pH, Hardness, and Humic Acid Influence Aluminum Toxicity to Rainbow Trout (Oncorhynchus mykiss) in Weakly Alkaline Waters

1994 ◽  
Vol 51 (6) ◽  
pp. 1345-1355 ◽  
Author(s):  
Deke T. Gundersen ◽  
Sjahrul Bustaman ◽  
Wayne K. Seim ◽  
Lawrence R. Curtis
Keyword(s):  
Rainbow Trout ◽  
Humic Acid ◽  
Oncorhynchus Mykiss ◽  
Growth Rates ◽  
Aluminum Toxicity ◽  
Alkaline Ph ◽  
Weakly Alkaline ◽  
Neutral Ph ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Specific Growth Rates

Juvenile rainbow trout (Oncorhynchus mykiss) were exposed for either 96 h (acute) or 16 d (subacute) to various combinations of aluminum and hardness concentrations or aluminum and humic acid concentrations between pH 7.14 and 8.58. Aluminum-induced mortality was higher at weakly alkaline pH (7.95–8.58) (attributed to up to 10-fold higher filterable aluminum concentrations) than near-neutral pH (7.14–7.64). Growth rates were higher in 16-d hardness tests at weakly alkaline pH (0.188–1.600% of initial weight∙d−1) than for fish exposed to similar aluminum concentrations at near-neutral pH (−0.535–0.756%∙d−1). This suggested that polymeric and colloidal forms of aluminum were more potent than soluble forms in restricting growth. Hardness and humic acid appeared most protective to trout against subacute aluminum toxicity. Cumulative mortality of trout exposed to 1.50 mg aluminum∙L−1 at 103 or 20 mg∙L−1 hardness as CaCO3 was 10 and 45%, respectively. Hardness did not significantly protect against aluminum-induced growth inhibition. Trout exposed for 16 d to aluminum (0.53–2.56 mg∙L−1) and humic acid 4.31–5.23 mg∙L−1) had higher specific growth rates and decreased mortality than those exposed to aluminum and ho humic acid at any pH.

Acclimation to hard or soft water at weakly alkaline pH influences gill permeability and gill surface calcium binding in rainbow trout (Oncorhynchus mykiss)

1995 ◽  
Vol 52 (12) ◽  
pp. 2583-2593 ◽  
Author(s):  
Deke T. Gundersen ◽  
Lawrence R. Curtis
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Calcium Binding ◽  
Binding Capacity ◽  
High Hardness ◽  
Alkaline Ph ◽  
Surface Binding ◽  
Weakly Alkaline ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Osmotic Water

Rainbow trout (Oncorhynchus mykiss) were acclimated for 10 d to soft (0.1 mM as CaCO3) or hard (1.0 mM as CaCO3) water at weakly alkaline pH (8.06–8.34). Following acclimation, individual gill arches were removed for examining the effects of low hardness or high hardness acclimation on gill water permeability, gill Ca2+ interactions, and gill aluminum interactions. Isolated gill arches were exposed to water of varying Ca2+ (0.0–1.0 mM) and aluminum (3.7–37 μM) concentration for osmotic permeability experiments. High hardness acclimated gills had significantly greater percent weight gain over time caused by osmotic water entry than low hardness acclimated gills, when exposed to distilled water (32.34 ± 1.15 and 24.86 ± 0.62%, respectively, after 60-min incubations); these differences were absent when Ca2+ (0.1–1.0 mM) was added to the incubation medium. Gill arch Ca2+ binding experiments resolved two gill surface binding site populations, which differed in their Ca2+ binding affinity. The higher affinity sites were probably associated with gill membrane permeability, because low hardness acclimated gills had more such sites (binding capacity, 0.322 ± 0.027 μmol Ca2+∙g−1) and less permeable gills than high hardness acclimated gills (binding capacity, 0.198 ± 0.004 μmol Ca2+∙g−1). Aluminum had little influence on gill permeability and gill Ca2+ binding.

Metabolic Effects of Bovine Growth Hormone and Genetically Engineered Rainbow Trout Growth Hormone in Rainbow Trout (Oncorhynchus mykiss) Reared at a High Temperature

1990 ◽  
Vol 47 (7) ◽  
pp. 1292-1301 ◽  
Author(s):  
Roy G. Danzmann ◽  
Glen J. Van Der Kraak ◽  
Thomas T. Chen ◽  
Dennis A. Powers
Keyword(s):  
Growth Hormone ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Growth Rates ◽  
Specific Growth ◽  
Genetically Engineered ◽  
Bovine Growth Hormone ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Treated Fish ◽  
Specific Growth Rates

The growth promoting ability of bovine growth hormone purified from natural sources (bGH) and genetically engineered rainbow trout growth hormone (rtGH) were compared in rainbow trout (Oncorhynchus mykiss) reared at 17.0 °C. Fish were fed high (on-demand feeding) and low (2.8–4.6% of body weight/d) rations. On both rations, length specific growth rates were significantly higher in bGH treated fish than in all other treatments. No significant differences in weight specific growth rates were detected between treatments. Testosterone levels in fish fed the high ration and treated with 1.0 μg/g rtGH or bGH were significantly elevated compared with controls as were 17-β-estradiol levels in females. bGH significantly reduced condition factors of low ration fish, and bGH and rtGH significantly depressed hepatosomatic indicies of high ration fish compared with controls. In a second experiment, weight and length specific growth rates were higher in rtGH and bGH injected fish than in saline controls but these differences were not significant. DNA standardized RNA levels were higher in rtGH and bGH treated fish than in saline control fish and these differences were significant in bGH treated fish. Results indicate that at high rearing temperatures GH administration does not have a major influence on growth but does stimulate steroidogenic and metabolic activity.

