Survival and behaviour of rainbow trout (Oncorhynchus mykiss) released from an experimental aquaculture operationThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1976-1988 ◽  
Author(s):  
Paul J. Blanchfield ◽  
Lori S. Tate ◽  
Cheryl L. Podemski
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
High Growth ◽  
High Growth Rate ◽  
Normal Operation ◽  
Farmed Fish ◽  
Experimental Lakes Area ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Study Lake ◽  
Cage Aquaculture

The potential for farmed fish that have escaped from open-cage aquaculture operations to affect native populations will depend on their survival and behaviour in the wild. We used standard commercial practices to rear 10 tonnes of rainbow trout ( Oncorhynchus mykiss ) in a 23 ha lake at the Experimental Lakes Area (Ontario, Canada). Each fall (2003–2005), we released farmed rainbow trout (escapees) into the study lake and monitored their movements using automated positioning telemetry. Rainbow trout experienced high annual mortality (~50%), with none surviving beyond 3 years. Farmed fish had narrowly defined pelagic distributions that comprised the upper few metres of the water column, even when at the cage site. Although released rainbow trout dispersed throughout the study lake, most spent significant portions of time at the cage site, especially during normal operation when commercial feed was available. Core use areas (50% Kernel) included the farm for half of the released fish. Surviving rainbow trout showed continued reliance upon the cage site in their second year. However, wide dispersal, high growth rate, and lack of reliance on the cage site by some escaped fish warrant further research to assess potential effects of open-cage aquaculture in the water bodies where the industry occurs.

scholarly journals TheInfluence of Extruded Feed with a high Protein Level Upon the Bioproductive Performances Obtained on the Rainbow Trout Females (Oncorhynchus mykiss)

2016 ◽  
Vol 73 (2) ◽  
pp. 150
Author(s):  
Mihaela Ancuta Boaru ◽  
Daniel Mierlita ◽  
Bogdan Georgescu ◽  
Cristina El-Mahdy
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Protein Level ◽  
High Growth ◽  
Environmental Parameters ◽  
High Protein ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Growth Performances ◽  
Extruded Feed ◽  
Current Stage

The succes ofartificial reproduction in the rainbow trout(Oncorhynchus mykiss), the development of gonads and the results obtained at incubation are significantly affected by the feeding of the breeders. The use of quality sexual  products is decisive for the assurance of the production of viable larvae and further of the estimated fish production, so that in addition to the assurance of optimal environmental parameters, the proper feeding of the breeders is required. Starting from the current stage of knowledge in the field,the main objective of the working paperwas to highlight the way the differentiatedfeeding of the rainbow trout females (Oncorhynchus mykiss) influences their growth and development. The extruded peeled feed with a high protein level upon theegg weightand the gonosomatic index were followed. The extruded peeled feed with 53% protein proved to be highly effective, materialized trough high growth performances, a better conversion and the growth of gonadal  weight.

Effects of an experimental rainbow trout (Oncorhynchus mykiss) farm on invertebrate community compositionThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1949-1964 ◽  
Author(s):  
Rebecca C. Rooney ◽  
Cheryl L. Podemski
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Rank Correlation ◽  
Organic Loading ◽  
Experimental Lakes Area ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Northwestern Ontario ◽  
Freshwater Aquaculture ◽  
Invertebrate Abundance ◽  
Production Cycles

We examined the development of changes in the zoobenthos along a transect from an experimental rainbow trout ( Oncorhynchus mykiss ) farm in Lake 375, Experimental Lakes Area, northwestern Ontario, Canada. After 2 months, invertebrate abundance was reduced under the fish cage (2542 ± 569 individuals·m–2) compared with samples collected 45 m away (16 137 ± 2624 individuals·m–2). Taxa richness was also depressed, but changes in biomass were variable. Reductions in abundance and richness at high organic loading levels are consistent with earlier models developed for the marine environment of responses to organic loading in marine systems. After two production cycles, the significant principal components axis explaining 76% of total variance in abundance was correlated with distance from the cage (Spearman rank correlation, r = –0.775, p = 0.014) and with chemical variables recommended for freshwater aquaculture monitoring (Pearson’s correlation coefficient, r = 0.78, 0.76, and 0.75 with p = 0.013, 0.018, and 0.020 for pore-water ammonia and sediment Cu and Zn, respectively). The effects of farming were localized, dissipating within 15 m of the cage edge. Invertebrate abundance demonstrated the most potential for incorporation into monitoring schemes at new farms. At established farms, richness may be a valuable monitoring metric.

