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1.
为研究环境与摄食因素对人工鱼礁区不同体长许氏平鲉分布的影响,采用2017—2018年山东省近岸3处鱼礁区环境和渔业资源的调查数据,利用变异系数CV均值将样本的体长分为10组,每组体长间隔为33 mm,并使用Bray-Curtis相似性指数比较不同海域许氏平鲉体长组成的相似性;运用去趋势对应分析(DCA)、典范对应分析(CCA)分析各环境要素对不同体长组许氏平鲉分布的影响;运用胃含物分析法分析许氏平鲉的食物组成。结果显示,西霞口与长岛鱼礁区样本体长组成相似性指数为70.66%,前三岛鱼礁区与西霞口鱼礁区、长岛鱼礁区的相似性指数较低,分别为54.94%和59.46%;大体长(299~365mm)许氏平鲉的分布与水深、水质指数(WQI)和化学需氧量(COD)相关性较大,喜好水深较深、营养丰富的水域;小体长(35~200 mm)许氏平鲉喜好水深较浅,水质好的水域。大体长(200~365 mm),高龄(2~3龄)的个体主要摄食鱼类、虾类和蟹类,优势饵料为鱼类(IRI为65.94%);小体长(35~200 mm),低龄(0~1龄)的个体主要摄食虾类和蟹类,优势饵料为虾类(IRI为45.69%)。研究表明,在浅水区域投放幼鱼保护型鱼礁,为幼鱼提供庇护所;将捕捞作业集中在深水区,减少对许氏平鲉小体长个体的兼捕,可以达到针对性增殖、保护许氏平鲉资源的目的。  相似文献   

2.
为探究人工鱼礁区许氏平鲉(Sebastes schlegelii)生长异质性及资源开发状况,本研究基于2017─2021年山东近海3处典型鱼礁区(长岛鱼礁区、西霞口鱼礁区和前三岛鱼礁区)的海洋环境和许氏平鲉资源调查数据,利用Bootstrap的ELEFAN方法探究了许氏平鲉的生长特征、基于变换体长渔获曲线法探究了许氏平鲉死亡特性,运用线性混合效应模型研究了许氏平鲉体长–体重关系时空异质性,基于Beverton-Holt模型和开发率探究了许氏平鲉资源利用状况。结果显示,前三岛鱼礁区许氏平鲉条件因子(a)明显高于西霞口鱼礁区和长岛鱼礁区;前三岛鱼礁区许氏平鲉渐进体长和渐进体重最大,西霞口鱼礁区次之,长岛鱼礁区最小;长岛鱼礁区总死亡系数和自然死亡系数分别为0.87和0.44,均高于西霞口鱼礁区和前三岛鱼礁区;线性混合效应模型得到参数a、b范围分别是1.48×10–5~5.92×10–5、2.85~3.13,相同体长条件下, 2020年春秋季前三岛鱼礁区许氏平鲉个体重最高, 2021年、2018年和2017年冬季西霞口鱼礁区个体重次之, 2019年夏...  相似文献   

3.
为了评价大长山人工鱼礁区许氏平鮋(Sebastes schlegelii)资源利用状态,为当地许氏平鮋资源的合理开发与管理提供科学依据,采用基于体长的贝叶斯评估方法(LBB)对2011-2015年大长山人工鱼礁区许氏平鮋资源进行了评估。研究结果表明大长山人工鱼礁区许氏平鮋最优体长L_(opt)为31cm,最佳开捕体长L_(c-opt)为28cm,平均M/K=1.5、F/K=4.82、Z/K=6.34、F/M=3.24,许氏平鮋最优现存资源量与原始资源量之比B/B_0(F=M,L_c=L_(c-opt))=0.366、实际年平均B/B_0=0.038 6,许氏平鮋最优的单位补充量渔获量Y/R'(F=M,L_c=L_(c-opt))=0.045 9kg,实际年平均Y/R'=0.003 44kg。  相似文献   

