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2.
Nuclear insulin-like growth factor 2 gene (IGF-2), growth hormone 1 gene (GH-1) and internal transcribed spacer 1 (ITS-1) of the ribosomal DNA as well as the mitochondrial NADH-3 and NADH-4 dehydrogenase genes (ND-3/4) exhibited species-specific restriction fragment patterns and three microsatellite loci (Sfo18, Ssa85 and Ssa197) had non-overlapping allele size ranges in Arctic charr and brook trout and were used as diagnostic markers for testing genetic purity of hatchery stocks and wild populations of Arctic charr and brook trout in Bavaria, Germany. Screening of four wild populations (three in Arctic charr and one in brook trout) revealed only a single hybrid (back-cross to brook trout) individual in L. Starnberg. In contrast, in three (out of five) hatchery stocks of Arctic charr and in both hatchery stocks of brook trout hybrids were detected with the frequency from 3 to 100%. Three hatchery stocks (SS2, SA and BS1) represent a hybrid swarm because they contained a very high proportion of hybrids (from 83 to 100%) and most or all hybrid individuals had alien alleles at only one or a few of six unlinked diagnostic loci, indicating that post-F1 hybrids represent the majority of individuals in these stocks and introgression has taken place. Release or escape of introgressed individuals from hatcheries into natural water bodies should be avoided in order to protect the biological diversity and genetic integrity of native fish populations.  相似文献   

3.
Characteristics and functional efficacy of digestive proteases of Catla catla, catla, Labeo rohita, rohu and Hypophthalmichthys molitrix, silver carp were studied. Total protease activity was significantly (P < 0.05) higher in rohu (1.219 ± 0.059 U mg protein−1 min−1) followed by silver carp (1.084 ± 0.061 U mg  protein−1 min−1), and catla (0.193 ± 0.006 U mg  protein−1 min−1). Trypsin activity of silver carp and rohu was 89–91% higher than catla. Chymotrypsin activity was significantly (P < 0.05) higher in silver carp compared with rohu and catla. The protease activity of rohu and silver carp displayed bell‐shaped curves with maximum activity at pH 9; whereas in catla, maximum activity was found between pH 8 and 11. Inhibition of protease activity with soybean trypsin inhibitor (SBTI), phenylmethylsulfonyl fluoride (PMSF) revealed the presence of serine proteases and inhibition of activity with N‐α‐p‐tosyl‐L‐lysine‐chloromethyl ketone (TLCK) and N‐tosyl‐L‐phenylalanychloromethane (TPCK) indicated the presence of trypsin‐like and chymotrypsin‐like enzymes in all these three carps. SDS‐PAGE showed the presence of several protein bands ranging from 15.3 to 121.9 kDa in enzyme extracts of catla, rohu and silver carp. The substrate SDS‐PAGE evidenced the presence of various protease activity bands ranging from 21.6–93.7, 21.6–63.8 and 26.7–98.5 kDa for catla, rohu and silver carp respectively. In pH‐stat hydrolysis of Chilean fishmeal showed significantly (P < 0.05) higher degree of hydrolysis compared with soybean meal, silver cup (a commercial fish feed of Mexico) and wheat flour, with enzyme preparations of three fishes. The rate of hydrolysis was significantly (P < 0.05) higher in silver carp compared with others.  相似文献   

4.
Since the end of the 20th century, some headwaters of rivers in the eastern Pyrenees have been designated as genetic refuges to protect remaining native brown trout (Salmo trutta) diversity. The declaration was based on limited or no evidence of genetic impact from released non‐native Atlantic hatchery fish. Hatchery releases were completely banned into the genetic refuges, but pre‐existing fishing activities were maintained. Specific locations in each refuge have been monitored every 2–3 trout generations to update genetic information to accurately assess the contribution of these reservoirs to the preservation of native brown trout gene pools. This work updates genetic information to year 2014 in three of these locations (in Ter, Freser and Flamisell rivers). Previous studies identified hatchery introgressed populations within refuges and suggested discrepancies between the underlying intention of the genetic refuges and the gene pools detected. Therefore, we also examined genetic divergences among locations inside refuge river segments. Combined information at five microsatellite and the lactate dehydrogenase C (LDH‐C*) loci showed reduced but significant temporal native allele frequency fluctuations in some of the above specific locations that did not modify overall levels of local diversity and river divergences. Bayesian clustering analyses confirmed the presence of differentiated native units within each genetic refuge. Some locations of the Freser River within the genetic refuge area showed high hatchery impact of non‐native fish (over 20%). We discuss additional local actions (releases of native fish, selective removals and fishery reinforcement with sterile individuals) to improve the conservation objective of genetic refuges.  相似文献   

