The influence of hatchery coho salmon (Oncorhynchus kisutch) on the productivity of wild coho salmon populations in Oregon coastal basins

2003 ◽  
Vol 60 (9) ◽  
pp. 1050-1056 ◽  
Author(s):  
Thomas Nickelson
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Wild Fish ◽  
Wild Populations ◽  
Large Numbers ◽  
Average Proportion ◽  
Coastal Basins ◽  
High Concentrations ◽  
Coastal River ◽  
Release Strategy

To aid in the recovery of depressed wild salmon populations, the operation of hatcheries must be changed to reduce interactions of juvenile hatchery fish with wild fish. Evidence suggests that productivity of wild populations can be reduced by the presence of large numbers of hatchery smolts in lower rivers and estuaries that attract predators. An index of productivity based on the density-independent rate of reproduction of wild coho salmon (Oncorhynchus kisutch) in 12 Oregon coastal river basins and two lake basins was negatively correlated with the average number of hatchery coho salmon smolts released in each basin. The index of productivity was not significantly correlated with the average proportion of hatchery coho salmon in each naturally spawning population or with habitat quality. Alterations to hatchery programs that could encourage recovery of wild populations include (i) avoiding release of large numbers of smolts in areas with high concentrations of wild fish, (ii) decreasing the number of smolts released, and (iii) using a volitional release strategy or a strategy that employs smaller release groups spread temporally.

Effects of Early Rearing Environment on Stress Response, Immune Function, and Disease Resistance in Juvenile Coho (Oncorhynchus kisutch) and Chinook Salmon (O.tshawytscha)

1993 ◽  
Vol 50 (4) ◽  
pp. 759-766 ◽  
Author(s):  
Kira Salonius ◽  
George K. Iwama
Keyword(s):  
Disease Resistance ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Vibrio Anguillarum ◽  
Oncorhynchus Kisutch ◽  
Significant Rise ◽  
Wild Fish ◽  
Handling Stress ◽  
Hatchery Fish ◽  
Natural Water Body

Coho (Oncorhynchus kisutch) and chinook salmon (0. tshawytscha) from aquaculture and wild environments were subjected to handling (30–60 s of netting and aerial emersion) and disease challenges. Plasma cortisol concentrations ([cortisol]pl) in both coho and chinook salmon from wild environments were significantly elevated 4 h after handling. Colonized coho salmon (hatchery-reared fish, transported into a natural water body as fry) responded in a similar fashion to wild fish, while those reared entirely in the hatchery showed no significant rise in [cortisol]pl. The responses to handling stress were retained in wild and colonized coho salmon after 7 mo of hatchery rearing. A transient increase in the leukocyte to red blood cell ratio in both wild and hatchery-reared chinook salmon occurred 4 h after handling. Handling signficantly decreased the antibody-producing cell (APC) number in wild fish and elevated their [cortisol]plrelative to hatchery fish. Wild fish had the highest APC number among the three groups before the handling. No difference in resistance to Vibrio anguillarum was apparent in coho and chinook salmon among the different rearing environments, although chinook salmon were generally more susceptible; disease resistance was reduced in wild coho salmon after 7 mo of rearing in a hatchery.

Survival and life history characteristics among wild and hatchery coho salmon (Oncorhynchus kisutch) returns: how do unfed fry differ from smolt releases?

2010 ◽  
Vol 67 (3) ◽  
pp. 486-497 ◽  
Author(s):  
Véronique Thériault ◽  
Gregory R. Moyer ◽  
Michael A. Banks
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Molecular Analysis ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Adult Survival ◽  
Life History Characteristics ◽  
Hatchery Program ◽  
Release Strategy ◽  
Integrated Hatchery Program

