Effects of Gamma Irradiation on Salmonella spp. in Smoked Lake Whitefish (Coregonus clupeaformis)

1971 ◽  
Vol 28 (5) ◽  
pp. 643-646 ◽  
Author(s):  
K. Ostovar ◽  
R. R. Pereira ◽  
R. A. Gallop

A dosage of 0.5 M rad was found sufficient to eliminate three species of Salmonella in smoked lake whitefish (Coregonus clupeaformis) regardless of the stage of processing at which steaks were inoculated with the bacteria. All three species survived smoking at temperatures up to 167 F. The dosages required for elimination of the bacteria when steaks were inoculated at various stages of processing were: before freezing at 0 F for 48 hr, 0.4 M rad for S. give, 0.3 for S. typhimurium, and 0.2 for S. java; before brining at 60 Salometer for 25 min, 0.4, 0.3, and 0.3; after smoking, 0.5, 0.4, and 0.35. Salmonella give was more resistant to heat than the other two species.


1987 ◽  
Vol 44 (S1) ◽  
pp. s55-s63 ◽  
Author(s):  
K. H. Mills ◽  
S. M. Chalanchuk

Responses of an unexploited population of lake whitefish (Coregonus clupeaformis) to the fertilization of Lake 226 in the Experimental Lakes Area, northwestern Ontario, are described for the fifth through eighth years of fertilization (1977–80) and for three years after fertilization was terminated (1981–83). A vinyl curtain separated Lake 226 into two basins. One basin (L226NE) received additions of phosphorus, nitrogen, and carbon; the other (L226SW) received nitrogen and carbon. Lake whitefish in L226NE were faster growing, had higher condition (k), were more numerous, had higher survival from age 0 to age 1, had greater biomass, and had greater production than L226SW whitefish from 1977 to 1980. Some of these effects continued in 1981 and 1982 after fertilization was terminated, but only biomass differences remained by 1983.



1981 ◽  
Vol 38 (12) ◽  
pp. 1790-1807 ◽  
Author(s):  
P. E. Ihssen ◽  
D. O. Evans ◽  
W. J. Christie ◽  
J. A. Reckahn ◽  
R. L. DesJardine

Ecological, morphological, and electrophoretic variation among five allopatric Ontario lake whitefish (Coregonus clupeaformis) stocks was studied. The stocks differ in terms of diet, growth rate, movement patterns, fecundity, and egg and larval size. Morphologically, the five stocks were also different for characters such as number of gill rakers, number of pyloric ceca, and in size, adjusted for fork length, of the tail, dorsal fin, and the eye. Discriminant functions, derived from body measurements and meristic counts, classified specimens accurately into their lakes of origin. Highly significant allele frequency differences were found at 6 of the 32 electrophoretic loci examined. Standard genetic distances, derived from electrophoretic allele frequency differences, corresponded roughly to the order in which these stocks became isolated following retreat of the last continental glaciation. The genetic distance of the Opeongo stock from the other stocks is about one order of magnitude larger than the genetic distances among the other stocks. The Opeongo stock is also somewhat unusual ecologically, having different egg size and fecundity characteristics compared with the other stocks and being a member of a sympatric dwarf/normal pair. Dendrograms, derived from the Mahanalobis distances for the meristic variation and the Nei genetic distances for the electrophoretic variation, showed similar branching patterns, but the branching patterns for the morphometric versus the biochemical variation were different. A significant part of the morphometric variation among the stocks was related to differences in growth rates of the stocks, most body measurements being negatively correlated with growth rate. The Mahanalobis distances for the meristic variation (including pyloric ceca counts) were correlated with the standard genetic distances from the electrophoretic data. The ecological, morphological, and biochemical variation among the stocks, in relation to local adaptation, is discussed.Key words: lake whitefish, stock concept, genotype, phenotype, ecology, morphology, meristics, multivariate analysis, electrophoresis, growth, diet, fecundity



2010 ◽  
Vol 36 ◽  
pp. 121-134 ◽  
Author(s):  
Tyler Wagner ◽  
Michael L. Jones ◽  
Mark P. Ebener ◽  
Michael T. Arts ◽  
Travis O. Brenden ◽  
...  


2017 ◽  
Vol 69 ◽  
pp. 294-301 ◽  
Author(s):  
Lindy M. Whitehouse ◽  
Chance S. McDougall ◽  
Daniel I. Stefanovic ◽  
Douglas R. Boreham ◽  
Christopher M. Somers ◽  
...  


1975 ◽  
Vol 32 (3) ◽  
pp. 404-407 ◽  
Author(s):  
M. C. Healey ◽  
C. W. Nicol

We found no significant differences in slope or intercept for the regression of loge fecundity on loge fork length among samples of whitefish from four lakes near Yellowknife in the Northwest Territories. The equation describing the relationship between fecundity and fork length for these populations was:[Formula: see text]Five other populations for which length–fecundity relationships could be calculated had length exponents ranging from 3.20 to 4.38, suggesting a nonlinear relationship between weight and fecundity. Six of the nine populations as well as four others for which limited data were available all had similar relative fecundities. Fish from Buck Lake in Alberta and from Lake Erie had high relative fecundities while fish from Great Slave Lake had low relative fecundity.



