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Largemouth perch (Percichthys colhuapiensis) represents one of the most economically important fish species in the Argentine Patagonia. However, little research has been done on the age and growth and population dynamics of this fish, though both studies are essential to properly deal with fisheries forecasts and management. As a contribution to elaborating management programmes for P. colhuapiensis, we evaluated the age and growth of this species in the Negro river via scale and whole otolith reading methods. The sample consisted of 579 specimens ranging in total length (TL) from 90 to 475 mm, captured seasonally from December 1994 to December 1995. The formation of scale annuli (end of winter) and the hyaline zone on otoliths (winter) of adult fish coincided with the beginning of the spawning season (end of winter-beginning of spring). The maximum estimated age was 11 years, which indicates that this is a relatively long-lived species. Otoliths were useful for ageing specimens 1–5 years-old, but above this age whole otoliths yielded lower age estimates than scales. Isometric growth of weight with length was found for total population, juveniles, and separate sexes (p > 0.25 in all cases). No significant differences between the length–weight relationships of sexes were observed (p > 0.10). Length at first maturity was significantly higher for males (TL50 = 271 mm TL; r = 0.88) than for females (TL50 = 243 mm TL; r = 0.96) (p < 0.01). Largemouth perch exhibited a consistent pattern of increase in length with age, with a period of fast growth during the first 5 years, and a slow-growing phase during the rest of his life. The growth parameters based on scale data were L∞: 462.1 mm, k = 0.23 and t0 = −0.94 for total population, L∞: 402.3 mm, k = 0.33 and t0 = −0.67 for males, and L∞: 548.4 mm, k = 0.15 and t0 = −1.59 for females, whereas those based on otolith reading were L∞: 537.4 mm, k = 0.17 and t0 = −1.0 for total population, L∞: 497.6 mm, k = 0.21 and t0 = −0.79 for males, and L∞: 582.0 mm, k = 0.14 and t0 = −1.53 for females. Scales are concluded to be the best structure to age P. colhuapiensis because they rendered L∞ values closer to the maximum TL observed, high precision, easiness of collection, low processing time, and the possibility of performing non-destructive monitoring studies.  相似文献   
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鲈鱼的形态生态特征与养殖效果的关系   总被引:1,自引:0,他引:1  
本文根据现有文献和笔者的研究,比较了不同产地、不同种群鲈鱼的形态、生态特征和各地的养殖结果,分析了产生不同结果的主要原因。  相似文献   
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温度和盐度对花鲈胚胎及前期仔鱼发育影响的初步报告   总被引:30,自引:0,他引:30  
花鲈(Lateolabrax japonicus)胚胎发育的适宜温度为10~22℃,10℃组中的畸形率偏高,因此最适宜温度为13~22℃。短时期的7℃低温对胚胎发育没有影响;前期仔鱼的适温范围与胚胎的适温范围基本一致。胚胎发育的适宜 盐度为19‰~28‰,以22‰~25‰为最佳;仔鱼对盐度的要求与胚胎期近似。以低盐度和高盐 度相比较,4日龄以后,低盐度似有利于仔鱼存活。  相似文献   
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脂肪和L-肉碱对大口黑鲈饲料中蛋白质的节约作用   总被引:4,自引:1,他引:3  
本试验旨在探讨脂肪和L-肉碱对大口黑鲈饲料中蛋白质的节约作用.采用3 × 2(蛋白质脂肪比×L-肉碱)完全随机设计,配制了不同蛋白质脂肪比(39.9%/7.4%、30.3%/13.9%和21.5%/19.5%)和L-肉碱水平(0和1 g/kg饲料)的6种等能饲料.选取平均初重为(3.27±0.21)g的大口黑鲈幼鱼270尾,随机分为6组(每组3个重复,每个重复15尾),随机饲喂1种饲料,试验期6周.结果表明:随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%),鲈鱼的增重率从685%显著降低到176%(P<0.05),饲料效率从1.15增加到2.33(P<0.05),且投喂蛋白质脂肪比为21.5%/19.5%饲料的鲈鱼的肥满度显著低于投喂蛋白质脂肪比为39.9%/7.4%和30.3%/13.9%饲料的鲈鱼(P<0.05).投喂蛋白质脂肪比为21.5%/19.5%饲料的鲈鱼体水分含量显著低于投喂蛋白质脂肪比为39.9%/7.4%的饲料(P<0.05),且随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%).全鱼脂肪含量从5.6%显著升高到11.5%(P<0.05),全鱼粗蛋白质含量从15.6%显著下降到10.4%(P<0.05).鱼体肝脏和肌肉中脂肪含量以及肝体指数在投喂蛋白质脂肪比为21.5%/19.5%饲料时达到最高值.此外,随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%),淋巴细胞百分比由38.30%升高到48.41%(P<0.05),粒细胞百分比由51.75%下降到42.14%(P<0.05).由此得出,以节约蛋白质为目的的过量添加脂肪会导致鱼体生长速度降低,甚至引起脂肪肝的发生和机体免疫系统的应激反应.此外,饲料中添加1 g/kg的L-肉碱并不能提高大口黑鲈的生长性能,但蛋白质脂肪比和L-肉碱对淋巴细胞百分比和粒细胞百分比存在互作作用,并在饲喂添加1 g/kg L-肉碱的蛋白质脂肪比为21.5%/19.5%的饲料时达到峰值.  相似文献   
