二种对虾白斑综合征组织与细胞病理研究

对自然发病、投喂感染和注射感染的中国对虾、凡纳滨对虾白斑综合征进行组织与细胞病理研究，结果发现：中国对虾与凡纳滨对虾的病理变化相似，但不同感染方式的患病对虾有差异。临床病理：相同点表现为游动无力，反应迟钝，胃中无食，体色变暗，肌肉浑浊，肝胰腺肿大；不同点为自然发病和投喂感染的对虾临床病理变化比注射人工感染明显，病程长。显微病理：相同点表现为细胞核肿大，细胞变性、坏死等；不同点为自然发病和投喂感染的病虾胃、肝胰腺的病理变化比注射感染严重，坏死细胞数量多，组织大面积坏死溶解；注射感染病虾的肌肉组织显微病理变化比自然发病、投喂感染严重。超微病理：相同点表现为细胞肿大、变性、坏死、溶解，线粒体、内质网等细胞器形态变异，肿大，膜溶解或整体崩解；细胞核肿大或固缩或溶解．部分细胞核中可见WSSV；不同点为注射感染的患病对虾肌肉组织的超微病理变化比自然发病、投喂感染严重，肌细胞核中观察到WSSV的几率较高；投喂感染、自然发病对虾的胃上皮细胞、肝胰腺细胞的超微病理变化比注射感染严重。另外，不同类型的细胞对WSSV的易感性不相同，血细胞为最常见的被病毒感染的靶细胞，血细胞通过细胞变形或形成伪足，贴附于其它组织细胞膜上。     

中国对虾（Penaeus chinensis）杆状病毒病的研究↑（*）

１９９３年养殖的中国对虾（ＰｅｎａｅｕｓＣｈｉｎｅｎｓｉｓ）发生了暴发性流行，经人工感染和电镜观察，证实是由杆状病毒引起的。病虾活力差。体色暗淡或微红，头胸甲上有浅黄色至白色的斑点，头胸甲与表皮下粘连，容易剥离，血淋巴混浊，淋巴器官和肝胰腺肿大，糜烂，在肝胰腺，淋巴器官，中肠，皮下组织和鳃等组织细胞的核内均发现有大量病毒粒子，病毒粒子杆状，无包涵体，具囊膜，平均长３５０ｎｍ，宽１５０ｎｍ，核衣壳体     

杆状病毒性的皮下及造血组织坏死─对虾暴发性流行病的病原和病理学

１９９３年对虾暴发性流行病的患病对虾经光镜组织病理学研究和电镜观察，在对虾的皮下组织（包括前肠上皮、后肠上皮、真皮和鳃等）、结缔组织、造血组织、触角腺及血淋巴细胞等的细胞核均发现核肿大和深的嗜酸性着色。在电镜下，病变组织的细胞核内为一种杆状病毒充满，病毒大小为１２０ｎｍ×３６０ｎｍ，有囊膜，在细胞内不形成核型多角体或颗粒体类包涵体，属于杆状病毒属的无包涵体型杆状病毒亚群，即Ｃ型杆状病毒亚群。根据该对虾暴发性流行病的症状、病毒感染的靶组织和病毒的特征，该病毒被认为是一种新的对虾病毒，暂定名为皮下及造血组织坏死杆状病毒。     