Survival and life history characteristics were evaluated for a coho salmon ( Oncorhynchus kisutch ) integrated hatchery program using two stocking strategies. Fish were released as unfed fry or smolts and returned as adults, and then molecular analysis was employed to pedigree the entire population. We showed that mean adult survival of individuals released as unfed fry was less than that of individuals released as smolts (0.03% vs. 2.39%). The relative reproductive success (RRS) of the fry release strategy to wild spawning was significantly greater for one of two cohorts, whereas the smolt release strategy to wild RRS was significantly greater for both cohorts. Fish released as smolts were significantly smaller upon returning as adults than either those released as unfed fry or wild returns. Mean run timing was also significantly biased towards an earlier run time for hatchery-released fish when compared with the wild component. The incidence of jacking (males maturing at age 2) was greater among fish stocked as smolts than for fish stocked as fry. Differences in survival, RRS, and life history appeared to be the result of hatchery practices and indicated that a fry stocking strategy produced fish more similar to the wild component of the population than to that of fish released as smolts.

Coho salmon (Oncorhynchus kisutch) ocean migration patterns: insight from marine coded-wire tag recoveries

2002 ◽  
Vol 59 (7) ◽  
pp. 1100-1115 ◽  
Author(s):  
Laurie Weitkamp ◽  
Kathleen Neely
Keyword(s):  
Geographic Variation ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Principal Component ◽  
Distribution Patterns ◽  
Geographic Region ◽  
Small Scale ◽  
Adult Size ◽  
Wild Populations ◽  
Specific Distribution

We investigated geographic variation in the ocean migration of coho salmon (Oncorhynchus kisutch) by examining recovery locations of 1.77 million coded-wire tagged fish from 90 hatcheries and 36 wild populations along the west coast of North America. Principal component, cluster, and similarity analyses were used to reveal both large- and small-scale variation in marine recovery patterns. We identified 12 distinct ocean distribution patterns, each associated with a particular geographic region. Despite these distinct patterns, however, fish from a given population were widely dispersed in the coastal ocean. Recovery patterns for tagged wild populations were consistent with those of hatchery populations from the same region, suggesting that marine distributions based on hatchery populations are reasonable proxies for distributions of wild populations. These region-specific distribution patterns suggest unappreciated life history diversity for coho salmon in the marine environment. When combined with region-specific adult size variation, they suggest migratory differences earlier in the ocean residence period as well. These results provide a novel framework with which to view geographic variation in salmon ocean ecology, conservation, and management.

Use of Hatchery Coho Salmon (Oncorhynchus kisutch) Presmolts to Rebuild Wild Populations in Oregon Coastal Streams

1986 ◽  
Vol 43 (12) ◽  
pp. 2443-2449 ◽  
Author(s):  
Thomas E. Nickelson ◽  
Mario F. Solazzi ◽  
Steven L. Johnson
Keyword(s):  
Surface Area ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Early Time ◽  
Wild Populations ◽  
Pool Surface ◽  
Coastal Streams

We evaluated the effectiveness of using hatchery coho salmon (Oncorhynchus kisutch) presmolts to rebuild wild populations in Oregon coastal streams. Juvenile and adult populations were monitored in 15 stocked and 15 unstocked streams from summer 1980 until summer 1985. During the summers following the planting of presmolts, the number of juveniles per square metre of pool surface area was higher in the stocked streams than in the unstocked streams. However, wild juveniles were significantly less abundant in the stocked streams during the 2 yr when density of wild juveniles was estimated separately from hatchery juveniles. Adult returns to the stocked streams were not significantly different from adult returns to the unstocked streams, but returns tended to be earlier in the stocked streams than in the unstocked streams. Despite similar numbers of adults per kilometre in the stocked streams and unstocked streams in the years the presmolts returned to spawn, the resulting densities of juveniles in the stocked streams were significantly lower than the densities of juveniles in the unstocked streams. We concluded that the early time of spawning of the hatchery coho salmon was largely responsible for their failure to rebuild the populations in the streams stocked with presmolts.

