大口鲶耗氧率与窒息点的初步研究

大口鲶具有肉质细嫩、生长快、适应性强、疾病少、易于起捕等优良特性，其驯化养殖近年来在全国各地得到迅猛发展。有关其生物学特性、养殖技术都有研究，尚未见有共耗氧率与窒息点的研究报道。本试验于1996年6月至9月份期间对大口鲶耗氧规律与窒息点进行了测定分析，其目的旨在为大口鲶规模集约化养殖提供理论依据和参考。l材料和方法1．l材料试验鱼取自本所试验场当年人工繁殖并培育成的不同规格的大口鲶鱼种，均健康正常。1．2方法1．2．1耗氧率的测定试验鱼运回实验室首先在水簇箱中驯养一周，试验前1－2天停食。试验用水采用充分曝气并…     

池养南方大口鲶人工繁殖和苗种培育试验

１９９９年４月至５月在湖北省荆州市窑湾渔场进行了４批池养南方大口鲶人工繁殖和苗种培育试验,对池养南方大口鲶人工繁殖方法、孵化条件和池养南方大口鲶的受精率、孵化率、苗种生长等进行了研究,并探讨采用人工繁殖和饲养的南方大口鲶后代进行人工繁殖的可行性,以减少对天然南方大口鲶亲本的需求,保护南方大口鲶天然种质资源。     

水下金属的腐蚀电场诱发西伯利亚鲟摄食行为反应

鲟具有古老的电感受系统, 但鲟的电感受功能一直是有争议和被忽略的研究方向。为确定西伯利亚鲟 (Acipenser baerii)电感受在摄食中的作用, 本研究通过行为学的方法, 研究了人工养殖的西伯利亚鲟对水下铝棒、 绝缘铝棒和塑料棒的行为反应。西伯利鲟对水下铝棒、绝缘铝棒和塑料棒都产生了类似觅食的绕棒反应, 且绕棒次数没有显著差异(P＞0.05); 但鲟对铝棒比对绝缘铝棒和塑料棒有更强烈吸吮棒表面的行为反应(P＜0.01), 鲟对铝棒的摄食偏好强度为 2, 而对绝缘铝棒和塑料棒的摄食偏好强度为 0.96 和 0.28, 表明水下腐蚀电场诱发了西伯利亚鲟摄食反应, 鲟的电感受在摄食行为的最后阶段起到了饵料判别的作用。本研究结果也表明, 对金属腐蚀电场的反应可以作为验证鲟电感受是否存在的一个行为模型, 同时也对鲟资源的保护提出了新的思路。     

大口鲶人工配合饲料网箱养殖技术操作规程

本文介绍了大口鲶 (Silurusmeridionalis)网箱养殖技术的操作规程。根据湖北省各地水库养殖大口鲶的情况 ,结合其他网箱养殖对象的饲养技术 ,制定了网箱的设置标准、水源水质要求 ,鱼种放养规格数量与网箱标准 ,投饲驯化、日常管理与鱼病防治等技术 ,为各地网箱规模化养殖大口鲶提供了一套操作规程     

南方大口鲶仔鱼的生长和摄食的初步研究

本文研究了南方大口鲶仔鱼的生长和摄食。研究结果表明,南方大口鲶仔鱼在0～15日龄内,全长与日龄之间呈线性相关,L=4．5849＋1．7892T（r=0．9942）,体重与日龄呈幂函数相关W=3．2664e0．3221T（r2=0．9783）。个体之间的生长差异较为明显,变异系数由0日龄的5．59升至15日龄的9．95,目增量率随日龄的增长呈双峰抛物线下降曲线,8～13日龄仔全对鲤鱼水花和水丝蚓的援食系数分别为4．76和4．02,对鲤鱼的摄食强度较高。通过对南方大口鲶生物学习性观察,发现其仔鱼具有明显的负趋光性和昼夜摄食节律,对饵料生物的选择依消化器官和游泳器官的发育程度依次为轮虫、桡足类幼体──枝角类、桡足类──水丝蚓和家鱼水花。     

中华乌塘鳢纤毛嗅神经元的分离及其电生理

应用酶消化和机械吹打相结合的方法,快速分离出中华乌塘鳢(Bostrychys sinensis)嗅囊中纤毛嗅觉感受神经元。再应用全细胞膜片钳技术记录中华乌塘鳢纤毛嗅觉感受神经元的静息电位、动作电位及电压门控离子通道电流等电生理学特征。结果表明,中华乌塘鳢纤毛嗅觉感受神经元具有典型的双级神经元结构特征,包括细胞体,轴突,树突以及树突顶端的嗅结和纤毛。嗅觉感受神经元静息电位为(57±6.37)mV,动作电位峰值为(38.30±0.95)mV。在60～+80 mV的阶梯去极化脉冲刺激中,内向电流在60～40 mV激活,20～0 mV达到最大值,内向电流峰值为(69.08±44.15)pA。外向电流在+40 mV时达最大值,峰值为(267.55±73.67)pA。本研究结果为纤毛嗅觉感受神经元上性信息素受体感受性信息素的电生理机制以及性信息素的应用提供了方法和理论基础。     

