scholarly journals Inter-population differences in salinity tolerance of adult wild Sacramento splittail: osmoregulatory and metabolic responses to salinity

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Christine E Verhille ◽  
Theresa F Dabruzzi ◽  
Dennis E Cocherell ◽  
Brian Mahardja ◽  
Fred Feyrer ◽  
...  
Keyword(s):  
San Francisco ◽  
Salinity Tolerance ◽  
Plasma Osmolality ◽  
Metabolic Cost ◽  
Central Valley ◽  
Metabolic Responses ◽  
Metabolic Rates ◽  
Spawning Habitat ◽  
Osmoregulatory Capacity ◽  
Sacramento Splittail

Abstract The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allopatric upstream spawning habitat of the Central Valley (CV) population connects with the sympatric rearing grounds via relatively low salinity waters, whereas the San Pablo (SP) population must pass through the relatively high-salinity Upper SFE to reach its allopatric downstream spawning habitat. We hypothesize that if migration through SFE salinities to SP spawning grounds is more challenging for adult CV than SP splittail, then salinity tolerance, osmoregulatory capacity, and metabolic responses to salinity will differ between populations. Osmoregulatory disturbances, assessed by measuring plasma osmolality and ions, muscle moisture and Na+-K+-ATPase activity after 168 to 336 h at 11‰ salinity, showed evidence for a more robust osmoregulatory capacity in adult SP relative to CV splittail. While both resting and maximum metabolic rates were elevated in SP splittail in response to increased salinity, CV splittail metabolic rates were unaffected by salinity. Further, the calculated difference between resting and maximum metabolic values, aerobic scope, did not differ significantly between populations. Therefore, improved osmoregulation came at a metabolic cost for SP splittail but was not associated with negative impacts on scope for aerobic metabolism. These results suggest that SP splittail may be physiologically adjusted to allow for migration through higher-salinity waters. The trends in interpopulation variation in osmoregulatory and metabolic responses to salinity exposures support our hypothesis of greater salinity-related challenges to adult CV than SP splittail migration and are consistent with our previous findings for juvenile splittail populations, further supporting our recommendation of population-specific management.

Reduced prosthetic stiffness lowers the metabolic cost of running for athletes with bilateral transtibial amputations

2017 ◽  
Vol 122 (4) ◽  
pp. 976-984 ◽  
Author(s):  
Owen N. Beck ◽  
Paolo Taboga ◽  
Alena M. Grabowski
Keyword(s):  
Lower Limb ◽  
Metabolic Cost ◽  
Ground Reaction Forces ◽  
Metabolic Rates ◽  
Distance Running ◽  
Cost Of Transport ◽  
Leg Stiffness ◽  
Metabolic Costs ◽  
In Series ◽  
Reaction Forces

Inspired by the springlike action of biological legs, running-specific prostheses are designed to enable athletes with lower-limb amputations to run. However, manufacturer’s recommendations for prosthetic stiffness and height may not optimize running performance. Therefore, we investigated the effects of using different prosthetic configurations on the metabolic cost and biomechanics of running. Five athletes with bilateral transtibial amputations each performed 15 trials on a force-measuring treadmill at 2.5 or 3.0 m/s. Athletes ran using each of 3 different prosthetic models (Freedom Innovations Catapult FX6, Össur Flex-Run, and Ottobock 1E90 Sprinter) with 5 combinations of stiffness categories (manufacturer’s recommended and ± 1) and heights (International Paralympic Committee’s maximum competition height and ± 2 cm) while we measured metabolic rates and ground reaction forces. Overall, prosthetic stiffness [fixed effect (β) = 0.036; P = 0.008] but not height ( P ≥ 0.089) affected the net metabolic cost of transport; less stiff prostheses reduced metabolic cost. While controlling for prosthetic stiffness (in kilonewtons per meter), using the Flex-Run (β = −0.139; P = 0.044) and 1E90 Sprinter prostheses (β = −0.176; P = 0.009) reduced net metabolic costs by 4.3–4.9% compared with using the Catapult prostheses. The metabolic cost of running improved when athletes used prosthetic configurations that decreased peak horizontal braking ground reaction forces (β = 2.786; P = 0.001), stride frequencies (β = 0.911; P < 0.001), and leg stiffness values (β = 0.053; P = 0.009). Remarkably, athletes did not maintain overall leg stiffness across prosthetic stiffness conditions. Rather, the in-series prosthetic stiffness governed overall leg stiffness. The metabolic cost of running in athletes with bilateral transtibial amputations is influenced by prosthetic model and stiffness but not height. NEW & NOTEWORTHY We measured the metabolic rates and biomechanics of five athletes with bilateral transtibial amputations while running with different prosthetic configurations. The metabolic cost of running for these athletes is minimized by using an optimal prosthetic model and reducing prosthetic stiffness. The metabolic cost of running was independent of prosthetic height, suggesting that longer legs are not advantageous for distance running. Moreover, the in-series prosthetic stiffness governs the leg stiffness of athletes with bilateral leg amputations.

