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1.
Attempts were made to complete all possible interspecific hybrid crosses between Atlantic salmon (Salmo salar), rainbow trout (Salmo gairdneri), brook trout (Salvelinus fontinalis), lake trout (Salvelinus namaycush), and Arctic char (Salvelinus alpinus). Survival was appreciable only in (giving female first) lake × brook, salmon × char, brook × char and char × brook hybrids. Growth rates over a weight increment of 3–30 g averaged 2.14% wet weight/day for all species and hybrids (14.5–17.0°C — excess rations). The highest growth rate, 2.74%, was obtained with the brook (female) × char (male) hybrid and the lowest, 1.63%, in lake trout. Salmon (female) × char (male) hybrids grew faster than salmon; brook trout (female) × char (male) hybrids grew faster than brook trout. Salmo species grew no faster than Salvelinus species but became silvery and had greater salinity tolerance at a smaller size and earlier age. Intergeneric hybrids between female Salmo spp. and male Salvelinus spp. more closely resembled the female parent in processes related to smoltification (silvering and salinity tolerance). 相似文献
2.
Triploid hybrids between female rainbow trout (Oncorhynchus mykiss Walbaum) and male brown trout (Salmo trutta L.) were tested for farming performances, with reference to parental species. The main drawback of hybrids lay in embryonic
and larval mortalities, amounting to 60% on average, and displaying a large variability between spawns. Further survival was
inferior to that of diploid, but similar to that of triploid rainbow trout. Hybrid body weight was intermediate between weights
of rainbow and brown trout of the same age, mainly as a consequence of differences in precocious growth. Analysis of relative
growth rates from 6 to 18 months showed that hybrids were surpassed by rainbow controls in common rearing, but not in separate
rearing. Hybrid behaviour was similar to that of rainbow trout. These results are discussed in the scope of providing fisheries
managers with original and sterile game fishes.
An erratum to this article can be found at . 相似文献
3.
Importance of fatty acids in broodstock diets with emphasis on Arctic char (Salvelinus alpinus) eggs
The importance of long-chain polyunsaturated fatty acids, especially the eicosanoid precursors, is addressed in this paper.
It has been generally recognized that eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) are of significant
importance in fish reproduction while arachidonic acid (AA, 20:4n-6) has often been overlooked. The ratio between C20 fatty
acids EPA and AA might be important for many physiological functions depending on the species evolution and its requirements.
Arctic char (Salvelinus alpinus) has a much more pronounced freshwater history and therefore different fatty acid requirements than the other commonly farmed
salmonids such as salmon (Salmo salar), brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). Therefore there is reason to formulate a feed that is more suitable for farming of this freshwater species. In this study,
freshwater wild-origin char eggs were compared to farmed eggs of char. The ratio n-3/n-6 of total phospholipids of eggs was
much lower in the wild fish, 3.5 versus 13.5, and the hatching rate of eggs from natural environment was much higher (20–70%
vs. >80%). We conclude that feed based on marine raw product does not fulfill the requirements for essential fatty acids for
freshwater char and we suggest that AA is supplemented to the broodstock diet and that at least linoleic acid (18:2n-6) is
included in the on-growth diet formulas to lower the n-3/n-6 fatty acid ratio. 相似文献
4.
Although non‐native species can sometimes threaten the value of ecosystem services, their presence can contribute to the benefits derived from the environment. In the Great Lakes, non‐native brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) support substantial recreational fisheries. With current efforts underway to restore once‐native Atlantic salmon (Salmo salar) to Lake Ontario, there is some concern that Atlantic salmon will impede non‐native contributions to the recreational fishery because Atlantic salmon exhibit niche overlap with brown trout and rainbow trout, particularly during the juvenile life stage. We therefore examined competition and growth of juvenile Atlantic salmon, brown trout and rainbow trout in semi‐natural streams. We found that brown trout were the most dominant and had the greatest growth rate regardless of what other species were present. Rainbow trout were more dominant than Atlantic salmon and consumed the most food of the three species. However, in the presence of brown trout, rainbow trout fed less frequently and exhibited negative growth as compared to when the rainbow trout were present with only Atlantic salmon. These data suggest that, outside of density‐dependent effects, Atlantic salmon will not impact stream production of brown trout and rainbow trout. 相似文献
5.