4.
采用地笼网与流刺网对山海关海洋牧场人工鱼礁区进行了春秋两个航次的渔业资源调查。调查结果表明:人工鱼礁区的重要经济品种为许氏平鮋、大泷六线鱼、矛尾刺鰕虎鱼,春季礁区内许氏平鮋、大泷六线鱼、矛尾刺鰕虎鱼的单位捕捞努力量分别是对照区的8.12倍、3.29倍和1.96倍,秋季礁区内是对照区的3.04倍、3.96倍和1.59倍。礁区内的尾均体质量普遍比对照区要大,春季礁区内的许氏平鮋较对照区高出60.92%,大泷六线鱼高出5.83%,矛尾刺鰕虎鱼高出33.33%,秋季礁区内的许氏平鮋较对照区高36.72%,黑鲷高出36.72%,大泷六线鱼高出5.27%。调查结果显示,人工鱼礁区重要经济资源已得到有效养护,增殖效果明显。  相似文献   

5.
根据2017—2018年大连海域渔业资源底拖网调查数据,基于FISATⅡ软件对大连海域小黄鱼、高眼鲽、长绵鳚、大泷六线鱼和许氏平鲉这5种常见经济鱼类的生长、死亡及资源利用现状进行评估。研究结果显示,5种鱼类的渐近体长(L)为222.4~495.5 mm,生长系数(K)介于0.36~0.69间。当前5种经济鱼类的开发率(E)为0.57~0.71,均大于0.5和单位补充渔获量最高时开发率(Emax),表明资源已处于过度开发状态;结合Bverton-Holt动态综合模型结果,当前5种鱼类的捕捞强度偏大、开捕体长较小。综合考虑鱼类的拐点年龄、临界年龄、繁殖及经济利益,建议小黄鱼、高眼鲽、大泷六线鱼、长绵鳚和许氏平鲉的最适开捕体长分别为136、237、207、297 mm和160 mm。本研究结果可作为这5种经济鱼类资源管理的参考,在具体的渔业政策制定中,还需要进一步保证调查数据的时效性和调查方式的全面性、科学性。  相似文献   

6.
为了探究大型海藻和人工鱼礁对鱼类的诱集作用,依据崂山湾人工鱼礁区游泳动物和大型海藻调查结果,以海黍子、孔石莼、带形蜈蚣藻、石花菜和小珊瑚藻5种优势藻类,许氏平鲉和大泷六线鱼2种优势鱼类以及人工鱼礁模型为研究对象,于室内实验水槽观察了许氏平鲉和大泷六线鱼幼鱼在海藻和模型礁中的行为反应和分布。结果显示,水槽中未投放模型礁和海藻时,实验鱼密集出现在水槽边缘区(A9),分布率分别为75.71%±7.79%和73.63%±4.41%。放入模型礁和海藻丛后,许氏平鲉和大泷六线鱼出现短暂的排斥反应,然后迅速聚集其中;2种鱼对带形蜈蚣藻的响应时间最短[(12.75~21.00)s],对模型礁的响应时间最长[(66.50~151.25)s];带形蜈蚣藻聚集许氏平鲉用时最短[(151.50±8.14)s],海黍子聚集大泷六线鱼用时最短[(56.00±2.53)s];大泷六线鱼对模型礁的聚集时间为(216.25±5.59)s,远低于许氏平鲉(1343.50±5.38)s;2种鱼在模型礁中的停留时间远长于海藻丛,且大泷六线鱼的停留时间(211.85±7.96)s长于许氏平鲉(199.75±16.82)s。海藻丛和模型礁对2种岩礁性幼鱼的诱集效果明显,实验区幼鱼的分布率由未投放模型礁和海藻前的0.91%~8.78%上升到4.21%~31.42%;高密度带形蜈蚣藻和海黍子的诱集效果最好,对许氏平鲉和大泷六线鱼的聚集率分别达到30.42%±1.14%和31.42%±1.74%,而低密度小珊瑚藻的诱集作用不明显。  相似文献   

