Factors affecting swim bladder volume in rainbow trout (Oncorhynchus mykiss) held in gas supersaturated water

Abstract

We examined the response of the rainbow trout (Oncorhynchus mykiss) swim bladder to gas supersaturated water. Cannulas positioned in the swim bladder of fish were connected to a pressure transducer, allowing direct measurement of swim bladder pressure. When denied access to the surface, fish held in supersaurated water showed an increase in swim bladder pressure. This response showed a strong dependence on the total gas pressure and the oxygen partial pressure of the water. The minimum level of gas supersaturation observed to cause this response corresponds to a ΔP of 27 mmHg [Formula: see text]; 1 mmHg = 133.3 Pa). The threshold ΔP for swim bladder inflation increased as the partial pressure of dissolved oxygen increased. Movement of supersaturated gases from the arterial system into the swim bladder is passive and causes a rise in swim bladder pressure until the diffusion gradient is nil or the gas is expelled through the pneumatic duct. The threshold for release of gas out the pneumatic duct is dependent on the size of the fish. Small fish have higher duct release pressures and are subject to a higher degree of pressure buildup within the swim bladder than larger fish.

Understanding Barotrauma in Fish Passing Hydro Structures: A Global Strategy for Sustainable Development of Water Resources

“…Physostomes are able to quickly expel gas via the pneumatic duct, using the gass-puckreflex (gas spitting reflex; Franz 1937), which is under autonomic control. Shrimpton et al (1990) determined that smaller Rainbow Trout had a higher gas pressure release threshold than larger fish (when examining fish in a range from less than 10 to ~250 g). Shrimpton et al (1990) determined that smaller Rainbow Trout had a higher gas pressure release threshold than larger fish (when examining fish in a range from less than 10 to ~250 g).…”

“…Physostomes are able to quickly expel gas via the pneumatic duct, using the gass-puckreflex (gas spitting reflex; Franz 1937), which is under autonomic control. The rate of this reflex is likely critical in reducing injury due to rapid decompression but appears to vary between-and even within-species (Harvey et al 1968;Shrimpton et al 1990). Shrimpton et al (1990) determined that smaller Rainbow Trout had a higher gas pressure release threshold than larger fish (when examining fish in a range from less than 10 to ~250 g).…”

“…The rate of this reflex is likely critical in reducing injury due to rapid decompression but appears to vary between-and even within-species (Harvey et al 1968;Shrimpton et al 1990). Shrimpton et al (1990) determined that smaller Rainbow Trout had a higher gas pressure release threshold than larger fish (when examining fish in a range from less than 10 to ~250 g). Additionally, there have been observations of siluriform Catfish with everted stomachs (Figures 2A and 2B) downstream of hydroelectric facilities, which indicates that gas was not released fast enough from their physostomous swim bladder to avoid barotrauma during rapid decompression.…”

Buoyancy Regulation by Hatchery and Wild Coho Salmon during the Transition from Freshwater to Marine Environments

“…However, accounting for this expansion (assuming that all marine fish were at 3-m depth when collected) results in a mean SBV that is still lower (0.037 mL/g) than that measured for freshwater collections (0.053 mL/g). In addition, swim bladder pressure required for gas release is inversely proportional to pneumatic duct diameter and, thus, to fish size; considerably more pressure is required before gas escapes from small fish (like those used here) than from large fish (Shrimpton et al 1990b). These patterns suggest that while the escape of gas from the swim bladder may have added noise to the measurements of WFD and SBV, it probably was not responsible for the observed differences between fish collected from freshwater and marine environments.…”

A Simple Apparatus for Maintaining Gas‐Supersaturated Seawater in the Laboratory for Experimental Purposes

“…To create a gas-supersaturated environment, researchers have used a variety of techniques, including (1) mixing warm and cold water (Machado et al 1987;Krise and Smith 1993;Mesa and Warren 1997), (2) using pressurized water from depth (Beyer et al 1976;Bouck 1980), (3) utilizing air-injected pressure systems (Rucker and Kangas 1974;Gray et al 1982Gray et al , 1985Shrimpton et al 1990;Caldwell and Hinshaw 1994;Schisler et al 1999), or (4) using a combination of heating and air injection (Chamberlain et al 1980). The methods employed generally have created a single saturation level and have not allowed for control of water temperature.…”