5.
A strain of Brachionus‘Nevada’, which belongs to the Brachionus plicatilis species complex, and is commonly found in European hatcheries, was investigated in terms of its mixis potential. Two feeding regimes used for mass culturing were employed. Rotifer populations were fed on phytoplankton (Tetraselmis suecica) and either baker's yeast, Saccharomyces cerevisiae (treatments A) or Culture Selco® (treatments B). In order to promote mixis, the salinity of the culture medium was reduced from 40 to 20 g L−1. Indeed, the rotifer populations of lower salinity (A 20, B 20) showed a twofold increase in mixis rates compared with those of higher salinity (A 40, B 40). In addition, treatment A 20 showed significantly higher levels of mixis (22.59±2.07%) compared with B 20 (16.56±1.46%). The opposite trend was observed for the parthenogenetic growth rates (A 20: 0.46±0.01; B 20: 0.62±0.01). It is thus concluded that Culture Selco leads to a higher abundance of amictic ovigerous females, whereas yeast supports a higher abundance of males and mictic females carrying resting eggs. The two types of feeding regimes can be used for different purposes in a hatchery.  相似文献   

6.
Coho salmon, Oncorhynchus kisutch (Walbaum), is intensively cultured in Chile. An increasing proportion of the eggs necessary to sustain the culture are locally produced by some hatcheries. However, there is no information about the origin or the genetic variability in these strains. The present study analysed allozymic variability and its distribution within and between some commercial strains of coho salmon in southern Chile. The genetic variability was estimated using horizontal starch gel electrophoresis. Samples of coho salmon were obtained randomly from four Chilean hatcheries. Twenty‐five enzymatic systems were examined, representing 51 enzymatic loci. Eight loci showed variability in at least one strain, which represented a total polymorphism (P) of 15.7%. Only the PGM‐1* locus was variable in all strains. The remaining loci were fixed in at least one strain. Total heterozygosity (HT) and within population heterozygosity (HS) were 0.35% and 0.36% respectively. The index of genetic diversity (GST) was 1.5%. The results confirm previous reports of low genetic variability in cultured strains of coho salmon in Chile, below that observed in their native range, which suggests loss of the genetic variability caused by genetic drift or other causes in these strains.  相似文献   

7.
Abstract. Over a 15-year period hatchery brown trout, Salmo trutta L., have been added 10 Lower Lough Erne, Northern Ireland to supplement declining native populations. Introductions have mainly comprised eyed ova and fingerlings, stocked into a number of rivers in the Erne drainage. Utilizing a natural genetic tag an electrophoretic assessment of the stocking programme was undertaken. The percentage hatchery genetic contribution in trout populations varied widely from river to river (19%-91%). Lough-caught brown trout (3+ and older) showed a substantial (21·5%) hatchery genetic component. Introgression of native-and hatchery stocks was evident. The resultant deleterious genetic consequences for the conservation of the unique Lough Erne brown trout gene pool arc discussed and alternative management strategies are proposed.  相似文献   

8.
After more than 20 years of hatchery production of Asian seabass in Thailand, genetic information is still lacking for effective genetic management and a selective breeding programme. This study aimed to evaluate genetic status of existing hatchery populations and genetic consequences of a selective breeding attempt. We examined genetic relatedness in seven hatchery samples, including a selectively bred population (RACF‐F1), compared with three wild samples using 11 microsatellite loci. Genetic diversity and relatedness values within most hatchery samples, except for RACF‐F1, did not differ from those of wild populations (P > 0.05). RACF‐F1 had the lowest allelic diversity and effective population size (Ar = 6.99; Ne = 7.8) and highest relatedness values (mean rxy = 0.075–0.204). Pairwise ΦST values, principal component analysis and model‐based cluster analyses revealed three genetically distinct hatchery groups: Eastern Thailand (CHN, RACF, NSCF and SKCF), Southern Thailand (NICA) and the Andaman Sea (STCF). Results suggest that exiting domestic populations capture reasonable amount of genetic variation and can be useful for a base population for genetic improvement programmes. In addition, given the rapid increase in relatedness that we observed in one selectively bred population, we recommend using selection methods and hatchery practices that reduce variability in family contribution in the subsequent generations.  相似文献   

