Carcass additions increase juvenile salmonid growth, condition, and size in an interior Columbia River Basin tributary

2020 ◽  
Vol 77 (4) ◽  
pp. 703-715 ◽  
Author(s):  
Matthew J. Kaylor ◽  
Seth M. White ◽  
Edwin R. Sedell ◽  
Dana R. Warren
Keyword(s):  
Body Size ◽  
Growth Rates ◽  
Life Histories ◽  
Freshwater Ecosystems ◽  
Steelhead Trout ◽  
Juvenile Salmonids ◽  
Early Fall ◽  
Juvenile Chinook ◽  
The Relationship

Numbers of anadromous fish returning to freshwater ecosystems have declined precipitously across much of western North America, reducing a potentially important resource subsidy for juvenile salmonids. We added carcasses to three sections of a Snake River tributary and assessed juvenile Chinook salmon (Oncorhynchus tshawytcha) and steelhead trout (Oncorhynchus mykiss) growth, body condition, size, and diet responses in summer and early fall. Juvenile salmonids consumed an abundance of eggs and carcass tissue, which increased energy rations. Within 3 weeks of carcass additions, juvenile Chinook and steelhead growth rates were 1.1–5 and 6–23 times greater in treatment reaches relative to control reaches, respectively. We used long-term tagging and detection data from this system to assess the relationship between juvenile Chinook size and emigration survival for two different juvenile life histories. The increased growth rates and body size in response to carcass additions, coupled with a positive relationship between body size and survival, suggest that juvenile salmonid rearing productivity and emigration survival may be limited by depressed returns of anadromous fishes in this system and potentially other tributaries of the Columbia Basin.

Relationship between body size and population growth rate in two opportunistic polychaetes

2002 ◽  
Vol 82 (3) ◽  
pp. 403-408 ◽  
Author(s):  
D. Prevedelli ◽  
R. Simonini
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Sex Ratio ◽  
Population Growth ◽  
Growth Rates ◽  
Life Histories ◽  
Population Growth Rate ◽  
Population Growth Rates ◽  
The Relationship ◽  
Dinophilus Gyrociliatus

The relationship between body size and population growth rate λ has been studied in two species of opportunistic polychaetes, Dinophilus gyrociliatus and Ophryotrocha labronica, which colonize harbour environments. These species exhibit a semi-continuous iteroparous reproductive strategy, are phylogenetically closely-related but differ in body size and in some aspects of their sexuality. Ophryotrocha labronica is about 4 mm in body length, displays only slight sexual dimorphism and its sex ratio is biased towards the female sex in the ratio 2:1. Dinophilus gyrociliatus is about 1 mm in length, the males are extremely small and the sex ratio is strongly biased (3:1) in favour of the females. In spite of the considerable differences in all traits of their life histories and in many demographic parameters, the growth rates of the two populations are very similar. The analyses carried out have shown that the rapid attainment of sexual maturity of D. gyrociliatus gives it an advantage that offsets the greater fecundity of O. labronica. It is very likely that the reproductive peculiarities of D. gyrociliatus help to raise the population growth rates. The ‘saving’ on the male sex achieved both by the shift of the sex ratio in favour of the females and by the reduction in the males' body size would appear to enable D. gyrociliatus to grow at the same rate as O. labronica, a larger and more fecund species.

scholarly journals Adjacency to a harvest trail increases drought resistance of interior Douglas-fir (Pseudotsuga menziesii var. glauca) in partially harvested stands in central British Columbia

2018 ◽  
Vol 48 (7) ◽  
pp. 809-820 ◽  
Author(s):  
Neil P. Thompson ◽  
Kathy J. Lewis ◽  
Lisa M. Poirier
Keyword(s):  
British Columbia ◽  
Drought Tolerance ◽  
Pseudotsuga Menziesii ◽  
Growth Rates ◽  
Habitat Management ◽  
Odocoileus Hemionus ◽  
Douglas Fir ◽  
Ring Analysis ◽  
The Relationship

Drought tolerance of trees may be affected by competition, but most studies quantifying the relationship do not consider the effect of stem clustering. Trees are often clustered in interior Douglas-fir (Pseudotsuga menziesii var. glauca (Mayr) Franco) forests near the grassland interface in central British Columbia due to past harvesting practices or habitat management for mule deer (Odocoileus hemionus hemionus (Rafinesque, 1817)). Climate change projections indicate continued increases in temperature, an outcome that would stress trees growing in dry environments. Trees placed in different states of competition by mechanical harvesting in the 1970s were sampled to provide a 40-year comparison of three levels of competition during 1–2 year droughts. Tree-ring analysis was used to assess the reduction in growth during drought years and resumption of growth in subsequent years. A clear separation of growth rates was evident between open-growing trees, trees on the edge of harvesting trails, and trees within the unharvested interior. Edge trees had intermediate growth rates but no differences were found in the long-term climate–growth relationship compared with open-growing trees. Both Edge and Open classes showed less relative growth reduction during droughts than Interior trees growing between harvest trails. Precipitation throughfall rates and competition for resources are likely driving short-term drought tolerance in combination with other factors.

