利用中国明对虾单对杂交亲本及其F↓（2）群体构建RAPD遗传连锁图谱

由中国明对虾(Fenneropenaeus chinensis)单对杂交亲本(G♀和G♂)及其F2为作图群体,构建了中国明对虾RAPD分子标记的遗传连锁图谱。109个引物共产生284个符合孟德尔分离规律的位点,符合1∶1孟德尔分离类型的位点共234个,符合3∶1孟德尔分离类型的位点50个。利用拟测交理论分别构建中国明对虾雌虾、雄虾的遗传连锁图谱。107个1∶1分离标记分布于雌虾连锁图谱中,包括31个连锁群,图谱总长度为1 406.1 cM,所有标记间的平均间隔为18.5 cM;91个1∶1分离标记分布于雄虾连锁图谱中,包括26个连锁群,图谱总长度为1 187.7 cM,所有标记间的平均间隔为18.27 cM;利用F2自交模型构建了雌虾和雄虾共同的分子标记,35个3∶1分离标记分布于雌雄共有的连锁图谱中,包括10个连锁群,图谱总长度为432.9 cM,所有标记间的平均间隔为17.3 cM。     

三疣梭子蟹遗传连锁图谱的初步构建

利用AFLP和SSR标记技术结合"拟测交"策略,以三疣梭子蟹莱州湾、舟山野生群体杂交(1♂×3♀)产生的F2代家系为作图群体,初步构建了三疣梭子蟹雌、雄性遗传连锁图谱。用经过筛选的60对AFLP引物和3对SSR引物对亲本及108个F2代个体进行遗传分析,共得到母本分离标记214个,其中155个标记(AFLP标记153个,SSR标记2个)符合1∶1孟德尔分离规律;父本分离标记195个,139个标记(AFLP标记138个,SSR标记1个)符合1∶1孟德尔分离规律。雌性图谱包括100个遗传标记,分布在9个连锁群,6个三联体,15个连锁对,图谱总长度为1544cM,标记平均间隔22.0cM,总覆盖率为52.9%。雄性图谱包括71个遗传标记,分布在6个连锁群,6个三联体,11个连锁对,图谱总长度1174.2cM,标记平均间隔24.0cM,总覆盖率为49.5%,图谱中遗传标记分布比较均匀。     

牙鲆遗传连锁图谱的构建

利用基因组测序得到的大量微卫星序列,以681383B为父本、6812E36为母本杂交获得的F1为作图群体,构建了牙鲆(Paralichthys olivaceus)微卫星标记(SSR)遗传连锁图谱。雌雄图谱共定位SSR标记529个,其中雄性连锁图谱包括418个标记,分布在24个连锁群上,总长度1 418.1 cM,标记平均间隔3.62 cM,图谱覆盖率为88.7%;雌性连锁图谱包括437个标记,分布在24个连锁群上,总长度1 298.1 cM,标记平均间隔为3.16 cM,图谱覆盖率为89.1%。牙鲆中密度遗传图谱的构建为QTL分析以及分子标记辅助育种进一步奠定基础,并可以有效推动牙鲆的遗传改良工作,推动牙鲆养殖业的可持续发展。     

坛紫菜遗传连锁图谱的构建

以野生型坛紫菜纯系(♀)和红色型坛紫菜纯系(♂)作为杂交亲本,结合四分子分析法及单个体细胞克隆的丝状体途径,创建了由157个株系组成的坛紫菜DH作图群体,并用经过筛选的24对SRAP引物和16对SSR引物对父母本及作图群体各株系进行双标记分析,获得了224个多态性标记,其中157个标记符合孟德尔分离规律。根据标记间的连锁规律,首次构建了坛紫菜的分子遗传连锁图谱,所构建的遗传图谱由包含124个标记(含SRAP标记104个,SSR标记20个)的5个连锁群组成,总长度为879.2cM,平均标记间隔为7.09cM,各个连锁群长度为134.2～213.6cM,包含标记18～31个。最后采用3种不同方法计算得到坛紫菜的估计基因组长度平均为955.3cM,由此得到坛紫菜遗传连锁图谱的基因组覆盖率为92.0%。     

半滑舌鳎微卫星标记遗传连锁图谱的构建

利用全基因组测序方法筛选出微卫星标记,以渤海近海野生个体和人工养殖的半滑舌鳎(Cynoglossus semi-laevis)为亲本交配产生的F1全同胞家系为作图群体,构建了半滑舌鳎雌、雄微卫星标记遗传连锁图谱。用320对引物对父母本和92个F1个体进行遗传分析,共得到288个分离标记,其中包含112个偏分离标记(P<0.05)。其中雌性框架图包含242个标记,分布在21个连锁群上,总长度1 311.9 cM,标记间平均距离为4.9 cM,图谱覆盖率为83.3%;雄性框架图定位标记218个,21个连锁群,总长度1 316.2 cM,标记间平均距离为5.5 cM,覆盖率为82%。半滑舌鳎遗传连锁图谱的构建为半滑舌鳎重要经济性状QTL定位、分子标记辅助育种和性别控制奠定了重要基础。     