The response of zooplankton in a whole-lake experiment on the effects of a cage aquaculture operation for rainbow trout (Oncorhynchus mykiss)

2010 ◽  
Vol 67 (11) ◽  
pp. 1852-1861 ◽  
Author(s):  
Michael J. Paterson ◽  
Cheryl L. Podemski ◽  
Wilhelmina J. Findlay ◽  
David L. Findlay ◽  
Alex G. Salki
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Egg Production ◽  
Crustacean Zooplankton ◽  
Zooplankton Community Structure ◽  
Ecosystem Impacts ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Freshwater Aquaculture ◽  
Multiple Variables ◽  
Cage Aquaculture

There is hope that increased development of aquaculture will help meet future global needs for protein. The growth of the freshwater aquaculture industry in Canada, however, has been hampered by insufficient information on environmental impacts. We examined the effects of an experimental cage aquaculture operation for rainbow trout ( Oncorhynchus mykiss ) on planktonic Crustacea and rotifers using 6 years of precage and 7 years of postcage data. Following the initiation of aquaculture, total crustacean and rotifer biomass, egg production, and depth distributions did not change significantly when compared with data from three nearby unimpacted lakes. We found statistically detectable increases in densities of Bosmina  cf.  longirostris and Diacyclops thomasi and an overall change in crustacean zooplankton community structure using correspondence analysis. The response of zooplankton was less than we expected because comparatively large changes were observed in phytoplankton biomass, hypolimnetic O2, and densities of invertebrate ( Mysis diluviana ) and fish predators. Our study emphasizes the need to monitor multiple variables when assessing the ecosystem impacts of potential stressors such as aquaculture.

Prevalence and Antimicrobial Resistance Profile of Listeria Species Isolated from Farmed and On-Sale Rainbow Trout (Oncorhynchus mykiss) in Western Iran

2018 ◽  
Vol 81 (6) ◽  
pp. 886-891 ◽  
Author(s):  
RAMIN REZAI ◽  
ELHAM AHMADI ◽  
BEHNAM SALIMI
Keyword(s):  
Rainbow Trout ◽  
Antimicrobial Resistance ◽  
Oncorhynchus Mykiss ◽  
Foodborne Pathogens ◽  
Molecular Techniques ◽  
Farmed Fish ◽  
Western Iran ◽  
Listeria Species ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Sanitary Conditions

ABSTRACTListeria species are important foodborne pathogens, among which L. monocytogenes and L. ivanovii cause human listeriosis. The purpose of this study was to evaluate the incidence and antimicrobial resistance profiles of Listeria species in farmed and on-sale rainbow trout (Oncorhynchus mykiss) in Kurdistan province, western Iran. A total of 240 fresh rainbow trout fish (120 samples from farms and 120 samples from retail outlets) were collected and analyzed phenotypically for the presence of Listeria. All Listeria isolates were differentiated with molecular techniques, and L. monocytogenes strains were identified to serotype. The antibiotic susceptibility of all Listeria isolates also was determined. Among the 240 samples, 86 (35.83%) were contaminated with Listeria: 32 samples of farmed fish and 54 samples of on-sale fish. The prevalence among the 240 samples was 9.16% (22 samples) for L. monocytogenes, 6.66% (16 samples) for L. ivanovii, 3.75% (9 samples) for L. welshimeri, 4.99% (12 samples) for L. grayi, 7.5% (18 samples) for L. innocua, and 3.75% (9 samples) for L. seeligeri. The prevalences of the human pathogenic strains L. monocytogenes and L. ivanovii were 4.16% (5 samples) and 14.16% (17 samples) in farmed fish and 5.83% (7 samples) and 7.5% (9 samples) in on-sale fish, respectively. Of the 22 L. monocytogenes isolates, 15, 3, and 4 were identified as serotypes 4b, 1/2a, and 1/2b, respectively. The highest rates of antibiotic resistance among the 86 Listeria isolates was observed against tetracycline (62.79% of all isolates), enrofloxacin (56.97%), and ciprofloxacin (38.37%). Very high resistance was also detected against penicillin (36.04%) and ampicillin (34.88%). These results highlight the potential public health threat posed by fish contaminated with Listeria species, including L. monocytogenes, in the west of Iran. Regular monitoring of Listeria contamination, upgrading of sanitary conditions in the fish industry, and prudent use of antibiotics is strongly recommended in the region. At-risk individuals also should be aware of possible Listeria contamination in these fish.

Reduced swimming performance and increased growth in domesticated rainbow trout, Oncorhynchus mykiss

2009 ◽  
Vol 66 (7) ◽  
pp. 1025-1032 ◽  
Author(s):  
Drew Reinbold ◽  
Gary H. Thorgaard ◽  
Patrick A. Carter
Keyword(s):  
Rainbow Trout ◽  
Body Size ◽  
Oncorhynchus Mykiss ◽  
Body Mass ◽  
Growth Rates ◽  
Swimming Performance ◽  
Large Body ◽  
High Growth ◽  
Hybrid Progeny ◽  
Rainbow Trout Oncorhynchus Mykiss

Domesticated populations of rainbow trout ( Oncorhynchus mykiss ) probably have been selected for high growth rates and large body size, which may have resulted in reduced sprint swimming performance. We hypothesized that more domesticated populations of rainbow trout would have higher growth rates and larger body size, but slower swim speed, relative to semiwild populations. We tested this hypothesis by measuring body mass, body length, and sprint swim speed multiple times over 92 days in progeny from crosses between males from three clonal lines and an outbred female. We found significantly higher body masses and significantly slower swim speeds in the highly domesticated Arlee and Hot Creek progeny groups compared with the semiwild Swanson hybrid progeny group, supporting our hypothesis. Growth rates also differed significantly among groups, but at the ages measured, the Swanson hybrid progeny had an intermediate growth rate. However, given the differences in body mass, either growth rates were higher in the more domesticated progeny groups at young unmeasured ages and (or) they hatched at a significantly larger body mass than the semiwild Swanson hybrid.

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