LA TOXICITÉ DU DDT POUR LE SAUMON DE L'ATLANTIQUE (SALMO SALAR LINNÉ) ET LES ALEVINS DE TRUITE (SALVELINUS FONTINALIS MITCHILL)

1958 ◽  
Vol 36 (4) ◽  
pp. 479-487 ◽  
Author(s):  
André Gagnon

The relative sensitivity of brook trout fry, salmon fry, and 1- and 2-year-old parrs to known quantities of DDT was studied in hatchery-trough experiments with larger numbers of specimens than were used by previous workers. In troughs, in which part-time water circulation was achieved and DDT used at the rate of 0.5 lb./acre (0.32 p.p.m.), high mortality rates (93–100%) were recorded for salmon fry, trout fry, and 1-year-old parrs. Moreover, it was shown that group susceptibility decreases in the following manner: salmon fry > 1-year-old parrs > trout fry. In another series of experiments, under identical conditions, it was shown that sensitivity in salmon decreases with age. Using salmon fry, in troughs deprived of water circulation, a study was made of the effects of various concentrations of DDT: 0.33, 0.18, 0.072, and 0.036 p.p.m. corresponding to 0.5, 0.25, 0.1, and 0.05 lb. of DDT/acre, respectively. The average lethal dose (L.D. 50) was found to be 0.072 p.p.m. A comparison between two series of experiments shows how mixing of the DDT with water makes the poison more deadly than when used as a DDT–oil solution on the surface of water.


2018 ◽  
Vol 75 (11) ◽  
pp. 1949-1959
Author(s):  
Scott D. Roloson ◽  
Kyle M. Knysh ◽  
Michael R.S. Coffin ◽  
Karen L. Gormley ◽  
Christina C. Pater ◽  
...  

The purpose of this study was to update rainbow trout (Oncorhynchus mykiss) invasion status, delineate factors that increase the invasion probability, and quantify habitat overlap between invasive rainbow trout and native Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) on Prince Edward Island, Canada. Analysis of landscape-level variables in 26 watersheds (14 with and 12 without rainbow trout) demonstrated that watershed slope, percent agricultural land use, and distance to the nearest rainbow trout population significantly increased the probability of rainbow trout establishment. Two independent reach-level fish community surveys were conducted by electrofishing in combination with habitat surveys. Reaches with rainbow trout had higher stream slope, Atlantic salmon were found in wider reaches with larger substrate, and brook trout were typically dominant in headwater reaches with finer substrate. Findings at multiple ecological scales illustrated that rainbow trout invasion success is positively influenced by the presence of high-slope habitat. Habitat separation of the three salmonid species indicates that competition with introduced rainbow trout may not be the most significant threat to native salmonid populations.



1985 ◽  
Vol 42 (7) ◽  
pp. 1290-1295 ◽  
Author(s):  
Rocco C. Cipriano ◽  
Stephen W. Pyle

Adjuvant-dependent immunity resulted in agglutinin activity against Aeromonas salmonicida in sera of convalescent fishes. Rainbow trout (Salmo gairdneri), brown trout (Salmo salar), and brook trout (Salvelinus fontinalis) that had recovered from natural furunculosis produced serum agglutinin antibodies predominately against a specific chromatographic fraction (EcF1) of the bacterium's extracellular product. EcF1 was resolved by ion-exchange chromatography from DEAE SephadexA-25. When EcF1 was emulsified in Freund's incomplete adjuvant and injected intraperitoneally, brook trout were protected against experimental challenge; brook trout vaccinated with EcF1 only were not protected against furunculosis. EcF1, examined by immunodiffusion tests, SDS – polyacrylamide gel electrophoresis, and Western blot immunoassays, shared certain properties with bacterial endotoxin. EcF1 and endotoxin preparations both contained immunoreactive lipopolysaccharides which indicated that adjuvant-dependent immunity to A. salmonicida is related to endotoxin.



1972 ◽  
Vol 29 (1) ◽  
pp. 27-29 ◽  
Author(s):  
C. T. Hatfield ◽  
J. M. Anderson

The experiments were conducted in large outdoor concrete pools in which the salmon had access to a safe haven. After exposure for 24 hr to 1.0 ppm of the organophosphate insecticide, Sumithion, Atlantic salmon (Salmo salar) parr were more vulnerable than unexposed fish to prédation by large brook trout (Salvelinus fontinalis). Sumithion at 0.1 ppm, and DDT at 0.07 ppm, had no noticeable effect. The results, particularly for Sumithion, correlate well with previous laboratory work on the effect of insecticides on the learning ability of salmon.



1990 ◽  
Vol 47 (8) ◽  
pp. 1623-1630 ◽  
Author(s):  
D. R. Mount ◽  
M. J. Swanson ◽  
J. E. Breck ◽  
A. M. Farag ◽  
H. L. Bergman

Brook trout fry were exposed for thirty days to temporal combinations of two water qualities: (1) pH 5.21, 51 μg/L total aluminum, with 2.39 mg/L calcium (baseline); and (2) pH 4.59, 329 μg/L total aluminum, with 1.56 mg/L calcium (pulse). Although continuous exposure to the latter conditions caused nearly complete mortality, exposures alternating between the two conditions caused much less mortality. In fact, fish experiencing 18 d of baseline conditions before their first pulse exposure had mortality rates equal to fish never experiencing a pulse, indicating acclimation to acid/aluminum/low calcium stress. We conclude that the pattern of fluctuating acid/aluminum/low calcium exposure is very important in determining its toxicity, and that the toxicity of acidic "pulses" in field situations may be lower than would be expected from laboratory exposures using naive fish, due to the existence of acclimation.



