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1.
    
Length-weight relationships for seven fish species caught from tidepools in an intertidal rocky shore in the Gulf of Cadiz are presented. Fish were sampled monthly (April 2008–January 2012), using hand nets (mesh size 1.5 mm). The values of b parameter remained within the expected range of 2.5–3.5 for all fish species. An ANCOVA test was used to evaluate differences in the b growth parameter between females and males. Gobius cobitis, G. incognitus and G. paganellus showed significant differences in the parameters of the length-weight relationships according to the sex.  相似文献   

2.
    
The length-weight relationships (LWRs) were studied for eight seagrass fish from Wenchang, China, using gill nets (150*1 m, mesh size 0.5 cm), including Gerres oblongus, Ambassis kopsii, Halichoeres nigrescens, Sillago aeolus, Yongeichthys criniger, Oxyurichthys tentacularis, Lethrinus haematopterus and Hypoatherina tsurugae, in November 2017, March and August 2018. Results suggest that mean LWR parameters b for these eight seagrass fish varied from 2.801 for L. haematopterus to 3.640 for A. kopsii, and r2 valued from .950 for L. haematopterus to 0.993 for H. nigrescens. This study will help us to better understand the ecological parameters these seagrass fish.  相似文献   

3.
    
This study aimed to estimate the parameters of length-weight relationships (LWRs) for six freshwater fish species that inhabit in the Xiangjiang River of Guangxi region, China. The specimens were sampled in April, July, and October 2014 and in January 2015 using electrofishing (CWB-2000P, China; 12 V import, 250 V export) and traps (mesh size 8.5 mm; length 200 m) at five sampling sites. For each sampling site, a trap was settled on one nearshore zone of the river for 24 hr, and the electrofishing was applied within 30 min from downstream to upstream with 200 m long. Standard length was measured (be accurate to 0.1 cm) and total weight determined (be accurate to 0.1 g) after preservation in formaldehyde (10%). The values for the parameter b of the length-weight relationships were estimated together with the coefficient of determination scores. In addition, this study provides a new tentative LWRs for the six species.  相似文献   

4.
    
As one of the largest Southeast Asian rivers, flowing through China, Myanmar, and Thailand, the Nujiang (Salween) River contains a unique and rich diversity of fish species. In the present study, we investigated the length–weight relationships (LWRs) of four fish species (Pteronemacheilus meridionalis, Devario shanensis, Exostoma gaoligongense, and Glyptothorax granosus) collected from the lower reaches of the Nujiang River and its tributaries (24.175N~25.842N, 98.861E~98.903E), including the Mengboluo, Kungong, Luomingba and Laowo rivers in southwest China. Specimens were collected by using drift gill nets (100 m length × 1.5 m depth or 3 m depth, mesh-size: 1 cm-5 cm), cast nets (6.5 m, mouth opening: 35 × 45 cm2, mesh-size: 4 mm) , and an electric shocker apparatus (12 V, 200 Hz) from different regions in the Nujiang River basin in September and October 2019 and June and September 2020. Before the collected fishes were placed in formalin, standard length (SL) and net weight (W) were measured respectively to the nearest 0.1 cm and 0.1g, respectively. Based on searches of the FishBase database and other relevant scientific literature, this study provides a new record of maximum size for P. meridionalis and LWRs for the four fish species.  相似文献   

5.
    
The length-weight relationships (LWRs) of six Nemacheilid species (Schistura chindwinica, S. fasciata, S. khugae, S. minuta, S. reticulata and S. rubrimaculata) have been analyzed. Fish samples were collected on quarterly basis from March 2018 to February 2019. Sampling was performed using cast nets (mesh size 5–10 mm; about 50 sq m area covered each time and water depth was 4 ft approx.), and electrofishing (Ultrasonic Inverter Electro Fisher, 24 volts, 4 m) in the day time. The total length (TL) of individual fish was measured to 0.1 cm with a digital caliper and body weights (BW) were measured to 0.001 g with digital electronic balances. The parameters for the LWR equations were calculated, and the respective statistics such as the 95% confidence interval for parameters “a” and “b” are provided as well as the coefficient of correlation. For five species a new maximum total length has been documented.  相似文献   

6.
    
The present study describes the length-weight (LWR) and length-length (LLR) relationships for three indigenous fish species from the Qingshui River, southwestern China. Fishes were collected by electrofishing in May 2015 in the middle Qingshui River. Total length (TL), standard length (SL) and fork length (FL) were measured to the nearest 0.1 cm with a digital calliper and weight (W) was determined with an electronic balance to an accuracy of 0.01 g. In addition, provides a new maximum total length for two species.  相似文献   

7.
    
