Juvenile coho salmon (Oncorhynchus kisutch) responses to salmon carcasses and in-stream wood manipulations during winter and spring

2007 ◽  
Vol 64 (2) ◽  
pp. 324-335 ◽  
Author(s):  
Guillermo R Giannico ◽  
Scott G Hinch

We investigated the growth rate, winter survival, presmolt size, and emigration timing of juvenile coho salmon (Oncorhynchus kisutch) in response to salmon carcasses and in-stream wood. Experimental trials were conducted during two consecutive years and pre-winter fish size and densities differed between years. Sixteen pens with emigration traps were built in a side-channel of the Mamquam River, British Columbia. Pens were randomly assigned salmon carcasses, in-stream wood, both carcasses and in-stream wood, or neither (control). Our first trial was conducted between December 1996 and August 1997 and the second between December 1997 and August 1998. Initial rearing densities and average individual body mass were 3.1 fish·m–2 and 2.4 g, respectively, in the first trial and were 1.6 fish·m–2 and 6.6 g, respectively, in the second trial. Results were influenced by both fish initial size and density. During the first trial (smaller-sized fish at high densities), salmon carcasses increased fish growth rates and presmolt size. Winter survival did not increase in response to any treatment; however, a pre-winter size-related survival pattern was observed during the first trial. During the second trial, (larger-sized fish at low densities), no treatment influenced fish growth rates or presmolt size but all treatments augmented fish survival.

2006 ◽  
Vol 63 (4) ◽  
pp. 917-930 ◽  
Author(s):  
Dirk W Lang ◽  
Gordon H Reeves ◽  
James D Hall ◽  
Mark S Wipfli

This study examined the influence of fall-spawning coho salmon (Oncorhynchus kisutch) on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon on the Copper River Delta, Alaska, USA. During the fall of 1999 and 2000, fish rearing in beaver ponds that received spawning salmon were compared with fish from ponds that did not receive spawners and also with fish from ponds that were artificially enriched with salmon carcasses and eggs. The response to spawning salmon was variable. In some ponds, fall-spawning salmon increased growth rates and improved the condition of juvenile coho salmon. The enrichment with salmon carcasses and eggs significantly increased growth rates of fish in nonspawning ponds. However, there was little evidence that the short-term growth benefits observed in the fall led to greater overwinter growth or survival to outmigration when compared with fish from the nonspawning ponds. One potential reason for this result may be that nutrients from spawning salmon are widely distributed across the delta because of hydrologic connectivity and hyporheic flows. The relationship among spawning salmon, overwinter growth, and smolt production on the Copper River Delta does not appear to be limited entirely to a simple positive feedback loop.


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.


2012 ◽  
Vol 69 (6) ◽  
pp. 1016-1032 ◽  
Author(s):  
David E. Rupp ◽  
Thomas C. Wainwright ◽  
Peter W. Lawson

Better fisheries management is often given as one justification for research on improving forecasts of fish survival. However, the value gained from expected improvements in forecast skill in terms of achieving management goals is rarely quantified as part of research objectives. Using Monte Carlo simulations of population dynamics, we assessed the effect of forecast skill under two strategies for managing Oregon coast natural (OCN) coho salmon ( Oncorhynchus kisutch ). The first, or status quo, strategy is currently being used to rebuild threatened OCN coho populations. This strategy determines harvest based on both a forecasted marine survival rate and parental spawner abundance. The second strategy relies on a forecast of preharvest adult abundance to achieve a constant spawner escapement target. Performance of the status quo strategy was largely insensitive to forecast skill, while the second strategy showed sensitivity that varied with escapement target and specific performance metric. The results imply that effort towards improving forecasts is not justifiable solely on the basis of improved management under the status quo strategy, though it may be were the management strategy altered.


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.


Aquaculture ◽  
2020 ◽  
Vol 528 ◽  
pp. 735468 ◽  
Author(s):  
Leigh P. Gaffney ◽  
Rosalind A. Leggatt ◽  
Annette F. Muttray ◽  
Dionne Sakhrani ◽  
Carlo A. Biagi ◽  
...  

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.


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.


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.


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