Metabolic cost of grade running in dogs

1976 ◽  
Vol 41 (4) ◽  
pp. 532-535 ◽  
Author(s):  
J. L. Raab ◽  
P. Eng ◽  
R. A. Waschler
Keyword(s):  
Steady State ◽  
Minimum Energy ◽  
Canis Familiaris ◽  
Metabolic Cost ◽  
Metabolic Rates ◽  
Run Up

Dogs (Canis familiaris) were run up and down 7.4, 11.8, and 20.4% gradesas well as on the horizontal at speeds of 3 and 6 km/h while their steady-state oxygen comsumption was measured. On positive grades the metabolism wasdirectly dependent on both grade and speed. On the negative grades the metabolic rates were dependent only on speed and for each dog were depressed about the same amount below the metabolism needed for horizontal running ateach speed. The clustering of the metabolic rates for the downhill slopes means that to cover a given distance gorizontally and downhill the dog will use the minimum energy if it descends via the gentlest grade. This is so because such a route allows the animal to maintain the lowest metabolism for the longest time. There is no best uphill route. The grade metabolism of the dogs was an almost exact duplicate of that found for humans running on grades which implies similarity of mechanical and biochemical aspects of running.

Energy dynamics and growth of Chinook salmon (Oncorhynchus tshawytscha) from the Central Valley of California during the estuarine phase and first ocean year

2010 ◽  
Vol 67 (10) ◽  
pp. 1549-1565 ◽  
Author(s):  
R. Bruce MacFarlane
Keyword(s):  
San Francisco ◽  
Chinook Salmon ◽  
Climate Models ◽  
Oncorhynchus Tshawytscha ◽  
Energy Content ◽  
Central Valley ◽  
Energy Dynamics ◽  
Period Data ◽  
Energy Gains ◽  
Engraulis Mordax

The greatest rates of energy accumulation and growth in subyearling Chinook salmon ( Oncorhynchus tshawytscha ) occurred during the first month following ocean entry, supporting the importance of this critical period. Data from an 11-year study in the coastal ocean off California and the San Francisco Estuary revealed that juvenile salmon gained 3.2 kJ·day–1 and 0.8 g·day–1, representing 4.3%·day–1 and 5.2% day–1, respectively, relative to estuary exit values. Little gain in energy (0.28 kJ·day–1) or size (0.07 g·day–1) occurred in the estuary, indicating that the nursery function typically ascribed to estuaries can be deferred to initial ocean residence. Calculated northern anchovies ( Engraulis mordax ) equivalents to meet energy gains were one anchovy per day in the estuary (8% body weight·day–1) and about three per day immediately following ocean entry (15% body weight·day–1). Energy content in the estuary was positively related to higher salinity and lower freshwater outflow, whereas in the ocean, cooler temperatures, lower sea level, and greater upwelling resulted in greater gains. These results suggest that greater freshwater flows, warmer sea temperatures, and reduced or delayed upwelling, all of which are indicated by some (but not all) climate models, will likely decrease growth of juvenile Chinook salmon, leading to reduced survival.

