Mirror-Elicited Agonistic Behaviour and Body Morphology as Predictors of Dominance Status in Juvenile Coho Salmon (Oncorhynchus kisutch)

1993 ◽  
Vol 50 (3) ◽  
pp. 676-684 ◽  
Author(s):  
L. Blair Holtby ◽  
Douglas P. Swain ◽  
G. Michael Allan
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Fork Length ◽  
Mirror Image ◽  
Large Fish ◽  
Agonistic Interactions ◽  
Dominance Status ◽  
Body Depth ◽  
Body Morphology ◽  
Eventual Dominance

We tested whether body morphology and aggressive behaviour, measured through mirror image stimulation (MIS), could predict the eventual dominance status of juvenile coho salmon (Oncorhynchus kisutch) tested in paired contests and in stream tank interactions with several individuals. Dominance in paired contests was predicted by MIS behaviour on the fifth observation day using newly emerged juveniles and by MSS behaviour on the first observation day using 7-wk-old juveniles. In both.w420020 dstrials, deeper bodied fish tended to be dominant. In the stream tank tests, the MIS behaviour SAM (swim-against-mirror) and fork length were the best predictors of dominance. Large fish with high levels of SAM tended to be dominant. After removing the effects of fish size, neither body depth nor fin size consistently predicted dominance ability. SAM was positively correlated with overt aggressive behaviours in stream tanks but not with lateral displays, juvenile coho salmon appeared to react to conspecifics and to their own mirror images in a quantitatively similar way, and both MIS behaviour and body morphology were significant predictors of the outcome of agonistic interactions among individuals.

Natural Mortality Rate in Last Winter of Life of Coho Salmon (Oncorhynchus kisutch) Resident in Puget Sound

1974 ◽  
Vol 31 (6) ◽  
pp. 1158-1160 ◽  
Author(s):  
Stephen B. Mathews ◽  
Raymond Buckley
Keyword(s):  
Mortality Rate ◽  
Coho Salmon ◽  
Puget Sound ◽  
Oncorhynchus Kisutch ◽  
Fork Length ◽  
Natural Mortality

The natural mortality rate during a 3.5-mo period of the last year of life of coho salmon (Oncorhynchus kisutch) resident in Puget Sound was estimated to be 48% of the population at the beginning of this period. This estimate was based on recaptures of 29 fish out of 169, averaging 32 cm in fork length, tagged in January and early February, and 20 out of 61 averaging 41 cm tagged in May and early June, 1970.

Survival, Ocean Growth, and Ocean Distribution of Differentially Timed Releases of Hatchery Coho Salmon (Oncorhynchus kisutch)

1989 ◽  
Vol 46 (7) ◽  
pp. 1216-1226 ◽  
Author(s):  
Stephen B. Mathews ◽  
Yukimasa Ishida
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Adult Survivors ◽  
Small Fish ◽  
Large Fish ◽  
Release Date ◽  
Marine Life ◽  
Coos Bay ◽  
The Mean ◽  
Marine Survival

Estimates of growth rates in early ocean life and length frequency distributions at time of release for adult survivors were inferred from scale measurements for lots of coho salmon (Oncorhynchus kisutch) released at several dates from a Columbia River hatchery (Big Creek) and a southern Oregon hatchery (Coos Bay). Analysis of these measurements failed to support either of two literature-suggested hypotheses for the variability of marine survival of hatchery coho by date of release: (1) intraseasonal variability of food supply during early marine life; and (2) intraseasonally improving ability of smaller individuals within release lots to convert to salt water. Marine survival improved substantially with date of release at both hatcheries. However, fish released earliest, which survived relatively poorly, grew as fast in early marine life as fish released later, which survived better. Thus, poor survival of the early released fish did not appear related to lack of food at early ocean life. For the Big Creek hatchery, no significant differences were seen between the mean lengths at date of release and the mean release-date lengths of adult survivors back calculated from their scales, for lots released on May 5, June 3, and July 2. Apparently, small and large fish of each lot survived with equal probability. For the Coos Bay hatchery, the mean release-date lengths of adult survivors were significantly larger than the mean lengths of all fish released, for each of six lots released between early June and late July. Thus, large fish apparently survived better than small ones within each of these six lots. But there was no seasonal trend in survivability of small fish relative to large ones, contrary to hypothesis (2)

Effects of solar ultraviolet radiation on the behaviour of juvenile coho salmon (Oncorhynchus kisutch): avoidance, feeding, and agonistic interactions

2008 ◽  
Vol 65 (4) ◽  
pp. 701-711 ◽  
Author(s):  
L Blair Holtby ◽  
Max L Bothwell
Keyword(s):  
Ultraviolet Radiation ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Agonistic Interactions ◽  
Solar Ultraviolet Radiation ◽  
Full Spectrum ◽  
Size Dependent ◽  
Mediated Effects ◽  
Dependent Growth ◽  
Solar Ultraviolet

The behaviour of juvenile coho salmon (Oncorhynchus kisutch) was observed in outdoor experimental flumes in which three different spectral regimes were created by plastic covers that selectively blocked all or portions of natural ultraviolet radiation (UVR). The three light treatments were (i) photosynthetically active radiation (PAR, 400–700 nm), (ii) PAR plus longer wavelength ultraviolet (PAR + UVA, 320–700 nm), and (iii) full-spectrum sunlight with both long and short wavelength ultraviolet included (PAR + UVA + UVB, 280–700 nm). Observations made at different times of the day and under both overcast and sunny skies allowed an assessment of PAR intensity on behaviour in addition to that of UVR. We quantified shade-seeking behaviour, feeding strikes, and agonistic interactions (approaches, chases, and nips) between individuals. Under higher PAR intensities, a greater proportion of juvenile coho tended to take cover under rocks. Shade-seeking behaviour increased significantly in the presence of UVR. Feeding and agonistic interactions were partially inhibited at higher PAR intensities and very significantly depressed by UVR. For all behaviours tested, the effects were mediated by UVA with no significant additional impacts from UVB. UVR-mediated effects on behaviour could have ecological consequences through influencing summer densities, density-dependent growth, and size-dependent winter and early marine survivals.

