Fingerling Brook Trout Research Articles

The lethal and sublethal impacts of two tire rubber-derived chemicals on brook trout (Salvelinus fontinalis) fry and fingerlings

Recent toxicity studies of stormwater runoff implicated N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone (6PPD-quinone) as the contaminant responsible for the mass mortality of coho salmon (Oncorhynchus kisutch). In the wake of this discovery, 6PPD-quinone has been measured in waterways around urban centers, along with other tire wear leachates like hexamethoxymethylmelamine (HMMM). The limited data available for 6PPD-quinone have shown toxicity can vary depending on the species. In this study we compared the acute toxicity of 6PPD-quinone and HMMM to Brook trout (Salvelinus fontinalis) fry and fingerlings. Our results show that fry are ∼3 times more sensitive to 6PPD-quinone than fingerlings. Exposure to HMMM ≤6.6 mg/L had no impact on fry survival. These results highlight the importance of conducting toxicity tests on multiple life stages of fish species, and that relying on fingerling life stages for species-based risk assessment may underestimate the impacts of exposure. 6PPD-quinone also had many sublethal effects on Brook trout fingerlings, such as increased interlamellar cell mass (ILCM) size, hematocrit, blood glucose, total CO2, and decreased blood sodium and chloride concentrations. Linear relationships between ILCM size and select blood parameters support the conclusion that 6PPD-quinone toxicity is an outcome of osmorespiratory challenges imposed by gill impairment.

Testing for Microgeographic Effects on the Strength of Interspecific Competition

Local adaptation to an environment can vary across very fine scales—as little as a few meters in some species, kilometers in others. This divergence at microgeographic scales has been linked to dispersal ability and could be responsible for geographic variation in the strength of species interactions. For example, the spread of maladaptive traits across short distances could lead to inferior performance and local extinctions across the landscape. We utilized a model study system (headwater streams of New Hampshire) with known differences in dispersal, gene flow, and intraspecific competition to test for microgeographic variation in interspecific competition. We conducted a common garden experiment and measured survival and growth of larval Spring Salamanders from different stream reaches (fish and fishless) in response to the presence of conspecific salamanders or heterospecific Brook Trout fingerlings. We predicted that Spring Salamanders from reaches with fish would have higher competitive performance w...

Effects of Protective Limestone Treatment on Water Chemistry and Fisheries Management in Laurel Bed Lake, Virginia

Dolomitic limestone additions to the acidic water of Laurel Bed Lake in southwestern Virginia have resulted in significant improvements in both the water quality and fishery. Pretreatment water quality showed the lake and its tributary to have high acidity with pH near or <5.0; negative acid neutralizing capacity (ANC) values; aluminum concentrations (AlT) > 150 μg/L; and low calcium to hydronium (Ca/H) ratios. The acidity is the result of atmospheric acid deposition, natural acidity from wetland origins and lack of carbonate-bearing minerals in the watershed. Limestone treatments have achieved target pH >6.5, ANC >100 μeq/L, AlT <60 μg/L and Ca/H >600. Iron and trace element concentrations have decreased. The dose-mass and frequency of limestone treatment to maintain circumneutral conditions has been found to be 150 tons introduced at two year intervals. Prior to implementation of this project, rock bass (Ambloplites rupestris) were overabundant and stunted (mean Total Length (TL) = 155 mm). The lake was drained, and the rock bass were removed. Stocked fingerling brook trout (Salvelinus fontinalis) survived and grew well following lake liming. Smallmouth bass (Micropterus dolomieu), stocked in response to the recurrence of rock bass, also performed well. An angler survey suggested that both species were important to the lake's fishery. The lake is now managed as a catch-and-release fishery for smallmouth bass and a put-and-grow fishery for brook trout.