9.
Salmo trutta abanticus is a non‐anadromous trout species native to Lake Abant and Seven Lakes in Turkey. A restocking programme by captive breeding was initiated in 1999 to support S. trutta abanticus population. Reared 2‐year‐old juveniles from randomly caught wild parental individuals in Maçka breeding farm were introduced into Lake Abant. We aimed to compare genetic and morphological divergences between wild‐ and captive‐bred populations using seven microsatellite loci and geometric morphometric measurements. A significant genetic and morphological divergences were detected between all population in Fst and canonical variate analysis based on geometric morphometric with 10 homolog landmark. Eighty‐six microsatellites alleles were recorded across loci. Number of private alleles, observed alleles and observed heterozygosity are statistically significant higher in Maçka captive‐bred population than Lake Abant and Seven Lakes populations. Of 42 tests, three departures from Hardy–Weinberg equilibrium were detected in all populations after Bonferroni correction. Two pairs of loci (Ssa85 – Str73 and Str73‐Str543) in Maçka, one pairs of loci (Ssa85‐Str73) in Abant and two pairs of loci (Ssa85‐Str60 and Str73‐Str543) in Seven Lakes populations show linkage disequilibrium. Population structure analysed with Structure software showed three genetic groups (?K = 3) in our studied populations. Relatedness estimates show higher mean relatedness values (r = 0.220 ± 0.230) for Maçka captive‐breed population than wild populations of Abant Lake and Seven Lakes (r = 0.140 ± 0.210 and r = 0.170 ± 0.200 respectively).  相似文献   

10.
The escape or release of cultured and domesticated organisms into the wild poses a threat to the genetic integrity of natural populations. Based on data from 17 microsatellite loci, the genetic differentiation between wild and hatchery Oujiang color common carp Cyprinus carpio var. color was investigated, and its potential application for identifying the escapees of hatchery strains was assessed using Bayesian genetic assignment. No significant differences were observed between pooled hatchery and pooled wild populations in terms of allelic richness (A R), observed heterozygosity (H O), and inbreeding coefficient (F IS). Analysis of molecular variance and pairwise F ST comparisons suggested significant genetic differentiation between hatchery strains and between hatchery and wild populations, which was further confirmed by principal components analysis and Bayesian clustering analysis. Bayesian genetic alignment showed high self-assignment accuracy (ranging from 86.0 to 96.0%) in the original populations, demonstrating the ability of this technique to identify hatchery Oujiang color common carp escapees in the wild population.  相似文献   

11.
An experiment was conducted to compare rice straw mat and kanchi (bamboo sticks) as substrates in periphyton‐based polyculture systems. The experiment had three treatments: (a) no substrate (control), (b) rice straw as a substrate (3 × 2.7 kg pond?1) and (c) kanchi as a substrate (390 kanchi pond?1). Fingerlings (n=40) of rohu, Labeo rohita (24.5±0.5 g); mrigal, Cirrhinus mrigala (25.1±0.6 g); catla, Catla catla (25.8±0.5 g); common carp, Cyprinus carpio (27.6±0.6 g), and silver carp, Hypophthalmichthys molitrix (30.4±0.9 g) were stocked at a 3:2:2:2:1 ratio and cultured for 90 days. There were no differences in the number of plankton, periphyton and macro‐zoobenthos among the treatments. The total plate count of bacteria was higher in the rice straw treatment (41 320 million cfu m?2) than that in the kanchi treatment (11 780 million cfu m?2). Growth and the final mean weight of rohu, catla and common carp were higher in the substrate treatments than those in the control. Rice straw and kanchi treatment, respectively, resulted in 38% and 47% higher combined total weight gain over control. Gross margin analysis showed that rice straw treatment resulted in more profit than the control and kanchi treatment. Therefore, rice straw has the potential to be used to increase production in the low‐input rural aquaculture.  相似文献   

