Comparisons of the Index of Return for Several Stocks of British Columbia Salmon to Study Variations in Survival

1958 ◽  
Vol 15 (5) ◽  
pp. 891-908 ◽  
Author(s):  
H. Godfrey

The "index of return" (ratio of offspring catch to parent catch) was used to compare annual survival among several stocks of British Columbia salmon. Over a period of almost 30 years the major stocks of pink salmon in the Province, excepting those of the Fraser River, exhibited quite similar annual variations in survival. The Fraser River stock behaved somewhat independently of the other stocks. There are indications that among pink salmon early ocean survival, probably during residence in estuarial and inshore waters, has played a major role in determining the level of final ocean survival. Among pink and sockeye salmon that entered the sea in the same year there is some similarity in early ocean survival. The latter relationship, if confirmed, may become useful for predicting sockeye ocean survival one or two years before the adult fish return.

1960 ◽  
Vol 17 (3) ◽  
pp. 347-351 ◽  
Author(s):  
J. D. Wood ◽  
D. W. Duncan ◽  
M. Jackson

During the first 250 miles (400 km) of spawning migration of Fraser River sockeye salmon (Oncorhynchus nerka) the free histidine content of the muscle, alimentary tract, and head+skin+bones+tail decreased to a small fraction of the initial value. A further decrease occurred in the levels of this amino acid in the alimentary tract during the subsequent 415-mile (657-km) migration to the spawning grounds, no change being observed with the other tissues. Comparatively small changes in free histidine were found with heart, spleen, liver, kidney and gonads during migration.


2004 ◽  
Vol 133 (6) ◽  
pp. 1396-1412 ◽  
Author(s):  
R. J. Beamish ◽  
J. T. Schnute ◽  
A. J. Cass ◽  
C. M. Neville ◽  
R. M. Sweeting

2000 ◽  
Vol 203 (7) ◽  
pp. 1161-1172 ◽  
Author(s):  
I. Novales Flamarique

This study examines the spectral sensitivity and cone topography of the sockeye salmon Oncorhynchus nerka throughout its life history with special emphasis on ultraviolet sensitivity. Electrophysiological recordings from the optic nerve show that ultraviolet sensitivity is greatly diminished at the smolt stage but reappears in adult fish weighing about 201 g. Concomitantly, light microscopy observations of the retina show that ultraviolet cones disappear from the dorsal and temporal retina at the smolt stage but reappear at the adult stage. These changes occur for sockeye salmon raised in fresh water or salt water after smoltification. In contrast to this ultraviolet cycle, the other cone mechanisms (short-, middle- and long-wavelength-sensitive) and the rod mechanism remain present throughout ontogeny. The natural appearance and disappearance of ultraviolet cones in salmonid retinas follows surges in blood thyroxine at critical developmental periods. Their presence coincides with times of prominent feeding on zooplankton and/or small fish that may be more visible under ultraviolet light. It is proposed that the primary function of ultraviolet cones in salmonids is to improve prey contrast.


1969 ◽  
Vol 26 (5) ◽  
pp. 1363-1368 ◽  
Author(s):  
David W. Narver

Although Owikeno Lake is the third highest producer of adult sockeye salmon in North America in terms of mean annual total return (catch plus escapement) per unit of lake nursery area, limited measurements of other indices of lake productivity suggest that its primary productivity is much lower than that of the other four highest sockeye-producing lakes. The implications of these results to sockeye production are discussed.


2009 ◽  
Vol 87 (6) ◽  
pp. 480-490 ◽  
Author(s):  
M. R. Donaldson ◽  
S. J. Cooke ◽  
D. A. Patterson ◽  
S. G. Hinch ◽  
D. Robichaud ◽  
...  

The objective of this study was to combine radio telemetry with individual thermal loggers to assess the extent to which adult migrating sockeye salmon ( Oncorhynchus nerka (Walbaum in Artedi, 1792)) behaviourally thermoregulate during their migration through the Fraser River mainstem, British Columbia. The Fraser mainstem represents a region of the migration route that contains some of the highest mean temperatures encountered by sockeye salmon during their life history. We found that throughout the study area, individual sockeye salmon body temperatures occasionally deviated from ambient temperatures (ΔT), yet individuals maintained a ΔT of –1 °C or cooler for only 5% of their migration through the study region. There were moderate mean deviations of ΔT in two segments that are known to contain thermally stratified waters. In one of the study segments with the greatest ΔT, mean body temperatures decreased as river temperatures increased and ΔT became increasingly positive with higher river discharge rates, but these relationships were not observed in any of the other study segments. No relationship existed between ΔT and migration rate. While periodic associations with cool water were evident, mean body temperatures were not significantly different than mean river temperatures throughout the lower Fraser mainstem. This finding raises further conservation concerns for vulnerable Fraser River sockeye stocks that are predicted to encounter increasing peak summer river temperatures in the coming decades.