Competitive Asymmetry and Coexistence in Size-Structured Populations of Brook Trout and Spring Salamanders

The question of coexistence of competing species has generated much of the basic theory of community ecology. The question becomes more complex when competition occurs between size-structured populations of predators in which the nature of the interaction extends beyond exploitative competition. I conducted a field experiment examining the interactions between fingerling brook trout, Salvelinus fontinalis (total length 78-101 mm), and larval spring salamanders, Gyrinophilus porphyriticus (snoutvent length 35.7-62.4 mm), in an array of replicate experimental streams. Brook trout affected both the growth and survival of larval spring salamanders, reducing survival by 50 % and growth by > 90 % for mass and 44 % for SVL. Brook trout also altered the habitat use of larval G. porphyriticus. G. porphyriticus had no effect on any of the responses of fingerling S. fontinalis. These results parallel those found in an earlier experiment on interactions between small adult brook trout and larval spring salamanders. Interactions between size-structured populations of G. porphyriticus and S. fontinalis are characterized by strong asymmetry in favor of S. fontinalis across a wide range of relative body sizes. This calls into question the mechanisms allowing continued coexistence of G. porphyriticus and S. fontinalis, and in general, the persistence of stream salamanders with predatory fish. Persistence is likely a complex function of the interactions between the life history and local demography of both G. porphyriticus and S. fontinalis, coupled with characteristics of the local environment, rather than the result of classic mechanisms of species coexistence such as niche divergence or alpha selection. Such complex mechanisms of species coexistence are likely more common in situations involving competition between size-structured populations than single factor explanations based on models of exploitative competition between competitors of fixed body sizes and life stages

Distribution of fingerling brook trout, Salvelinus fontinalis (Mitchill), in dissolved oxygen concentration gradients

A self‐recording linear gradient tank and procedures are described in which individual brook trout fingerlings unstressed by recent transfer, unaccustomed surroundings or the presence of an observer could move freely in 16 oxygen concentration gradients within the limits of 1 and 8.9 mg O21−1. They avoided oxygen concentrations below 4 mg 1−1 most of the time and preferred 5 mg 1−1 or higher more than half the time, which supports the field‐derived belief that fish avoid oxygen concentrations below 5 mg l−1 in the natural environment if they can.

Production and Growth Efficiency of Brook Trout (Salvelinus fontinalis) in Two Adirondack Mountain (New York) Lakes Following Liming

Yearling and spring fingerling brook trout (Salvelinus fontinalis) stocked in two Adirondack lakes after liming in the spring of 1985 produced 10–14 kg∙ha−1yr−1 at average standing crops of 8–10 kg∙ha−1 during the first year after stocking. These values were similar to levels observed in other limed and circumneutral Adirondack lakes, which collectively support a limited range of biomass (10–20 kg∙ha−1) and production (7–16 kg∙ha−1) compared with more fertile waters in other regions. The estimated level of food consumption required to maintain initial production rates observed in the two limed lakes was 80–100 kg∙ha−1. This level of predation was sufficient to significantly alter the size structure and composition of the invertebrate prey community within a few months after stocking. However, mean production efficiency in these populations remained at levels of 20–25% and the development of adverse water quality conditions in the first year after liming appeared to be of greater significance than food limitation in regulating production and biomass of these stocked brook trout populations. Reacidification of one lake 5 mo after liming resulted in rapid declines in biomass and production as a result of both increased mortality and reduced growth.

Histopathologic changes in surficial tissues of brook trout, Salvelinus fontinalis (Mitchill), exposed to acute and chronic levels of pH.

Fingerling brook trout, Salvelinusfontinalis (Mitchill), were subjected to acute and chronic pH stress for maximum periods of 10 000 min in a series of continuous-flow dilutions of sulphuric acid or sodium hydroxide from pH 2.2 to 10.8 at 10 and 20 °C after acclimation at 15 °C and pH 6.8. Various tissues, gill, eye, naris, integument, and alimentary tract, were examined histologically and compared with control samples kept at pH 6.8. No differences in the degree or form of tissue injury were detected between series for corresponding pH levels at 10 and 20 °C. Thresholds for tissue and cellular derangements were pH 5.2 and 9.0. Mucous cells of gills, nares, and integument exhibited progressive degrees of hypertrophy and excessive secretion of mucus with increased pH stress. Epithelial necrosis and sloughing occurred extensively on gills, corneae, and integument. At the lethal levels (pH 3.5 and 9.8), epithelial necrosis also occurred in the esophagus. No cellular injury was detected in the stomach or any part of the intestine.