12.
Abstract

Construction and operating costs for three common snook (Centropomus undecimalis) hatcheries in Florida, USA, are illustrated. Hypothetical capacities and targets of the three hatcheries (Scenarios I, II and III respectively) were 615, 000 juveniles (8 ‐ 10 g in weight) for stock enhancement, and 1, 275, 000 and 3, 000, 000 juveniles (1‐g in weight) for commercial grow‐out. Estimated production costs were lower than for many marine finfish species. The 20‐year mean costs per 1, 000 juveniles were estimated to be $324, $215, and $159, for hatcheries I, II, and III respectively, and the initial capital investments were $731, 660, $1, 162, 460, and $1, 896, 0301, respectively. Major cost items of annual production were labor (22 ‐ 33%), supplies (14 ‐ 20%), fixed costs (15 ‐ 17%), and interest (13 ‐ 15%). The most profitable hatchery was the 3 million 1‐g juvenile hatchery due to the hatchery size effect, with a net present value (NPV) of $1, 760, 000, an internal rate of return (ERR) of 81%, a payback period of 3.6 years, and a profitability index of $2.86 for every dollar invested. Possible cost reductions to increase financial profitability were discussed.  相似文献   

13.
The large-scale spatial patterns of straying of marked chinook salmon, Oncorhynchus tshawytscha (Walbaum), produced at hatcheries in the Columbia River (north-west USA) are described. Straying rates were extremely variable among hatcheries (from 1% to 95%). Fish produced near the mouth of the river strayed more commonly than those produced farther upriver. While the large-scale straying patterns were well explained by the distance between the hatchery of origin and alternative destinations, substantial deviations from this pattern were observed at smaller scales. Three distinct areas of origin were identified and most straying occurred between hatcheries and natural spawning grounds within each area. The location of the stream where the hatchery of origin is located affects the patterns of straying. Fish reared at hatcheries in the main stem of the river did not stray into tributaries as often as predicted by a model based exclusively on linear distance between alternative locations. Likewise, fish released from large tributaries strayed to main stem hatcheries less often than predicted by the model. Fish produced at hatcheries on north bank tributaries appeared to stray less into southern streams than fish released from southern streams. These findings indicate that salmon are more likely to stray to spawning areas similar to their natal site than to dissimilar sites, in addition to the tendency to stray to nearly sites. In addition to the general patterns, examination of data from two types of transplants indicated that there is a genetic component to homing/straying behaviour within the watershed. However, salmon transplanted into the Columbia River watershed from elsewhere showed homing precision comparable to that of local fish, although they retained their ancestral marine distribution.  相似文献   

14.
The cultural practices used to produce fingerling walleye, Stizostedion vitreum, in drainable earthen ponds are described for a state fish hatchery in Nebraska and two federal hatcheries in North Dakota. The ponds were filled 1 to 7 days before D2-D4 (Dl=the day of hatch) walleye fry were stocked. At one hatchery, ponds were sometimes double-cropped, first for production of northern pike, Esoxlucius. The two federal hatcheries fertilized ponds with ground alfalfa hay or pellets, while the standard practice at the Nebraska hatchery was not to fertilize walleye ponds, because of concern that fertilization would result in weed problems and oxygen depletion. One hatchery seeded the ponds with rye grass in the fall. Two of the hatcheries regularly used herbicides to prevent the stranding of fingerlings during harvest and their mortality caused by entangment with net algae, Hydrodicton. When used, herbicide treatment was applied before ponds were filled (AquazineTM) or as needed during the culture interval (AquazineTM) or copper sulfate). Harvesting was done after 24 to 58 days; the extreme range represented variation among hatcheries; the variation among ponds at a given hatchery ranged from 4 to 10 days. Harvest occurred when fingerlings were 25 to 50 mm total length and weighed 1,500-5,440 fish/kg. Harvests ranged from 11,933 to 308,537 fingerlings/ha. Survival ranged from 3 to 104% of the estimated number of fry stocked.  相似文献   