Competitive interactions among multiple non‐native salmonids and two populations of Atlantic salmon 
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下载免费PDF全文 Competitive interactions with non‐native species can have negative impacts on the conservation of native species, resulting in chronic stress and reduced survival. Here, juvenile Atlantic salmon (Salmo salar) from two allopatric populations (Sebago and LaHave) that are being used for reintroduction into Lake Ontario were placed into semi‐natural stream tanks with four non‐native salmonid competitors that are established in Ontario streams: brown trout (S. trutta), rainbow trout (Oncorhynchus mykiss), Chinook salmon (O. tshawytscha) and coho salmon (O. kisutch). Brown trout and rainbow trout reduced the survival and fitness‐related traits of Atlantic salmon, whereas Chinook salmon and coho salmon had no impact on these traits. These data support theories on ecological niche overlap and link differences in observed aggression levels with competitive outcomes. Measurements of circulating hormones indicated that the Atlantic salmon were not chronically stressed nor had a change in social status at the 10‐month time point in the semi‐natural stream tanks. Additionally, the Sebago population was better able to coexist with the non‐native salmonids than the LaHave population. Certain populations of Atlantic salmon may thus be more suitable for some environments of the juvenile stream phase for the reintroduction into Lake Ontario. 相似文献
6.
Saltwater performance of triploid Atlantic salmon Salmo salar L. brown trout Salmo trutta L. hybrids
Survival and growth in a saltwater net-pen of sexually immature triploid Atlantic salmon Salmo salar L. brown trout Salmo trutta L. hybrids was comparable to that of immature diploid Atlantic salmon. Following 17 months of freshwater rearing, the experimental fish were individually tagged and transferred to a saltwater net-pen where they were raised communally for 376 days. Initial and final average weights were 158 and 760 g per fish for the diploid Atlantic salmon and 209 and 1010 g per fish for the triploid hybrids; weights for the hybrids were significantly larger in both cases (α= 0.05). Survival from transfer to harvest was 43% for the Atlantic salmon and 48% for the hybrids. Average specific growth rate of fish which survived to harvest was 0.42% day-1 for Atlantic salmon and 0.41% day-1 for hybrids; these values were not significantly different. No significant differences were observed in average condition factor and dress-out percentage between crosses. Average gonadal weights and gonadosomatic indices were not significantly different for male diploid Atlantic salmon, female triploid hybrids and male triploid hybrids, but were significantly greater for female Atlantic salmon. 相似文献
7.
se Helen Garseth Torfinn Moldal Siri Kristine Gsnes Monika Jankowska Hjortaas Vegard Pedersen Sollien Anne‐Gerd Gjevre 《Journal of fish diseases》2019,42(3):391-396
In 2017, a PCR‐based survey for Piscine orthoreovirus‐3 (PRV‐3) was conducted in wild anadromous and non‐anadromous salmonids in Norway. In seatrout (anadromous Salmo trutta L.), the virus was present in 16.6% of the fish and in 15 of 21 investigated rivers. Four of 221 (1.8%) Atlantic salmon (Salmo salar L.) from three of 15 rivers were also PCR‐positive, with Ct‐values indicating low amounts of viral RNA. All anadromous Arctic char (Salvelinus alpinus L.) were PCR‐negative. Neither non‐anadromous trout (brown trout) nor landlocked salmon were PRV‐3 positive. Altogether, these findings suggest that in Norway PRV‐3 is more prevalent in the marine environment. In contrast, PRV‐3 is present in areas with intensive inland farming in continental Europe. PRV‐3 genome sequences from Norwegian seatrout grouped together with sequences from rainbow trout (Oncorhynchus mykiss Walbaum) in Norway and Coho salmon (Oncorhynchus kisutch Walbaum) in Chile. At present, the origin of the virus remains unknown. Nevertheless, the study highlights the value of safeguarding native fish by upholding natural and artificial barriers that hinder introduction and spread, on a local or national scale, of alien fish species and their pathogens. Accordingly, further investigations of freshwater reservoirs and interactions with farmed salmonids are warranted. 相似文献
8.
