Recent Changes in Stock Composition of Atlantic Salmon (Salmo salar) in the Miramichi River, New Brunswick

1973 ◽  
Vol 30 (6) ◽  
pp. 779-786 ◽  
Author(s):  
C. P. Ruggles ◽  
G. E. Turner

Data collected from 1954 to 1971 show that the recent decline in Miramichi River Atlantic salmon (Salmo salar) abundance has been accompanied by changes in the ratio of grilse to large salmon (2-sea-years and older) entering the river. From 1954 to 1962 trap samples were composed of about equal numbers of grilse and large salmon. Since 1963 the grilse catch has averaged 87%. Large declines in abundance of the fall-run grilse portion of the spawning stock occurred in 1968 and similar declines occurred in the fall-run large salmon component in 1969. An increase in commercial fishing mortality of large salmon is believed responsible for shifting the river escapement in favor of grilse. The result has been a reduction in reproductive potential and declines in the fall-run stocks of both large salmon and grilse.

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.


1989 ◽  
Vol 46 (12) ◽  
pp. 2210-2218 ◽  
Author(s):  
R. G. Randall

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.


1989 ◽  
Vol 46 (4) ◽  
pp. 714-719 ◽  
Author(s):  
J. R. Foster ◽  
C. B. Schom

Experiments were conducted to determine if a process similar to imprinting occurs during each seaward migration of Atlantic Salmon (Salmo salar). Displaced Atlantic salmon kelts homed to the site from which they had previously emigrated to sea as smolts (Big Salmon River, New Brunswick, Canada) and did not home to their release sites, or their overwintering sites 150 km away. Delaying release of kelts past the time of normal seaward migration did not cause the behavioral changes associated with interference of the imprinting process described for smolts. Delayed release kelts did not remain near their seawater or estuarine release sites, home to their release sites, or non-selectively home to suitable spawning streams near their release sites. Delayed released kelts travelled away from the release site faster than kelts released during their normal time of seaward migration, but they did not return either to Passamaquoddy Bay or their natal stream in the calendar year of their release (the normal time for this stock) or in subsequent years.


Sign in / Sign up

Export Citation Format

Share Document