The Influence of Metallurgical and Mechanical Pre-Damage on Creep-Crack and Fatigue-Crack Growth Rates of CrMoV Steel

2004 ◽  
Author(s):  
Masaru Sekihara ◽  
Shigeo Sakurai
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Creep Crack Growth ◽  
Creep Crack ◽  
The Relationship ◽  
Crack Growth Rates

The effects of mechanical degradation on the creep- and fatigue-crack growth rates in power plants operated long-term were studied. Creep-crack growth tests and fatigue-crack growth tests were performed using creep-pre-strained and repetitive-strained CrMoV rotor-steel specimens. It was found that the creep-crack growth rates, da/dt, of the creep-pre-damaged specimens were larger than those of virgin specimens under constant load. It was also found that under the same stress intensity factor K, da/dt in the case of about 10%-crept and creep void induced specimens was increased five times, while in the case of 0.8%- and 2.8%-crept specimens, it only increased a little. However, all the data fell in a narrow scatter band in the relationship between C* and da/dt. The effect of long-term operating degradation appeared on the creep- and fatigue-damage under the Slow-Fast waveform. Also the crack density was larger in the damaged specimens compared with the virgin specimens. Other results showed that the fatigue-crack growth rates, da/dN, of creep- and fatigue-pre-damaged specimens were larger than those of virgin specimens. Under the same stress intensity factor range ΔK, da/dN in a specimen with approximately 10%-creep was increased 20 times. Moreover da/dN in fatigue-pre-damaged specimens was accelerated 10 times. However, the results of the strain-controlled crack growth test fell in a narrow scatter band in the relationship between J integral range ΔJ and da/dN. These results suggest that the creep remaining lives and fatigue remaining lives of mechanically damaged CrMoV steel can be estimated using the C* & ΔJ values considering the creep rate and the deformation rate of the pre-damaged materials and the da/dt and da/dN values of the virgin material.

Habitat Selection and Spatial Interaction by Juvenile Chinook Salmon and Steelhead Trout in Two Idaho Streams

1972 ◽  
Vol 29 (1) ◽  
pp. 91-100 ◽  
Author(s):  
F. H. Everest ◽  
D. W. Chapman
Keyword(s):  
Chinook Salmon ◽  
Spatial Interaction ◽  
Physical Space ◽  
Steelhead Trout ◽  
Short Term ◽  
Near Surface ◽  
Juvenile Chinook Salmon ◽  
Size Groups ◽  
Early Fall ◽  
Juvenile Chinook

During summer sympatric steelhead trout and summer chinook salmon segregated in Crooked Fork and Johnson creeks. In short-term allopatry, each species occupied the same types of habitat as in sympatry. Most age 0 steelhead lived over rubble substrate in water velocities and depths of less than 0.15 m/sec and 0.15 m, respectively; most age 0 chinook lived over silt substrate in water velocities of less than 0.15 m/sec and depths of 0.15–0.3 m; most age I steelhead resided over large rubble substrate in water velocities of 0.15–0.3 m/sec (near bottom) and 0.75–0.9 m/sec (near surface), and in depths of 0.6–0.75 m. As fish of each species became larger they moved into faster, deeper water. Juvenile chinook and steelhead of the same size used the same physical space. But steelhead spawn in spring and chinook spawn in early fall, and disparate times of spawning create discrete intra- and inter-specific size groups of pre-smolts. The size differences minimize potential for social interaction, both intra- and inter-specific.

Roots and routes in adult musical participation: investigating the impact of home and school on lifelong musical interest and involvement

2009 ◽  
Vol 26 (3) ◽  
pp. 241-256 ◽  
Author(s):  
Stephanie Pitts
Keyword(s):  
Music Education ◽  
Life Histories ◽  
Music Educators ◽  
Musical Life ◽  
British Music ◽  
The Impact ◽  
The Relationship ◽  
Home And School ◽  
The Ideal

This paper analyses a collection of musical life histories, drawn from 71 British respondents who have maintained a lifelong interest in music as regular concert-goers, amateur performers and/or music educators. These respondents reflect on the influences and opportunities which have contributed to their lifelong engagement in music, and in doing so illustrate the impact of changes in British music education and culture over the last 50 years. Particular analytical focus is placed here on the relative influence of home and school, on the ideal characteristics of each environment, and the relationship between them. The value of a long-term perspective on music education is debated, and conclusions drawn about the challenges to teachers and researchers that are evident from this study.

scholarly journals Unraveling Flooding Dynamics and Nutrients’ Controls upon Phytoplankton Functional Dynamics in Amazonian Floodplain Lakes

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 154 ◽  
Author(s):  
Cleber Kraus ◽  
Marie-Paule Bonnet ◽  
Ina de Souza Nogueira ◽  
Maria Morais Pereira Souza Lobo ◽  
David da Motta Marques ◽  
...  
Keyword(s):  
Essential Role ◽  
Hydrological Cycle ◽  
Freshwater Ecosystems ◽  
Floodplain Lakes ◽  
Functional Dynamics ◽  
Carbon Compounds ◽  
Environmental Variations ◽  
The Stability ◽  
The Relationship

