Relationship between natural productivity and the frequency of wild fish in mixed spawning populations of wild and hatchery steelhead (Oncorhynchus mykiss)

2003 ◽  
Vol 60 (9) ◽  
pp. 1057-1067 ◽  
Author(s):  
Mark W Chilcote

The proportion of wild fish in 12 mixed populations of hatchery and wild steelhead (Oncorhynchus mykiss) was evaluated for its relationship to mean and intrinsic measures of population productivity. The population mean of ln(recruits/spawner) was used to represent mean productivity. Intrinsic productivity was represented by values for the Ricker a parameter as estimated from fits of spawner and recruit data. Significant regressions (p < 0.001) were found between both measures of productivity and the proportion of wild fish in the spawning population (Pw). The slopes of the two regressions were not significantly different (p = 0.55) and defined a relationship suggesting that a spawning population comprised of equal numbers of hatchery and wild fish would produce 63% fewer recruits per spawner than one comprised entirely of wild fish. Study findings were not sensitive to likely levels of data error or confounded by extraneous habitat correlation with Pw. Population status assessments and conservation monitoring efforts should include Pw as a critical variable. For natural populations, removal rather than addition of hatchery fish may be the most effective strategy to improve productivity and resilience.

2006 ◽  
Vol 63 (7) ◽  
pp. 1627-1638 ◽  
Author(s):  
Megan S Hill ◽  
Gayle Barbin Zydlewski ◽  
William L Gale

Hatchery steelhead trout (Oncorhynchus mykiss) smolts, progeny of a newly founded native origin broodstock, were released into Abernathy Creek, Washington, in 2003 and 2004. After release, saltwater tolerance, gill Na+,K+-ATPase activity, and habitat use were compared. A subsample of hatchery and wild steelhead trout were implanted with 23 mm passive integrated transponder (PIT) tags each year. PIT-tagged migrants were used for physiological comparisons. Hatchery fish were significantly larger than wild fish. Hatchery migrants expressed significantly lower levels of gill Na+,K+-ATPase activity than wild migrants. After a 24 h seawater challenge, hatchery migrants had significantly higher plasma osmolality and [Na+] than wild migrants. Microhabitat use of PIT-tagged hatchery and wild individuals in a control (wild fish only) and effect (hatchery and wild fish) site were compared before and after the introduction of hatchery fish. No difference was detected in hatchery and wild smolt habitat use. Wild fish did not change their habitat use after the introduction of hatchery fish. Although hatchery and wild fish differed in smolt physiology, differences in short-term use of freshwater habitat were not detected, and hatchery fish did not appear to displace wild fish.


2011 ◽  
Vol 68 (10) ◽  
pp. 1827-1835 ◽  
Author(s):  
Shuichi Kitada ◽  
Hirohisa Kishino ◽  
Katsuyuki Hamasaki

The evaluation of the reproductive success (RS) of hatchery fish in the wild is one of the most important issues in hatchery supplementation, aquaculture, and conservation. Estimates of the relative reproductive success (RRS) have been used to evaluate RS. Because RRS may vary greatly depending on cross, years of release, and environmental conditions, we introduced a log-normal distribution to quantify the variation. The classical estimator of RRS based on multiple measurements is contrasted with the mean of this distribution. We derived the mean, variance, and relative bias and applied our Bayesian hierarchical model to 42 empirical RRS estimates of steelhead trout ( Oncorhynchus mykiss ) in the Hood River, Oregon, USA. The RRS estimate generally had an upward bias. Although the average level of RRS implied the reproductive decline of hatchery fish and wild-born hatchery descendants, we could not reject the null hypothesis that hatchery fish and their descendants have the same chance of having smaller RS than wild fish as they do of having larger RS than wild fish.


2000 ◽  
Vol 57 (3) ◽  
pp. 628-636 ◽  
Author(s):  
Barry A Berejikian ◽  
E Paul Tezak ◽  
Thomas A Flagg ◽  
Anita L LaRae ◽  
Eric Kummerow ◽  
...  