7.
为研究资源评估模型的不确定性及其对管理参考点的影响,以东、黄海星康吉鳗(Conger myriaster)为研究对象,对单位补充量渔获量(YPR)模型各参数进行敏感性分析,探究影响单位补充量渔获量和生物学参考点估算的关键参数,并利用蒙特卡洛方法模拟YPR模型中的参数不确定性,评估不确定性存在下星康吉鳗种群的资源现状及可能产生的风险。研究结果表明,当前东、黄海星康吉鳗的捕捞死亡系数Fcur远高于F0.1的估计值,接近Fmax。自然死亡系数M、生长系数K和开捕年龄tc是估算生物学参考点Fmax和F0.1的敏感性参数,而幂指数系数b、渐近体长L、生长系数K和自然死亡系数M则是计算渔获量的敏感性参数。在参数不确定性的影响下,对东、黄海星康吉鳗渔业状况产生误判的概率,即P (Fcur0.1)和P (Fcur>Fmax),将随不确定水平的升高...  相似文献   

8.
2016年7-11月,对唐山海洋牧场海域人工鱼礁内和礁区外许氏平鮋(Sebastes schlegelii)进行采样,共采集191尾,其中鱼礁内159尾,礁区外32尾,对采集的样品胃含物组成进行定量分析和研究,结果表明,许氏平鲉摄食强度以四级为主(40.91%),其次为三级(23.30%),平均摄食强度为2.66。月份不同,胃含物种类不同,7-9月虾类占比100%;11月虾类占比66.99%,鱼类占比33.01%,同时底质不同,胃含物种类也不同,在礁内泥地底质中,虾类占比97.46%;石头地底质中,虾类占比64.42%,鱼类占比33.48%。对不同月份许氏平鮋饵料种类进行聚类分析,结果显示7月与9月饵料相似度高。不同体长组的摄食强度等级频度不同,具体表现为随体长组的增加,摄食强度等级增加,在50~60 mm达到峰值,占比81%。  相似文献   

9.
不同尺寸网目与缩结系数对许氏平鲉的选择性   总被引:1,自引:0,他引:1       下载免费PDF全文
为探究不同尺寸网目及缩结系数对许氏平鲉(Sebastesschlegelii)的选择性,本研究基于实验水槽中的套网法试验,测得许氏平鲉的生物学特征参数,采用Logistic模型曲线拟合得到不同尺寸网目及缩结系数对许氏平鲉的选择性曲线,并用极大似然法估算选择性参数。结果表明:网目尺寸为63 mm、82 mm、93 mm时,许氏平鲉的50%选择性体长(L50)分别为18.49 cm、23.90 cm、25.12 cm,选择范围(SR)分别为3.18、3.6、3.85,选择因素(SF)分别为2.93、2.91、2.70,随着网目尺寸的增大,许氏平鲉的L50、SR逐渐增大, SF逐渐减小;当82 mm网目的缩结系数(Et)分别为0.5、0.6、0.707时,许氏平鲉的50%选择性体长(L50)分别为21.47 cm、23.90 cm、22.02 cm,选择范围(SR)分别为3.23、3.6、3.38,选择因素(SF)分别为2.65、2.91、2.68,随着网目缩结系数的增大,许氏平鲉的L50、SR、SF先增大后减小,在Et为0.6时均达到最大。为保护许氏平鲉幼鱼资源,建议在鱼礁区使用网目规格为70 mm, Et为0.6的笼壶渔具进行采捕。  相似文献   

10.
为探究人工鱼礁区单片刺网对许氏平鲉(Sebastes schlegeli)和大泷六线鱼(Hexagrammos otakii)的选择性, 于 2021 年 10 月在荣成北部人工鱼礁区使用 4 种网目尺寸(40 mm、50 mm、60 mm、70 mm)的单片刺网进行选择性实验。在 SELECT 模型的架构下, 使用 Normal、Lognormal、Gamma、Bi-normal 模型进行选择性拟合, 根据赤池信息指数(AIC)和模型残差(MD)选择最佳拟合模型。结果表明: Lognormal 模型拟合效果最佳, 其 AIC 值和 MD 值均为最低值。根据 Lognormal 模型, 不同网目尺寸许氏平鲉的模型拟合长度分别为 114.23 mm、142.79 mm、 171.35 mm、199.90 mm; 大泷六线鱼的模型拟合长度分别为 129.67 mm、162.09 mm、194.51 mm、226.92 mm。许氏平鲉和大泷六线鱼的体长与最大剖面周长的线性关系分别为: G=0.2877L+0.7463(R2 =0.6722), G=0.2468L– 3.8531(R2 =0.6851)。选取 150 mm 作为许氏平鲉和大泷六线鱼的理论成熟体长(MBL)进行分析, 结合幼鱼留存比例, 发现网目尺寸为 60 mm 和 70 mm 的刺网能够保护人工鱼礁区许氏平鲉和大泷六线鱼的幼鱼资源。研究结果可为人工鱼礁区渔业资源的管理和养护提供参考。  相似文献   

