Growth of Juvenile Coho Salmon (Oncorhynchus kisutch) off Oregon and Washington, USA, in Years of Differing Coastal Upwelling

1988 ◽  
Vol 45 (6) ◽  
pp. 1036-1044 ◽  
Author(s):  
J. P. Fisher ◽  
W. G. Pearcy

Estimated growth rates, condition, and stomach fullness of juvenile coho salmon (Oncorhynchus kisutch) caught in the ocean in early summer, when mortality was most variable, were as high in 1983 and 1984, years of very low survival and low early upwelling, as in 1981, 1982, and 1985, years of higher survival and higher early upwelling. Chronic food shortage leading to starvation, poor condition, or slow growth apparently was not the cause of the increased mortality of juvenile coho salmon in 1983 and 1984. Survival of juvenile coho salmon was positively correlated with purse seine catches of fish in June and with early summer upwelling, 1981–85. Hence, year-class success probably was determined early in the summer, soon after most juvenile coho salmon entered the ocean. Spacing of the first five ocean circuli, which was positively correlated with growth rate, was not significantly different for fish caught early in the summer and those caught late in the summer, suggesting that growth rate selective mortality in the ocean was not strong. The increase in mortality in 1983 and 1984 may have been caused by increased predation on juvenile coho salmon due to decreased numbers of alternative prey for predators.

1997 ◽  
Vol 75 (2) ◽  
pp. 335-337 ◽  
Author(s):  
Anthony P. Farrell ◽  
William Bennett ◽  
Robert H. Devlin

We examined the consequence of remarkably fast growth rates in transgenic fish, using swimming performance as a physiological fitness variable. Substantially faster growth rates were achieved by the insertion of an "all-salmon" growth hormone gene construct in transgenic coho salmon (Oncorhynchus kisutch). On an absolute speed basis, transgenic fish swam no faster at their critical swimming speed than smaller non-transgenic controls, and much slower than older non-transgenic controls of the same size. Thus, we find a marked trade-off between growth rate and swimming performance, and these results suggest that transgenic fish may be an excellent model to evaluate existing ideas regarding physiological design.


1984 ◽  
Vol 41 (7) ◽  
pp. 1097-1105 ◽  
Author(s):  
J. C. Scrivener ◽  
B. C. Andersen

Natural patterns in emergence times, seaward movements, instream distributions, densities, and growth of coho salmon fry (Oncorhynchus kisutch) between March and September are contrasted with patterns observed during and after logging in the Carnation Creek watershed. After streamside logging in 1976–77, fry emerged up to 6 wk earlier and moved seaward more quickly than during years before logging. These observations are attributed to higher water temperatures during the winter and to emergence during a period of more frequent freshets. Increased fry movement from the stream could result in habitat being underutilized. In sections affected by intense streamside logging, the deposition of "fine" logging debris led to increased fry densities during the summers of 1977 and 1978. After major freshets in November 1978, which removed this fine debris and affected channel morphology in these sections, fry densities declined below those observed prior to logging. Growth rate of fry was inversely correlated with density in all stream sections. Growth rates, after correction for density, tended to be greater in all sections after the adjacent streamside was logged. Larger fry and more variable numbers of fry remained in the stream in September after logging than before logging. Their increased size is attributed to the longer growing season afforded by earlier emergence. This complex of interacting factors determines the number and size of fry in autumn and it can influence the production of smolts the following spring.


1987 ◽  
Vol 129 (1) ◽  
pp. 165-178
Author(s):  
K. J. Farbridge ◽  
J. F. Leatherland

Coho salmon (Oncorhynchus kisutch Walbaum) parrs and smolts, maintained in a laboratory under a fixed artificial 12 h light:12 h dark photoperiod from the time of hatching, exhibited a pattern of alternating periods of rapid and slow growth in body mass; the peaks and troughs in growth rate were significantly different from one another. The alternating growth rate changes were rhythmic in nature, of approximately 14 to 15 days in length. Evidence for cyclic patterns of growth in relative length and in food consumption was also found in coho salmon parr. Peak food intake appeared to occur 2–4 days after each peak of growth in relative mass. Although the pattern of growth in relative length was less clear, there was evidence to suggest that growth in length might be out of phase with growth in mass. There was no pattern of cycling growth rates in coho salmon parr subsampled from a common stock. The significance of this is discussed. The data suggest that the lunar cycle acts as a Zeitgeber for synchronization of the growth rate rhythms.


1979 ◽  
Vol 36 (12) ◽  
pp. 1497-1502 ◽  
Author(s):  
L. J. Buckley

The protein, DNA, and RNA content of larvae maintained at 1.0 plankter/mL increased at the rates of 9.3, 9.9, and 9.8% per day, respectively, for the 5 wk after hatching. Protein reserves of larvae held at 0 or 0.2 plankters/mL were depleted by 45 and 35%, respectively, prior to death 12–13 d after hatching. Starved larvae had similar protein concentrations (percent of dry weight), lower RNA concentrations, and higher DNA concentrations than fed larvae. Larvae held at higher plankton densities had higher RNA–DNA ratios and faster growth rates than larvae held at lower plankton densities. The RNA–DNA ratio was significantly correlated (P < 0.01) with the protein growth rate. The RNA–DNA ratio appears to be a useful index of nutritional status in larval Atlantic cod (Gadus morhua) and may be useful for determining if cod larvae were in a period of rapid or slow growth at the time of capture. Key words: RNA–DNA ratio, starvation, protein, nucleic acids, growth, larval fish, Atlantic cod