This study investigated whether culturing age-0 steelhead (Oncorhynchus mykiss) in habitat-enriched rearing tanks, containing a combination of in-water structure, underwater feeders, and overhead cover, affected competitive ability and habitat use compared with juveniles cultured in more conventional vessels. In laboratory tests, steelhead juveniles grown in the enriched tanks socially dominated size-matched competitors grown in conventional tanks. When both treatments were introduced into separate sections of a quasi-natural stream, no differences in growth were found between them. However, when intermixed, fish reared in the enriched tanks grew at a higher rate than conventionally reared competitors, suggesting greater competitive ability of juveniles grown in the enriched tanks. Visual isolation and defensible food resources in combination in the enriched tanks were considered as the primary factors causing the observed competitive asymmetries. Steelhead juveniles from the two rearing environments exhibited very similar use of woody structure in the quasi-natural stream, both in the presence and in the absence of mutual competition. Rearing steelhead in more naturalistic environments could result in hatchery fish that behave and integrate into the postrelease (natural) environment in a manner more similar to wild fish.


1993 ◽  
Vol 50 (4) ◽  
pp. 759-766 ◽  
Author(s):  
Kira Salonius ◽  
George K. Iwama

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.


2021 ◽  
Vol 13 (12) ◽  
pp. 19791-19798
Author(s):  
Sudam Charan Sahu ◽  
Manas Ranjan Mohanta ◽  
N.H. Ravindranath

Heritiera fomes Buch.-Ham. is assessed as an endangered mangrove species by IUCN, and information on population status is lacking. The present study assesses the status of H. fomes in Mahanadi Mangrove Wetland on the east coast of India. Three forest blocks were selected and sampled for this study. Among these, the mean girth at breast height (GBH) of H. fomes was the highest in Hetamundia (HD) forest block. GBH of H. fomes was inversely proportional to the cumulative disturbance index (R2= 0.7244, p value <0.005). The relative density was maximum for H. fomes (56%) at Bhitarkharnasi (BK), and for Excoecaria agallocha at Hetamundia (HD; 35%) & Kansaridia (KD; 54%), respectively. Excoecaria agallocha is a dominant species possibly impacting natural populations of H. fomes. Climate change and rising sea levels may also negatively affect the existence of this species. Therefore, appropriate strategies should be taken for conservation of this globally threatened mangrove species prior to its extinction.


2020 ◽  
Vol 77 (6) ◽  
pp. 1000-1009
Author(s):  
Barry A. Berejikian ◽  
Christopher P. Tatara ◽  
Donald M. Van Doornik ◽  
Michael A. Humling ◽  
Matt R. Cooper ◽  
...  

Female steelhead trout (Oncorhynchus mykiss) reared for 1 year (traditional, “S1”) and 2 years (experimental, “S2”) in captivity in the Methow River Basin, Washington, produced very similar numbers of offspring in replicate spawning channels over 3 consecutive years. In contrast, S1 anadromous males outcompeted S2 males for access to nesting females and, as a result, produced significantly more offspring. Male dominance was positively associated with body mass, but body mass did not account for differences between S1 and S2 males. Much smaller precocious S2 males that matured during rearing in hatchery raceways sired offspring in all six breeding groups. Contributions from precocious males were nearly always the result of sneak spawning events, although on rare occasions, precocious males were able to stimulate females to spawn in the absence of an anadromous male. Similarities in female breeding success suggest that S1 and S2 hatchery steelhead should exhibit similar productivity under natural conditions, but S1 male steelhead may result in greater rates of gene flow from hatchery to natural populations.


2010 ◽  
Vol 67 (11) ◽  
pp. 1840-1851 ◽  
Author(s):  
Kevin S. Williamson ◽  
Andrew R. Murdoch ◽  
Todd N. Pearsons ◽  
Eric J. Ward ◽  
Michael J. Ford

Understanding the relative fitness of naturally spawning hatchery fish compared with wild fish has become an important issue in the management and conservation of salmonids. We used a DNA-based parentage analysis to measure the relative reproductive success of hatchery- and natural-origin spring Chinook salmon ( Oncorhynchus tshawytscha ) in the natural environment. Size and age had a large influence on male fitness, with larger and older males producing more offspring than smaller or younger individuals. Size had a significant effect on female fitness, but the effect was smaller than on male fitness. For both sexes, run time had a smaller but still significant effect on fitness, with earlier returning fish favored. Spawning location within the river had a significant effect on fitness for both sexes. Hatchery-origin fish produced about half the juvenile progeny per parent when spawning naturally than did natural-origin fish. Hatchery fish tended to be younger and return to lower areas of the watershed than wild fish, which explained some of their lower fitness.


