^(15) N_(oto) and fi sh WMTδ^(15) N(δ^(15) N_(wmt))and the feasibility of usingδ^(15) N_(oto) in characterizing the TLs of marine fi shes,we conducted nitrogen stable isotope analysis(SIA)in the otolith and WMT of 36 marine fi sh species sampled from the Yellow Sea and northern East China Sea in 2011-2014.Bothδ^(15) N_(oto) andδ^(15) N_(wmt) were analyzed using an elemental analyzer coupled with an isotope ratio mass spectrometer(EA-IRMS).Multiple otoliths were combined to make each otolith measurement and were analyzed as-is without a carbonate dissolution pre-processing step.δ^(15) N_(oto) andδ^(15) N_(wmt) comparisons for species in the Yellow Sea and northern East China Sea are currently lacking and would be helpful for both regional studies and for increasing the number of species for whichδ^(15) N_(oto) andδ^(15) N_(wmt) have been compared.Additionally,to determine the relative accuracy of trophic level calculated usingδ^(15) N_(oto),we compared TL calculated fromδ^(15) N_(oto) to traditional trophic level metrics calculated usingδ^(15) N_(wmt).The results showed a positive and highly signifi cant correlation(R=0.780,P<0.001)betweenδ^(15) N_(oto) andδ^(15) N_(wmt).Trophic level estimation using WMT(TL wmt)and otolith(TL oto)showed congruence in our study,which is not entirely surprising given thatδ^(15) N_(oto) was regressed againstδ^(15) N_(wmt) and the resulting regression coefficient was used to convertδ^(15) N_(oto) toδ^(15) N_(wmt) prior to calculating TL oto.This conversion was required in order to be consistent with previousδ^(15) N_(wmt)-based calculations of TL for comparison.TL oto calculations resulted in TL values that were largely within 5%-10%of TL values calculated withδ^(15) N_(wmt).Our fi ndings show thatδ^(15) N_(oto) is a feasible technique for characterizing the TLs of marine fi sh and can also assist in food web and marine ecosystem studies.
基金Supported by the National Natural Science Foundation of China(No.31360635)the Tianshan Talent Training Project of Xinjiang(No.2023 TSYCCX 0128)the Science and Technology Public Relations Planning in Key Fields of the XPCC Science and Technology Bureau(No.2022 DB 019)。
文摘This study explored the morphological characteristics and differences of the otoliths in three native species,Schizothorax biddulphi,S.eurystomus and S.curvifrons,in the Yarkand River of the Tarim River,Xinjiang,China.A total of 93 specimens(27 S.biddulphi,39 S.eurystomus,and 27 S.curvifrons)were analyzed using six basic otolith morphological parameters(OA,R_(max),R_(min),OP,OL,OW)to derive six factors(F_(1),F_(2),F_(3),F_(4),F_(5),F_(6))and seven indices(RO,FF,CI,RE,EL,RR,AR)for morphological assessment.A discriminant analysis incorporating 77 Fourier coefficients of the otoliths revealed distinct morphological differences among the species.A significant power function relationship between otolith morphology and standard length was observed across the species,with R2 values ranging from 0.409 to 0.749.Principal component analysis(PCA)of 7 traditional otolith morphological indicators explained 81.243%of the variance,yielding an overall species discrimination rate of 81.65%.Further PCA of 77 Fourier harmonic values enhanced the discrimination accuracy,with the first 3 components accounting for 77.49%of the total variation and an improved discrimination rate of 100.00%.Cluster analysis resulted in the grouping of S.biddulphi and S.curvifrons together and revealed their association with S.eurystomus,indicating notable morphological distinctions.Both otolith shape indices and elliptical Fourier analysis have been useful in distinguishing the phenotypic units of different fish species.In this study,otolith morphology was applied for the first time to identify Schizothorax species,providing an in-depth description of species distribution and evolutionary history.This study provides a reference for the identification and systematic classification of Schizothorax species and a scientific basis for formulating effective species protection measures,for promoting the sustainable management of species and important habitats.
基金supported by the Impact and Response of Antarctic Seas to Climate Change(No.IRASCC 2020-2025)from the Ministry of Natural Resources of the Peo-ple’s Republic of China.