湖北省潜江地区克氏原螯虾(procambarus clarkii)白斑综合征(White Spot Syndrome)PCR诊断及组织病理学观察

近年来在湖北省范围内人工养殖的克氏原螯虾暴发了严重的疾病,其中白斑综合征病毒（WSSV）已成为危害克氏原螯虾健康养殖的重要病原。2016年5月湖北省潜江市养殖区暴发了一种传染性疾病,为探究此次疾病病因和流行规律,将染病虾进行临床症状观察、对病料进行PCR检测、系统发育树分析、人工感染和组织病理学观察。结果显示,发病克氏原螯虾临床症状主要表现为摄食减少,活力下降,反应迟钝;组织病理学观察结果显示,克氏原螯虾的肝胰腺、肠、肌肉、鳃组织均出现不同程度变性和坏死以及炎性细胞浸润等典型病理学变化,与WSSV感染克氏原螯虾出现的病变相似;PCR检测患病克氏原螯虾样品,结果显示WSSV呈阳性,阳性检出率为55.56%（15/27）,未检测到斑节对虾杆状病毒（MBV）和传染性皮下及造血组织坏死病毒（IHHNV）;检测产物测序并进行系统发育树分析,结果显示,该基因序列与WSSV的EG3株（KR083866.1）核苷酸序列同源性为100%。将病虾的肝胰腺、肠和肌肉组织投喂健康克氏原螯虾,投喂组均表现为急性死亡（累积死亡率为100%）,并出现与自然发病虾相同的症状。WSSV的巢式PCR检测结果显示,人工感染病虾为WSSV阳性。根据以上显示,本次养殖克氏原螯虾大规模死亡的病原是WSSV。     

湖北省潜江地区克氏原螯虾白斑综合征PCR诊断及组织病理学观察

近年来在湖北省范围内人工养殖的克氏原螯虾暴发了严重的疾病,其中白斑综合征病毒(WSSV)已成为危害克氏原螯虾健康养殖的重要病原。2016年5月湖北省潜江市养殖区暴发了一种传染性疾病,为探究此次疾病病因和流行规律,将染病虾进行临床症状观察、对病料进行PCR检测、系统发育树分析、人工感染和组织病理学观察。结果显示,发病克氏原螯虾临床症状主要表现为摄食减少,活力下降,反应迟钝;组织病理学观察结果显示,克氏原螯虾的肝胰腺、肠、肌肉、鳃组织均出现不同程度变性和坏死以及炎性细胞浸润等典型病理学变化,与WSSV感染克氏原螯虾出现的病变相似;PCR检测患病克氏原螯虾样品,结果显示WSSV呈阳性,阳性检出率为55.56%(15/27),未检测到斑节对虾杆状病毒(MBV)和传染性皮下及造血组织坏死病毒(IHHNV);检测产物测序并进行系统发育树分析,结果显示,该基因序列与WSSV的EG3株(KR083866.1)核苷酸序列同源性为100%。将病虾的肝胰腺、肠和肌肉组织投喂健康克氏原螯虾,投喂组均表现为急性死亡(累积死亡率为100%),并出现与自然发病虾相同的症状。WSSV的巢式PCR检测结果显示,人工感染病虾为WSSV阳性。根据以上显示,本次养殖克氏原螯虾大规模死亡的病原是WSSV。     

首例斑节对虾越冬亲虾发生杆状病毒的皮下及造血组织坏死症研究

湛江长洪对虾苗种实验场的斑节对虾转入越冬池后３～１０ｄ内发生暴发性死亡，症状与北方地区杆状病毒的皮下及造血组织坏死症一致。病理学研究表明，所有发病虾样的皮下组织、造血组织、结缔组织、肝胰腺血窦、淋巴器官等细胞核均存在严重的ＨＨＮＢＶ病灶，只有２０％的发病对虾肝胰腺中观察到轻微感染的ＭＢＶ包涵体。ＨＨＮＢＶ单抗的酶联免疫染色，可对ＨＨＮＢＶ的病灶产生特异性着色，对虾组织结构和ＭＢＶ包涵体均不着色。在山东培育三代并养殖１６个月的斑节对虾中也观察到与湛江发病的越冬亲虾相同的情况。以上说明，近年来在广东一带ＨＨＮＢＶ是值得重视的病原，其危害可能重于ＭＢＶ。对于发生过对虾暴发性流行病的群体来说，不宜用来作为亲虾。     