2016 ◽  
Vol 145 (2) ◽  
pp. 348-362 ◽  
Author(s):  
Richard J. Beamish ◽  
Chrys M. Neville ◽  
Ruston M. Sweeting ◽  
Terry D. Beacham ◽  
Joy Wade ◽  
...  

1994 ◽  
Vol 51 (9) ◽  
pp. 2115-2125 ◽  
Author(s):  
Timothy L. McDaniels ◽  
Michael Healey ◽  
Richard Kyle Paisley

In 1991, a substantial program of cooperative salmon fishery management involving First Nations was initiated in British Columbia. This paper considers how ongoing cooperative management initiatives in this fishery could be designed and implemented. The process discussed in the paper could be viewed as an adaptive management experiment in institutional design for cooperative management. First, sets of fundamental objectives for cooperative management and strategies for achieving these objectives are developed. The methods for structuring objectives and developing strategies are drawn from decision analysis practice. Then the actual experience in implementing a version of one of the strategies during the 1992 Fraser River sockeye salmon First Nations fishery is discussed. The highly publicized and controversial events of the 1992 season are instructive about how cooperative management should be implemented in other contexts.


2012 ◽  
Vol 69 (5) ◽  
pp. 970-982 ◽  
Author(s):  
G.R. Pess ◽  
R. Hilborn ◽  
K. Kloehn ◽  
T.P. Quinn

When barriers are removed, what biotic and abiotic factors determine how fish populations will colonize newly available habitats? We used counts of adult pink salmon ( Oncorhywnchus gorbuscha ) from 1947 to 1987 in 66 streams of the Fraser River system, British Columbia, Canada, to determine when colonizing pink salmon populations became self-sustaining after a long-term migration blockage at Hell’s Gate (river kilometre 209) was reduced. The abundance of salmon in available habitats were largely controlled by extrinsic factors such as an initially large source population, high intrinsic growth rates linked to favorable climate-driven conditions, a constant supply of dispersers, and large amounts of newly available habitat. Temporal variation in flows at Hell’s Gate also affected recolonization success. Self-sustaining populations were developed within years of barrier removal and have continued to help expand the overall population of Fraser River pink salmon. However, pink salmon were considerably more abundant in the early 1900s than in the 1980s (∼48 million vs. ∼2.7 million), and the majority of spawning shifted from the historic areas above Hell’s Gate prior to the rockslide to below Hell’s Gate in the lower Fraser River after the long-term blockage was reduced, so the system has not returned to the former abundance and distribution patterns.


2014 ◽  
Vol 7 (1) ◽  
pp. 23-28
Author(s):  
Robert Brouwer ◽  
Amanda Ross ◽  
Ian Trepanier ◽  
Ronald W. Tanasichuk

We compared: 1) rearing mortality, 2) size at release (mean length), 3) jack, male and female sizes, and 4) jack, female, and adult returns of coho salmon (Oncorhynchus kisutch) from three consecutive brood years reared at the Nitinat River hatchery using a conventional or a semi-natural rearing method. The semi-natural method included feeding restrictions, shading of the rearing ponds, lower rearing temperature and rearing densities, exposure to a predator and a volitional release. We found no significant effects of brood year or rearing method on rearing mortality; it was significantly lower during the marking to release phase than during the other two phases (eyed-egg to ponding, ponding to marking). Conventionally reared smolts were significantly longer. Conventionally reared males were longer. As a proportion of number of smolts released, semi-natural rearing produced 86% fewer jacks, the same proportion of females and 15% more adults. Adult production trends, described as marine survival rate (returning adults • smolt-1) for Nitinat River Hatchery coho, and as ln recruits • female spawner-1 for a nearby wild coho population, were similar. Jacking rates were lower in Nitinat River hatchery coho than for the nearby wild coho population. We concluded that the semi-natural rearing methodology produces adult fish more efficiently than the conventional rearing method does, and at 73% of the cost.


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