Joseph B. Hunn

Interactive Toxicity of Aluminum and Acidity to Early Life Stages of Brook Trout

Abstract The influences of exposure to aluminum and increased acidity on mortality, growth, behavior, and biochemical responses of brook trout Salvelinus fontinalis were evaluated as a function of developmental stage. Eyed eggs and young brook trout were exposed until 30 d after hatching in proportional diluters to pHs of 4.5, 5.5, and 7.2, with and without aluminum (300 μg/L); 37-d-old brook trout that had been held in experimental control water since hatching were exposed to these same conditions for 30 d. Exposure conditions (i.e., aluminum and calcium concentrations and pH) simulated conditions in some headwater lakes and streams in the northeastern United States. Adverse effects on exposed brook trout generally increased as pH decreased from 7.2 to 4.5 and potentiation of effects by aluminum occurred at pHs of 5.5 to 7.2. However, embryos and fish older than 36 d were more tolerant of acidic conditions and aluminum than were larvae less than 15 d old. We conclude that the adverse effects on mortality...

Toxicity of sodium selenite to rainbow trout fry

In a study designed to examine the long-term effects of inorganic selenium (IV) on early life stages of rainbow trout (Salmo gairdneri), survival was significantly reduced at selenium concentrations of 47 and 100 μg l−1 after 90 days of exposure. Length and weight were significantly reduced after 90 days of exposure to 100 μg l−1. Whole-body residues of selenium increased with increasing exposure concentrations but appeared to decline between 30 and 90 days of exposure. Analyses of trout backbone indicated little change in bone development with exposure to selenium (IV) with one exception; calcium concentrations were significantly decreased in fish exposed to ⩾ 12 μg l−1 of selenium. Results of our study indicates that a recommended safe level of 10 μg l−1 for inorganic selenium would not significantly affect growth and survival of rainbow trout; however, concentrations of selenium near this level can reduce the levels of calcium in the backbones of trout.

Sensitivity of Young Striped Bass to Organic and Inorganic Contaminants in Fresh and Saline Waters

Abstract The toxicity to young striped bass Morone saxatilis of a contaminant mixture composed of organic and inorganic chemicals was determined in fresh and saline waters when the fish were 35–80 d old. Decreases in water hardness and associated decreases in alkalinity and pH increased the toxicity of the mixture. This increase was attributed to changes in the speciation of inorganic chemicals in water of differing qualities. Under standard conditions for acute toxicity tests, cadmium, copper, zinc, nickel, and chromium were more toxic to striped bass in soft than in slightly saline water. Overall, striped bass were as sensitive as most salmonid species to seven inorganic chemicals and three organic insecticides, and much more sensitive than the cyprinids, ictalurids, and centrarchids that have been tested.

Chemical Composition of Rainbow Trout Urine following Acute Hypoxic Stress

Abstract Rainbow trout (Salmo gairdnerii) were anesthetized with MS-222, catheterized, and introduced into urine collecting chambers. Twenty-four hours after introduction, a 4-hour accumulation of urine was collected to serve as the control. Water flow to the chambers was then discontinued for 30 minutes during which the oxygen content of the water exiting in the chamber dropped from 4.9 to 2.8 mg/1. Following this hypoxic stress fresh water was restored and accumulated urine samples were taken for analysis at 1, 4, and 20 hours post-hypoxic stress. Rainbow trout excrete abnormally high concentrations of Na, K, Mg, Cl, and inorganic PO4 following hypoxia.

Urine Flow Rate in Freshwater Salmonids: A Review

Abstract Urine flow rate in salmonid fishes was first measured in 1937 and reported to range from 50 to 160 mL/kg per day at 10°C. Later studies on the kidney function of salmonid fishes in fresh water indicated that urine flow rate is influenced by (a) nutrition and disease, (b) environmental temperature and water quality, (c) handling and anesthesia, (d) hypoxic stress and confinement, (e) exposure to certain xenobiotics, and (f) entry into seawater.