RNA/DNA ratios in white muscle as estimates of growth in rainbow trout held at different temperatures

1990 ◽  
Vol 68 (7) ◽  
pp. 1494-1498 ◽  
Author(s):  
Moira M. Ferguson ◽  
Roy G. Danzmann
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
White Muscle ◽  
Specific Growth ◽  
Fish Size ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Different Temperatures ◽  
Specific Growth Rates ◽  
Rna And Dna

The concentrations of RNA, DNA, and protein in white muscle from 240 uniquely tagged rainbow trout (Oncorhynchus mykiss) held at three temperatures (5, 8 (control), and 11 °C) were measured. Both RNA and RNA/DNA ratios were better predictors of recent length- and weight-specific growth rates than they were of absolute fish size. Furthermore, RNA concentrations were better predictors of growth than RNA/DNA ratios. The strength of the regression between either RNA/DNA ratio or RNA and growth rate did not differ consistently among temperatures. Fish reared at warmer temperatures had lower concentrations of RNA for both a given growth rate and a given DNA concentration compared with cold-reared trout. Warm-reared fish also had lower concentrations of DNA and higher protein/DNA ratios than cold-reared trout when fish size was standardized. The concomitant decrease in both RNA and DNA concentrations resulted in marginally lower RNA/DNA ratios in warm-reared fish.

Growth and age validation of Rainbow Trout, Oncorhynchus mykiss (Walbaum)' in Lake Eucumbene, NSW

1992 ◽  
Vol 43 (5) ◽  
pp. 1033 ◽  
Author(s):  
RA Faragher
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Growth Rates ◽  
Age Estimation ◽  
New South ◽  
Age Validation ◽  
Scale Reading ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
South Wales ◽  
Second Year

Growth rates of finclipped rainbow trout (Oncorhynchus mykiss) released into Lake Eucumbene, New South Wales, at an age of 0+ years were examined for each year between 1986 and 1988. Traps and nets yielded significant numbers of marked fish for validation of age estimation and length backcalculation from scale reading. Poor recognition of the marks by anglers was confirmed, indicating that survival of the fish was higher than was implied by angling returns. The diffuse nature of the second annulus in scales provided initial difficulty in ageing, particularly because of a similarly diffuse false check formed during the second year. Care was required in separating the annuli after asymptotic growth was reached (3 years), Growth rates in Lake Eucumbene were comparable with those found in studies in Tasmania and Victoria. Back-calculated lengths were in agreement with those from fish of known ages. The presence of finclipped fish aged 2 + and 3 + years in a spawning population confirmed that stocked fish contributed to the spawning stocks. The study reconfirms the importance of validation of ageing techniques in fisheries investigations.

Chronic exposure of rainbow trout (Oncorhynchus mykiss) to simulated climate warming and sublethal ammonia: a year-long study of their appetite, growth, and metabolism

1998 ◽  
Vol 55 (3) ◽  
pp. 576-586 ◽  
Author(s):  
Tyler K Linton ◽  
I J Morgan ◽  
P J Walsh ◽  
Chris M Wood
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Temperature Increase ◽  
Temperature Cycle ◽  
Small Temperature ◽  
Juvenile Rainbow Trout ◽  
Warming Scenario ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Total Ammonia ◽  
Specific Growth Rates

This study was conducted to assess, over the thermal cycle of an entire year, the effects (on appetite, growth, and metabolism) of a chronic small temperature increase (+2°C) and sublethal ammonia (70 µmol ·L-1) on rainbow trout (Oncorhynchus mykiss). Juvenile rainbow trout ( approx 11 g initially) were exposed for 14 months to four treatments: the natural water temperature cycle of the inshore region of Lake Ontario, this cycle +2°C to simulate a global warming scenario, and these temperature cycles in the presence of an additional 70 µmol total ammonia ·L-1 (NH3 range: 0.005-0.013 mg ·L-1). The additional +2°C substantially increased appetite over winter, significantly elevating specific growth rates. These gains were lost, however, over summer due to suppression of appetite and growth at high temperature. Ammonia alone tended to elevate growth, but the combination of +2°C and ammonia resulted in a general decrease in the activity of enzymes involved in nitrogen metabolism (alanine aminotransferase, aspartate aminotransferase, glutamate dehydrogenase, and glutamine synthetase). These results document the dramatic influence of a +2°C warming scenario on the growth and feeding metabolism of juvenile rainbow trout. Moreover, the data indicate that a chronic small temperature increase, together with low-level ammonia pollution, substantially alters protein dynamics, and hence growth, in juvenile freshwater fishes; juvenile rainbow trout without thermal refuge will experience an increase in t a warmer, more polluted environment.

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