Pattern and prevalence of predator damage on adult Atlantic salmon, Salmo salar L., returning to a river system in north-east Scotland

1999 ◽  
Vol 6 (4) ◽  
pp. 335-343 ◽  
Author(s):  
P. M. THOMPSON ◽  
F. MACKAY
1969 ◽  
Vol 26 (9) ◽  
pp. 2535-2537 ◽  
Author(s):  
J. H. C. Pippy

Bacterial kidney disease was presumptively identified in each of 25 hatchery-reared juvenile salmon (Salmo salar) but in only 2 of 235 wild juveniles in the Margaree River system. Apparently spread of disease from the hatchery to wild salmon in the river is very gradual.


2007 ◽  
Vol 64 (3) ◽  
pp. 563-573 ◽  
Author(s):  
Sean C Mitchell ◽  
Richard A Cunjak

Stream discharge has long been associated with abundance of returning adult spawning salmonids to streams and may also affect body size distribution of adult salmon as low flows interfere with returns of larger-bodied fish. We examined these relationships of abundance and body size within Catamaran Brook, a third-order tributary to the Miramichi River system of New Brunswick, Canada, to investigate the causes of a declining trend in annual returns of Atlantic salmon (Salmo salar) to this stream. Regression models of adult abundance, proportion of the run as grilse, and body size of returning adults as functions of maximum daily stream discharge during the period of upstream spawner migration were constructed. Adult abundance shows a logarithmic relationship with stream discharge and provides good predictive ability, while appearing to not be significantly related to adult abundance in the larger Miramichi system. The proportion as grilse in the run and female body size are also logarithmically related to stream discharge, with low flow years being very influential in the regressions. These relationships of Atlantic salmon population abundance and body size characteristics have implications with respect to stock integrity and production of the following generation.


1988 ◽  
Vol 45 (8) ◽  
pp. 1330-1339 ◽  
Author(s):  
D. M. Blouw ◽  
S. D. Saxon ◽  
E. M. P. Chadwick

The assumption is generally made in stock identification studies that variation within stocks is not confounded with variation among them. To evaluate whether this assumption is tenable we test the null hypothesis of temporal stability in five key meristic traits of a single stock of Atlantic salmon (Salmo salar). We used smolts collected over a 10-yr period in the downstream migrations from one small river system. Individuals were tagged when captured and preserved, so we can estimate variability within, as well as among, runs. The meristic traits are remarkably homogenous within runs and cohorts. However, the null hypothesis of stability over time among runs and cohorts is strongly rejected for each trait. We conclude that temporal variation is both extensive and persistent. There is limited covariation among the traits, but they are largely independent of scores of environmental variables and of variation in the biological attributes of the stock. Because among-group variability is meaningful only in context of within-group variation, and because the within-group variation is large, our results have serious implications for sampling design in stock identification studies.


1989 ◽  
Vol 67 (6) ◽  
pp. 1453-1461 ◽  
Author(s):  
E. Verspoor ◽  
L. J. Cole

Atlantic salmon (Salmo salar) from Little Gull Lake on the Gander River system of central Newfoundland were found to be electrophoretically polymorphic at 5 of 20 protein loci screened. Four of the polymorphic loci were structural and one was regulatory. Major heterozygote deficiencies relative to Castle–Hardy–Weinberg expectations were detected at the two most polymorphic loci, Aat-3 and Mdh-3,4, and significant nonrandom associations between genotypes at these loci and the other polymorphic loci, Sdh-1, Me-2, and Pgm1-t, were also found. The heterozygote deficiencies and the nonrandom genotype associations were attributable to the admixture of genetically distinct gene pools of resident and anadromous salmon in the lake. This is the first documented case of coexistence of reproductively separated populations of Atlantic salmon of the two life history types, and shows that the sympatric occurrence of the two forms can represent between-population variation.