15.
Different laboratory synthesized metal nanoparticles viz. Copper oxide (CuO), Zinc oxide (ZnO) and silver doped titanium dioxide (Ag‐TiO2) were studied for their effect on hatching and survival of larvae and fry of Indian major carp, rohu, Labeo rohita both in direct application in tank water & coated onto tanks. Among these nanoparticles, CuO and ZnO nanoparticles exhibited highest percentage of hatching in both direct addition (78.0 ± 3.1% and 78.05 ± 4.2%, respectively) and coating onto tanks (58.6 ± 2.1% and 61.2 ± 2.7%, respectively) at 1 mg mL?1 while least percentage of hatching was recorded in Ag‐TiO2 nanoparticles irrespective of its concentration & mode of supplementation. Highest survival of L. rohita fry (50.13 ± 2.2%) was observed after 15 days post hatching in CuO coated tanks followed by ZnO coated tanks (38.6 ± 2.8%) while least was recorded in Ag‐TiO2 coated tanks (22.53 ± 3.0%). However in control tanks coated with Poly‐Urethane base with hardener and uncoated control tanks, the survival was 42.4 ± 1.2% and 41.36 ± 1.8% respectively. Further, significantly lower microbial load of water was recorded in CuO nanoparticles coated tanks (1.5 × 1010 CFU L?1) as compared to uncoated control tanks (1.1 × 1016 CFU L?1) without affecting water quality parameters. On the other hand, in Ag‐TiO2 coated tanks, significantly lower microbial load (1.0 × 106 CFU L?1) as compared to uncoated control tanks at 15 days post hatching was recorded. However, Ag‐TiO2 was toxic to L. rohita larvae & fry both in direct application and coating onto tanks. Considering the beneficial effects of CuO nanoparticle application, it has the scope of being used in a more eco‐friendly way in hatchery operations.  相似文献   

16.
Protein polymorphism and allelic variation were investigated in the blood of the catfish, Synodontis schall (Bloch‐Schneider, 1801) and S. serratus (Ruppel, 1829) from three localities along the White Nile. The first sampling locality at khartoum, the second at Jebel Aulia Dam, 45 km south of khartoum and the third locality was 45 km southward along the White Nile. Seventeen gene loci were identified in separating 13 enzymes and proteins. Nine loci were polymorphic and eight were monomorphic in the two species. Two alleles were observed for each polymorphic locus. Except for serum albumin (ALB*) and erythrocyte glucose phosphate isomerase (GPI‐1*), all corresponding allozymes in the two species revealed similar mobilities and separation patterns. Serum albumin (ALB*) was monomorphic with a molecular weight of 67 kd in S. schall and 60–62 kd in S. serratus. Glucose phosphate isomerase (GPI‐1*) was polymorphic in S. schall, but monomorphic in S. serratus. A contingency (χ2) test shows significant interspecies heterogeneity in allele frequency at (haemoglobin (HB*)), (6‐phosphogluconate dehydrogenase (6PGD*)) and (superoxide dismutase (SOD*)) but none of the other polymorphic loci. Average heterozygosity was (0.26) for both species and the genetic distance between the two species was (0.22).  相似文献   

17.
The Apostichopus japonicus is a valuable aquaculture species in China. In this study, 51 single nucleotide polymorphisms (SNPs) were identified from expressed sequence tags of sea cucumber using high‐resolution melting. The average observed heterozygosity (Ho) and expected heterozygosity (He) were 0.2462 and 0.2897, respectively. Thirty‐two of these loci were used for estimating the genetic similarity and variation between the five hatchery stocks from China and two wild stocks from Japan. No significant differences in Ho or He were observed between the wild and hatchery populations. The pairwise Fst (which ranged from 0.0119 to 0.0236) and the genetic identity (which varied from 0.9802 to 0.9915) showed no significant differentiation between the wild and cultured stocks. The analysis of molecular variance indicated the source of variation was at the level of “within the populations.” The information on the genetic variation and differentiation in cultured and wild populations of A. japonicus obtained in this study is useful for setting up suitable guidelines for founding and maintaining of cultured stocks and for future genetic improvement by selective breeding.  相似文献   

