A Field Experiment to Test the Importance of Estuaries for Chinook Salmon (Oncorhynchus tshawytscha) Survival: Short-Term Results

1988 ◽  
Vol 45 (8) ◽  
pp. 1366-1377 ◽  
Author(s):  
J. Stevenson Macdonald ◽  
Colin D. Levings ◽  
Carey D. McAllister ◽  
U. H. M. Fagerlund ◽  
J. R. McBride

In late April of 1983, 1984, and 1985, 140 000 marked chinook salmon (Oncorhynchus tshawytscha) smolts (2–4 g) were transported by helicopter from Quinsam Hatchery to four release sites near Campbell River, B.C. (river, estuarine, transition, and marine), in an experiment to test the importance of estuarine residency to chinook survival. At the marine site, fish were released directly into seawater. These fish had high cortisol levels and larger interrenal nuclear diameters than those at the estuarine site, indicating a transitory stress response to seawater exposure. Nevertheless, there was little direct mortality due to stress or osmoregulatory shock at any of the release sites. Marine-released fish were exposed to more bird and fish predators. Mortality of caged chinook was higher at the marine location than at all other sites despite seawater challenge tests indicating that the chinook were smolted and "ready for sea." Beach seine data obtained biweekly for 4 mo after the releases showed that fish released directly into marine waters rarely dispersed to the Campbell River estuary. Fish released immediately adjacent to the mouth of the estuary (transition zone) had the widest immediate dispersal pattern, with many of them returning to the estuary. Estuarine zone fish displayed the most restricted distribution. Fish released to the river and estuary remained in the sampling area for a longer period (34–47 d) than those released in the marine or transition zone (20–23 d).

1986 ◽  
Vol 43 (7) ◽  
pp. 1386-1397 ◽  
Author(s):  
C. D. Levings ◽  
C. D. McAllister ◽  
B. D. Chang

From March 1982 to December 1983, juvenile chinook salmon (Oncorhynchus tshawytscha) were sampled by beach-seine in the Campbell River estuary and adjacent waters of Discovery Passage in order to examine estuarine use by wild and hatchery stocks. Wild juvenile chinook entered the estuary as migrant fry and were present in the estuarine zone mainly in late April to June, in the transition zone in mid-May to July, and in the marine zone in July. Hatchery fish were released from early May to early July. Maximum catches of wild stocks were similar in the estuarine and transition zones, while the maximum catches of most hatchery stocks were higher in the transition zone. For both wild and hatchery chinook, catches in the marine zone were much lower than in the estuarine and transition zones. Wild fry resided in the estuary for 40–60 d, while most hatchery fish used the estuary for about one-half this period. Wild stocks showed a relatively constant rate of increase in mean size from May to September. Higher rates of increase in the mean size of hatchery fish were shown by groups with earlier release dates and smaller mean sizes. Residency time and growth rates for wild fish were comparable with those observed in an estuary without hatchery fish. Potential for interaction between wild and hatchery stocks was greatest in the transition zone, where hatchery fish were most abundant and because hatchery releases occurred when catches of wild fish were highest in this foreshore area.


1987 ◽  
Vol 44 (6) ◽  
pp. 1233-1246 ◽  
Author(s):  
J. Stevenson Macdonald ◽  
I. K. Birtwell ◽  
G. M. Kruzynski

Salmonid behaviour and abundance in several microhabitats within the Campbell River estuary was observed monthly, from May to July, by divers using snorkels and face masks. Concurrent vertical profiles of physical and biological parameters at each microhabitat were taken to characterize habitats frequented by the fish. Data were collected at high and low tide to record behavioural reactions to changes in water velocity, salinity, and temperature associated with tidal height and salt wedge intrusion. Samples of plankton collected at each microhabitat were compared with stomach contents of salmonids caught nearby to determine if interspecific differences in diet could be correlated with differences in the habitats they occupied. Fish occurred in loose assemblages, aligned with the current, feeding near estuarine banks. As water velocities increased with the ebbing tide, the fish concentrated in a shear region near the mouth of a slough and behind large rocks and submerged vegetation. At both high and low tide, larger coho (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus tshawytscha) (usually hatchery reared) were in deeper, frequently more saline water and further from shore than the smaller conspecifics. Hatchery chinook, however, were also seen in sloughs where water velocity was low. Marine influence as reflected in plankton composition and salmonid diet was greater in the outer estuary and in the deep salt water that intrudes the inner regions of the estuary. Differences in the habitats occupied by the fish were reflected in differences in their diets.