文摘The otolith nucleus captures a fish’s life history during egg and hatching stages,offering insights into species-specific differences in element types and concentrations as well as the endogenous and exogenous factors shaping these variations.This study aimed to investigate the variation in the types and concentrations of elements within the otolith nuclei of three Antarctic fish species,including Pagothenia borchgrevinki,Trematomus hansoni,and Trematomus bernacchii,collected from Prydz Bay,East Antarctica.Nine elements,^(23)Na,^(24)Mg,^(29)Si,^(31)P,^(39)K,^(57)Fe,^(66)Zn,^(88)Sr,and^(137)Ba,were selected for analyses because of their concentrations and ecological significance.Ratios of each element to Ca(Me/Ca)were used for analysis,and Me/Ca in the otolith nuclei of these species were analyzed to explore species-specific variations in element types.Significant differences in element composition,except for Fe/Ca and Ba/Ca,were found in different species.Temperature,salinity,reproduction,pelagic larval lifestyle,and diet composition were considered as key endogenous and exogenous factors influencing these differences.Decision tree discriminant analysis,based on the variation of the types and concentrations of elements,was used to identify P.borchgrevinki,T.hansoni,and T.bernacchii with accuracy rates of 86.54%,82.61%,and 73.33%,respectively.Principal component analysis showed overlapping 95%confidence el-lipses for the three species at 79.96%,67.31%,and 56.71%,respectively.As these species belong to the Nototheniidae family and share a similar hatching period,the accuracy of species discrimination is reduced.Considering the high probability of error in distin-guishing species using otolith nucleus elements,we recommend otolith shape should also be considered to improve identification ac-curacy.
文摘Background:Vestibular assessments,such as the video ocular counter roll(vOCR)test,offer valuable insights into the interactions between age,otolith function,and vestibular performance.Objective:To analyze the relation between age and vOCR gains as a potential marker of age-related otolith degeneration.Methods:A total of 107 participants underwent vOCR testing.Descriptive statistics and simple linear regression analyses were conducted to explore the association between age and vOCR gains.Results were presented using regression coefficients,95%confidence intervals,p-values,and R-squared values.Results:In the overall sample,statistically significant associations were observed between age and vOCR gains in both ears.For the right ear,vOCR gains decreased with increasing age(coefficient:-0.03;95%CI:-0.05 to-0.01;p<0.001;R^(2)=0.08),while the left ear showed a slightly stronger association(coefficient:-0.04;95%CI:-0.07 to-0.02;p<0.001;R²=0.12).These findings indicate a moderate age-related decline in otolith-mediated vestibular responses.Conclusion:vOCR gains appear to decline with age,reflecting potential age-related otolith degeneration.These results support the clinical value of vOCR as a non-invasive method to assess vestibular function and its changes across the lifespan.
基金supported by National Basic Research Program of China (Grant No. 2010CB833400)National Natural Science Foundation of China (Grant No. 40873082)
文摘Otoliths are biogenic carbonate minerals whose microstructure and microchemistry have been used for age determination, stock identification, life history and environmental tracing. Using X-ray diffraction （XRD） and Fourier transform infrared （FTIR） spectroscopy, we have determined the mineral types and crystalline characteristics of three pairs of otoliths from naked carp Gymnocypris przewalskii, the predominant fish in Lake Qinghai. The results indicate that the mineral of both lapillus and sagitta of the naked carp is aragonite, and that of asteriscus is vaterite. The aragonite of lapillus has prefect crystallization. Given the shape of lapillus and the sensitivity of its aragonite to water chemistry, lapillus was used to analyze temporal Sr/Ca ratios along the maximal growth axis by an electron probe microanalyzer （EPMA）. Consistent variations of Sr/Ca ratios with a range of 1.0x10-3-5.0~10-3 on the long and short radii indicate that Sr/Ca ratios of lapillus potentially respond to the chemical compositions of the host waters during the period of the naked carp＇s growth and migration. Discontinuous （dark） zones of lapillus were formed during fall and winter when the naked carp grows slowly in Lake Qinghai, resulting in similar low Sr/Ca ratios to lake water, whereas incremental zones with higher St/Ca ratios respond to its migratory river waters during spring and summer. Various Sr/Ca ratios of incremental zones suggest that the migratory pattern of the naked carp may be much more flexible, rather than in a single river. Therefore, high-resolution otolith microchemistry of the naked carp can be used to trace its migratory behavior, which is of significance for determining its migratory pattern and life history of this precious species inhabiting the Tibetan Plateau.