The processes in tropical floodplain lakes enable maintaining phytoplankton nutrient requirements over a hydrological year. The nutrients such as nitrogen, phosphorus and carbon compounds play an essential role in phytoplankton growth. However, the way that nutrients and phytoplankton interact and how this relationship varies seasonally in tropical freshwater ecosystems is not clear. In this study, we evaluate the relationship between phytoplankton–nutrients over the hydrological cycle in Amazonian floodplain lakes and verify if this relationship influences the biomass of cyanobacteria. We also check what factors linked to nutrients act in structuring phytoplankton community. Using the phytoplankton functional approach, we verified how their ability to respond to hydrological and environmental variations reflects the ecological conditions and investigated how these interactions work. The results show that the Amazonian floodplain lakes could maintain long-term nutrient enrichment status. The nutrients input conduces to cyanobacteria dominance, that allied to other factors, play an essential role in supporting the stability of the phytoplankton–nutrients relationship over the hydrological cycle.

Allometry of cooling, supercooling, and freezing in the freeze-tolerant turtle Chrysemys picta

1991 ◽  
Vol 261 (3) ◽  
pp. R626-R632 ◽  
Author(s):  
D. L. Claussen ◽  
P. A. Zani
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Bound Water ◽  
Chrysemys Picta ◽  
Ice Formation ◽  
Term Survival ◽  
Freeze Tolerant ◽  
The Relationship ◽  
Kinetics Of

Although several vertebrates are freeze tolerant, little is known of the relationship between body size and the kinetics of cooling and freezing. We compared these responses for six hatchling and eight adult Chrysemys picta from an Ohio population. All turtles initially recovered from freezing, and all adults, but only two hatchlings (which experienced ice contents of approximately 35%), exhibited long-term survival. Rapid thawing may have compromised hatchling survival. Turtle water content was inversely related to body mass, but we found no significant correlation between the extent of supercooling and body size. Prefreezing and postfreezing cooling rates scaled with body mass to the -0.55 and -0.40 power, respectively, but the latter rate was more than two orders of magnitude slower. Theoretical (assuming 20% bound water) and calorimetric estimates of body ice agreed reasonably well. Ice contents were both body mass and time dependent. The absolute rate of ice formation scaled with body mass to the 0.4 power. Body size strongly influences the freezing response of ectotherms and deserves more attention.

scholarly journals Body size and extinction risk in Brazilian carnivores

2009 ◽  
Vol 9 (2) ◽  
pp. 45-49 ◽  
Author(s):  
German Forero-Medina ◽  
Marcus Vinícius Vieira ◽  
Carlos Eduardo de Viveiros Grelle ◽  
Paulo Jose Almeida
Keyword(s):  
Body Size ◽  
Litter Size ◽  
Life Histories ◽  
Linear Models ◽  
Extinction Risk ◽  
Habitat Destruction ◽  
Phylogenetically Independent Contrasts ◽  
Relationship Of ◽  
The Relationship ◽  
Natural Reserves

Because extinctions are not random across taxa, it is important for conservation biologists to identify the traits that make some species more vulnerable. Factors associated with vulnerability include small geographical ranges, low densities, high trophic level, "slow" life histories, body size, and tolerance to altered habitats. In this study we examined the relationship of body size, reproductive output, longevity, and extinction risk for carnivores occurring in Brazil. We used generalized linear models analyses on phylogenetically independent contrasts to test the effect of body size alone, and the combined effect of body size, litter size and longevity on extinction risk. Body size appeared in the two best models according to the selection criteria (AIC), and it was the most plausible bionomic variable associated with extinction risk. Litter size and longevity, bionomic traits previously associated with threat risk of Brazilian carnivores, were implausible. The higher extinction risk for larger species could result from body size influencing vulnerability to different human activities, such as killing, habitat destruction and fragmentation, and the small size of natural reserves.

Structural Imbalances in Canadian Labor Markets

1994 ◽  
Author(s):  
S. Gera ◽  
S. S. Rahman ◽  
J. L. Arcand
Keyword(s):  
Labor Market ◽  
Labor Markets ◽  
Growth Rates ◽  
Employment Growth ◽  
Dominant Factor ◽  
Industrial Sectors ◽  
Potential Sources ◽  
Interregional Disparities ◽  
The Relationship

The nature of structural imbalances in the Canadian Labor market is identified by analyzing the relationship between unemployment and job vacancies. Three potential sources of imbalances are examined: (1) the regional nature of the Canadian economy; (2) the rise in the incidence of long-term unemployment (of 12 months or more); and (3) differences in the rate of growth of unemployment across industrial sectors. The major findings are: growing structural imbalances; an increase in long-term unemployment was the major cause of the shift in most cases; both inter-and intraregional effects played a significant role, but interregional disparities were the dominant factor; and the dispersion in employment growth rates across industrial sectors did not seem to play a role.

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