2017 ◽  
Vol 74 (2) ◽  
pp. 157-167 ◽  
Author(s):  
James S. Lamperth ◽  
Thomas P. Quinn ◽  
Mara S. Zimmerman

Anadromous fishes need to store sufficient energy at sea to migrate and reproduce, but the energetic demands of freshwater migration distance have been difficult to distinguish from the demands of fasting in fresh water prior to spawning. In addition, differences in stored energy may result from differences in metabolic storage or marine diet. We estimated somatic lipids (SL) and stable isotopes of N and C (as indices of marine trophic position and feeding location) in adult wild and hatchery steelhead (Oncorhynchus mykiss) of summer (stream-maturing) and winter (ocean-maturing) runs that migrate similar distances to spawn. We found that SL at return depended on several factors. Summer steelhead had twice the SL as winter steelhead, and within each run SL decreased with arrival date, converging on about 1% SL. In summer steelhead, females had 19% more SL than males, and wild fish had 21% more SL than hatchery fish. In winter steelhead, females had 27% less SL than males, and there was no difference between rearing origins. No differences were detected in δ15N or δ13C between ecotypes or rearing origins. Taken together, the results indicated different patterns of energy storage among and within ecotypes despite no apparent differences in marine trophic position or foraging area.


2016 ◽  
Vol 76 (1) ◽  
pp. 209-217
Author(s):  
S. O. Saraiva ◽  
P. S. Pompeu

Abstract The fish stocking in captivity for later release into natural water bodies has historically been applied in Brazil, as a measure to mitigate impacts caused by dams. However, the released fish are adapted to the hatchery environment, which is totally different from the natural, which results in low post-release survival rates and ineffectiveness of stocking as a management measure. Worldwide, several studies have demonstrated the existence of large phenotypic differences between farmed and wild fish, but in Brazil, there is a great need for this kind of study. Based on this, our objective here was to verify if hatchery fish differ morphologically from its wild counterparties, at the same size class. Hence, a population of young Prochilodus lineatus raised in a fish farming station was compared with another from marginal lagoons of the Grande river. The results indicated that the fish farming resulted in morphologically different individuals of P. lineatus and a less diverse population, compared with wild fish. Measures such as environmental enrichment of hatchery tanks should be studied as a way to increase environmental heterogeneity and increase the morphological variability of the fingerlings produced.


2019 ◽  
Vol 71 (4) ◽  
pp. 629-637
Author(s):  
Nemanja Rajcevic ◽  
Biljana Nikolic ◽  
Petar Marin

Many studies show the influence of the environment on terpene composition, but not many of them deal with the terpene composition variability in correlation with environmental factors in Pinus. We chose two endemic species ? P. heldreichii Christ. (Bosnian pine) and P. peuce Griseb. (Macedonian pine) ? two relict and (sub)endemic species of the Balkan peninsula. They mainly form pure stands but can appear in mixed populations, most commonly with each other. These species belong to different subgenera and thus differ greatly, especially in needle anatomy. ?-pinene, limonene and germacrene D predominated in Bosnian pine leaf oleoresins, while Macedonian pine oleoresin contained high amounts of ?-pinene. Furthermore, there were three chemotypes present in Bosnian, and only one in Macedonian pine. Oleoresins of Bosnian pine did not show correlation with climate, however, its composition changed in response to geological substrate type. Macedonian pine oleoresin showed a high correlation with the climate but changed only a little in response to geological substrate type. The oleoresin profiles showed strong species-dependent composition and variability. However, since each species expressed different responses to tested environmental conditions, it is important to take into consideration these variables when analyzing natural populations of the species.


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