11.
对从凡纳滨对虾(Litopenaeus vannamei)肠道中分离出的鲍鱼希瓦氏菌(Shewanella haliotis)、蜡样芽孢杆菌(Bacillus cereus)和双壳气单胞菌(Aeromonas bivalvium)3株有益菌株,利用正交设计得到9种复合比例,通过饲料中添加上述9种比例混合的菌体(菌数总量为109 cfu/g)饲喂凡纳滨对虾,经过28 d养殖实验,评价其对凡纳滨对虾生长、免疫指标的影响。随后,利用氯化铵调节水体氨氮浓度至26.67 mg/L,经过16 d的氨氮毒性实验,研究不同比例复合益生菌对凡纳滨对虾抗氨氮能力的影响。研究结果表明,9个复合益生菌实验组的增重率和特定生长率均显著高于对照组(P0.05),并且以3株菌菌数6︰1︰3比例效果较好;不同配比的复合益生菌能够显著提高酸性磷酸酶(ACP)、碱性磷酸酶(ALP)、总超氧化物歧化酶(T-SOD)活力(P0.05),并表现出了不同的影响效果,其中,3株菌菌数(菌数总量为109 cfu/g,下同)2︰3︰3、4︰2︰3及6︰1︰3比例对ACP活力具有显著促进作用(P0.05),3株菌菌数4:2︰3和6︰1︰3比例对ALP活力具有显著促进作用(P0.05);3株菌菌数2︰1︰1比例对T-SOD活力具有显著促进作用(P0.05);各比例的复合菌对溶菌酶活力的影响不显著(P0.05);氨氮浓度26.67 mg/L条件下,不同比例复合菌组对虾累计存活率显著高于对照组(P0.05),其中以3株菌菌数4︰3︰1和6︰3︰2比例组累计存活率较高,即抗氨氮效果较好。  相似文献   

12.
The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 103 to 3.76 × 105 cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 105 cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

13.
Using mark-recapture methods, the movements of the fluvial form of masu salmon (Oncorhynchus masou masou) in a mountain stream on the island of Kyushu, Japan, were studied. Most (78%) of the masu salmon were recaptured in the pool in which they had been originally caught and tagged. Of those that moved between pools, the proportion of individuals that moved during the breeding period was not significantly higher than the proportion that moved during the non-breeding period. However, during the breeding period, a higher proportion of larger salmon moved than did smaller fish. The proportion of mobile large males during breeding period was higher than that for small males. Also, it was found that a few individuals showed long-range movement in the autumn. As a long-term movement, 78 individual fish (65%) that were recaptured more than three times showed high sedentary tendencies. Sixteen individual mobile fish (13%) moved and returned to the original pool. Fluvial form of masu salmon in Kyushu show a high sedentary nature; however, large mature males seem to actively move in search of female during breeding period.  相似文献   

14.
OAA, the potent anti-HIV protein from Oscillatoria agardhii NIES-204 belongs to a new lectin family, shows strict binding specificity for high-mannose N-glycans, and has an extremely high association constant in the picomolar range for recombinant gp120, an envelope protein of HIV. In this study we have cloned the gene encoding OAA from the genomic DNA of the cyanobacterium, and efficiently expressed the recombinant lectin (rOAA) in Escherichia coli. The rOAA expressed as a His-tagged fusion protein was recovered in a soluble form and purified in high yield (48 mg/1 l-culture) by metal chelate chromatography. The fusion protein was cleaved with factor Xa, and the resulting rOAA was isolated in a final yield of 14.8 mg/1 l-culture by reversed-phase HPLC. Both the N-terminal sequence and the molecular mass of rOAA were found to be identical with those of OAA. The rOAA was fully functional with the same properties as OAA, as evidenced by hemagglutination activity, hapten-inhibition test, and binding specificity for high-mannose-type N-glycans. This rOAA should be applicable as a specific probe for high-mannose N-glycans and should contribute to elucidation of the molecular basis of its strict carbohydrate-binding specificity and potent anti-HIV activity.  相似文献   

