Migration and rearing histories of chinook salmon (Oncorhynchus tshawytscha) determined by ion microprobe Sr isotope and Sr/Ca transects of otoliths

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.


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.



2009 ◽  
Vol 87 (10) ◽  
pp. 920-927 ◽  
Author(s):  
P. Rosengrave ◽  
R. Montgomerie ◽  
V. J. Metcalf ◽  
K. McBride ◽  
N. J. Gemmell

Sperm traits of externally fertilizing fish species are typically measured in fresh (or salt) water, even though the spawning environment of their ova contains ovarian fluid. In this study, we measured sperm traits of Chinook salmon ( Oncorhynchus tshawytscha (Walbaum in Artedi, 1792)) in both fresh water and dilute ovarian fluid at 10 and 20 s postactivation, using a computer-assisted sperm analysis system. Spermatozoa swam faster, and had both higher percent motility and a straighter path trajectory for a longer period of forward motility when activated in ovarian fluid compared with activation in fresh water. Comparing sperm activity of 10 males in water versus ovarian fluid, we found a weak but significant correlation for sperm swimming speed at 10 s postactivation (r = 0.34, p = 0.01), but not for any other sperm traits measured. Most important, across males, mean sperm swimming speed in water accounted for <10% of the observed variation in mean sperm swimming speed in ovarian fluid. Thus, we argue that sperm traits measured in fresh water are not particularly relevant to those same traits during normal spawning in this species. We suggest that sperm performance measured in fresh water should be used with caution when comparing the potential for individual males to fertilize ova, especially in studies of sperm competition in externally fertilizing species.



1993 ◽  
Vol 71 (4) ◽  
pp. 683-688 ◽  
Author(s):  
Nicholas J. Bernier ◽  
Daniel D. Heath ◽  
David J. Randall ◽  
George K. Iwama

Precocious sexual maturation in salmonid parr occurs under both wild and culture conditions. We investigated the possibility of repeat maturation in precocious chinook salmon parr from the Nicola River, British Columbia. Precocious and immature (control) yearling parr were reared in fresh water from March 1990 to mid-June, and then transferred to salt water (29–30 ppt) until September 1990. The precocious parr were significantly larger than the controls from March to July and there were no differences in relative growth rate between the groups throughout the study. Total mortalities were 45.7 and 5.9% for precocious and control fish, respectively. All of the precocious, but none of the control fish, produced milt in March in fresh water. None of the fish produced milt soon after the transfer to salt water in June, but all precocious fish and 18.8% of the controls produced milt in September. There were no significant differences in the average plasma concentrations of Na+, Cl−, and cortisol between groups in September, suggesting that both precocious parr and control groups were saltwater competent. These data demonstrate that male precocious chinook salmon parr have the physiological capability to mature more than once in seawater.



2003 ◽  
Vol 60 (8) ◽  
pp. 910-918 ◽  
Author(s):  
Carol Seals Price ◽  
Carl B Schreck

Two experiments were conducted to determine the effects of a mild or severe stressor on the saltwater preference of juvenile spring chinook salmon (Oncorhynchus tshawytscha). To observe the response of fish to an overhead threat, we presented stressed fish with an avian predator model in the second experiment. Experiments were conducted in 757-L tanks containing a stable vertical salinity gradient. Only 69% of fish stressed by being chased for 2 min before saltwater introduction (mild stressor) held in salt water, whereas 95% of unchased control fish preferred the saltwater layer. After the more severe handling and confinement stressor, only 20% of fish entered and remained in salt water compared with 100% of unstressed controls. After the presentation of the avian model, stressed fish holding in fresh water moved into the saltwater layer, but this behavioral response was transient. Fish began returning to fresh water within 10 min, and after 1 h, only 26% of stressed fish remained in the saltwater layer. Stress significantly decreases the saltwater preference of chinook salmon that would otherwise select full-strength salt water and may affect behavior in the estuary. Although smoltification primes these fish for seawater residence, stress apparently induced a conflicting physiological motivation.



1983 ◽  
Vol 40 (3) ◽  
pp. 287-297 ◽  
Author(s):  
Karl K. English

Juvenile chinook salmon, Oncorhynchus tshawytscha, were raised in 90-m3 mesh enclosures in Saanich Inlet, B.C. The enclosures permitted ample water and zooplankton circulation while retaining 5–6 g juvenile salmon. Mean growth rate was 1.8% wet body weight/d over 6 wk. Weekly growth rates ranged from 3.9%/d while food was abundant, to −0.5%/d when food was scarce. Zooplankton concentration inside and outside enclosures without fish were not significantly different. Organisms associated with the sides of the enclosures (non-pelagic) were not a major contributor to the growth of the juvenile chinook. There was a strong relationship between the fish growth rates and the abundance of 1.4- to 4.5-mm zooplankton. Rates of successful search varied directly with the size and inherent contrast of a prey item. The minimum rate of successful search was 2.3 m3/h for salmon feeding on 1.4- to 4.5-mm zooplankton. This rate of successful search, while far greater than previously suspected, is still within the visual capabilities of the juvenile salmon. The enclosed salmon grew rapidly on zooplankton concentrations that were 1/1000 of those required to sustain similar growth rates in tank experiments.Key words: predator–prey relationship, planktivorous salmonid, marine, "in situ" enclosures, search efficiency



2021 ◽  
Vol 78 (1) ◽  
pp. 68-77
Author(s):  
Catherine S. Austin ◽  
Timothy E. Essington ◽  
Thomas P. Quinn

Median timing of reproduction in salmonid populations is generally consistent among years, reflecting long-term patterns of natural selection from characteristics of the local environment. However, altered selection from factors related to climate change or human intervention might shift timing over generations, with implications for the population’s persistence. To study these processes, we modeled median timing of redd (nest) counts as an index of spawning timing by natural-origin Chinook salmon (Oncorhynchus tshawytscha) in the Skagit River system in Washington State, USA. Over the last 2–6 decades, natural-origin salmon have been spawning later by 0.03–0.52 days·year–1, while a naturally spawning group that is influenced by strays from a hatchery has been spawning earlier by 0.19 days·year–1. Trends in the spawning timing of hatchery-origin strays may reflect opposing selection from the hatchery, where egg take for propagation has become earlier by 0.58 days·year–1. As mean August river temperatures have risen over the period of record, hatchery timing trends may be moving in the opposite direction from the plastic or adaptive patterns expressed by natural-origin fish.



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


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.



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