人工饲料驯养大口鲶的试验效果

大口鲶（ＳｉｌｕｒｕｓｍｅｒｉｄｏｎｌｉｓＣｈｅｎ） ,俗称南方大口鲶 ,是长江流域大型肉食性鱼类 ,具有肉质细嫩、味道鲜美、易于驯养等特点 ,目前已成为名优品种重点开发对象之一。但其养殖规模受到饵料制约 ,且养殖成本大 ,为此 ,各地相继开展了大口鲶的人工饲料研究。本试验对南方大口鲶的饲料驯化、当年鱼种养成商品鱼等进行了研究 ,取得了明显效果。现详细报告如下。１材料与方法１．１试验鱼取自华中农业大学自繁自育的南方大口鲶 ,体长为３．０～１１．０ｃｍ ,平均体长为６．３ｃｍ。１．２试验条件本所鳜鱼基地水泥池 ,面积分…     

不同中药组方对大口鲶消化功能的影响

中草药饲料添加剂在促进鱼类的消化功能方面研究很少.实验通过对采食不同中药饲料添加剂后大口鲶的各项消化生理指标进行检测,筛选出促进大口鲶消化的最佳中药组方,为大口鲶的养殖生产及饲料添加剂开发提供理论基础.     

南方大口鲶仔鱼的生长和摄食

本文研究了南方大口鲶仔鱼的生长和摄食。研究结果表明,南方大口鲶仔鱼在0—15日龄内,全长与日龄之间里线性相关,L=4．5849＋1．7892T（r=0．9912）,体重与日龄呈幂函数相关W=3．2664de0.3221T（r2=0．9783）。个体之间的生长差异较为明显,变异系数由0日龄的5．59升至15日龄的9.95,日增重率随日龄的增长呈双峰抛物线下降曲线,8—13日龄仔鱼对鲤鱼水花和水丝蚓的摄食系数分别为4．76和4．02,对鲤鱼的摄食强度明显大于水丝蚓。通过对南方大口鲶仔鱼生物学习性观察,发现其仔鱼具有明显的负趋光性和昼夜摄食节律,对饵料生物的选择依消化器官和游泳器官的发育程度依次为轮虫、桡足类幼体──枝角类、桡足类──水丝蚓或家鱼水花。     

大口鲶苗种发育阶段的食性研究

大口鲶幼苗阶段一般以摄食轮虫、枝角类、桡足类等浮游动物为食。在进行大口鲶菌种规模化生产中,这些活体饵料生物难以得到保障,制约了大口鲶苗种的规模化生产。因此,本试验采用不同饵料对不同发育阶段大口鲶苗种食性进行投喂试验,为解决苗种阶段的饵料供给问题作一尝试。     

Influence of Electronarcosis on Behavioral Responses,Blood Markers,and Fillet Properties of Silver Catfish (Rhamdia quelen)

Behavioral responses, blood markers, and fillet properties were investigated after silver catfish exposure to different electric field strengths, frequency, and duration of electric current in the preslaughter stunning. All combinations of electric fields and frequencies were able to stun fish. Longer apparent stun was obtained at the intermediate electrical frequencies. High electric field strength detracted the texture of fillets. At least 5 s was required to stun fish, and longer exposure to electrical current did not prolong the apparent stun or damage fillet properties. Results indicate that silver catfish are relatively resistant to electronarcosis.     

Development of boom electric fishing equipment for use in large rivers and canals in the United Kingdom

Abstract. The construction of a multiple electrode fishing boom is described. The efficiency of the equipment was compared with more conventional hand-held electric fishing equipment and seine netting in a series of field trials. Differences were found in the fishing efficiencies of the equipment teslcd. The boom electric fishing equipment with a pulsed direct current output produced better and more consistent catches and is considered to he a good cost-effective method for sampling large linear water bodies.     

Movement of flathead catfish in the Missouri River: examining opportunities for managing river segments for different fishery goals

The dispersal patterns of 2939 flathead catfish, Pylodictis olivaris (Rafinesque), were determined within a 90‐km section of the Missouri River, USA. Fish were captured by electric fishing and tagged in early June each year from 1999 through 2001. Dispersal was determined via angler tag returns between 1999 and 2001 or by subsequent recapture during sampling 1 or 2 years after initial tagging (June 2000 or 2001). Dispersal was localised for the majority of the 370 flathead catfish recaptured in the Missouri River. Over 80% of recaptures were within 5 km of tagging location, and 94% were within 20 km of tagging location. Maximum displacement was 160 km. To examine differences in movement patterns of various sized fish, flathead catfish were placed into one to three size groups (305–380, 381–507, or ≥508 mm). A significant difference (P < 0.001) was detected in dispersal patterns among the three size groups; the largest size group moved greater distances than either of the smaller size groups. Movements average 4.5, 5.6 and 12.6 km for small, medium, and large size classes, respectively. Dispersal movements of flathead catfish in the Missouri River appeared to be localised, suggesting that different sections of the Missouri River could be managed for different fishery goals for flathead catfish to accommodate a variety of angler types and desires.     