Overwinter Survival of Fingerling Brook Trout with Single and Multile Fin Clips

In an evaluation of overwinter survival of fin-clipped and unmarked brook trout in a reclaimed pond in Maine, 10,000 fall fingerlings were divided into 20 treatment groups, 19 of which were marked by the removal of either single or multiple fins. Analysis of returns from creel and trap-net sampling indicated that: (1) survival of unmarked, unanesthetized trout was significantly higher than that of marked, anesthetized fish; (2) survival of trout with multiple fin excisions was lower than that of fish with single fin excisions; (3) removal of the adipose fin had little or no effect on survival; and (4) removal of a pectoral fin was no more detrimental than the removal of a ventral fin. Spring recaptures indicated that fish of all groups were equally vulnerable to both sampling methods. Overwinter survival was low for all groups.

Lethal levels of pH for brook trout, Salvelinus fontinalis (Mitchill)

Fingerling brook trout, Salvelinus fontinalis (Mitchill), were subjected to acute and chronic pH stress for maximum periods of 10 000 min in a series of dilutions of sulfuric acid or sodium hydroxide at 10 and 20C after acclimation at 15C and pH 6.8. Lethal limits of pH were estimated to be pH 3.5 and 9.8 at both temperatures. There were no observable differences in the resistance times at lethal pH stresses between test temperatures. The order of death was not significant in relation to length or weight of the fish.

Effects of Lead and Hydrocarbons from Snowmobile Exhaust on Brook Trout (Salvelinus fontinalis)

Abstract Lead and hydrocarbons from snowmobile exhaust were found in the water at high levels during the week following ice-out in a Maine pond. Fingerling brook trout (Salvelinus fontinalis) held in fish cages in the pond showed lead and hydrocarbon uptake. These contaminants accumulated during the previous winter when snowmobile operation on the pond was equivalent to one snowmobile burning 250 liters of fuel per season on a .405 hectare pond with average depth of 1 m. Lead content of the water rose from 4.1 ppb before snowmobiling to 135 ppb at ice-out; exposed trout contained 9 to 16 times more lead than controls. Hydrocarbon levels undetectable prior to snowmobiling reached 10 ppm in the water and 1 ppm in exposed fish. Trout held in aquaria for 3 weeks in melted snow containing three different concentrations of snowmobile exhaust also showed lead and hydrocarbon uptake. Their digestive tract tissue contained the most lead. (2 ppm) and gills the least (0.2 ppm). Stamina, as measured by the ability to...

The effect of some DDT and methoxychlor analogs on temperature selection and lethality in brook trout fingerlings

The effects of several DDT and methoxychlor analogs on trout fingerling temperature selection and lethality were investigated. The molecular requirements for lethality and alteration of temperature selection were different. Only p, p′-DDT, p, p′-DDD, and p, p′-methoxychlor were toxic in the range 10–50 ppb used. All the compounds tested, except DDE-type analogs, altered temperature selection. The effect of p, p′-methoxychlor on temperature selection progressively decreased until normal values were obtained 5 days after exposure. The effect of p, p′-DDT was still pronounced 9 days after exposure.

Relation between Water Temperature and Metabolism of Dietary Phosphorus by Fingerling Brook Trout

Abstract Fingerling brook trout (Salvelinus fontinalis) were force fed a capsulated food that contained P32-labeled phosphorus. A negligible direct effect of water temperature from 36° F. to 66° F. was measured on the recovery of the labeled phosphorus in the tissues of the trout through 4 days after feeding. Warmer water accelerated the rate of passage of the food through the digestive tract and the rate of digestion of the food equally. Consecutive daily feedings at water temperatures of 51°F. and 61°F. produced similar results for both water temperatures.