1982 ◽  
Vol 60 (10) ◽  
pp. 2239-2244 ◽  
Author(s):  
Robert G. Randall

Postemergent downstream dispersal of Atlantic salmon fry (Salmo salar) was monitored using drift samplers during spring 1978 in two Miramichi River, N.B., tributaries. Catch rates of salmon fry peaked during the 2nd and 3rd weeks of June in both streams, coinciding with peak emergence of the salmon from the gravel. Very few trout fry (Salvelinus fontinalis) were captured in the drift nets, but electrofishing results indicated trout emergence preceded salmon by about 3 weeks.The earlier emergence of the trout gave them an early growth advantage over the salmon, so that trout fry were usually larger than salmon fry inhabiting the same stream areas. Early growth rates of both salmon and trout were quite varied among four stream sites during 2 years when growth was monitored; growth differences were discussed in relation to stream temperatures and density-dependent growth. Salmon fry were more abundant than trout fry at most sites in both years.



2003 ◽  
Vol 60 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Matthew J Raffenberg ◽  
Donna L Parrish

Competitive interactions among stream salmonids in resource-limited environments have been linked to reduced success for many species. Few studies have focused on interactions at scales larger than individual fish or stream reach. We chose to focus our study on these larger scales to provide information for managing species that have complex life histories transcending multiple scales. Our objective was to explore age-0 Atlantic salmon (Salmo salar) growth and survival in relation to trout abundance (introduced rainbow (Oncorhynchus mykiss) and native brook (Salvelinus fontinalis) trout) and prey resources at 24 stream reaches across two Vermont watersheds that flow into the Connecticut River. Simple linear and multilinear regressions were conducted on response and predictor variables related to fish and invertebrate prey. Age-0 Atlantic salmon survival was greatest at the site with highest trout abundance; however, no linear relationships to trout abundance were detected possibly because Atlantic salmon growth and survival were highly variable across sites. In contrast, a positive significant multivariate relationship was identified among age-0 Atlantic salmon survival, the abundance of age-1+ brook trout (i.e., 100–130 mm), and benthic prey abundance. These results suggest that stocking streams based on trout abundance may not increase Atlantic salmon growth and survival during the first summer of life.



1984 ◽  
Vol 41 (2) ◽  
pp. 377-380 ◽  
Author(s):  
P. M. Ryan

The catch per unit effort (CPUE) data of brook trout (Salvelinus fontinalis) and Atlantic salmon (Salmo salar) in fyke nets set in two small lakes in central Newfoundland were compared with population densities estimated with Schnabel multiple mark–recapture experiments each spring and fall from 1978 to 1982. The catchability of brook trout did not differ significantly between lakes or seasons, and CPUE was an index of the relative abundance of trout within and between lakes. In contrast, the catchability of Atlantic salmon differed greatly between lakes and varied seasonally, being greater in the spring but less in the fall than the catchability of brook trout. Comparisons of relative salmon abundance between lakes or of the relative abundance of brook trout to Atlantic salmon within or between lakes require a correction for seasonal differences in the catchability of salmon.



1970 ◽  
Vol 27 (9) ◽  
pp. 1656-1661 ◽  
Author(s):  
Robert T. Lackey

Seasonal depth distributions of landlocked Atlantic salmon (Salmo salar), brook trout (Salvelinus fontinalis), landlocked alewives (Alosa pseudoharengus), and American smelt (Osmerus mordax) were determined monthly in Echo Lake, Maine, using vertical and horizontal gillnets.Salmon were wide-ranging fish, but generally not captured in very shallow or very deep water. Brook trout were primarily an inshore species, not often captured in water deeper than 25 ft, and nearly always found close to the lake bottom. The majority of captured alewives were taken from shallow to middepths (0–30 ft) in summer and fall and in deep water during winter and spring. Smelts were widely distributed, but the majority were captured in water deeper than 30 ft every month.No clear temperature or dissolved oxygen preference could be shown for any of the four species.



2001 ◽  
Vol 58 (8) ◽  
pp. 1672-1682 ◽  
Author(s):  
Zhongyan Weng ◽  
Nandita Mookerji ◽  
Asit Mazumder

The impact of a major flood and recovery of the stream communities under contrasting nutrient conditions were studied in two second-order streams of Sainte-Marguerite River, Quebec. A massive flood during the summer of 1996 caused extensive displacement of the stream substratum and severe reductions in the abundance of all biota: periphyton, benthic invertebrates, juvenile Atlantic salmon (Salmo salar), and brook trout (Salvelinus fontinalis) (especially in the 0+ age-class). In the postflood recovery phase, nutrient-enriched sections recovered significantly more rapidly than the nonenriched sections. After 1 month, periphyton biomass in the enriched sections had increased to five times that of the preflood levels, and after 2 months, the invertebrate communities had recovered to preflood levels. Fish densities and growth rates also returned to normal levels more rapidly in the enriched sections. Our results suggest that nutrient-rich systems are more resilient to massive disturbances, and so, nutrient enrichment may represent a viable tool for restoring nutrient-limited systems.



Science ◽  
1930 ◽  
Vol 72 (1875) ◽  
pp. 582-583 ◽  
Author(s):  
M. F. Crowell ◽  
C. M. Mccay


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