基金Project supported by the National Natural Science Foundation of China.
文摘Two basic questions must be solved in age determination of the early life stage of the eel, Anguilla japonica, in daily precision: (i) recognizing the initial increment in otolith and determining the timing of the initial increment formation; (ii) confirming the deposition rate of the increment. A clear understanding of the first question in the otolith of larvae and glass eel, Anguilla japonica, has not been got, such as how to confirm the initial increment in age determination of glass eel, determine the timing of hatch check formation and validate the microstructure in the otolith of the early life stage of Anguilla japonica.
基金This research was funded by Maine Sea Grant(grant number NA10OAR4170081)the Maine DMR(through the Halibut Fund established under 12 M.R.S.Sec.6039).
文摘Atlantic halibut(Hippoglossus hippoglossus,Linnaeus,1758)are a data-poor stock within the waters of the United States.This study evaluated the use of otolith measurements to back-calculate lengths of Atlantic halibut at previous ages.Back-calculations have proven useful for estimating length at age and growth rates of other species.To the best knowledge of the authors,this study is the first to document the use of this method for Atlantic halibut.Otolith back-calculations rely on a few key assumptions,such as proportionality of fish length and otolith length,which are not always met.This study shows that backcalculations using the Fraser-Lee method can provide reasonable estimates of Atlantic halibut length at previous ages,especially when samples from young halibut are included to improve estimates of the intercept of the linear regressions.Based on back-calculated estimates,female and male halibut in the Gulf of Maine showed different growth rates after age five.There was no evidence of changes in growth rates over an approximately 15 year time period.Halibut caught in the Gulf of Maine and on the neighboring Scotian Shelf showed some differences in growth rates;however,the results did not support strong conclusions about differences between the two regions as the direction of the differences was not consistent between the sexes and previous tagging studies have shown extensive movement between the two areas.The finding of reasonably accurate back-calculated lengths at previous ages is important for this data-poor species,as back-calculations increase the amount of information that can be obtained from otoliths.
文摘This study examined the right and left otoliths of 174 individuals of Pseudotolithus senegalensis from the Porto-Novo lagoon, Lake Nokoué and the Atlantic coast. The results show a significant variation in the population according to geographic location. Mixed-effects linear analysis showed no significant variation by site, side or sex (p > 0.05). Analysis of otolith shape using ANOVA showed significant differences for length, width and area (p 0.05). Canonical discriminant analysis revealed significant differences between sites (p < 0.05). Finally, shape analyses showed significant differences between sites (p = 0.0001) and between right and left sides (p = 0.007), but no difference by sex (p = 0.395). The study of otolith morphology is therefore proving to be a valuable tool for differentiating stocks and understanding ecological variations.
基金The fund from the Laoshan Laboratory under contract No.LSK202203802the National Programme on Global Change and Air-Sea Interaction under contract No.GASI-02-SCS-YD sum/spr/aut。
文摘The lanternfishes are mesopelagic fish that are highly productive as common bycatch of deep-sea shrimp trawlers,but they are often neglected or discarded.Despite being one of the dominant lanternfish species in the Arabian Sea,little is known about the life history of Diaphus thiollierei and its role in marine ecosystems.In this study,103 D.thiollierei were collected in the Arabian Sea during October-November 2020 to study population growth based on sagittal otolith daily ages;and 10 fish collected during April–May 2021 were subjected to otolith microchemistry analysis to reconstruct the vertical migration in their life history using LA-ICP-MS technique.The standard length–dry weight(SL-DW)relationships for D.thiollierei revealed both negative allometric growth and a significant difference between the sexes.Using daily growth annuli counts on the sagittal section of otoliths,the von Bertalanffy growth equation for D.thiollierei was determined.The pattern of four elemental ratios(Sr to Ca,Mg to Ca,Li to Ca,and Ba to Ca)in sagittal otolith suggested that,in general,D.thiollierei descended continually after hatching until the post-larval(PL)stage when they reached a depth of approximately 200 m.Subsequently,from the PL stage to the post-metamorphosisⅡ(PMⅡ)stage,D.thiollierei likely further sank from 200 m to a depth of approximately 300 m,and then in the daytime they were at a depth of approximately 300–800 m to take refuge from predators.This pilot study explored to unravel the vertical migration during life history in D.thiollierei from sagittal otoliths,whereas further investigation on otolith is needed to better delineate the population ecology in detail,and thus to provide basic information for the exploitation of the lanternfish resource and the understanding of their ecological roles.