Behavior of Splake and Brook Trout Fingerlings

Behavior of Splake and Brook Trout Fingerlings

溪流区に放流したマス稚魚の生残に関する研究-II

1. Estimation of population size was made directly through observation with water-glass in an experimental area settled in a mountain brook. 2. The research period was divided into four periods owing to the occurrence of principles having influence on the errors of observation. 3. The flood was defined newly. 4. With use of errors of observation measured, a deviced procedure of correction of apparent survival or mortality rate was actually applied. 5. Some adjustment were applied tb apparent observed data including the population size of naturally propagated fingerlings of rainbow trout together with that of stocked rainbow trout fingerlings. 6. The change of behavioristic character made a cause to change the method of adjustment. Change of fishing method involved also made a cause to change the method of adjustment. (However, as the fishing method is subordinate to the change of behavioristic character of fingerlings, the actual principle should be taken to be the latter.) 7. Floods caused a large mortality showing the measures of 50.4 to 62% in rainbow trout fingerlings, and 67.9 to 83.7% in brook trout fingerlings at each flood. 8. Floods had scouring effect on mortality, and of decreased fingerlings 75.3 to 95.5% with rainbow trout and 99.0 to 100% with brook trout were estimated to be swept away from the experimental area, though some of them were expected to remain over some downstream area. 9. The intervals of measuring date in survivor survey before and after the occurrence of flood was thought to have some influence on the measure of scouring effect as well as on that of mortality caused by flood. In this case, the dispersion of fingerlings made on the days of usual flow was considered to be the actual agency to reduce the apparent impression of violence of flood, the action of which emerged in mortality of fingerlings and scouring effect.

Results from Stocking Brook Trout of Wild and Hatchery Strains at Stillwater Pond

In 1948 and 1949, 1,000 fingerling brook trout of a wild strain and 4,500 fingerlings of a hatchery-developed strain were stocked in Stillwater Pond, a 55-acre pond in Putnam County, New York. All fingerlings were fin-clipped for recognition. Returns from plantings in both years followed similar patterns. Yields from the wild strain were disproportionately low in the first season after planting and disproportionately high in the second season. Field observations indicated that individuals of the two groups were consistently different in appearance and generally could be separated by characteristics of body shape and color. Length-weight data, expressed as condition factors, illustrate morphological differences in trout of the two groups after they had been in the pond for 18 months. Angling returns indicate that better angler satisfaction may be obtained here from stocking trout of both strains together than from stocking either one alone. It is concluded that differences in these two strains of trout as exhibited in this situation are hereditary (racial) and are of sufficient magnitude to be important in management of a brook trout fishery.

Modification of the Sexual Cycle in Brook Trout (Salvelinus Fontinalis) by Control of Light

Abstract To facilitate handling of brook trout fingerlings during winter and to permit a shorter holding period for catchable-sized trout, experiments on shortening the sexual cycle by control of light were conducted on a commercial scale from 1939 to 1950. Light was increased over normal daylight and then decreased below normal daylight. This procedure caused fish to spawn as early as late July. Artificially lengthening the day in the fall retarded spawning. Early spawned eggs had a higher survival than normally spawned eggs and general hatchery efficiency was improved when early eggs were used.

Various Sulfonamide Treatments of Furunculosis in Brook Trout, Salvelinus Fontinalis

Abstract Sulfamerazine, sulfamethazine, sulfathiazole, and sulfamerazine alternated at 4-day intervals with sulfathiazole, were compared in the treatment of furunculosis among yearling and fingerling brook trout at the Leetown Station of the U. S. Fish and Wildlife Service, Kearneysville, West Virginia, in 1947. The daily dosage rates were: for sulfamerazine and sulfamethazine, 6 grams per 100 pounds of fish (13.2 grams per 100 kilograms); for sulfathiazole, 12 grams per 100 pounds. The drugs were mixed thoroughly with the food. The courses of the epizootics were very different in the two age groups. With yearlings, mortalities were as follows: controls, 100 percent; sulfathiazole, 75 percent; sulfamethazine, 62 percent; sulfamerazine-sulfathiazole, 43 percent; sulfamerazine, 29 percent. With fingerlings, treatment was initiated sooner after the onset of the disease. Although mortality was finally heavy in the fingerling control, sulfonamide therapy was very much more effective and losses correspondingly ...