18.
Genetic variation in seven reared stocks of gilthead sea bream Sparus aurata, originating from Greek commercial farms, was assessed using five polymorphic microsatellite markers and was compared with that of two natural populations from the Ionian and the Adriatic Seas. The total number of alleles per marker ranged from 11 to 19 alleles, and hatchery samples showed the same levels of observed heterozygosity with samples from the wild but substantially smaller allelic diversity and expected heterozygosity. The global genetic differentiation for the cultivated samples was significant as indicated by Fst analysis, which might indicate random genetic drift and inbreeding events operating in the hatcheries. On the contrary, no significant difference was found between the two wild populations. Population pairwise tests between farmed and wild stocks were also significant, with the exception of one hatchery sample, the Central Greece 1, which was not significantly different from the two wild samples perhaps due to its recent use in aquaculture from wild‐caught animals. The UPGMA tree topology grouped the wild samples together with the Central Greece 1 stock, and showed a clear division between wild and farmed sample sets for the six remaining hatchery samples. Knowledge of the genetic variation in S. aurata cultured populations compared with that in the wild ones is essential for setting up appropriate guidelines for the proper monitoring and management of the stocks either under traditional practices or for the implementation of selective breeding programmes.  相似文献   

19.
An experiment was conducted from December 2003 to April 2004 to observe the over‐wintering growth of freshwater prawn, Macrobrachium rosenbergii, with catla, Catla catla and rohu, Labeo rohita in polyculture using formulated diets. The study was conducted in eight experimental ponds, each 80 m2. Three experimental diets containing 30% protein were prepared using fish meal, meat and bone meal, mustard oilcake, rice bran, wheat bran and molasses (binder), and assigned to treatments T1, T2 and T3 respectively. A commercial diet from Saudi‐Bangla Fish Feed was assigned to T4 (reference diet). Each treatment had two replicate ponds. Juvenile prawns and catla and rohu fingerlings (initial weight 1.60±0.10, 30.0±1.2 and 25.0±1.1 g respectively) were stocked at a ratio of 2:1:1 (prawn:catla:rohu). A total of 160 prawn and fish (20 000 ha?1) were stocked in each pond. Fish were fed twice daily at 3% body weight (b.w.) for the first 3 months and 5% b.w. for the last 2 months. Prawns in T1 fed diet 1 had significantly higher (P<0.05) weight gain compared with that of T3. The reference group and T2 had intermediate values not significantly different from either. Weight gains of catla and rohu were significantly higher in T1. The feed conversion ratio values of different diets ranged between 1.89 and 2.13. Survival (%) ranged from 90.0% to 95.0% for catla, 87.5% to 92.5% for rohu and 70.0% to 76.3% for M. rosenbergii, and there were no significant differences (P>0.05) among different treatments. Total production ranged between 2196 and 2679 kg ha?1, with T1 showing significantly higher production and net profit (taka 56 531.9 ha?1). The results of the study demonstrated that it is possible to culture M. rosenbergii with carp in polyculture during the winter utilizing the late‐produced PLs. Further study is needed to determine the optimum stocking density of M. rosenbergii in carp polyculture.  相似文献   

20.
Anaesthetic agents are very useful for reducing the stress caused by handling, sorting, transportation, artificial reproduction, tagging, administration of vaccines and surgical procedures in fish. The efficacy of two anaesthetics: MS‐222 and AQUI‐S® were tested on rohu, Labeo rohita advanced size fry. The lowest effective doses that produced induction in 3 min or less and recovery times 5 min or less and meet the most criteria of good anaesthetic characteristics were 125 mg L?1 of MS‐222, and 30 mg L?1 of AQUI‐S® in rohu, Labeo rohita advanced size fry. Induction times were significantly decreased with increased in the concentrations of any of the two tested anaesthetic agents. The lowest doses suitable for transportation of rohu advanced size fry observed were: 10–15 mg L?1 of MS‐222 and 2.5 mg L?1 AQUI‐S®. Both anaesthetics showed promising to be used as anaesthetics for handling and transportation in rohu (Labeo rohita) advanced fry.  相似文献   

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