Sensitivity of brook trout to low pH, low and elevated aluminum concentrations during laboratory pulse exposures

Yolk-sac larvae of brook trout (Salvelinus fontinalis) were exposed to four sequential low pH and calcium (Ca) pulses, nominally ranging from pH 6.5 to 4.0 in 0.5 pH unit increments, with and without 300 mg/l aluminum (Al) in 28-day toxicity tests. Calcium concentrations during the pulses varied from 0.5 to 1.3 mg/1. Swim-up larvae that had begun to feed were exposed to a single pulse of the same pH and Ca concentrations with 300 mg/l Al. The larvae were allowed to recover for 120-h at circumneutral pH and Ca concentrations that varied from 2.1 to 3.3 mg/l after each pulse exposure. Effects of the pulse exposures on survival, growth, whole-body ion concentrations, and behavioral development were monitored. Mortality of larvae was significant in all low pH and Ca treatments with Al after the first pulse and after the first low pH and Ca pulse at pH 4.0. Growth was significantly reduced among larvae exposed to the low pH and Ca pulses at pH 4.0. In general, growth was most severely affected among larvae exposed to the low pH and Ca pulses with Al at pH 6.1 and lower. Relative to controls, the low pH and Ca pulse exposures with and without Al reduced whole-body Na+, Ca2+, K+, Mg2+ P, and Cl−, Wholebody Ca2+ was most severely reduced followed by Na+, K+, Cl−, P, and Mg2+. The pulse exposures also caused delayed development and significant reductions in swimming activity and feeding of the larvae. These results support field observations that cyclic pH and Ca depressions, and concurrent increases in Al concentrations may cause mortality and have other adverse effects on natural fish populations.

Influence of pH and aluminum on developing brook trout in a low calcium water

Eyed embryos of brook trout (Salvelinus fontinalis) were exposed to nominal pHs of 4.5, 5.5 and 7.5 with and without aluminum (300 microg liter(-1)) in extremely soft water (hardness <9mg liter (-1)) at 12 degrees C. Embryo mortality exceeded 80% at pH 4.5, averaged 15 to 18% in the pH 5.5 treatments and was less than 2% in the pH 7.5 treatments. Aluminum significantly reduced embryo mortality (85.3% vs 99.5%) at pH 4.5 but did not affect mortality at pH 5.5 or pH 7.5. Percent hatch and poor hatch were pH dependent and were not significantly influenced by aluminum. Brook trout larvae cumulative mortalities were 100% within 30 days at pH 4.5, with or without aluminum; 69% after 60 days at pH 5.5; 100% in 15 days at pH 5.5 with aluminum and 20% after 60 days at pH 7.5 with or without aluminum. Fish that survived the pH 5.5 treatment showed decreased growth and behavioral impairments compared to the controls (pH 7.5 without aluminum).

The effect of anesthetization and urinary bladder catheterization on renal function of rainbow trout

Abstract 1. 1. Rainbow trout were anesthetized with MS-222 (Sandoz) or methylpentynol and catheterized. Urine was collected at selected intervals up to 48 hr. 2. 2. Effects of MS-222 anesthesia on urine flow and composition were isolated from the stress of catheterization by re-anesthetizing the fish 18 to 20 hr post-catheterization. 3. 3. Urine output patterns were similar following MS-222 or methylpentynol anesthesia and catheterization. Highest urine flows were measured 4 to 8 hr post-treatment. The highest urine output after re-anesthetization with MS-222 was observed 2 to 4 hr post-anesthesia. 4. 4. Highest concentrations of Na + , K + , Ca 2+ , Cl − and inorganic PO 4 in the urine were measured in the first 2 hr after anesthesia and catheterization. 5. 5. Flow rates and chemical composition of urine indicate that “normal” renal function is re-established 12 to 24 hr post-treatment.

Influence of Sampling on the Blood Chemistry of Atlantic Salmon

Abstract Blood samples were taken from laboratory-reared Atlantic salmon (Salmo salar) to determine the physiological status of the fish. The Atlantic salmon were also subjected to one of eight treatments before blood sampling to determine the influence of various handling stresses on the blood analyses. Treatments included holding the fish in nets in water or air for 2 or 4 min, or anesthesia with benzocaine, benzocaine hydrochloride, or tricaine for 3 min. Fish stunned by a blow to the head were used as controls. These treatments resulted in no major changes in selected blood chemistry characteristics: hematocrit, plasma glucose and chloride levels, and osmolality. Atlantic salmon exhibit a limited stress response to netting, as indicated by minor changes in plasma glucose concentrations.

Renal excretion in coho salmon (Oncorhynchus kisutch) after acute exposure to 3-trifluoromethyl-4-nitrophenol

Coho salmon (Oncorhynchus kisutch) exposed to an acute, sublethal concentration of 3-trifluoromethyl-4-nitrophenol (TFM) exhibited an increased output of urine when compared with controls, but the urinary excretion of Na, K, Ca, Mg, and Cl was not affected. About 35 times more conjugated TFM than free TFM was excreted during the 24-h study period.