Measurement of hydrostatic pressure in salmonid eggs

1984 ◽  
Vol 62 (10) ◽  
pp. 1977-1987 ◽  
Author(s):  
D. F. Alderdice ◽  
J. O. T. Jensen ◽  
F. P. J. Velsen
Keyword(s):  
Hydrostatic Pressure ◽  
Internal Pressure ◽  
Pacific Salmon ◽  
Turgor Pressure ◽  
Applanation Tonometry ◽  
Salmo Gairdneri ◽  
Zona Radiata ◽  
Effective Filtration Pressure ◽  
Measured Pressure ◽  
Salmonid Eggs

A method is described, based on applanation tonometry of the human eye, for measurement of hydrostatic (internal, turgor) pressure in salmonid eggs. The area of an egg flattened by an external applanating force is related to the volume of the egg displaced by applanation. The hydrostatic pressure in steelhead trout eggs (Salmo gairdneri) (1248 h postfertilization, 5 °C) was 53 (−7, +8) mmHg (1 mmHg = 133.322 Pa). Unfertilized, flaccid eggs of the species, with an assumed zero internal pressure, had a measured pressure of 1.1 (−0.6, +1.1) mmHg, taken as equivalent to the force required to bend the relatively thick capsule (zona radiata) wall. Hence, the corrected internal pressure is estimated as 51.9 mmHg. Internal pressure in fertilized eggs of three species of Pacific salmon (Oncorhynchus nerka (sockeye), O. gorbuscha (pink), and O. tshawytscha (chinook)) increased during incubation at 10 °C. Between 2 and 8 h after fertilization, hydrostatic pressure was approximately 15 mmHg for sockeye, 25 mmHg for pink, and 40 mmHg for chinook. After 1000 h of incubation, the pressures (millimetres Hg) were approximately 76 for sockeye, 47 for pink, and 51 for chinook. Possible relations between hydrostatic and osmotic pressures are discussed with reference to effective filtration pressure, as well as the potential influence of the latter on oxygen transport across the capsule.

Changes of Internal Hydrostatic Pressure and Body Shape in Acanthocephalus Ranae

1966 ◽  
Vol 45 (2) ◽  
pp. 197-202
Author(s):  
R. A. HAMMOND
Keyword(s):  
Hydrostatic Pressure ◽  
Internal Pressure ◽  
Body Length ◽  
Body Shape ◽  
Muscular Activity ◽  
The Body ◽  
Trunk Muscles ◽  
Rapid Rise ◽  
Indirect Methods ◽  
Pressure Changes

1. Two indirect methods for recording changes of hydrostatic pressure within the trunk of Acanthocephalus ranae have been described. 2. Internal pressure has been shown to be lowest when the trunk is fully contracted and the proboscis invaginated, and highest when the trunk is fully elongated. 3. A rapid rise of internal pressure occurs when the circular trunk muscles contract. 4. Overall internal pressure changes of up to 0.5 cm. Hg have been shown to occur in active specimens. 5. The body length when fully extended is only 40-50% greater than when contracted. 6. The correlation between muscular activity, body shape, and internal hydrostatic pressure in A. ranae is discussed

Fine structure of the external egg membrane of five species of Pacific salmon and steelhead trout

1985 ◽  
Vol 63 (3) ◽  
pp. 552-566 ◽  
Author(s):  
E. P. Groot ◽  
D. F. Alderdice
Keyword(s):  
Fine Structure ◽  
Chum Salmon ◽  
Pacific Salmon ◽  
Salmo Gairdneri ◽  
Membrane Thickness ◽  
Steelhead Trout ◽  
Outermost Layer ◽  
Additional Layer ◽  
Egg Membrane ◽  
Pore Canals