2013 ◽  
Vol 97 (6) ◽  
pp. 731-740 ◽  
Author(s):  
Thomas P. Quinn ◽  
J. Anne Shaffer ◽  
Justin Brown ◽  
Nicole Harris ◽  
Chris Byrnes ◽  
...  

2010 ◽  
Vol 67 (3) ◽  
pp. 524-533 ◽  
Author(s):  
David K. Hering ◽  
Daniel L. Bottom ◽  
Earl F. Prentice ◽  
Kim K. Jones ◽  
Ian A. Fleming

A novel application of full-duplex passive integrated transponder (PIT) tag technology was used to investigate movements of individual subyearling Chinook salmon ( Oncorhynchus tshawytscha ; fork length ≥ 60 mm) into and out of tidally flooded salt marsh habitat in the Salmon River estuary, Oregon, USA. PIT interrogation was effective, with mean tag detection ≥ 92%. Salmon movement peaked late during both flood and ebb tide periods, indicating that salmon did not drift passively. Most movements were in the direction of tidal currents, but 20% of individuals entered the channel against the ebbing tide. Individuals occupied the intertidal channel for a median 4.9 h and as long as 8.9 h per tidal cycle, and few were detected moving when water depth was <0.4 m. Some individuals used the channel on multiple successive tidal cycles, and others entered intermittently over periods of up to 109 days. Using an individual-based approach, we characterized diversity of juvenile Chinook salmon behavior within a marsh channel, providing insight into the value of such habitats for conservation and restoration of salmon populations.


1986 ◽  
Vol 43 (3) ◽  
pp. 565-573 ◽  
Author(s):  
Eric B. Taylor ◽  
P. A. Larkin

In Slim Creek, a tributary to the upper Fraser River east of Prince George, B.C., chinook salmon (Oncorhynchus tshawytscha) fry summer and overwinter in their natal stream before migrating seaward as yearlings; they are "stream-type" in juvenile life history pattern. From the Harrison River, a tributary to the lower Fraser River, chinook fry migrate to the Fraser River estuary sometime during their first spring or early summer; they are "ocean-type." Newly emerged chinook fry from Slim Creek showed a stronger positive current response, were more aggressive in mirror image stimulation tests and intra- and inter-specific (with coho salmon (O. kisutch) fry) stream tank tests, and had larger and more brightly colored median fins than chinook fry from the Harrison River. These differences between Slim Creek and Harrison River chinook fry are in a direction consistent with their different patterns of length of freshwater residence as juveniles, since aggressive behavior, positive rheotaxis, and bright fin coloration are important components of extended stream residence in salmonids.


1982 ◽  
Vol 39 (2) ◽  
pp. 270-276 ◽  
Author(s):  
D. A. Levy ◽  
T. G. Northcote

Large numbers of juvenile chinook salmon (Oncorhynchus tshawytscha), chum salmon (O. keta), and pink salmon (O. gorbuscha) were present within tidal channels of a marsh area in the Fraser Estuary between March and June 1978. The tidal channels investigated dewatered at low tide, necessitating daily emigrations by juvenile salmon out of the channels. While pink fry emigrated from tidal channels at the early and middle stages of ebbing tides, most chum and chinook fry emigrated near the later stages of ebbing tides. Mark–recapture studies demonstrated that chinook and chum fry resided temporarily in the marsh prior to migrating into the Pacific Ocean and returned to the same channel on several tidal cycles. Pink fry were abundant in the channels, but appeared to be transient. Chinook and chum showed an increase in average length which was attributable to estuarine growth.Key words: chinook salmon, chum salmon, pink salmon, juvenile residency, marsh tidal channel, Fraser Estuary, estuary growth