1985 ◽  
Vol 63 (2) ◽  
pp. 396-399 ◽  
Author(s):  
Hilda Lei Ching

As a result of experimental infections in chicks, diplostomula found in the retina of chinook salmon from the Nechako River were identified as Diplostomum (Diplostomum) baeri bucculentum. Eyeflukes in other salmonids were considered to be the same species based on similar measurements and site in the eyes. These eyeflukes varied in prevalence and mean intensity in seven salmonid species surveyed in nine localities in 1979–1981. The following fish were sampled: rainbow trout (Salmo gairdneri), 505; mountain whitefish (Prosopium williamsoni), 334; lake whitefish (Coregonus clupeaformis), 32; Dolly Varden (Salvelinus malma), 66; lake trout (S. namaycush), 13; kokanee or sockeye salmon (Oncorhynchus nerka), 323; and chinook salmon (O. tshawytscha), 164. Eyeflukes had prevalences ranging from 84 to 100% in six lakes, 64% in the river, 53% in one reservoir site, and a prevalence of 15% in the other reservoir site. Mountain and lake whitefishes had high mean intensities while kokanee had low mean intensities. Correlation of increased intensity with increased fish size was significant for 6 of 27 samples. Four samples of lake whitefish, mountain whitefish, rainbow trout, and chinook salmon showed significant asymmetry when numbers of diplostomula were compared between eyes. More of the heavily infected fish showed asymmetry than did the lightly infected fish.



1974 ◽  
Vol 31 (1) ◽  
pp. 55-62 ◽  
Author(s):  
J. S. Loch

Adult lake whitefish (Coregonus clupeaformis) from Clearwater Lake and second generation adults of offspring from Clearwater whitefish transplanted to Lyons Lake were compared with respect to morphometric and meristic characters and isozymes of L-glycerol-3-phosphate dehydrogenase (GPDH). Feeding habits and abundance of pelagic and benthic foods were compared in the two lakes.Gill raker number, lateral line scale count, and interorbital width remained constant between parental and offspring populations. Gill raker length was the main character found to differ between the populations. This was found to be related to the percentage and type of benthic food eaten. Abrasion of the gill rakers is offered as an explanation for the differences in gill raker length. Differences were found in various other meristic and morphological characters, as well as in electrophoretic phenotype frequencies of isozymes of GPDH.



1997 ◽  
Vol 60 (9) ◽  
pp. 1029-1033 ◽  
Author(s):  
NORMA S. LÁZARO ◽  
ANITA TIBANA ◽  
ERNESTO HOFER

Tonsils and inguinal, mesenteric, and prescapular lymph node samples collected from 115 swine carcasses from two abattoirs and a family-run operation in the State of Rio de Janeiro, Brazil, were cultured for the presence of Salmonella species. Salmonella spp. were detected in 40 (34.8%) of the swine samples with the following distribution; tonsils (31/40, 77.5%), mesenteric lymph nodes (16/40, 40.0%), inguinal lymph nodes, (9/40, 22.5%), and prescapular lymph nodes (7/40, 17.5%), Scalding tank water and environmental swabs collected from the abattoirs were also analyzed. Salmonella spp. were recovered from 13 of 51 (22.5%) of the environmental samples from one of the two abattoirs, none from those from the other abattoir. Salmonella spp. were recovered from the evisceration tables (5/11, 45.5%), the killing room (3/10, 30.0%), the holding pen (2/10, 20.0%), the butchering saw (2/10, 20.0%), and the scalding tank (1/10, 10.0%). The most frequently detected serovar was Salmonella Muenster. The results show the necessity of adopting more effective hygienic measures in the abattoirs as well as in the areas where swine are raised in order to reduce the role of abattoirs and storage facilities in the spread of Salmonella contamination.



1995 ◽  
Vol 73 (10) ◽  
pp. 1860-1877 ◽  
Author(s):  
Jean-Claude DesLandes ◽  
Sylvie Guénette ◽  
Yves Prairie ◽  
Réjean Fortin ◽  
Dominique Roy ◽  
...  

Catches per unit of effort (CPUE) with experimental gill nets, recruitment, growth, and condition were monitored between 1977 and 1992 to evaluate the impact of impoundment on the main fish species of La Grande 2, Opinaca, and Caniapiscau reservoirs and the Boyd–Sakami diversion. CPUE and recruitment of northern pike (Esox lucius) and lake whitefish (Coregonus clupeaformis) increased markedly at most stations after impoundment and decreased at the end of the series. The lake whitefish and cisco (Coregonus artedii) showed their most striking rise in CPUE at two bay stations of La Grande 2 and Opinaca reservoirs. CPUE and recruitment of the longnose sucker (Catostomus catostomus), white sucker (Catostomus commersoni), and lake trout (Salvelinus namaycush) (Caniapiscau) showed a general decrease following impoundment. CPUE for the walleye (Stizostedion vitreum) also decreased at several stations; however, the two most southerly stations in La Grande 2 reservoir and the Boyd–Sakami station showed high CPUE during the series. Concentration–redistribution phenomena explain part of the observed variations in CPUE. Correlation analyses showed that walleyes and white suckers were attracted to the warmer, more turbid stations, and that the high primary and secondary productivity of bay stations attracted the coregonines. Growth and condition of the main species increased during variable time intervals after impoundment and decreased at the end of the series.



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