Lake Use by Wild Anadromous Atlantic Salmon, Salmo salar, as an Index of Subsequent Adult Abundance

1986 ◽  
Vol 43 (1) ◽  
pp. 2-11 ◽  
Author(s):  
P. M. Ryan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Seasonal Changes ◽  
Catch Per Unit Effort ◽  
Age Composition ◽  
Atlantic Salmon Salmo Salar ◽  
Spawning Areas ◽  
Population Sizes ◽  
Standing Waters ◽  
Adult Abundance

Atlantic salmon, Salmo salar, were censused each spring and fall for 5 or 6 yr in two lakes at the headwaters of the Gander River, Newfoundland. Density, biomass, and age varied seasonally and annually, ranging from 5.2 to 78.7 fish∙ha−1, 0.2 to 3.4 kg∙ha−1, and 1 to 7 yr, respectively. Seasonal changes in age composition were used to calculate net numbers and ages of fish moving into and out of the lakes. Population sizes typically increased from fall to spring as young fish moved into the lakes from downstream spawning areas and decreased from spring to fall as older fish moved downstream. The calculated net number of spring to fall emigrants over 6 yr was positively correlated (r = 0.835) with adult abundance (catch per unit effort) in the recreational fishery 1 yr later. The varying modal age of these emigrants was identical to the modal freshwater age of returning adults in each of four comparable years. Censusing of young Atlantic salmon in standing waters can be used to monitor smolt production and assist in prediction of the subsequent abundance of sea-run adults.

Changes in Mean Weight, Sea-Age Composition, and Catch-per-Unit-Effort of Atlantic Salmon (Salmo salar) Angled in the Godbout River, Quebec, 1859–1983

1986 ◽  
Vol 43 (2) ◽  
pp. 281-287 ◽  
Author(s):  
Alex T. Bielak ◽  
Geoffrey Power
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Age Groups ◽  
Fishing Effort ◽  
Commercial Fisheries ◽  
Catch Per Unit Effort ◽  
Age Composition ◽  
Atlantic Salmon Salmo Salar ◽  
The Mean ◽  
Selective Effects

A weight-age classification, based on recent catches, was retroactively applied to angled Atlantic salmon (Salmo salar) catches recorded in the log of the Godbout salmon club between 1859 and 1983. Over this period, numbers of salmon caught have fluctuated with a periodicity of 20–30 yr but catches have been maintained. There has been a big increase in fishing effort, and the proportion of two-sea-year to previously spawned fish has increased. The mean weight of these age groups has declined 0.005–0.009 kg∙yr−1. These changes are attributed to the selective effects of commercial fisheries on the stock.

Relationship of upstream migrating adult Atlantic salmon (Salmo salar) and stream discharge within Catamaran Brook, New Brunswick

2007 ◽  
Vol 64 (3) ◽  
pp. 563-573 ◽  
Author(s):  
Sean C Mitchell ◽  
Richard A Cunjak
Keyword(s):  
Body Size ◽  
Atlantic Salmon ◽  
New Brunswick ◽  
Salmo Salar ◽  
Predictive Ability ◽  
River System ◽  
Low Flow ◽  
Stream Discharge ◽  
Atlantic Salmon Salmo Salar ◽  
Adult Abundance

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.

Effect of Sea-Age on the Reproductive Potential of Atlantic Salmon (Salmo salar) in Eastern Canada

1989 ◽  
Vol 46 (12) ◽  
pp. 2210-2218 ◽  
Author(s):  
R. G. Randall
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Reproductive Potential ◽  
Female Size ◽  
Eastern Canada ◽  
Age Composition ◽  
Atlantic Salmon Salmo Salar ◽  
Egg Deposition ◽  
Different Populations ◽  
Spawning Run