Fine structure of the external egg membrane of five species of Pacific salmon (sockeye, Oncorhynchus nerka; pink, O. gorbuscha; chum, O. keta; coho, O. kisutch; and chinook, O. tshawytscha) and the anadromous steelhead trout (Salmo gairdneri), is examined and compared using the scanning electron microscope. Membrane thickness in fixed material varies for the six species as follows (micrometres, [Formula: see text]): sockeye, 34.15 ± 0.15; pink, 61.64 ± 1.53; chum, 53.05 ± 0.33; coho, 27.96 ± 0.48; chinook, 50.82 ± 0.74; steelhead, 30.74 ± 0.11. The membrane consists of a thin outermost layer, the externus, 0.2–0.3 μm thick, and the internus, 24–55 μm thick, which constitutes the remainder of the membrane. In sockeye, pink, and chum salmon and steelhead trout, an additional layer 3–8 μm thick, the "subinternus," occurs beneath the internus. The entire membrane appears fibrous except for the thin and apparently solid externus. Pores in both the inner and outer surfaces are arranged in a hexagonal pattern and are connected by pore canals traversing the membrane. Except in the sockeye, plugs commonly were seen blocking the external openings of the pore canals. Significance of the egg membrane fine structure is considered in relation to several of its roles in the water-activated egg: semipermeability, retention of internal pressure, and mechanical protection. A structural and functional analogy is drawn between the fine structure of the salmonid egg membrane and the mammalian aorta.

Influence of Casing Inner Wall Corrosion on Internal Pressure Strength

2011 ◽  
Vol 199-200 ◽  
pp. 555-558
Author(s):  
Zhi Qian Xu ◽  
Xiang Zhen Yan ◽  
Xiu Juan Yang
Keyword(s):  
Service Life ◽  
Corrosion Rate ◽  
Internal Pressure ◽  
Empirical Method ◽  
Thickness Reduction ◽  
Time Varying ◽  
Distribution Law ◽  
Curve Method ◽  
Well Depth ◽  
Measured Pressure

Considering the differences of pressure and temperature along well depth, the distribution law of casing inner wall corrosion rate was calculated with the Norsok model. According to the measured pressure values, the law of well pressure changing with the time can be obtained with the empirical method or the derivative curve method. Then the changing laws of the corrosion rate and the thickness reduction of casing inner wall are derived during the casing service life. Finally, the time-varying characteristic of casing internal pressure strength influenced by corrosion is researched.

The Effect of the State of Stress on the Strain at Fracture

1974 ◽  
Vol 96 (3) ◽  
pp. 190-194
Author(s):  
E. A. Davis
Keyword(s):  
Hydrostatic Pressure ◽  
Internal Pressure ◽  
The State ◽  
Tubular Specimen ◽  
State Of Stress ◽  
Tension Tests ◽  
Pressure Tests

Tension tests on solid cylindrical specimens and internal pressure tests on one type of tubular specimen showed that a superimposed hydrostatic pressure increased the ductility. Internal pressure tests on a similar tubular specimen that was supported in a different manner showed that the hydrostatic pressure had almost no effect on the ductility.

Design and Experimental Validation of a Novel Magnetorheological Damper With Internal Pressure Control

2015 ◽  
Author(s):  
Nicola Golinelli ◽  
Andrea Spaggiari
Keyword(s):  
Magnetic Field ◽  
Hydrostatic Pressure ◽  
Internal Pressure ◽  
Experimental Validation ◽  
High Pressures ◽  
Pressure Control ◽  
Magnetorheological Damper ◽  
The Other ◽  
The One ◽  
Ferromagnetic Particles

In the present paper we investigated the behaviour of magnetorheological fluids (MRFs) under a hydrostatic pressure up to 40 bar. We designed, manufactured and tested a magnetorheological damper (MRD) with a novel architecture which provides the control of the internal pressure. The pressure was regulated by means of an additional apparatus connected to the damper that acts on the fluid volume. The MRD was tested under sinusoidal inputs and with several values of magnetic field and internal pressure. The results show that the new architecture is able to work without a volume compensator and bear high pressures. On the one hand, the influence of hydrostatic pressure on the yield stress of MRFs is not strong probably because the ferromagnetic particles cannot arrange themselves into thicker columns. On the other hand, the benefits of the pressure on the behaviour of the MRD are useful in terms of preventing cavitation.