应用SSR和SRAP标记构建青虾遗传连锁图谱

采用SSR和SRAP标记结合拟测交策略构建青虾(Macrobrachium nipponense)遗传连锁图谱。共有175个标记(含27个SSR、148个SRAP标记)分布在53个连锁群上。每个连锁群含2~8个标记,其中不少于3个标记的连锁群有35个,连锁对18个,平均每个连锁群的标记数为3.3个;连锁群长度在6.7~91.2 cM之间,相邻标记间最大间隔为49.0 cM,最小为1.4 cM,平均间隔为13.1 cM。青虾框架图谱长度为997.2 cM,图谱观察总长度为2 270.5cM,根据估算,青虾遗传连锁图谱预期长度为4 380.6 cM,图谱的覆盖率为51.83%。本研究构建了青虾遗传连锁图谱,该图谱也是淡水虾蟹类第一张遗传连锁图谱,可为青虾QTL定位、基因克隆、遗传选育等提供指导,并为进一步构建高密度的青虾遗传连锁图谱奠定了基础。     

中国对虾连续两代的DNA随机扩增多态性及其遗传规律分析

为评估DNA随机扩增多态性标记在中国对虾遗传连锁图谱构建中的应用前景,利用中国对虾单对交配亲本及其子二代材料,对RAPD标记及其遗传规律进行了研究。22条RAPD随机引物扩增结果的统计分析表明,标记在中国对虾F2的遗传规律可归为不分离标记和分离标记:不分离标记,指在亲本和后代中均不分离的标记,占总位点的54.1%;分离标记占总位点的45.9%。其中,分离标记又包括符合孟德尔遗传分离的标记、偏离孟德尔遗传分离标记和异常分离标记。符合孟德尔分离的标记中,分离比例为3∶1的标记占分离标记的14.7%;总的1∶1标记占分离标记的64.7%;偏离孟德尔分离和异常分离的标记分别占分离标记的11.7%和8.9%。在这些分离的标记中,有76.5%的位点在"双假测交理论"的策略中适合构建中国对虾的遗传连锁图谱,这为以中国对虾F2为作图群体,并利用RAPD标记构建中国对虾遗传连锁图谱提供了理论支持。     

中国对虾遗传连锁图谱的构建

利用RAPD、SSR和AFLP三种标记技术结合"拟测交"策略,以中国对虾"黄海1号"雌虾与野生雄虾作为亲本进行单对杂交产生的F1家系为作图群体,初步构建了中国对虾雌、雄性遗传连锁图谱.对460个RAPD引物和44对SSR引物进行筛选,共选出61个.RAPD和20对SSR引物,结合88对AFLP引物组合对父母本和82个F1个体进行了遗传分析.共得到783个分离标记(RAPD标记237个,微卫星标记45个,AFLP标记501个),761个标记用于连锁分析.雌性图谱包括40个连锁群和15个三联体,20个连锁对,标记间平均间隔为12.5 cM,图谱共覆盖2835.5 cM,覆盖率为73.5%;雄性图谱包括41个连锁群和6个三联体,12个连锁对,标记间平均间隔为11.9 cM,图谱共覆盖2776.7 cM,覆盖率为73.3%.中国对虾遗传图谱的构建为其分子标记辅助育种、比较基因组作图及数量性状位点(QTL)的定位与克隆奠定了基础.     

中国对虾近交两代的DNA随机扩增多态性及其遗传规律分析

为评估DNA随机扩增多态性标记在中国对虾遗传连锁图谱构建中的应用前景，利用中国对虾单对交配亲本及其子二代材料，对RAPD标记及其遗传规律进行了研究。22条RAPD随机引物扩增结果的统计分析表明，标记在中国对虾F2的遗传规律可归为不分离标记和分离标记：不分离标记，指在亲本和后代中均不分离的标记，占总位点的54.1%；分离标记占总位点的45.9%。其中，分离标记又包括符合孟德尔遗传分离的标记、偏离孟德尔遗传分离标记和异常分离标记。符合孟德尔分离的标记中，分离比例为3:1的标记占分离标记的14.7%;总的1:1标记占分离标记的64.7%；偏离孟德尔分离和异常分离的标记分别占分离标记的11.7%和8.9%。在这些分离的标记中，有76.5%的位点在“双假测交理论”的策略中适合构建中国对虾的遗传连锁图谱，这为以中国对虾F2为作图群体，并利用RAPD标记构建中国对虾遗传连锁图谱提供了理论支持。     

鲢鳙杂种亲本连锁图标记加密和共线性比较

鲢(Hypophthalmichthys molitrix)与鳙(Aristichthys nobilis)杂种的养殖性能优于亲本,在水产养殖中利用广泛.为促进鲢、鳙遗传资源管理、经济性状定位等研究,已构建了鲢鳙种间杂种亲本的遗传连锁图,但图谱以AFLP标记为主,利用范围有限.为提高图谱质量和可用性,本研究采用新开发的微卫星标记加密了鲢鳙杂种亲本连锁图.雌性亲本鲢的连锁图标记总数从153增加到288(包括新开发微卫星标记93个),雄性亲本鲢的连锁图标记总数从271增加到511(包括新开发微卫星标记136).鳙图谱总长度从852.0 cM增加到965.8 cM,鲢图谱总长度从952.2 cM增加到1049.6 cM.鲢、鳙图谱共线性比较甄别出22个同缘连锁群,标记排列只存在轻微重排现象.亲本间共享的76个微卫星标记界定的标记间隔总长度在亲本间无差异(雌:雄＝1:1),与鳞鲢种内杂种亲本共享微卫星标记界定间隔的总长度雌雄比(1:0.45)显著不同.与模拟自然受精(种内杂种)相比,混精受精(种间杂种)可增加雄性亲本基因组范围的重组率.鲢鳙形态相似,染色体组型相同,杂种可育,鲢鳙杂交对重组率没有影响或影响很小.根据研究结果,认为混精授精回避了精子竞争,强化了全基因组重排,不利于新形成的和已有的优良单倍型的保留,是鲢鳙养殖性能退化的原因之一.     

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.