2013 ◽  
Vol 70 (4) ◽  
pp. 617-629 ◽  
Author(s):  
Jessica A. Miller ◽  
David J. Teel ◽  
Antonio Baptista ◽  
Cheryl A. Morgan

We evaluated the relative importance of “bottom-up” (production-limited) and “top-down” (predator-mediated) processes during early marine residence in a population of Chinook salmon (Oncorhynchus tshawytscha) from the upper Columbia River, USA. We examined length, mass, and condition index of age-0 juveniles collected in the ocean during June and September across 11 years in relation to conditions in the river, estuary, and coastal ocean and to future adult returns. Characteristics of juveniles in September, but not June, were related to adult returns. During years when coastal waters were relatively cool and productive, juveniles captured in September displayed relatively low condition and reduced otolith growth compared with years when coastal waters were relatively warm and unproductive; this contrast indicates that top-down effects such as selective mortality or competition are important during early marine residence. Key physical (river plume volume during emigration) and biological (condition) variables and their interaction accounted for >95% of the variation in adult returns. Future research should focus on evaluating predators and competitors and understanding how river plume structure influences survival.


2010 ◽  
Vol 67 (10) ◽  
pp. 1671-1684 ◽  
Author(s):  
Michela Burla ◽  
António M. Baptista ◽  
Edmundo Casillas ◽  
John G.  Williams ◽  
Douglas M.  Marsh

Are smolt-to-adult return rates (SARs) for wild steelhead (i.e., sea-run rainbow trout, Oncorhynchus mykiss ) and wild Snake River spring–summer Chinook salmon ( Oncorhynchus tshawytscha ) related to changes in the Columbia River plume at the time that juvenile migrants enter the ocean? We used three-dimensional (3D) numerical models of the baroclinic circulation in the Columbia River estuary–plume–shelf system to simulate within-season variation in plume size and location, comparing the results with SARs for each day that juvenile salmon entered the ocean for 1999–2003. We found that steelhead benefited from the plume environment at a narrow window of time around their ocean entry. However, when large-scale ocean conditions turned unfavorable, the contribution of local plume conditions to the overall variability in steelhead survival became not significant. A similar evaluation revealed that the plume did not affect survival of Chinook salmon, at least at the fine scale of variability considered. The differential response between the two species is consistent with observed and previously reported behavioral characteristics they exhibit. We speculate that steelhead mainly use the plume to move quickly away from coastal habitats and the predation pressures associated with this environment, for a more direct migration than Chinook salmon to ocean habitats in the Gulf of Alaska.


2004 ◽  
Vol 61 (12) ◽  
pp. 2425-2439 ◽  
Author(s):  
Charles R Bacon ◽  
Peter K Weber ◽  
Kimberly A Larsen ◽  
Reginald Reisenbichler ◽  
John A Fitzpatrick ◽  
...  

Strontium isotope and Sr/Ca ratios measured in situ by ion microprobe along radial transects of otoliths of juvenile chinook salmon (Oncorhynchus tshawytscha) vary between watersheds with contrasting geology. Otoliths from ocean-type chinook from Skagit River estuary, Washington, had prehatch regions with 87Sr/86Sr ratios of ~0.709, suggesting a maternally inherited marine signature, extensive fresh water growth zones with 87Sr/86Sr ratios similar to those of the Skagit River at ~0.705, and marine-like 87Sr/86Sr ratios near their edges. Otoliths from stream-type chinook from central Idaho had prehatch 87Sr/86Sr ratios ≥0.711, indicating that a maternal marine Sr isotopic signature is not preserved after the ~1000- to 1400-km migration from the Pacific Ocean. 87Sr/86Sr ratios in the outer portions of otoliths from these Idaho juveniles were similar to those of their respective streams (~0.708–0.722). For Skagit juveniles, fresh water growth was marked by small decreases in otolith Sr/Ca, with increases in Sr/Ca corresponding to increases in 87Sr/86Sr with migration into salt water. Otoliths of Idaho fish had Sr/Ca radial variation patterns that record seasonal fluctuation in ambient water Sr/Ca ratios. The ion microprobe's ability to measure both 87Sr/86Sr and Sr/Ca ratios of otoliths at high spatial resolution in situ provides a new tool for studies of fish rearing and migration.


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