The present study reports on length-weight relationships (LWRs) for 37 of the most abundant fish species in the Lefini River basin, one of the largest right bank tributaries of the Congo River in the Republic of the Congo. The study area comprised 12 stations along 103 km of the river. Each station was sampled during March 2007 to August 2008 following standardized methods utilizing five monofilament gill nets of 10, 12, 15, 20 and 30 mm mesh size. Sample size, lengths, weights, LWRs, 95% confidence intervals of a and b, coefficient of correlation r2 and growth type are provided for each species. Values of allometric coefficient b of the LWRs (W = aSLb) ranged from 2.556 for Synodontis nigriventris to 3.363 for Brycinus poptae. These results represent the first study of length-weight relationships for fish species in a large affluent of the Congo basin as a whole.  相似文献   

8.
    
Length-to-weight and length-to-length ratios were estimated for six cavefishes including Yunnanilus longibarbatus, Yunnanilus bailianensis, Yunnanilus jinxiensis, Oreonectes polystigmus, Paranemachilus pingguoensis, and Paranemachilus genilepis from the upper reaches of the Pearl River, Guangxi Province, China (between 106.26E, 23.14N and 111.42E, 24.85N). The fish were captured between May and October in 2018 and 2019 using trap nets (mesh size 7 mm) set in front of selected caves at 6:30–7:30 p.m. and were hauled out at 6:30–7:30 a.m. the next day. After removal, the fish were measured and weighed immediately to the nearest 0.1 cm and 0.1 g, respectively. The regression parameter r2 was between .95 and .98. The total length-to-standard length ratios were also calculated with r2 ≥ .98. This study should provide a useful reference for biological studies and biodiversity conservation of cavefish.  相似文献   

9.
Investigations were made on the length-weight relationship and condition factor of Esomu danricus (Ham) from ponds and flowing water channels. These relationships could be represented by the regression equations, log W = -2.6252 + 3.2451 log L (for channel fishes) and log W = -1.5390 + 2.6318 log L (for pond fishes). The correlations were significantly high (P < 0.001). The mean values of condition factors were 0.529 and 0.713 for pond and channel fishes, respectively. The additive action of various factors in stagnant ponds, such as oxygen deficiency, stratification of indispensahle nutrients at the bottom, accumulation of body wastes of fishes, and unoxidized chemical compounds, competition for many necessities of life as space, food, shelter, seemed to adversely affect the growth rate and condition factor of pond dwelling fishes. Contrary to this the circulation of water induced by currents in the channels appeared to cause mixing of water at all depths to even out differences in dissolved oxygen concentration, temperature, nutrients, besides minimizing the effect of repressive factor. Such conditions invariably offered more opportunities to fishes to conserve almost all the available space and other resources in the habitat. This ensured rapid growth as evidenced by higher condition factor of the flowing-water fishes as compared to their counterparts occurring in ponds.  相似文献   

10.
    
This study deals with the length-weight relationships (LWRs) of three commercially important marine fishes belonging to the family Clupeidae from the major landing centers in Tuticorin, Mandapam, Thondi, Nagapattinam and Chennai in southeast coast of India. Monthly sampling were done at the respected landing centers from June, 2018 to April, 2019 from the commercial trawlers (with cod-end mesh size of 25–35 mm) and gill netters (with different mesh size vary from 20 to 170 mm). The estimated ‘b’ values ranged from 3.1215 (Sardinella albella) to 3.1819 (Amblygaster clupeoides) and ‘a’ values varied from 0.0059 (A. clupeoides) to 0.0074 (S. albella). The study also provides a new maximum total length (TLmax) for two species A. clupeoides and Sardinella fimbriata.  相似文献   

11.
    
In the present study the length–weight relationships (LWRs) of 6 fish species which are endemic to Western Greece, caught in the natural Lake Trichonis by experimental gillnets and electrofishing were estimated. Benthic (mesh size 5–55 mm; height 1.5 m; length 30 m) and pelagic (mesh size 6.25–55 mm; height 6 m; length 27.5 m) Nordic type multimesh gillnets were used seasonally, between February 2019 and November 2019, at different depth zones (0-57m). Electrofishing (80 Hz) conducted in the littoral zone of the lake during four samplings (2018, 2019). All the estimated LWRs were highly significant (p < .05) with high correlation coefficient (r2 ≥ 0.962). The estimated b values ranged from 3.058 to 3.344. For five of the studied species (Trichonis spined loach (Cobitis trichonica Stephanidis 1974), Trichonis blenny (Salaria economidisi Kottelat 2004), Trichonis rudd (Scardinius acarnanicus Economidis 1991), Acheloos roach (Leucos panosi (Bogutskaya & Iliadou 2006)) , Hellenic minnowroach (Tropidophoxinellus hellenicus (Stephanidis 1971)) new maximum total body lengths (TL) were recorded, while for two species (T. hellenicus and L. panosi) LWRs are presented for the first time.  相似文献   