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.

Spatial and interannual variability of juvenile coho salmon growth in the Strait of Georgia (2012-2015)

2020 ◽  
Vol 646 ◽  
pp. 145-160
Author(s):  
ML Journey ◽  
C Neville ◽  
G Young ◽  
M Trudel ◽  
BR Beckman
Keyword(s):  
Growth Factor ◽  
Regional Variation ◽  
Positive Relationship ◽  
Coho Salmon ◽  
Regional Growth ◽  
Oncorhynchus Kisutch ◽  
Fork Length ◽  
Small Scale ◽  
Short Term ◽  
Strait Of Georgia

We conducted a 4 yr (2012-2015) study of regional growth of juvenile coho salmon Oncorhynchus kisutch in the Strait of Georgia (British Columbia, Canada). Size (fork length) and growth (insulin-like growth factor-1 [IGF-1] concentration) varied both regionally and inter-annually. Additionally, we found a positive relationship between IGF-1 concentration and fork length that varied between years, with slopes and y-intercepts higher in 2012 and 2014, respectively, as compared to 2013 and 2015. An ordinal increase of IGF-1 concentration from the south to north in 2012 and 2014 was coupled with an increase in the prevalence of both juvenile herring and juveniles of other fish species in the diet. Across all years, there was a positive relationship between regional mean IGF-1 concentration and regional mean percent of juvenile herring in the diet. Our study demonstrates relatively small-scale spatial heterogeneity in juvenile coho salmon growth that in part, was attributed to regional variation in diet. These findings also demonstrate the utility of short-term growth measures (such as IGF-1) for assessing relatively small-scale spatial and temporal differences in growth.

Predation risk breaks size-dependent dominance in juvenile coho salmon (Oncorhynchus kisutch) and provides growth opportunities for risk-prone individuals

1999 ◽  
Vol 56 (7) ◽  
pp. 1206-1212 ◽  
Author(s):  
Ulrich G Reinhardt
Keyword(s):  
Predation Risk ◽  
Risk Taking ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Small Fish ◽  
Agonistic Interactions ◽  
Dominance Hierarchies ◽  
Size Dependent ◽  
Gain Access ◽  
Better Than

Groups of coho salmon (Oncorhynchus kisutch) fry in stream tanks formed size-determined dominance hierarchies, which were upheld through aggressive interactions and led to smaller fish occupying inferior feeding positions. Under simulated predation risk, the frequency of agonistic interactions was reduced, but more intensive aggressive behaviours were performed. This allowed small fish to gain access to better feeding positions. The effect of the predation threat on coho behaviour seemed to extend across a riffle into a second pool that served as a refuge. Smaller fry that chose to be in the exposed pool had greater growth rates than those that mainly occupied the refuge, while large fry that exposed themselves to predation did not grow better than their risk-avoiding counterparts. Differences in risk taking and growth among small coho fry in this experiment may support reports for Atlantic salmon (Salmo salar) of a split into different life history trajectories. The observations suggest that the presence of predators creates opportunities for the expression of alternative behavioural strategies that are absent under size-dependent dominance hierarchies.

Differences in Morphology and Behavior between Juvenile Coho Salmon (Oncorhynchus kisutch) Rearing in a Lake and in its Tributary Stream

1989 ◽  
Vol 46 (8) ◽  
pp. 1406-1414 ◽  
Author(s):  
Douglas P. Swain ◽  
L. Blair Holtby
Keyword(s):  
Aggressive Behavior ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Mirror Image ◽  
Laboratory Rearing ◽  
Pectoral Fins ◽  
Inlet Stream ◽  
And Behavior ◽  
Lake Type ◽  
Total Behavior

Juvenile coho salmon (Oncorhynchus kisutch) rear both in Mesachie Lake, B.C., and in its inlet stream. The duration and frequency of aggressive behavior were greater among stream-rearing than lake-rearing juveniles in mirror image stimulation and stream tank tests of agonistic behavior. Lateral displays made up a higher proportion of total behavior among the stream-rearing fish compared with the lake-rearing fish. Lake-type fish had more posteriorly placed pectoral fins, shallower bodies and smaller, less brightly colored dorsal and anal fins than did stream-type fish, even after 2 mo of laboratory rearing in a common environment. Diminished aggression, a shift in aggressive behavior away from lateral displays, a more streamlined shape, and reduced coloration, all appear to be adaptations to a schooling lifestyle in the open waters of the lake.

Induced ovulation in coho salmon (Oncorhynchus kisutch). I. Further studies on the use of salmon pituitary preparations

Aquaculture ◽  
1981 ◽  
Vol 26 (1-2) ◽  
pp. 117-127 ◽  
Author(s):  
George A. Hunter ◽  
Edward M. Donaldson ◽  
Helen M. Dye
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Induced Ovulation
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