Trichodina truttae Mueller, 1937 (Ciliophora: Peritrichida), a common pathogenic ectoparasite of cultured juvenile salmonid fishes in British Columbia: redescription and examination by scanning electron microscopy

1984 ◽  
Vol 62 (9) ◽  
pp. 1842-1848 ◽  
Author(s):  
J. R. Arthur ◽  
L. Margolis
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
British Columbia ◽  
Pacific Salmon ◽  
Salmo Gairdneri ◽  
Diagnostic Features ◽  
Detailed Surface ◽  
Juvenile Pacific Salmon ◽  
Oral Surface ◽  
Scanning Electron

The trichodinid ciliate Trichodina truttae Mueller, 1937 is redescribed from silver-impregnated specimens collected from the skin of cultured juvenile Pacific salmon (Oncorhynchus spp.) and steelhead trout (Salmo gairdneri) from British Columbia, and its detailed surface topography was examined by scanning electron microscopy (SEM). Diagnostic features evident by light microscopy are the large size (body diameter 114–179 μm), high denticle number (28–30), and high number (about 20) of radial pins per denticle. Especially noteworthy characters revealed by SEM that may be important for species identification are the presence of radial ridges on the oral surface and two markedly different lengths of cilia within the adoral ciliary spiral. This is the first verified report of T. truttae from Canada.

Kudoa thyrsites (Gilchrist, 1924) (Myxozoa) in the cardiac muscle of Pacific salmon (Oncorhynchus spp.) and steelhead trout (Salmo gairdneri)

1989 ◽  
Vol 67 (2) ◽  
pp. 341-342 ◽  
Author(s):  
Z. Kabata ◽  
D. J. Whitaker
Keyword(s):  
British Columbia ◽  
Cardiac Muscle ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Salmo Gairdneri ◽  
Oncorhynchus Keta ◽  
Steelhead Trout ◽  
Myxozoan Parasite ◽  
Kudoa Thyrsites ◽  
Pacific Salmonids

An examination of the cardiac muscle of returning adults of all species of British Columbia Pacific salmonids, including steelhead trout (Salmo gairdneri), for infection by the myxozoan parasite Kudoa thyrsites showed that all species but chum (Oncorhynchus keta) and sockeye (Oncorhynchus nerka) are susceptible to infection. The prevalence of observed infection was low. Its intensity was not determined, but the small numbers of spores observed suggest that it was low. The possible causes of these observations are discussed.

Occurrence of threespine sticklebacks (Gasterosteus aculeatus) in the open North Pacific Ocean: migration or drift?

1989 ◽  
Vol 67 (11) ◽  
pp. 2850-2852 ◽  
Author(s):  
T. P. Quinn ◽  
J. T. Light
Keyword(s):  
Pacific Ocean ◽  
Fish Species ◽  
North Pacific ◽  
Gasterosteus Aculeatus ◽  
Pacific Salmon ◽  
North Pacific Ocean ◽  
General Rule ◽  
Salmo Gairdneri ◽  
Small Fish ◽  
Long Distance

This paper documents the occurrence of a small fish species, the threespine stickleback (Gasterosteus aculeatus), in the open North Pacific Ocean. Sticklebacks were incidentally caught in 77 of 4138 (1.86%) purse seine sets for Pacific salmon and were found in the stomachs of 31 of 639 (4.85%) steelhead trout (Salmo gairdneri) caught on the high seas. If destined to reproduce, these pelagic sticklebacks would be an exception to the general rule that long distance migration is undertaken only by large fish species, but it is also possible that they were isolated from breeding populations.

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