1976 ◽  
Vol 33 (7) ◽  
pp. 1585-1603 ◽  
Author(s):  
David A. Higgs ◽  
Edward M. Donaldson ◽  
Helen M. Dye ◽  
J. R. McBride

Groups of underyearling coho salmon (Oncorhynchus kisutch) were acclimated to 10 C well water and a photoperiod of 12 h L:12 h D. Excess ration (Oregon Moist Pellet) was presented daily. Doses of bovine growth hormone (5, 10, 20, 30, or 90 μg bGH/g body wt) and L-thyroxine (0.5, 5, or 30 μg T4/g) were administered over a period of 84 days (phase I) either by injection (via dorsal musculature or peritoneal cavity) or by hormone cholesterol implants into the muscle. Administration frequency of bGH and T4 was such (range 2 times/wk-1 time/3 wk) that fish theoretically received either 10 or 30 μg bGH/g per wk or 1 or 10 μg T4/g per wk. Control fish received either alkaline saline (pH 9.5) or a cholesterol pellet. After cessation of treatment the fish were observed for an additional 84 days (phase II). During phase I, growth rates (weight) for bGH fish (2.0–2.4% per day) and for T4 fish (0.97–1.1% per day) were significantly higher than those of control fish (0.42–0.59% per day). Among bGH fish, dorsal musculature injection (2 times/wk) was significantly more effective than intraperitoneal injection (1 time/2 wk).Increases in weight above control for bGH fish at 84 days ranged from 220 to 369%. Those for T4 fish extended from 47 to 78%. In phase II, control fish growth rates were higher (0.61–0.67% per day) than those for bGH fish (0.47–0.57% per day) and T4 fish (0.32–0.44% per day). Administration of bGH and T4 (high dose) caused a progressive decline in condition factor of fish from the control range. This trend was stopped and reversed in phase II.At 84 days, generally no significant differences were detected among groups for percentages of muscle water. However, some groups had significantly higher (bGH) and others lower (T4) percentages of muscle protein relative to those of control fish. Also, significant increases (T4) and decreases (bGH) in muscle lipid percentages were found. Hormone treatment altered the histological structure of the ovary, thyroid, exocrine (T4) and endocrine (bGH) pancreas, and somatotrop cells (T4) of the pituitary. A poor growth response was noted for two groups of coho administered bGH after acclimation to sea water.


1996 ◽  
Vol 42 (141) ◽  
pp. 255-260 ◽  
Author(s):  
R. B Alley ◽  
G. A. Woods

AbstractIntercept analysis of approximately bi-yearly vertical thin sections from the upper part of the GISP2 ice Core, central Greenland, shows that grain-size ranges increase with increasing age. This demonstrates that something in the ice affects grain-growth rates, and that grain-size cannot be used directly in paleothermometry as has been proposed. Correlation of grain-growth rates to chemical and isotopic data indicates slower growth in ice with higher impurity concentrations, and especially slow growth in “forest-fire” layers containing abundant ammonium; however, the impurity/grain-growth relations are quite noisy. Little correlation is found between growth rate and isotopic composition of ice.


Evolution ◽  
2005 ◽  
Vol 59 (7) ◽  
pp. 1560 ◽  
Author(s):  
L. Fredrik Sundström ◽  
Mare Lõhmus ◽  
Robert H. Devlin

2005 ◽  
Vol 62 (11) ◽  
pp. 2538-2547 ◽  
Author(s):  
Erin K McClelland ◽  
James M Myers ◽  
Jeffrey J Hard ◽  
Linda K Park ◽  
Kerry A Naish

Outbreeding is a potential genetic risk in Pacific salmon (Oncorhynchus spp.) when aquaculture practices introduce nonnative domesticated fish to wild environments, making interbreeding with wild populations possible. In this study, F1 and F2 hybrid families of coho salmon (Oncorhynchus kisutch) were created using a captive freshwater aquaculture strain and a locally derived hatchery population that is integrated with naturally spawning fish. Intermediate growth was detected in F1 and F2 hybrids from crosses reared in captivity; both generations had mean weight and length values between those of the parent populations after their first year (p < 0.05). In the early life history stages, maternal effects increased alevin growth in progeny of hatchery dams relative to those of captive dams (p < 0.001). Aquaculture control families showed greater growth rates than hybrids in late summer of their 1st year and in the following spring (p < 0.05), while the hatchery controls had lower growth rates during the first summer (p < 0.05). Line cross analysis indicated that changes in additive and dominance interactions, but not unfavorable epistatic interactions, likely explain the differences in weight, length, and growth rate observed in hybrids of these stocks of coho salmon.


1998 ◽  
Vol 180 (7) ◽  
pp. 1970-1972 ◽  
Author(s):  
Bradley S. Stevenson ◽  
Thomas M. Schmidt

ABSTRACT Inadequate regulation of the expression of additional plasmid-borne rRNA operons in Escherichia coli was exaggerated at slow growth rates, resulting in increases of approximately 100% for RNA concentration and 33% for doubling time. These observations are consistent with the hypothesis that multiple rRNA operons constitute a metabolic burden at slow growth rates.


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