斑节对虾杆状病毒在感染对虾中肠腺中的分布

利用组织切片法研究了斑节对虾杆状病毒（MBV）在养殖早期班节对虾及养成期斑节对虾中肠腺各部位的分布特点。斑节对虾的中肠腺可分为头部、亚头部、中部、亚尾部和尾部等5个部分，其上皮细胞包括E细胞、F细胞、B细胞和R细胞等4种类型。头部和尾部均以E细胞为主、亚头部、中部和亚尾部均以R细胞为主。在感染度较轻的样本中，MBV一般只感染F细胞、R细胞和B细胞。感染度较重时，E细胞也同时受累。在养殖早期虾和养成期虾中，MBV相对感染度在中肠腺各部分的分布均以中部最高，而且以中部的中间最高，离中部越远，相对感染度越低。     

虾池中蟹病毒的研究

１９９４年时发病虾池中死亡蟹的胃、肠和肝胰腺进行了电镜观察，发现肠组织细胞核中有大量具囊膜的杆状病毒粒子，大小为２５０×３１０×７５纳米。初步观察了蟹在虾池中的活动情况，并分析了蟹病毒传播途径的可能性。     

中国对虾暴发性流行病的血液病理研究

对患暴发性流行病的中国对虾进行了血液生理生化指标检测。与健康虾比较，自然发病与人工感染病虾的血清总蛋白、白蛋白、血糖含量减少，而甘油三酯、尿素氮、肌酐含量及血清碱性磷酸酶（ＡＫＰ）、谷丙转氨酶（ＧＰＴ）、乳酸脱氢酶（ＬＤＨ）活性增加。对人工感染试验病虾跟踪检测显示，对虾在病毒感染后２４ｈ，出现ＡＫＰ升高、血清总蛋白、白蛋白、血糖含量下降，随着感染时间延长，出现变化的血液指标增多，变化幅度也急速增加。结果表明，中国对虾暴发性流行病是杆状病毒急性感染后所引起的一种全身性疾病，患病虾在营养物质代谢、抗病力、消化、呼吸、排泄等方面的生理功能迅即受到严重损害。     

纯化病毒复制中华绒螯蟹“颤抖病”的组织病理观察

采用石蜡切片及超薄切片技术，对人工感染纯化病毒后具典型颤抖症状的中华绒螯蟹进行病理学观察。结果显示：人工感染“颤抖病”病毒发病与自然发病的病理变化相似，病蟹的肝胰脏、鳃、心脏及腹神经节等组织器官发生了病变，其病理特征主要表现为细胞浊肿、变性、坏死，某些细胞的细胞核固缩、碎裂或崩解；超薄切片电镜下可见细胞内存在病毒样颗粒，线粒体内嵴受损严重。病变严重的区域，组织细胞坏死，结构崩解。提示肝胰脏、鳃、心脏及神经组织是病毒感染主要靶器官。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Production of diatom–bacteria biofilm isolated from Seriola lalandi cultures for aquaculture application

Controlled incorporation of selected microalgae and bacteria in aquaculture systems can be beneficial because they can act as microbiological control. That is why the characteristics of biofilm generated naturally in Seriola lalandi culture cages were analysed, their potential benefit to the growth of larvae was studied, and their controlled use for improving the larval viability and as a vector to improve incorporation of previously studied probiotic bacteria was tested. According to biodiversity results, these biofilms are composed of a diatom–bacteria mix showing a decrease in biodiversity in laboratory culture conditions being dominated by Navicula phyllepta and bacteria of the family Rhodobacteraceae. This can be produced on mesh substrates incorporated in bioreactors with rapid growth rate and adhesiveness. Preliminary results from the addition of substrates with this specific biofilm in larvae culture systems showed that it is consumed by the larvae without negative effects, while positive effects on the viability of larvae in combination with probiotics were observed. Considering preliminary results, the addition of these specific substrates with diatom–bacteria biofilms could be a good improvement for aquaculture systems and together with the use of probiotics can contribute to maintaining a stable and controlled system improving the viability of the larval fish culture in its early stages.