Control of the Trematode Bolbophorus confusus in Channel Catfish Ictalurus punctatus Ponds Using Salinity Manipulation and Polyculture with Black Carp Mylopharyngodon piceus

This study evaluated the use of black carp Mylopharyngodon piceus and salinity manipulation for controlling the infection of channel catfish Ictalurus puncratus by a digenetic trematode (tentatively identified as Bolbophorus confusus ). Control methods focussed mainly on the eradication of the intermediate snail host, the marsh rams-horn Phanorbella trivolvis (previously referred to as Helisoma trivolvis ), and were evaluated in laboratory tests and field experiments at a commercial catfish culture facility in southern Louisiana that was seriously impacted by the trematode. Introduction of fingerling black carp into catfish ponds at a density of 62 carpha resulted in an almost total elimination of P. trivolvis . The farm is now successfully using a facility-wide stocking rate of 40 carp/ha. Laboratory experiments were conducted to investigate the effect of salinity manipulation using NaCl on free-swimming trematode cercariae, the snail P. trivolvis , and catfish fingerlings infected with the cercariae. A salinity of 2.5 ppt had a detrimental effect on snail survival, growth, and reproduction. Salinity did not have a negative effect on the other two aspects of the trematode life cycle tested (in fact, survival of both cercariae and infected catfish fingerlings showed a positive dependence on NaCl over the 0–2.5 ppt range). A field-experiment was then conducted in catfish ponds maintained at three salinities (2.5, 1.25, and 0.25 ppt) with rock salt, NaCl. Snail densities in ponds at 2.5 ppt salinity were consistently lower than in the other treatments and no trematode infection was noted among snails or catfish in the 2.5 ppt salinity ponds. Both the use of 2.5 ppt NaCl and black carp appear valuable management tools for controlling the digenetic trematode in caffish ponds.     

Stunning of farmed African catfish (Clarias gariepinus) using a captive needle pistol; assessment of welfare aspects

The objective of this study was to assess whether high‐pressure injection of air into the brain of African catfish (Clarias gariepinus) could render the animal unconscious and insensible immediately and permanently. In the study, 48 African catfish with a live weight of 900–1900 g were restrained and equipped with EEG and ECG electrodes and then stunned. The catfish were stunned mechanically using a captive needle pistol. The pressure to shoot the needle was 8 bar and that to inject the air was 3 bar for 1.5 s. The catfish behaviour was observed during and after stunning. τ and δ waves and spikes, which precede a stoppage in brain activity as measured on the EEG, were used as indices for the measurement of immediate induction of unconsciousness and insensibility In 23 of 42 fish, an iso‐electric line was observed after an average of 13.4 s, while in the remaining fish the τ and δ waves and spikes remained on the EEG during the recording period. In all cases, the ECG showed an irregular heart rate with fibrillation and extra systolae. Moreover, the configuration showed ischaemia. Before the captive needle stunning, free‐swimming fish (n=7) explored the tank for an average of 21±12 s before lying down at the bottom. After stunning, they showed clonic uncoordinated swimming movements. The movements stopped after an average of 38±50 s. In another group (n=7) that was stunned and subsequently placed in ice water, clonic cramps were observed in two out of seven animals. When taking into account the number of animals with a reliable EEG (n=42) and using 95% confidence intervals, it was concluded that at least 93% of the catfish were effectively stunned using a correctly positioned captive needle pistol. Furthermore, it is recommended to immobilize the stunned fish by chilling, as the post‐stun clonic cramps may hinder gutting and filleting.     

Drivers of the upper River Amazon giant catfish fishery

Artisanal fishers of the upper reaches of the Amazon River use a variety of tactics to catch giant Brachyplatystoma catfish species: Brachyplatystoma vaillantii Valenciennes, Brachyplatystoma rouseauxii (Castelnau) and Brachyplatystoma filamentosum (Lichtenstein). These catfish are migratory, caught with different gears, by different communities, and influenced by temporal and spatial changes in river conditions. Facing these factors, it was hypothesised that the catfish fishery yields in the headwaters of the Amazon are determined by fishing tactics efficiency, riverscape features and governance basis. Data on catfish yields were collected from two contrasting riverscapes (rapids and floodplains) in the most important Amazonian affluent in Colombia—the Caquetá River. Results indicated that: (1) catfish yield was strongly associated with fishing effort in both riverscapes, (2) seasonal drivers play an essential influence in the high rapids reach, and river level in the low floodplain reach, (3) community strategies affected yield, although the effect is different depending on the gear used as the environment profile affects enforcement. Based on the results, it was concluded that efficient upstream management of these species should combine specific measures for each riverscape with an integrated approach to the river production system that considers catfishes longitudinal migrations and the growth overfishing occurring in the Amazon estuary.     

