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

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.

2010 ◽  
Vol 67 (11) ◽  
pp. 1852-1861 ◽  
Author(s):  
Michael J. Paterson ◽  
Cheryl L. Podemski ◽  
Wilhelmina J. Findlay ◽  
David L. Findlay ◽  
Alex G. Salki

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.


1995 ◽  
Vol 73 (1) ◽  
pp. 154-165 ◽  
Author(s):  
Mark D. Powell ◽  
David J. Speare ◽  
Glenda M. Wright

Chloramine-T is a widely used prophylactic and therapeutic agent in freshwater aquaculture. This study examined the effects of repeated intermittent exposure of healthy rainbow trout (Oncorhynchus mykiss) fingerlings to sublethal concentrations of chloramine-T (0, 5, 10, or 20 mg/L) twice weekly in 1-h pulses at 11 °C for 4 weeks in a replicate-tank facility. Gills were excised from subsamples of fish prior to exposure and at the end of the 4-week experimental period. Tissue was fixed and processed for light microscopy and transmission and scanning electron microscopy. The gill epithelium from fish treated with 10 and 20 mg/L chloramine-T appeared swollen and vacuolated, with extensive intercellular edema. There was a significant reduction in the number of lamellar mucous cells and an apparent increase in the numbers of chloride cells. Chloride cells from both the base of the lamella and the lamellar surface of gills exposed to chloramine-T had a significant increase in the area of the apical plasmalemma after treatment with 10 and 20 mg/L, and a reduction in the thickness of the apical plasmalemma-associated glycocalyx. These morphological changes are consistent with a compensatory mechanism for the remedial uptake of ions, suggesting that chloramine-T increased epithelial ion permeability coincident with a possible influx of water leading to intercellular edema. Chloride cell proliferation and intercellular edema may also have affected gas exchange across the branchial epithelium.


2009 ◽  
Vol 66 (11) ◽  
pp. 1976-1988 ◽  
Author(s):  
Paul J. Blanchfield ◽  
Lori S. Tate ◽  
Cheryl L. Podemski

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.


Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
A Ghasemi Pirbalouti ◽  
E Pirali ◽  
G Pishkar ◽  
S Mohammadali Jalali ◽  
M Reyesi ◽  
...  

2014 ◽  
Author(s):  
Silvia Gonzalez-Rojo ◽  
Cristina Fernandez-Diez ◽  
Marta Lombo ◽  
Vanesa Robles Rodriguez ◽  
Herraez Maria Paz

2015 ◽  
Vol 2 (2) ◽  
pp. 32-38 ◽  
Author(s):  
N. Matvienko ◽  
A. Vashchenko ◽  
I. Tsiganok ◽  
L. Buchatsky

Aim. To investigate the epizootic state of fi sheries in Ukraine; to study the biological specifi cities of viral and bacterial isolates of fi sh in freshwater aquaculture. Methods. The epizootic state of fi sheries was defi ned ac- cording to the surveillance plan for fi sheries, virological (biosampling of sensitive fi sh species, virus isolation on sensitive passaged cell cultures), serological (enzyme immunoassay, virus neutralization test using sensitive passaged cell cultures) and molecular-biological (reverse transcriptase polymerase chain reaction − RTPCR) methods of investigation were used. The pathogenicity of the isolated bacteria was studied in the biosample. The identifi cation was performed using Bergey’s Manual. The express-identifi cation of bacteria was performed using the standardized test-system API 20E Bio Merieux (France). Results. The IPNV isolates of rainbow trout were fi rst isolated in the fi sheries of different forms of ownership in the western regions of Ukraine (Volyn, L’viv, Transcarpathian, Chernivtsi regions). It was demonstrated that different age groups of carp are infested with the virus in the fi sheries of L’viv, Donetsk, Chernihiv, Kyiv, and Odesa regions which testifi es to a wide spread of the virus in Ukraine. Out of fi sh infectious diseases the red spot-like disease and the swim bladder infl ammation of carp, the diseases of young trout and sturgeon were detected in the investigated fi sheries of Ukraine. Conclusions. The epizootic data were used to estimate the condition of the fi sheries in Ukraine in terms of fi sh infectious diseases. An infectious pancreatic necrosis virus, new for Ukraine, was revealed. It was found to affect rainbow trout (Oncorhynchus mykiss , Walbaum, 1792) and the spread of SVCV in carp fi sheries was demonstrated. As for bacterial fi sh diseases, the decrease in the epizootic situation was described along with considerable extension of the range of species of bacterial pathogens of fi sh. Annual systematic monitoring and measures of preventing the introduction of the agents of infectious diseases are the guarantee of protection of the specialized fi sheries of Ukraine.


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