12.
The anatomy of the anabantoid fish Luciocephalus is reinvestigated and the ontogeny of certain character complexes is described for the first time. Luciocephalus possesses the following previously unrecognized or equivocally interpreted anatomical characters: a clearly separate ectopterygoid bone, pharyngeal processes of the basioccipital, a toothless pharyngeal process of the parasphenoid, an infrapharyngobranchial I and an endoskeletal mental ossification. In addition, aspects of the ontogeny of the hyopalatine arch in the belontiids Belontia, Trichogaster and Ctenops are described. Species of these three genera all possess an ectopterygoid bone previously thought to be lacking in the family Belontiidae. The significance of the results for reconstructing interrelationships of the anabantoid families and the phylogenetic position of Luciocephalus is discussed. A revised hypothesis of anabantoid intrarelationships is presented. Four synapomorphic characters indicate that Luciocephalus is more closely related to the Belontiidae (including Osphronemus) rather than forming the sister group of all other anabantoids.  相似文献   

13.
博斯腾湖鱼类资源组成、体长与体重关系及生长状况   总被引:1,自引:0,他引:1  
博斯腾湖为西北高原地区湖泊,1958年开始商业化渔业生产,1962年开始鱼类引种工作,半个多世纪以来湖区鱼类资源组成处于不断的变动当中。本文围绕湖区鱼类群落组成动态、当前鱼类的体长与体重关系及种群生长状况开展研究,于2019年春季(4月)、夏季(8月)、秋季(10月),通过渔具采样和渔获物调查相结合的方法,在博斯腾湖共发现鱼类17种,隶属于4目8科,其中?(Hemiculter leucisculus)、池沼公鱼(Hypomesus olidus)、鲫(Carassius auratus)为优势种,鱼类资源结构小型化问题严重。描述了15种鱼类体长-体重关系与生长情况,其中12种鱼类为正异速生长,3种鱼类为负异速生长,优势鱼类的体长-体重关系式参数b值范围2. 95~3. 56,决定系数r2值范围0. 874~0. 997。本研究所得结果可为博斯腾湖鱼类资源保护与可持续利用提供基础资料和科学支撑。  相似文献   

14.
Our understanding of fish feeding interactions at Tijuana Estuary was improved by incorporating estimates of spatial and temporal variability into diet analyses. We examined the stomach contents of 7 dominant species (n=579 total fish) collected between 1994 and 1999. General feeding patterns pooled over time produced a basic food web consisting of 3 major trophic levels: (1) primary consumers (Atherinops affinis, Mugil cephalus) that ingested substantial amounts of plant material and detritus; (2) benthic carnivores (Clevelandia ios, Hypsopsetta guttulata, Gillichthys mirabilis, and Fundulus parvipinnis) that ingested high numbers of calanoid copepods and exotic amphipods (Grandidierella japonica); and (3) piscivores (Paralichthys californicus and Leptocottus armatus) that often preyed on smaller gobiids. Similarity-based groupings of individual species' diets were identified using nonmetric multidimensional scaling to characterize their variability within and between species, and in space and time. This allowed us identify major dietary shifts and recognize events (i.e., modified prey abundance during 1997–98 El Ni no floods) that likely caused these shifts.  相似文献   

15.
何少华  梁志奇  何卫东 《蛇志》2016,(4):410-411
目的观察季德胜蛇药对黄蜂蛰伤的治疗效果。方法将200例黄蜂蛰伤患者随机分为两组,其中对照组的100例患者给予常规西医治疗,治疗组100例患者给予中成药季德胜蛇药联合常规西医治疗,两组患者均治疗3天进行临床疗效比较。结果两组疗效比较,治疗组的痊愈率为92%,明显高于对照组的71%,差异有统计学意义(P0.05)。结论季德胜蛇药有助于缓解黄蜂蜇伤患者的临床症状。  相似文献   

16.
Length weight relationships (LWRs) were estimated for four species of low value fishes that belongs to four families from the southwest coast of India. The specimens of, Callionymus margaretae, Dactyloptena peterseni, Rogadius serratus and Minous inermis were collected for a period of 1 year from the fishing trawlers of Cochin Fisheries Harbour (Lat. 09° 56′ 327″ N, Long. 76° 15′ 764″ E). The estimated allometric coefficient b values ranged from 2.5020 (Rogadius serratus) to 3.2438 (Dactyloptena peterseni) and r2 values ranged from 0.9492 (Rogadius serratus) to 0.9869 (Dactyloptena peterseni). All the LWRs were highly significant, with p < .001.This study provides the first estimate of LWRs for these low value by catch fish species.  相似文献   

17.
    