Reproductive potential of Atlantic salmon (Salmo salar), defined as average eggs per fish in the spawning run, varied three-fold both within stocks over time and among stocks from different geographic areas. Eggs per spawner is a function of fecundity, sea-age, proportion of females, and female size; the latter three traits varied significantly among years for salmon in both the Miramichi and Restigouche Rivers, New Brunswick. Because all of the above traits are related to sea-age at maturity, eggs per spawner was significantly correlated with mean sea-age in both rivers (R2 = 0.88 and 0.61, respectively). Among 10 different populations in eastern Canada, reproductive potential was also correlated with sea-age; for mean sea-ages (MSA) ranging from 1.0 to 1.8 yr, reproductive potential (RP) was defined by the power regression: RP = 1831.26 MSA1.30 (R2 = 0.64 P < 0.05). Thus reproductive potential can be estimated for any population for which the sea-age composition of spawners is known. Assuming a target egg deposition rate of 2.4 × 104 eggs per hectare, required spawners varied inversely with reproductive potential among the 10 populations, from five spawners (MSA = 1.75 yr) to 16 spawners (MSA = 1.15 yr) per hectare.

Influence of Sea Temperature upon the Numbers of Grilse and Multi-Sea-Winter Atlantic Salmon (Salmo salar) Caught in the Vicinity of the River Dee (Aberdeenshire)

1985 ◽  
Vol 42 (9) ◽  
pp. 1513-1521 ◽  
Author(s):  
J. H. A. Martin ◽  
K. A. Mitchell
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
The Arctic ◽  
Average Weight ◽  
Regression Equations ◽  
Catch Per Unit Effort ◽  
Data Set ◽  
Sea Temperature ◽  
Atlantic Salmon Salmo Salar ◽  
High Seas

The possible influence of sea temperature upon the age of return of Atlantic salmon (Salmo salar) was examined using the catch and weight data of grilse and multi-sea-winter (MSW) salmon of the Aberdeen Harbour Board caught either within or adjacent to the River Dee (Aberdeenshire). This data set, apart from a 10-yr period of commercial confidentiality, is very suitable because uniformity of effort allowed catch per unit effort to be calculated. Only in the last few years was external pressure (high seas fishing) applied to the system. Various temperature series were examined but the known loci of high seas fishing and the temperature ranges involved suggested that the most relevant series is from the subarctic. Increase in temperature is shown to be associated with larger numbers of fish returning as MSW salmon and fewer as grilse. The average weight of grilse increases with grilse catch numbers. Regression equations for grilse and MSW salmon catch numbers are produced for the period 1877–1972. There is a marked 4-yr periodicity in the grilse catch data. A hypothesis is proposed that the temperature of the subarctic influences the migratory pattern, that fish travel further north into the Arctic/subarctic only during those years when the minimum temperature remains above 2 °C.

Fyke Net Catches as Indices of the Abundance of Brook Trout, Salvelinus fontinalis, and Atlantic Salmon, Salmo salar

1984 ◽  
Vol 41 (2) ◽  
pp. 377-380 ◽  
Author(s):  
P. M. Ryan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Relative Abundance ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Catch Per Unit Effort ◽  
Small Lakes ◽  
Population Densities ◽  
Atlantic Salmon Salmo Salar ◽  
Fyke Nets

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.

Prediction of Angler Success in an Atlantic Salmon, Salmo salar, Fishery Two Fishing Seasons in Advance

1986 ◽  
Vol 43 (12) ◽  
pp. 2531-2534 ◽  
Author(s):  
Patrick M. Ryan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Catch Per Unit Effort ◽  
Atlantic Salmon Salmo Salar ◽  
Unit Effort ◽  
Seaward Migration

The number of young Atlantic salmon, Salmo salar, in the spring in two lakes at the headwaters of the Gander River, Newfoundland, was positively correlated (r = 0.99) with the number of smolts in the subsequent seaward migration over a 5-yr period. Angler success (catch per unit effort) in the grilse fishery on the Gander River over a 7-yr period was positively correlated (r = 0.81) with the number of young in the lakes prior to the opening of the angling season of the previous year. Measures of the abundance of young salmon in freshwaters prior to the smolt run can be used to predict the size of the smolt run and allow for compensatory modifications to the adult fishery a year in advance of acticipated low adult returns.

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