Bjarne Gjerde 《Aquaculture (Amsterdam, Netherlands)》1984,40(2):109-114
The variation in semen production among farmed Atlantic salmon (Salmo salar) and rainbow trout (Salmo gairdneri) has been studied. Both species were stripped at weekly intervals, the Atlantic salmon four times and the rainbow trout three times.The individual variation in volume of semen was very high, particularly in rainbow trout. The total volume of semen obtained was 137 ml (20 ml/kg body weight) in Atlantic salmon and 23 ml (5 ml/kg body weight) in rainbow trout. The intraclass correlation for volume of semen was estimated at 0.73 in Atlantic salmon and at 0.59 in rainbow trout. The correlations between volume of semen and body size (weight and length) were all positive. They were all significant and medium in Atlantic salmon whereas in rainbow trout they were all low and significant only for volume of semen at first stripping.The number of males needed to supply the Norwegian fish farming industry with semen is discussed. It is concluded that the possibility of disseminating genetic improvement throughout the whole population of farmed Atlantic salmon and rainbow trout by transport of semen from selected males is considerable. 相似文献
9.
M. C. LUCAS 《Aquaculture Research》1993,24(3):355-364
Abstract. The food of brown trout, Salmo trutta L., and rainbow trout, Oncorhynchus mykiss (Walbaum). in a small stillwater put-and-take fishery in Surrey, England was examined by stomach content analysis of fish caught by angling between the months of April and September 1985. Overall, brown and rainbow trout tended to utilize different food sources. Mann-Whitney U-tests showed most major food items to be eaten in significantly different amounts, the most important exceptions being chironomid pupae and adult Diptera. In all months except April, rainbow trout utilized mainly midwater food, particularly Cladocera. Brown trout fed mainly on benthic food organisms and fish. Spearman rank correlations showed diets to be dissimilar during this period, with significant negative correlations in May and August. These results indicate an absence of interspecific competition for food, and imply spatial separation of brown and rainbow trout. In April both brown and rainbow trout fed extensively on the temporary bottom fauna, mainly trichopteran and megalopteran larvae, and diets were significantly positively correlated. 相似文献
10.
Süleyman Akhan F Delihasan Sonay I Okumus Ö KÖSE I Yandi 《Aquaculture Research》2011,42(11):1632-1638
Thermal shock‐induced triploid and unshocked control hybrids between rainbow trout (Oncorhynchus mykiss) and Black Sea trout (Salmo labrax) and their parental species were produced under hatchery condition by using heat shocks. Triploidization reduced eyed egg rate and alevin yield in all groups. Low survival rate was observed in both shock‐induced triploid hybrid and non‐shock‐induced control hybrids. Although hybrids demonstrated low body weight during the first feeding stage, they reached higher body weight by day 200 when compared with Black Sea trout and rainbow trout. A higher specific growth rate was calculated as 3.60 in the triploid hybrid groups, 1.41 in the triploid Black Sea trout groups and 2.27 in the triploid rainbow trout groups between days 110 and 200. A lower condition factor was determined in the hybrid than in the diploid parental species. A negative value of mid‐parent heterosis (MPH) performance was deected for condition factor, and a favourable MPH was detected for specific growth rate and weight in hybrids. 相似文献
11.
H. A. Urke J. Koksvik J. V. Arnekleiv K. Hindar F. Kroglund T. Kristensen 《Fish physiology and biochemistry》2010,36(4):845-853
High levels of hybridization between Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) have been reported in the Gyrodactylus salaris infected Rivers Vefsna and Driva in Norway. The survival and behaviour during the sea phase of such hybrids is unknown. The
reported work documents ionoregulatory status after 24 h seawater challenge tests (24hSW) and gill Na+/K+-ATPase (NKA) activity of migrating wild smolts of Atlantic salmon, brown trout and hybrids at two sampling dates during the
2006 smolt run in River Driva. Salmon, trout and hybrids contributed to 27, 52 and 21% of the catches, respectively. The large
contribution of hybrids suggests both a high hybridization rate and a high survival rate from fry to smolt. Both salmon and
hybrids had a well-developed seawater tolerance at the time of downstream migration, revealed by small ionoregulatory effects
and no or low mortality rates during the 24hSW tests. The trout were not fully adapted to seawater, and high mortality rates
were observed (71 and 92%) during the 24hSW tests. The NKA activity was not significantly different between salmon and hybrids.
Most of the hybrids were physiologically capable of direct entry to full strength seawater. The incomplete seawater tolerance
in trout compared to salmon corresponds well with differences in life-history patterns between these two species. The life
history strategy of the hybrids during the sea phase is not known, and further investigations on the marine behaviour and
survival is needed to evaluate the role of hybrids in the risk of spreading G. salaris to nearby river systems. 相似文献
12.