15.
Between 1995 and 1997, a traditional Norwegian oyster poll with an attachednursery was used for the production of scallop (Pecten maximus) spat.During summer 1997, four batches of 2 mm scallop spat were placed in thenursery. In June, hydroids (Obelia) caused problems with fouling andaccumulation of sediment in the nursery. Thereafter, the scallop spat wereheavily infested with tube dwelling polychaets (Polydora sp.). Thepolychaets were both introduced with poll water and reproduced inside thenursery. Infested spat suffered high mortalities. Although the spat could have been affected by the hydroids, as well as shortage of food, Polydorainfestations were considered the main cause of the mortalities. Dead andinfested spat were continuously sorted out and discarded, but the infestationproblems persisted. As a result, the scallop spat did not represent anycommercial value for the company, and in September, the nursery wasemptied. In total, approximately one million spat – representing onethird of Norway's intensive scallop spat production in 1997, was lost.  相似文献   

16.
杜仲对草鱼生长、肌肉品质和胶原蛋白基因表达的影响   总被引:1,自引:1,他引:0  
为研究杜仲对草鱼生长性能、肌肉品质及胶原蛋白基因COL1A1和COL1A2表达的影响,实验采用初始体质量为(215.0±0.4)g的草鱼120尾,随机分为2处理组(每组3重复,每重复20尾鱼),分别饲喂基础饲料(对照组)和添加2%杜仲的实验饲料(杜仲组),养殖时间为8周。结果显示,与对照组相比,添加2%杜仲对草鱼生长性能无显著影响,但能显著增加肌肉、皮肤和肝脏胶原蛋白水平,增加肌肉总必需氨基酸(TEAA)、总氨基酸(TAA)水平。2%杜仲可显著降低草鱼肌肉的冷冻失水率、离心失水率,但对肌纤维密度和肌纤维直径无显著影响。在胶原蛋白基因表达方面,2%杜仲显著增加了第4周、8周时草鱼的肌肉、皮肤和第8周时的肝脏组织COL1A1、COL1A2基因m RNA表达量。研究表明,饲料中添加2%杜仲可改善大规格草鱼的肌肉品质。  相似文献   

17.
Satisfying nutrient requirement of corals is still a major constraint for maintaining corals in marine aquariums. Corals are polytrophic in nature. Heterotrophic feeding on zooplankton is one of the corals’ strategies to overcome nutrient deficiency. Artemia salina nauplii are commonly used as biocarriers for many fish larvae in aquaculture and can also serve as a biocarrier for coral in aquariums, provided coral acceptability, optimal feeding rate, and digestibility of the nauplii are well understood. Feeding rate and digestibility of coral fed on A. salina nauplii at 100, 2,000, 4,000, 6,000, and 10,000 ind. l−1 under light and dark conditions was assessed in this study. The maximum feeding rates of Galaxea fascicularis under light and dark conditions was 113.6 ind. polyp−1 h−1 and 76.9 ind. polyp−1 h−1, respectively. The daily feeding rates of G. fascicularis varies and depends on nauplii density. Light plays an important role in coral feeding. Nevertheless, the quantity of A. salina nauplii consumed by the coral under light and dark conditions was not significantly different (P > 0.05). A. salina nauplii are well accepted by G. fascicularis. Complete nauplii digestion was observed after 180 min. Digestibility of A. salina nauplii by G. fascicularis was positively correlated with digestion time.  相似文献   