Fishing performance of environmentally friendly tubular pots made of biodegradable resin (PBS/PBAT) for catching the conger eel Conger myriaster

Lost or abandoned fishing gear made of synthetic fibers or plastics that do not decompose in the sea. These gear result in “ghost fishing”, that retain their function as fishing gear. To solve this problem, we developed fishing gear made of aliphatic polyester (PBS/PBAT), which is biodegraded by microorganisms after a certain period. The marine fishing performance of the biodegradable material of tubular pots for conger eel was compared with that of commercial pots in the southern coastal sea of Korea, where fishing gear loss rates are high. A comparative analysis of the elastic recovery of different types of funnel material was conducted. Two types of fishing gear were tested: (1) a pot with a body and funnel made of biodegradable materials and (2) a commercial pot made of recycled polyethylene (PE). Then, field experiments were conducted on the two pot types, which were arranged alternately. The funnel rips made of biodegradable material showed better elastic recovery than that of the commercial pot. Marine fishing performance of the biodegradable pots was similar to that of the commercial pots (Mann–Whitney test, p > 0.05). There was also no significant difference in the catch per unit effort (CPUE) by the Mann–Whitney test, p > 0.05. Thus, biodegradable materials represent an environmentally friendly alternative to recycled PE for fabricating tubular pots to catch conger eel.     

南方鲇幼鱼细菌性败血症病原与组织病理

从天然患病南方鲇(Silurus meridionalis Chen)幼鱼的肝脏中分离获得1株优势菌,命名为SCL1.用该菌株人工感染健康南方鲇幼鱼,发现菌株SCL1的感染致死率高,且患病症状与自然发病症状一致.再从人工感染的患病鱼肝脏中分离病原菌,再次感染健康南方鲇幼鱼,其症状与自然发病症状一致,确认分离菌株为南方鲇"败血症"的致病菌.该菌株形态学、生理生化特征和16S rDNA基因序列显示其为嗜水气单胞菌(Aeromonas hydrophila).药敏试验结果表明,该菌对土霉素、链霉素、氧氟沙星、氟哌酸、卡那霉素和庆大霉素高度敏感,而对青霉素钠、麦迪霉素、罗红霉素、甲氧苄啶、乙酞螺旋霉素不敏感.组织病理研究显示患病南方贴肝组织严重坏死,肝细胞排列紊乱,部分肝细胞核肿胀、崩解;脾脏细胞间界限不清,细胞核膨大,核内染色质疏松;肾小管上皮细胞肿胀,肾小囊腔间隙增大,可见该菌主要损伤南方鲇幼鱼肝、肾和脾.本研究旨在为南方站细菌性败血症的诊断与防治提供科学依据.     

Long‐term impacts of introduced flathead catfish on native ictalurids in a north Florida,USA, river

Introduction of flathead catfish, Pylodictis olivaris (Rafinesque), in waters of the USA has been widespread and often with negative impacts. Flathead catfish have been collected in Florida waters since the 1980s, and this study documents their impact on native fishes shortly after establishment. Four sites in the Choctawhatchee River, Florida, were sampled from 1997 to 2011, a time period spanning several years before and after the presence of flathead catfish at all sites. Flathead catfish expanded more than 91 river km in 2 years. The population increased rapidly and became the numerically dominant ictalurid at each site within 3 years of first detection at the site. Concurrent with the increases in flathead catfish was the precipitous decline of the native spotted bullhead, Ameiurus serracanthus (Yerger & Relyea). Electric fishing catch rates of flathead catfish significantly increased (P < 0.03) over time at all sites, while spotted bullhead catch rates significantly declined (P < 0.03) at three of four sites. Catch rates of flathead catfish and spotted bullhead were negatively correlated at all but the last site to be colonised by flathead catfish. This study provides evidence that introduced flathead catfish can quickly and significantly impact native ictalurids.     

养殖池底层鱼类电脉冲捕捞装置设计与试验

为了减轻土池养殖底层鱼类的捕捞劳动强度,提高捕捞效率,研制了具有脉冲宽度和脉冲频率可调、工作状态指示、报警等功能,以及操作简单、使用方便的助渔仪器。文章主要介绍鱼类电行为特性、水中脉冲放电产生的电场对鱼类行为作用的机理、系统电气性能参数和系统功能的确定、硬件实施及效果等。