Morphological Differences between Hatchery and Wild Populations of Coho Salmon (Oncorhynchus kisutch): Environmental versus Genetic Origin

1991 ◽  
Vol 48 (9) ◽  
pp. 1783-1791 ◽  
Author(s):  
D. P. Swain ◽  
B. E. Riddell ◽  
C. B. Murray
Keyword(s):  
Maternal Effects ◽  
Genetic Divergence ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Principal Component ◽  
Wild Populations ◽  
Genetic Origin ◽  
Environmental Component ◽  
Morphological Differences ◽  
Median Fins

Previous studies have demonstrated morphological differences between hatchery-reared coho salmon (Oncorhynchus kisutch) of hatchery origin and wild-reared coho of wild origin. We tested for a genetic component to this divergence by comparing coho from hatchery and wild populations both reared in the same hatchery environment and for an environmental component by comparing hatchery- and wild-reared coho both of wild origin. As in the previous studies, wild-reared fish from wild populations had greater head dimensions, larger median fins, and deeper bodies than did hatchery-reared fish from hatchery populations. This difference, summarized by the first principal component (PC1) of the size-adjusted data, was related to rearing environment rather than to genetic differences between hatchery and wild populations. Genetic divergence (or maternal effects) did occur between hatchery and wild populations along PC2 and PC3, but this divergence was slight compared with the environmentally induced differences between the two types of fish along PC1.

Changes in Cortisol Dynamics in Wild and Hatchery-Reared Juvenile Coho Salmon (Oncorhynchus kisutch) During Smoltification

1994 ◽  
Vol 51 (10) ◽  
pp. 2179-2187 ◽  
Author(s):  
J. Mark Shrimpton ◽  
Nicholas J. Bernier ◽  
David J. Randall
Keyword(s):  
Atpase Activity ◽  
Plasma Cortisol ◽  
Coho Salmon ◽  
Gradual Increase ◽  
Oncorhynchus Kisutch ◽  
Cortisol Concentration ◽  
Wild Fish ◽  
Hatchery Fish ◽  
Corticosteroid Receptor ◽  
Cr Concentration

Cortisol dynamics were examined in hatchery and wild juvenile coho salmon (Oncorhynchus kisutch) over the spring of 1991 and 1992 when the fish were smolting. Wild fish were caught in the upper Quinsam River, British Columbia and at the downstream enumeration fence when they started to migrate. Two groups of hatchery fish were from the top and bottom ends of an earthen rearing channel. Plasma cortisol levels increased during the spring in all groups, but were significantly greater in wild than in hatchery smolts. The half-life of plasma cortisol decreased as fish smolted; however, there was no difference among the groups. Corticosteroid receptor (CR) concentration and affinity decreased during the spring. Wild fish consistently possessed the greatest gill concentration of CR. The change in dissociation constant (kD) was similar for hatchery and wild fish during spring 1991. In 1992, hatchery fish showed a similar gradual increase. In contrast, wild fish did not show an increase in kD until May. The changes in cortisol concentration in the plasma and the CR kD occurred synchronously with the increase in Na+K+ATPase activity in wild fish, which showed the greatest increase in kD, plasma cortisol, and Na+K+ATPase activity.

Variation in Agonistic Behavior between Newly Emerged Juveniles from Hatchery and Wild Populations of Coho Salmon, Oncorhynchus kisutch

1990 ◽  
Vol 47 (3) ◽  
pp. 566-571 ◽  
Author(s):  
D. P. Swain ◽  
B. E. Riddell
Keyword(s):  
Agonistic Behavior ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Its Region ◽  
Population Level ◽  
Mirror Image ◽  
Aggressive Display ◽  
Wild Populations ◽  
Breeding Programs ◽  
Stimulation Tests

We compared agonistic behavior of newly emerged coho salmon (Oncorhynchus kisutch) between hatchery and wild populations using mirror image stimulation tests. We used hatchery populations from two different regions of Vancouver Island B.C., each matched with a wild population from its region. In both comparisons, hatchery juveniles were more aggressive than wild juveniles. Rates of aggressive display increased with time since emergence for both hatchery and wild fish, as did the differences in behavior between the two types. By the sixth day of observation (13 d postemergence), the overall effect of fish type was highly significant for all aggressive behaviours. Since the individuals compared were reared from eggs under identical conditions, these differences are presumably genetic. Comparisons involved relatively few families from each population. However, because heritability was moderate to low within populations, and variance between population types exceeded variance among families within populations, these results indicate real differences at the population level. These results may have important implications for programs to rebuild wild populations using hatchery transplants and for selective breeding programs to develop domestic stocks of coho.