Ø. Solem O. K. Berg E. Verspoor K. Hindar S. O. Karlsson J. Koksvik L. Rønning G. Kjærstad J. V. Arnekleiv 《Fisheries Management and Ecology》2014,21(5):357-365
Morphological characters were compared between smolts (standard length 110–220 mm) of Atlantic salmon Salmo salar L., anadromous brown trout Salmo trutta L. and their hybrids captured in River Driva, western Norway. Morphological discrimination between S. salar, S. trutta and their hybrids was correct for 93% of the individuals (correct form was determined genetically). Morphological discrimination of hybrids was incorrect with 9.1% (n = 7) classified as S. salar and 1.3% (n = 1) as S. trutta, suggesting that the hybrids were morphologically more similar to S. salar than S. trutta despite a bias towards S. trutta mothers (7 of 8 cases). The largest morphological differences were found in head (notably maxilla length) and caudal peduncle morphology. Hybrids between S. salar and S. trutta had the longest pectoral and pelvic fins. This indicates that precise discrimination based on morphological traits can be made between S. salar, S. trutta and their hybrids. 相似文献
13.
Farmed rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta were monitored over 3 years for infection with the blood-feeding gill fluke Discocotyle sagittata. Parasite transmission is seasonal: new infections take place during summer/autumn, and transmission is generally negligible during winter/spring. There are 2 sources of infection for naïve fish-of-the-year: limited invasion when fish are in the raceways by riverborne larvae originating external to the farm; and internally, within the farm, when 0+ fish are transferred to ponds previously occupied by older cohorts of infected fish. Thereafter, infection levels continue to increase in rainbow trout primarily through transmission within the farm. Prevalence rose to 100% in 1+ fish by the end of their second summer. In O. mykiss, mean abundance reached 194 worms/host for 1+ fish (up to 489 worms/host) and 160 worms/host for 2+ fish. By contrast, in S. trutta, parasite prevalence never exceeded 85% and, after the first year's invasions, infection levels decreased over time: in 1+ and 2+ brown trout, parasite mean abundance was < 4 (maximum 15) worms/host. We present evidence of the detrimental effects of D. sagittata on the host: high burdens are associated with pale gills, decreased body condition and host mortality. Parasite burdens become overdispersed during the warmer part of the year, as prevalence and mean abundance increase. However, the degree of parasite overdispersion decreases over winter; we cannot distinguish whether decreased aggregation is due to parasite losses from infected fish (including immune-mediated parasite mortality) or parasite-induced host mortality. 相似文献
14.
Odd J. Jacobsen 《Aquaculture (Amsterdam, Netherlands)》1977,11(1):81-84
The growth of brown trout (Salmo trutta) yearlings (18 months) was studied at environmental pH levels of about 6.26, 5.44 and 5.00 and a daily ration of 2.9% of the initial body weight. Growth increments for fish at each pH level during a 48-day period were similar. 相似文献
15.
To identify the pathogens causing saprolegniosis among farmed fish in Nova Scotia, 172 infected tissues and 23 water samples were collected from six species of teleosts: Atlantic salmon (Salmo salar), brown trout (Salmo trutta), Arctic charr (Salvelinus alpinus), brook trout (Salvelinus fontinalis), striped bass (Morone saxatilis) and rainbow trout (Oncorhynchus mykiss) at nine facilities over a 600 km range. Following laboratory culture, 132 isolates were recovered. Six species of oomycetes were identified from analysis of the internal transcribed spacer (ITS) sequence of the nrDNA: Saprolegnia parasitica, Saprolegnia ferax, Saprolegnia diclina, Saprolegnia aenigmatica, Saprolegnia torulosa, Saprolegnia sp. and Pythiopsis cymosa. Further phylogenetic analyses of the ITS and cytochrome c oxidase subunit 1 (Cox1) regions revealed four strains of Saprolegnia parasitica (named here as S1, S2, S3 and S4), of which S1 and S2 were common (37% and 42% of the isolates), and two strains of S. ferax. Among S. parasitica, S2 and S3 are more closely related to each other than to S1 based on the phylogenetic analyses and predicted RNA secondary structure of the ITS region. Sexual structures with a similar morphology were formed by S1 and S3 in vitro, but were not formed by S2. 相似文献
16.