2009 ◽  
Vol 66 (5) ◽  
pp. 865-870 ◽  
Author(s):  
Rocco C. Cipriano

AbstractCipriano, R. C. 2009. Antibody against infectious salmon anaemia virus among feral Atlantic salmon (Salmo salar). – ICES Journal of Marine Science, 66: 865–870. Archived sera from Atlantic salmon (Salmo salar) that returned to the Penobscot River (Maine), Merrimack River (Massachusetts), and Connecticut River (in Massachusetts) from 1995 to 2002 were analysed for antibodies against infectious salmon anaemia virus (ISAV) using an enzyme-linked immunosorbent assay (ELISA). Up to 60 samples were archived per river system per year. In a given year, the number of fish sampled by ELISA for ISAV antibodies in the Penobscot River ranged from 2.9 to 11.2%, and the range of salmon sampled in the Merrimack River and the Connecticut River was 31.3–100% and 20.0–67.5%, respectively. Archived sera were not available for the 1995 and 2002 year classes from the Connecticut River. In all, 1141 samples were processed; 14 serum samples tested positive for antibodies to ISAV. In the Penobscot River, serum from one fish tested positive in each of the 1995 and 1999 year-class returns, and sera from two fish tested positive in the 1998 returns. In the Merrimack River, sera from four fish tested positive in each of the 1996 and 1997 returns, and sera from two fish were positive in the 2002 return. None of the archived sera from Atlantic salmon that returned to the Connecticut River tested positive.


1974 ◽  
Vol 31 (9) ◽  
pp. 1467-1480 ◽  
Author(s):  
J. E. Paloheimo ◽  
P. F. Elson

Recaptures of Atlantic salmon (Salmo salar) tagged as smolts show that substantial numbers of those produced in the Maritimes are caught in Greenland waters. Percentage recoveries in the home-river system show a significant inverse correlation with levels of catches in Greenland. Analyses of detailed data collected since 1950 indicate that the Greenland fishery has caused serious reduction of Miramichi stocks of 2-sea-winter salmon and will affect the future long-term production of Atlantic salmon in Canada.Total landings have risen higher per million smolts produced in the Miramichi system since the Greenland fishery began. The escapement from fisheries and the potential spawning stock per given numbers of smolts has dropped correspondingly. Lowered escapement has been followed by lowered abundance of progeny as reflected by density of young in nursery stream areas. Significantly, recruitment as measured in numbers of underyearlings depends more crucially on numbers of salmon escaping the fishery than on numbers of grilse. As shown by this statistical analysis, the Greenland fishery has had a direct adverse effect on the numbers of salmon surviving to enter their spawning river. Consequently, the abundant smolt runs in 1964, 1965, and 1968 produced by good escapement some 4 yr earlier failed to maintain adequate levels of recruitment and have instead been followed by all-time low commercial catches and recruitment of young in rivers.


1976 ◽  
Vol 33 (5) ◽  
pp. 1139-1143 ◽  
Author(s):  
G.M. Hare ◽  
M. D. B. Burt

Ten parasite species (one protozoan, eight helminth, one mollusc) were collected from 1262 smolts of Atlantic salmon (Salmo salar) in the eight tributaries and estuary of the Miramichi River, New Brunswick, Canada during 1970 and 1971. Three of these parasites, Discocotyle sagittata, Diplostomum spathaceum, and Neoechinorhynchus rutili showed restricted distributions within the study area. Discocotyle sagittata infected 32.6% of 435 smolts collected from tributaries draining into the Main Northwest Miramichi River but only 0.3% of 604 smolts collected from tributaries draining into the Main Southwest Miramichi River. Diplostomum spathaceum infected 18.9% of 148 smolts collected from the Southwest Miramichi River but was absent in 819 smolts collected from the remaining tributaries. Neoechinorhynchus rutili infected 18.8% of 144 smolts collected from the Bartholomew River but only 0.2% of 895 smolts collected from the other tributaries. Presence of Discocotyle sagittata on smolts collected in the estuary of the Miramichi River would identify smolts that originated in the Main Northwest Miramichi River, thus allowing for a separation of smolts from this branch and the other main branch, the Main Southwest Miramichi River. Presence of Diplostomum spathaceum in smolts collected in the Main Southwest Miramichi River or in the estuary of the Miramichi River would identify smolts that originated in the Southwest Miramichi River. Presence of N. rutili in smolts collected in the Main Southwest Miramichi River would identify smolts of Bartholomew River origin.


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