18.
Different liposome formulations, includingseveral combinations of membrane composition,type of vesicle (multilamellar and largeunilamellar vesicles), preparation method, andvehiculated nutrient, have been assayed asbioencapsulation products to enrich Artemia nauplii with nutrients for feeding fish larvae.The stability of the liposome preparationsunder conditions of use as enrichment producthas been tested using water soluble fluorescentmarkers as leakage indicators. The content ofthe fatty acids and lipid classesbioencapsulated in Artemia nauplii withliposomes has been analyzed by gas and thinlayer chromatography, respectively, andcompared with other enrichment products. Theeffect of the liposome enriched Artemianauplii used as food for fish larvae has beenevaluated in sea bass cultures. Liposomes withhigh content in polyunsaturated fatty acidsleak out more than 50% of their aqueous phasein less than 2 hours, unless they arestabilized with cholesterol and formed as largeunilamellar vesicles. Such vesicles hold70% of the encapsulated material for 8 hours.Liposome enriched nauplii in this study reflectthe influence of the enrichment products,however, they are far from the commercialemulsion (Super Selco) in terms ofdocosahexaenoic acid content, except for thenauplii enriched with liposomes made of purekrill phospholipid extract by the method ofdetergent solubilization. The liposome enrichednauplii show a higher amount of polar lipids incontrast to the feed enriched with emulsions.The larvae fed liposome enriched nauplii haveonly a slightly lower docosahexaenoic acidcontent than those fed emulsion enrichednauplii. The results obtained confirm thesuitable potential use of liposomes as foodsupplement in larviculture. Problems andadvantages are discussed.  相似文献   

19.
为寻找冬春季鳢(Channa maculata)烂身病的病原,应用组织压片、组织切片、扫描电镜技术、HE常规染色法和Grocott六胺银染色法、霉菌分离纯化及ITS的序列分析等对冬春季患疑似溃疡综合征的烂身病鳢进行了病原学与病理学研究。病变组织压片观察到大量直径10~20μm,分枝较少、纤细菌丝。扫描电镜观察到肌肉组织中延伸出大量的纤细的丝状真菌。患病鳢皮肤和肌肉表现为变性、坏死与炎性细胞浸润,溃疡灶肌肉内可见大量的慢性肉芽肿结节和炎性细胞浸润。结节基本结构由类上皮细胞和多核巨细胞、炎性细胞、霉菌菌丝(横断面呈圆形,斜断或纵断呈丝状)组成,霉菌位于结节中央。Grocott六胺银染色观察到结节中有大量棕色菌体。无菌分离培养可观察到典型丝状霉菌;霉菌在灭菌池塘水20℃过夜, 12 h后可观察原代孢子群形成,真菌ITS序列分析表明其与侵袭丝囊菌(Aphanomyces invadans)同源性为100%。侵袭丝囊霉菌(A. invadans)是杂交鳢溃疡综合症病的主要病原,为鱼类流行病学调查和疾病防治的深入研究奠定基础。  相似文献   

20.
The present study was undertaken with a view to compare the precision and reliability of the age readings obtained from different bony structures of some important freshwater teleosts viz., Labeo rohita (Hamilton), Catla catla (Hamilton) and Channa marulius (Hamilton). Standard procedures were followed to prepare and study the age structures. In L. rohita and C. marulius percent agreement between reader's age estimates was highest for scales, i.e. 96.3% and 90.5%, respectively and in C. catla percent agreement was highest (93.3%) for opercular bone. When scale ages were compared with other alternative structures viz., otoliths, opercular bone, vertebral centra and dorsal fin rays, percent agreement was found highest between scale and opercular bone age estimates (77.8%) in L. rohita and between scale and otoliths (94.8%) in C. marulius. In case of C. catla highest percent agreement was found between opercular bone and scale age estimates. In L. rohita each of the ageing structure showed significant (P < 0.05) underestimation of age in comparison to scales. In C. catla mean age estimates from opercular bone were comparable (P > 0.05) to the values obtained from all other structures except dorsal fin rays. In C. marulius mean age estimates from scales were comparable (P > 0.05) to those from all other structures except from dorsal fin rays. Results indicated scales to be the most suitable structure for ageing L. rohita and C. marulius and opercular bone for C. catla. However, in C. catla also scales may be used as a non-destructive method of age estimation with satisfactory results.  相似文献   

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