The present study reports the length-weight relationships (LWRs) for eight fish species sampled in Hailang River, a left-bank tributary of the Mudan River in Northeast China. The fishes were collected from April to October bimonthly 2017 by electrofishing (fishing 2 kilometers along the river and within 5 meters from the bank) and netting (drift gillnet: mesh size 2 cm × 3 cm; 200 m net length). The specimens were weighed (nearest 0.1 g) and measured (nearest 0.1 cm) in the laboratory. This study provides an update in maximum lengths for five species.  相似文献   

18.
    
The prevalence and intensity of Opisthorchis viverrini metacercariae (OvMc) were investigated in fish from 3 southern administrative regions along the Mekong River in Cambodia, i.e., Phnom Penh, Takeo, and Kandal Provinces from 2017 to 2020. A total of 295 freshwater fish (24 species) were transported to our laboratory with ice and examined using the artificial digestion method. In Phnom Penh, among 4 fish species positive for OvMc, 9 (23.7%) of 38 specimens examined were infected, and their intensity of infection averaged 4.3 metacercariae per infected fish. In Takeo Province, among 10 fish species positive for OvMc, 24 (38.1%) out of 63 fish examined were infected, and their intensity of infection was av. 14.4 metacercariae per infected fish. In particular, all of 3 Osteochilus schlegelii fish examined were infected, and their infection intensity was high, 34.7 metacercariae per fish. In Kandal Province, among 6 fish species positive for OvMc, 46 (90.2%) out of 51 specimens examined were infected, and their infection intensity was 24.0 metacercaraie per infected fish. All fish of Systomus orphoides (n=17), Barbonymus altus (n=14), and Rasbora aurotaenia (n=2) were infected, and their intensity of infection averaged 37.7, 21.6, and 18.5 metacercariae per fish, respectively. Metacercariae of Haplochis yokogawai, Haplorchis taichui, and Centrocestus formosanus were detected in fish from Takeo and Kandal Provinces. From these results, it has been confirmed that a variety of fish species from Phnom Penh, Takeo, and Kandal Provinces are commonly infected with OvMc, and preventive measures to avoid human O. viverrini infection should be performed in Cambodia.  相似文献   

19.
刘文成  李君轶  吴金明  叶海明  李鹏程  沈丽  杜浩 《水生生物学报》2025,27(2):022503-1-022503-8

为科学评估长江上游长江鲟增殖放流效果, 研究基于2021—2023年宜宾、泸州和合江3个江段渔业监测数据, 对长江上游长江鲟野外种群恢复情况进行了分析。监测期间, 3个江段共采集长江鲟849尾, 其体长分布为14.70—93.00 cm [平均体长(45.19±14.01) cm], 优势组体长为25.10—65.00 cm, 占总体的88.98%; 体重分布为24.0—6850.0 g [平均体重(892.7±960.8) g], 优势组体重为0—1250.0 g, 占总体的83.18%。分析显示: (1) 2022年和2023年监测到的长江鲟体长、体重均值均显著高于2021 年(P<0.05), 体长均值均高于当年放流群体体长均值; (2)监测的长江鲟群体呈正异速生长, 体重增长速率大于体长增长速率, 且宜宾至合江江段的生长条件因子、异速生长参数具有明显的地点和时间差异(P<0.05); (3)长江鲟单位捕捞努力量渔获量为0.1—35.0 ind./(net·d), 不同季节间呈显著差异(P<0.05); (4)在2018—2023年各大单位加大放流力度且2021年长江十年禁捕政策出台并执行后, 2021—2023年监测期间长江鲟采集数量明显增加。研究结果表明, 禁捕后长江上游长江鲟资源正逐渐恢复, 且生长状况良好, 增殖放流效果初步显现。

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20.
怒江是中国西南地区重要的国际河流, 是云南六大水系之一。为了解怒江云南段的鱼类多样性现状及受威胁因素, 本研究于2019-2020年对怒江云南段的干流及其支流的53个采样点进行了系统的调查, 并对该流域的鱼类多样性和威胁因子进行了分析。结果表明, 怒江云南段共记录鱼类9目26科59属89种, 本研究采集到鱼类6目20科42属51种。相对重要性指数分析发现, 怒江云南段优势种为密带南鳅(Schistura poculi), 且指数得分远远高于其他鱼类。物种多样性指数表明, 怒江云南段 Shannon-Wiener多样性指数、Margalef物种丰富度指数、Simpson优势度指数、Pielou均匀度指数分别为2.10、5.91、0.71、0.53; 怒江干流以及两条较大支流罗明坝河和勐波罗河鱼类多样性较高。相似度分析发现, 怒江云南段各河段或河流鱼类组成差异较大。通过Pheatmap对威胁因子分析, 结果显示对怒江云南段鱼类多样性的主要威胁因素依次为农业/生活垃圾污染、捕捞、外来种入侵和支流水利水电工程建设。  相似文献   

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