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest(No.201003068)the National Natural Science Foundation of China(Nos.31172447,41176117)
文摘Black rockfish Sebastes schlegelii juveniles （30-40 mm total length） were immersed in a range of calcein （CAL） solutions at concentrations ranging from 50 to 250 mg/L and alizarin red S （ARS） solutions at concentrations ranging from 100 to 500 mg/L in filtered seawater （salinity 30） for 24 h. Fluorescent marks were detected in otoliths （sagittae, asteriscus）, scales, fin rays （dorsal, pectoral, ventral, anal, and caudal fin rays）, and fin spines （dorsal, ventral, and anal fin spines） after a 60-d growth experiment. With the exception of 50-100 rng/L CAL, acceptable marks were produced in the otoliths and fin spines by all concentrations of CAL and ARS. In particular, marks were clearly visible under normal light in the sagittae, asteriscus, and fin spines offish immersed in 200 500 mg/L, 300-500 rag/L, and 200-500 mg/LARS, respectively. Scales and fin rays had acceptable marks at much higher concentrations （≥50 mg/L CAL, ≥300 mg/L ARS for scales and ≥50 mg/L CAL,≥200 mg/L ARS for fin rays）. The mark quality was highest （i.e., acceptable marks were observed in all sampled structures after immersion marking） in fish immersed in 150-250 mg/L CAL or 300-500 mg/LARS. In addition, there was no significant difference in survival and growth of marked fish compared with controls 60 d post-marking （P〉0.05）.
基金Supported by the Special Fund for Agro-Scientific Research in the Public Interest(No.201003068)the National Natural Science Foundation of China(Nos.31172447,41176117)
文摘We tested the utility of chemical marking techniques in the juvenile black rockfish Sebastes schlegelii. Juveniles （30-40 mm total length） were immersed in a range of tetracycline hydrochloride （TC） solutions at concentrations ranging from 300 to 500 mg/L, and alizarin complexone （ALC） solutions at concentrations ranging from 200 to 400 mg/L in filtered sea water （salinity of 30） for 24 h, respectively. Otoliths （sagittae, asteriscus）, scales, fin rays （dorsal, pectoral, ventral, anal, and caudal fin rays）, and fin spines （dorsal, ventral, and anal fin spines） were sampled and used to detect fluorescent marks after a 60-day growth experiment. With the exception of 300 mg/L TC, acceptable marks were produced in the otoliths and fin spines by all concentrations of TC and ALC. In particular, we observed clearly visible marks in the sagittae, asteriscus, and fin spines under normal light at concentrations of200~00 mg/L, 250-400 mg/L, and 250-400 mg/L ALC, respectively. Scales and fin rays had acceptable marks at much higher concentrations （_〉350 mg/L TC, 〉250 mg/L ALC for scales and _〉350 mg/L TC, 〉300 mg/L ALC for fin rays）. The best mark quality （i.e., acceptable marks were observed in all sampled structures after immersion marking） were obtained following immersion in TC at between 350-500 rag/L, and ALC between 300-400 mg/L. In addition, there was no significant difference in survival and growth of TC and ALC marked fish compared to their controls up to 60 days post-marking （P〉0.05）.
文摘Objective:To study the potential role of subjective visual vertical(SVV)as a prognostic marker for canalith repositioning maneuver(CRM)in patients with posterior canal benign paroxysmal positional vertigo(PC-BPPV)for the Indian population.Methods:SVV was examined in 30 patients with PC-BPPV before and after canalith repositioning maneuver and after complete resolution of PC-BPPV.Study parameters included the mean of 10 angular tilt readings and direction of deviation,which were compared before and after CRM and following complete resolution of PC-BPPV.Results:The angle of SVV tilt was greater and deviated towards the affected ear before CRM in all patients,which decreased significantly shortly after CRM and continued to decrease after complete resolution of PC-BPPV(p<0.0001).Conclusions:SVV can be used to test utricular dysfunction in PC-BPPV.The angle of tilt improves in response to CRM,which may be used as a prognostic marker in patients with PC-BPPV receiving CRM.