Some Effects of Salinity on the Mysid Praunus Flexuosus

1971 ◽  
Vol 51 (3) ◽  
pp. 709-715 ◽  
Author(s):  
D. S. Mclusky ◽  
V. E. J. Heard
Keyword(s):  
Population Dynamics ◽  
Salinity Tolerance ◽  
The Body ◽  
Tolerance Range ◽  
Neomysis Integer ◽  
Body Tissues ◽  
Osmoregulatory Capacity

The population dynamics of the mysid crustacean Praunus flexuosus have been studied at Ardmaddy Bay, Loch Etive. A salinity tolerance range of 2–33‰ has been demonstrated, over which the body tissues experience the range 11–28‰. Comparison is made between the osmoregulatory capacity of Praunus flexuosus and the closely related Neomysis integer.

The entrainment role of photoperiod on hypoosmoregulatory and growth-related aspects of smolting in Atlantic salmon (Salmo salar)

1990 ◽  
Vol 68 (4) ◽  
pp. 707-715 ◽  
Author(s):  
James Duston ◽  
Richard L. Saunders
Keyword(s):  
Salinity Tolerance ◽  
Condition Factor ◽  
Plasma Osmolality ◽  
Natural Photoperiod ◽  
Group A ◽  
Challenge Tests ◽  
Subsequent Loss ◽  
Group B ◽  
Group D

Potential yearling (1+) smolts were maintained under 8.25 h light: 15.75 h dark and constant temperature (10.0 °C) from late December. Groups were subjected to an abrupt increase to 16 h light: 8 h dark on December 31 (group A), February 1 (group B), March 1 (group C), or March 31 (group D). Group E was maintained under constant 8.25 h light: 15.75 h dark for the duration of the experiment and group LDN was maintained under a simulated natural photoperiod cycle (45°N). Plasma osmolality levels following 24-h, 29‰ salinity challenge tests indicated a photoperiod-independent development of hypoosmoregulatory mechanisms preceding completion of smoltification that was significantly correlated with fish body size. As judged by 96-h, 37.5‰ salinity tolerance tests and changes in condition factor, completion of smolting occurred in sequence; in groups A and B it was advanced to late February, while groups C and D completed smolting in mid-March and mid-April, respectively, compared with late May for group LDN. Group E, maintained under constant 8.25 h light: 15.75 h dark, developed salinity tolerance in late May, but unlike other groups exhibited no large reduction in condition factor. Following smolting, an increase in condition factor and a loss of salinity tolerance occurred in all groups. The results support the hypothesis that changes in photoperiod entrain an endogenous circannual rhythm involved in controlling the completion of smoltification and subsequent loss of some smolt characteristics.

scholarly journals Intra-Specific Difference in the Effect of Salinity on Physiological Performance in European Perch (Perca fluviatilis) and Its Ecological Importance for Fish in Estuaries

Biology ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 89 ◽  
Author(s):  
Christensen ◽  
Stieglitz ◽  
Grosell ◽  
Steffensen
Keyword(s):  
Salinity Tolerance ◽  
Perca Fluviatilis ◽  
Estuarine Fish ◽  
Metabolic Rates ◽  
Respiratory Compromise ◽  
European Perch ◽  
Physiological Performance ◽  
Perch Perca Fluviatilis ◽  
In The Wild ◽  
Species Specific