Population viability of coho salmon, Oncorhynchus kisutch, in Oregon coastal basins: application of a habitat-based life cycle model

1998 ◽  
Vol 55 (11) ◽  
pp. 2383-2392 ◽  
Author(s):  
Thomas E Nickelson ◽  
Peter W Lawson
Keyword(s):  
Life Cycle ◽  
Habitat Quality ◽  
Coho Salmon ◽  
Extinction Risk ◽  
Oncorhynchus Kisutch ◽  
Population Viability ◽  
Life Cycle Model ◽  
Cycle Model ◽  
Coastal Basins ◽  
Marine Survival

To assess extinction risk for Oregon coastal coho salmon, Oncorhynchus kisutch, we developed a life cycle model based on habitat quality of individual stream reaches estimated from survey data. Reach-specific smolt output was a function of spawner abundance, demographic stochasticity, genetic effects, and density- and habitat-driven survival rates. After natural mortality and ocean harvest, spawners returned to their natal reaches. Populations in reaches with poor habitat became extinct during periods of low marine survival. With favorable marine survival, high productivity reaches served as sources for recolonization of lower quality reaches through straying of spawners. Consequently, both population size and distribution expanded and contracted through time. Within a reach, populations lost resilience at low numbers when demographic risk factors became more important than density-dependent compensation. Population viability was modeled for three coastal basins having good, moderate, and poor habitat. With constant habitat conditions, extinction risk in 99 years was negligible in basins with good and moderate habitat and 5-10% in the basin with poor habitat. Reductions in habitat quality up to 60% in 99 years resulted in reduced coho salmon populations in all basins and significantly increased extinction risk in the basin with poor habitat.

The Effect of Short-duration Seawater Exposure on the Swimming Performance of Wild and Hatchery-reared Juvenile Coho Salmon (Oncorhynchus kisutch) during Smoltification

1994 ◽  
Vol 51 (10) ◽  
pp. 2188-2194 ◽  
Author(s):  
C. J. Brauner ◽  
G. K. Iwama ◽  
D. J. Randall
Keyword(s):  
Fresh Water ◽  
Coho Salmon ◽  
Swimming Performance ◽  
Oncorhynchus Kisutch ◽  
Aerobic Metabolism ◽  
Wild Fish ◽  
Swimming Velocity ◽  
Hatchery Fish ◽  
Oxygen Carrying Capacity ◽  
Seawater Challenge

The critical swimming velocity (Ucrit) and haematology of wild and hatchery-reared coho salmon (Oncorhynchus kisutch) juveniles were examined in either fresh water or seawater following a 24-h seawater challenge, at the time of smoltification. In fresh water, wild smolts swam faster than hatchery-reared fish but this could largely be accounted for by scaling for body size. Transfer to seawater significantly elevated resting plasma [Na+] and reduced subsequent Ucrit in hatchery fish (by 12%) relative to that determined in fresh water but had no significant effect on resting plasma [Na+] and Ucrit in wild fish. Swimming the fish a second time in seawater after the initial 2-h exercise period resulted in a significant reduction in Ucrit relative to that in fresh water in both wild fish (16%) and hatchery fish (a further 14%); this relatively greater impairment in Ucrit in hatchery fish was due to a reduced hypo-osmoregulatory ability following seawater transfer that impairs conditions for muscle contractility and aerobic metabolism. Aerobic metabolism in seawater-exposed fish was affected in part through a reduction in haematocrit and an increase in plasma volume, reducing oxygen carrying capacity of the blood relative to conditions in fresh water.

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