基金The National Natural Science Foundation of China under contract No.31372533China Central Governmental Research Institutional Basic Special Research Project from Public Welfare Fund under contract No.2016PT01the“948”Program of the Ministry of Agriculture under contract No.2014-S6
文摘The migratory history of the engraulid fish Coilia nasus in the Rokkaku and Chikugo River estuaries of the Ariake Sea, Japan was assessed using otolith strontium（Sr） X-ray intensity maps and strontium：calcium（Sr：Ca） ratio life history transects by an electron probe microanalyzer（EPMA）. The results showed that seven of the ten specimens from the Rokkaku River Estuary（LJC） and all 15 specimens collected in the Chikugo River Estuary（ZHC） had low Sr：Ca ratios（≤3） at the central otolith area, indicating their riverine origin and initial freshwater residence. After the first regime shift adjacent to natal regions, the Sr level mapping displayed a wide variety of color patterns, and the Sr：Ca ratios obtained by the line transect analysis could be divided into one to six significantly different phases indicative of gradual life history transition. The other three specimens from the Rokkaku River Estuary had high Sr：Ca ratios（3–6.7） at the central otolith area but showed alternating changes between low and high values outside the natal region, suggesting that estuarine-origin individuals occurred in the Rokkaku River Estuary. The two-dimensional maps of the Sr level and average of the otolith Sr：Ca ratios along the life-history transects could be used as effective tools for reconstruction of past habitat use of the tapertail anchovy in estuaries of the Ariake Sea, Japan.
基金the Program for New Century Excellent Talents in University (NCET-06-0437)Shanghai Leading Academic Discipline Project (No T1101)
文摘Although chub mackerel （Scomberjaponicus） is a primary pelagic fish species, we have only limited knowledge on its key life history processes. The present work studied the age and growth of chub mackerel in the East China and Yellow Seas. Age was determined by interpreting and counting growth rings on the sagitta otoliths of 252 adult fish caught by the Chinese commercial purse seine fleet during the period from November 2006 to January 2007 and 150 juveniles from bottom trawl surveys on the spawning ground in May 2006. The difference between the assumed birth date of 1st April and date of capture was used to adjust the age determined from counting the number of complete translucent rings. The parameters of three commonly used growth models, the von Bertalanffy, Logistic and Gompertz models, were estimated using the maximum likelihood method. Based on the Akaike Information Criterion （AIC）, the yon Bertalanffy growth model was found to be the most appropriate model. The size-at-age and size-at-maturity values were also found to decrease greatly compared with the results achieved in the 1950s, which was caused by heavy exploitation over the last few decades.
基金Supported by the National Basic Research Program of China (973 program) (No.2005CB422306)the National Natural Science Foundation of China under the Science Fund for Creative Research Groups (No.40821004)the Natural Science Foundation of Shandong Province (No.Y2008D21)
文摘Otolith shape is species specific and is an ideal marker of fish population affiliation. In this study, otolith shape of spottedtail goby Synechogobius ommaturus is used to identify stocks in different spawning locations in the Yellow Sea. The main objectives of this study are to explore the potential existence of local stocks of spottedtail goby in the Yellow Sea by analysis of otolith shape, and to investigate ambient impacts on otolith shape. Spottedtail goby was sampled in five locations in the Yellow Sea in 2007 and 2008. Otoliths are described using variables correlated to size (otolith area, perimeter, length, width, and weight) and shape (rectangularity, circularity, and 20 Fourier harmonics). Only standardized otolith variables are used so that the effect of otolith size on the shape variables could be eliminated. There is no significant difference among variables of sex, year, and side (left and right). However, the otolith shapes of the spring stocks and the autumn stocks differ significantly. Otolith shape differences are greater among locations than between years. Correct classification rate of spottedtail goby with the otolith shape at different sampling locations range from 29.7%–77.4%.