Results from Plantings of Marked Fingerling Brook Trout (Salvelinus f. fontinalis Mitchill) in Hunt Creek, Montmorency County, Michigan

Fin-clipped fingerling brook trout (Salvelinus f. fontinalis Mitchill) both hatchery-reared and wild, were released in Hunt Creek in late summer or fall of 1939 and 1940. Their contribution to the catch in subsequent years was determined by creel census and anglersˈ reports. The extensive experiments involved release of 35,109 and 17,635 marked fingerlings, respectively, throughout the length of Hunt Creek. Marked fish entered the anglersˈ catches in 1941 and 1942, and made up from 0.27 to 2.56 percent of the observed catch of legal brook trout in various years. The total known percentages of recovery were 0.07 percent (26 fish) of the 1939 release, and 0.28 percent (49 fish) of the 1940 planting. Intensive experiments with both wild and hatchery-reared brook trout fingerlings marked by different fin combinations were carried on simultaneously in Section C of the experimental waters of Hunt Creek. Marked hatchery-reared fingerlings released in 1939 contributed from 0.0 to 0.26 percent of the total observed catches of legal brook trout in later years; 1940-marked hatchery fingerlings made up from 0.00 to 0.45 percent of total observed catches in later years. Wild fingerlings marked at the same time made up from 0.00 to 1.80 percent of catches recorded in subsequent seasons. Larger percentages of recovery were noted for the smaller of the two releases (1940). Through the use of the formula M = 1,000 A/BC where M = migration or abundance index from a release locality to a recovery locality, A = number of marked fish recovered in a given locality, B = number of fishing units of effort in a given locality, and C = total number of marked fish released in a given locality, it was demonstrated that the majority of wild and hatchery-reared marked fingerlings in the intensive experiment stayed within the limits of the experimental sections, although they did move out of Section C, except for the hatchery-reared fingerlings recovered in 1942, which were farther downstream than usual. General growth data on marked fingerlings of both types indicated that probably those fish which were largest at the time of marking and release came into the legal catch first. It was concluded that brook trout fingerling planting is a wasteful procedure because a low percentage reaches the anglersˈ creels. Creel census data demonstrate that despite the elimination of fingerling stocking in Hunt Creek following 1940, angling quality has not deteriorated.

A Contribution to the Etiology of Ulcer Disease of Trout

Abstract During the fall of 1947 and the late summer of 1948, outbreaks of ulcer disease occurred among brook trout fingerlings at the Leetown station and other hatcheries. From the ulcers, blood, and kidneys of the diseased trout were isolated bacteria which could be successfully cultivated only on media to which blood or fish-tissue extract had been added. Some characteristics of these bacteria are described. In a series of inoculation experiments, brook, brown, and rainbow trout were infected with pure cultures of the isolated bacteria. When the trout used for these tests were free from a latent infection of B. salmonicida, ulcer disease could be reproduced and the bacteria reisolated in pure culture from the inoculated fish. On the basis of the information on hand, it is believed that the isolated bacteria belong to the genus Hemophilus.

Recovery of Marked Fish following a Second Poisoning of the Population in Ford Lake, Michigan

In 1936, a 10.7-acre lake in Otsego County, Michigan, was treated with rotenone to eliminate a population of stunted yellow perch. An attempt to recover the entire population yielded 4,817 stunted perch, 27 trout in poor condition, and four species of minnows. The weight of what was assumed to be the total population was 516 pounds or slightly more than 50 pounds per acre. In 1937, an experimental planting of Montana grayling was made which was not successful owing to unauthorized introduction of bluegills about the same time. In 1941, 5,000 fingerling brook trout were stocked, but proved unable to compete with the rapidly increasing bluegill population and disappeared 4 years later. In 1943, walleyes were introduced in the hope of reducing the bluegill population to a point where survivors could make satisfactory growth. In 1946, when rotenone reappeared on the civilian market, the lake was treated with poison again, and an attempt made to recover the entire population. The total weight of fish recovered was 1,293 pounds, or 111.5 pounds per acre, more than twice the poundage found in 1936; the difference perhaps can be explained by bluegills being closer to the primary food chain than yellow perch. Of greater interest were the findings on completeness of recovery. Four and 3 days, respectively, prior to poisoning, 246 bluegills and 210 brook trout were fin-clipped and planted. Only 58.9 percent of the marked bluegills and 44.7 percent of the marked trout were recovered despite careful search. Considerable doubt is thereby cast on the prevalent practice of assuming practically complete recovery of fish populations following rotenone treatment, and figures on total fish production derived by this method.