Triploid hybrids between female rainbow trout Oncorhynchus mykiss and male brook charr Salvelinus fontinalis, Arctic charr S. alpinus and lake charr S. namaycush, together with diploid and triploid rainbow trout controls from the same dams, were tested in freshwater farming up to their fourth year of life. All hybrids displayed lower survival rates than the controls, the weakest genotype being the Arctic charr hybrid. Mortalities were mostly observed at the embryonic and larval stages and at the adult stage as a consequence of male sexual maturation. Growth of all hybrids was hindered (compared with controls) during the first year, but only moderate differences remained after 3 years. Sexual maturation resulted in a weight inferiority of males in all genotypes. As to carcass traits, female hybrids displayed a slightly higher dressing percentage than female triploid rainbow trout, as a result of lower visceral losses. These results are discussed with reference to hybrid resistance to rhabdoviruses from the viewpoint of fish farming improvement. 相似文献
17.
《水生生物资源》2000,13(5):355-360
The side-aspect acoustic target strengths (TS) of 19 Atlantic salmons (Salmo salar), 16 brown trouts (Salmo trutta), 10 whitefish (Coregonus lavaretus) and 9 pikes (Esox lucius) were measured using a 200 kHz split-beam echosounder, in order to study the relationship between TS and fish size indices (length, weight and side area). The effect of side aspect angle on TS was also studied. Linear models between TS and the logarithm of the fish size indices were fitted with length being best for predicting TS. Typically, the standard error of estimate was 1.2–2.9 dB. The side-aspect TS measurements with specimens of known size showed that the linear relationship between full side-aspect TS and the logarithm of fish length for salmonid (Salmo salar + Salmo trutta) was on average 4.7 dB (SE = 0.7), lower than for whitefish and pike combined. The effect of side aspect angle on TS was modelled with cos3 (2α) function. The differences in the TS between full side aspect and head/tail aspect were 17.4, 19.0 and 19.6 dB for salmonid, whitefish, and pike, respectively. 相似文献
18.
Hybridization experiments were carried out by crossing females of common rainbow trout with the males of albino rainbow trout. Survival rates in egg, hatchling, fry and yearling stages, and the annual growth rate were higher than those of either parent.Reciprocal crosses with females of albino rainbow trout and males of common rainbow trout showed poor survival rate. Gonadial development of these hybrids was normal. 相似文献
19.
In 2016, the Norwegian health monitoring programme for wild salmonids conducted a real‐time PCR‐based screening for salmon gill poxvirus (SGPV) in anadromous Arctic char (Salvelinus alpinus L.), anadromous and non‐anadromous Atlantic salmon (Salmo salar L.) and trout (Salmo trutta L.). SGPV was widely distributed in wild Atlantic salmon returning from marine migration. In addition, characteristic gill lesions, including apoptosis, were detected in this species. A low amount of SGPV DNA, as indicated by high Ct‐values, was detected in anadromous trout, but only in fish cohabiting with SGPV‐positive salmon. SGPV was not detected in trout and salmon from non‐anadromous water courses, and thus seems to be primarily linked to the marine environment. This could indicate that trout are not a natural host for the virus. SGPV was not detected in Arctic char but, due to a low sample size, these results are inconclusive. The use of freshwater from anadromous water sources may constitute a risk of introducing SGPV to aquaculture facilities. Moreover, SGPV‐infected Atlantic salmon farms will hold considerable potential for virus propagation and spillback to wild populations. This interaction should therefore be further investigated. 相似文献
20.
W. D. Riley P. I. Davison M. J. Ives D. L. Maxwell 《Fisheries Management and Ecology》2013,20(4):346-353
The predation impact of recently stocked triploid brown trout, Salmo trutta L., on migrating wild Atlantic salmon, Salmo salar L., smolts was investigated in two field‐based experiments. The first experiment employed a unique experimental facility to monitor 57 wild S. salar smolts through an enclosure containing a known density of stocked S. trutta to determine a predation rate. None of these smolts were preyed upon by the stocked S. trutta. The second experiment investigated the diet of free‐ranging stocked triploid S. trutta in a chalk stream during the spring. Although at least 6% of the free‐ranging stocked triploid S. trutta became piscivorous on Phoxinus phoxinus (L.), the results suggest that large, recently stocked, triploid S. trutta with a high condition factor do not represent a predation threat to wild S. salar smolts. However, it is recommended that a precautionary approach is maintained and the findings are not generalised until further investigation permits explicit management advice to be developed, and that the stocking of large triploid S. trutta is avoided before May/ June (regional variations to apply) each calendar year, where this can reasonably be achieved. 相似文献