Changes in environmental salinity challenge fish homeostasis and may affect physiological performance, such as swimming capacity and metabolism, which are important for foraging, migration, and escaping predators in the wild. The effects of salinity stress on physiological performance are largely species specific, but may also depend on intra-specific differences in physiological capabilities of sub-populations. We measured critical swimming speed (Ucrit) and metabolic rates during swimming and at rest at salinities of 0 and 10 in European perch (Perca fluviatilis) from a low salinity tolerance population (LSTP) and a high salinity tolerance population (HSTP). Ucrit of LSTP was significantly reduced at a salinity of 10 yet was unaffected by salinity change in HSTP. We did not detect a significant cost of osmoregulation, which should theoretically be apparent from the metabolic rates during swimming and at rest at a salinity of 0 compared to at a salinity of 10 (iso-osmotic). Maximum metabolic rates were also not affected by salinity, indicating a modest tradeoff between respiration and osmoregulation (osmo-respiratory compromise). Intra-specific differences in effects of salinity on physiological performance are important for fish species to maintain ecological compatibility in estuarine environments, yet render these sub-populations vulnerable to fisheries. The findings of the present study are therefore valuable knowledge in conservation and management of estuarine fish populations.

Conspiracy Rises Again

Qui Parle ◽  
2019 ◽  
Vol 28 (2) ◽  
pp. 307-333
Author(s):  
Poulomi Saha
Keyword(s):  
San Francisco ◽  
Central Valley ◽  
The United States ◽  
University Of California ◽  
British India ◽  
Philosophical Concept ◽  
The Past ◽  
Revolutionary Violence ◽  
The University ◽  
Indian Students

Abstract This essay takes up conspiracy as a discursive, political, and philosophical concept. By tracing the ideological and textual kinship between anticolonialism in India and Ireland and radicalism in the United States, it illuminates transcolonial circuits of a curiously shared revolutionary project. Rather than simply offer a historical account of those interconnections, it theorizes a practice of reading revolutionary violence as perpetual, repetitive haunting, a politics of the undead. It argues for a historiographical live burial by which violences of the past reappear to disrupt the imperial promise of futurity and continuity. From the 1916 “Hindu-German Conspiracy Trial” in San Francisco, during which members of the Ghadr Party—consisting of diasporic Indian students at the University of California, Berkeley, and Punjabi farmers in the Central Valley—were accused of conspiring with German diplomats to arm anticolonial revolt in British India, this essay tracks forms of radical sympathy that emerge, flourish, and stutter in an era of ethnonationalist constriction.

Early Life History of Fishes in the San Francisco Estuary and Watershed

2004 ◽  
Keyword(s):  
San Francisco ◽  
Chinook Salmon ◽  
Reference Group ◽  
Central Valley ◽  
Study Groups ◽  
San Francisco Estuary ◽  
Study Group ◽  
First Feeding ◽  
Back Calculation ◽  
Juvenile Chinook

<em>Abstract.</em>—We compared two approaches to back-calculation with otolith microstructure to develop a method for accurately estimating growth rates of juvenile fall-run Chinook salmon <em>Oncorhynchus tshawytscha </em>in California’s Central Valley. Total otolith width was a strong determinant of fork length (FL) in linear regressions used to determine the <em>y</em>-intercept in the fish size–otolith size relationship in two study groups of Chinook salmon. The Fraser-Lee back-calculation model estimated FL at first feeding in both study groups that did not differ significantly from lengths of first-feeding Chinook salmon in a reference group. In comparison, the biological-intercept method produced back-calculated lengths that were significantly greater in one study group than lengths of first-feeding Chinook salmon in the reference group. Chinook salmon emergence dates, estimated from counts of daily growth increments beyond the first-feeding check, corresponded with observed emergence periods in the river and hatchery populations from which the study groups were sampled. Size-at-age relationships were well described by a power function in both study groups, where mean FL over time approached an apparent asymptote at approximately 80 mm after 90 d postemergence. Growth rate estimates, using back-calculated size from the Fraser-Lee model, averaged 0.50 mm/d in one study group and 0.43 mm/d in the other study group. These estimates fell within the range of previous growth rate estimates for juvenile Chinook salmon in Central Valley riverine, floodplain, and delta environments and were about 2.5 times higher on average than an estimate for the San Francisco Estuary and about 2.3 times lower on average than estimates from the Strait of Georgia. We discuss the utility of otolith microstructure to not only estimate growth rates, but also to reconstruct emergence-date distributions in cohorts of emigrating juvenile Chinook salmon for stock identification purposes.

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