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垂体腺苷酸环化激酶多肽(pituitary adenylate cyclase-activating polypeptide,PACAP)是一种能够促进生长激素、促性腺激素和催乳素分泌的多效激素,属于胰高血糖素/分泌肽家族的成员.为探索PACAP基因多态性对大口黑鲈(icropterus salmoides)生长性状的影响,本研究采用直接测序的方法在PACAP基因上检测到一个单核苷酸多态性(single nucleotide polymorphism,SNP)位点:A-2282C,基因型检测共发现3种基因型:AA、AC和CC,其基因型频率分别为0.034、0.645和0.321,A等位基因频率为0.356 3,C等位基因频率为0.643 7.随机选取同批繁殖、同塘养殖的327尾大口黑鲈用Snapshot方法进行SNPs位点检测和分型,构建最小二乘分析模型,分析基因型与生长性状的相关性.X2检测结果显示,哈温-平衡常数为0.061 5,即该位点在所检测大口黑鲈群体中基本处于Hardy-Weinberg平衡状态,有效等位基因数(Ne)为1.846 5,期望杂合度(Ho)和观测杂合度(He)分别为0.540 9和0.644 2.方差分析结果显示,AC基因型群体的平均体质量、体高和全长相对于AA基因型群体分别增长了30.6%、10.7%和8.3%,相对于CC基因型群体分别增长了10.5%、4.7%和2.7%;且AC基因型群体在体质量、体高和全长上显著高于AA和CC基因型群体(P<0.05).另外,虽然AA基因型群体的平均体质量、体高和全长相对于CC基因型群体分别增长了18.1%、5.8%和5.4%,但AA型群体和CC群体在各生长性状上没有显著差异(P>0.05).该位点可能是影响大口黑鲈生长性状的的主效数量性状核苷酸(quantitative trait nucleotides,QTN)或与之紧密连锁,可作为大口黑鲈选育的候选分子标记.  相似文献   
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Monosex populations can be a valuable management tool in culture of larger size largemouth bass (>400 g). In this study, we investigated the effective mode and duration of oestrogen and androgen administrations to produce monosex largemouth bass populations. The experiment consisted of nine treatments. In oral administration groups, we fed 40-day-old fry either 200 mg of an oestradiol-17β (E2) kg−1 diet or 60 mg of a 17α-methyltestosterone (MT) kg−1 diet for 30, 45 or 60 days. In bath treatments, we immersed fry in a 1 mg MT L−1 solution for 5 h a day on three or six occasions. For control treatment, we fed fry an ethanol-treated diet for 45 days. The frequency of females in the control group was 53.1%. Oral administration of E2 at all durations resulted in slight increases in the frequency of females (59.8–70.5%). Both modes of androgen administration at all durations were ineffective in altering phenotypic sex. The experimental results of our study indicated that male differentiation passed the point of being completely and functionally influenced by exogenous oestrogens, while female differentiation had already taken place and was no longer responsive to exogenous androgens in 40-day-old (33.5 mm) largemouth bass fry.  相似文献   
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Largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus have been introduced into many countries and have become cosmopolitan exotic species. However, only a few studies show their impact on introduced communities. To investigate their impact, we performed natural snapshot experiments in 15 farm ponds in Saitama prefecture, eastern Japan. We selected 10 and 5 small ponds in similar environmental conditions, but with and without exotics, respectively. The numbers of fish, crustaceans, and nymphal odonates were smaller in ponds where exotics were found and some species were considered to be locally extinct in several ponds. On the other hand, the numbers of benthic organisms, i.e. tadpoles, chironomids, chaoborids, and Oligochaeta were more abundant in ponds with exotics. These two groups of organisms were separated clearly on the first axis of DCA, which indicats that this difference was mainly induced by bass predation. This result suggests a trophic cascade in which top-down effects induced by exotics propagated to fish, crustaceans, and nymphal odonates directly and to some benthic organisms indirectly. Therefore, when one is to conserve native organisms, attention should be paid not only to direct negative effects, but also to indirect effects propagating to various trophic levels. Because farm ponds are typical Japanese small lentic systems having rich biodiversities and bass and bluegill have been shown to change farm pond communities widely, conservational treatments including eradication of exotic fish should be conducted immediately.  相似文献   
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为研究硫辛酸对大口黑鲈抗氧化性能的影响,通过腹腔注射不同浓度硫辛酸评估其对大口黑鲈抗氧化酶活性的影响。该试验挑选60尾健康大口黑鲈随机分成3组,根据鱼体质量分别注射含有不同剂量的硫辛酸,设定对照组(0 mg/kg)、T20组(20 mg/kg)和T40组(40 mg/kg),注射6 h、12 h、24 h后分离其血清和肝脏,测定血清中过氧化氢酶(CAT)活性、肝脏中过氧化氢酶(CAT)和总超氧化物歧化酶(T-SOD)活性。结果表明:与对照组相比,T20组和T40组中血清CAT酶活性在6 h和12 h均显著提高(P<0.05);T20组肝脏CAT酶活性与对照组没有差异(P>0.05),T40组肝脏CAT酶活性在处理12 h后显著高于对照组和T20组;与对照组相比,T20组肝脏T-SOD酶活性在3个时间点均显著提高(P<0.05),而T40组肝脏T-SOD活性在6 h和12 h显著提高(P<0.05),且T20组T-SOD酶活性高于T40组。研究结果表明,注射硫辛酸可以促进大口黑鲈血清与肝脏中CAT和T-SOD酶活性,且该促进作用与硫辛酸使用剂量及处理时间有关。  相似文献   
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