Sounding Response of the Kokanee and Sockeye Salmon
- 1 June 1968
- journal article
- research article
- Published by Canadian Science Publishing in Journal of the Fisheries Research Board of Canada
- Vol. 25 (6) , 1115-1131
- https://doi.org/10.1139/f68-098
Abstract
When frightened, sockeye and kokanee salmon dive into deeper waters. This is termed the "sounding response."The sounding response in these fish is accompanied by the expulsion of gas from the swimbladder via the pneumatic duct. This gas loss is active and results from the contraction of the circular muscle fibers in the wall of the swimbladder.Gas loss on sounding is reduced or obviated after exposure to adrenergic blocking agents and enhanced in fish treated with sympathomimetics. Circular muscle fibers in intact and isolated strips of swimbladder contracted in response to sympathomimetics, but this response was prevented after adrenergic blockade. These results suggest the concentration of the swimbladder and associated gas expulsion is under adrenergic control.In untreated fish, an average pressure of 28.1 mm Hg was required to force gas out of the swimbladder through the pneumatic duct. In antropine-treated fish this duct-release pressure fell to an average of 0.2 mm Hg. This suggests constriction of the pneumatic duct is under cholinergic control.Histologically, the pneumatic duct was continuous with the oesophagus and extended as a convoluted duct to the anterior end of the swimbladder. Smooth muscle fibers surrounded the duct along its length and some striated fibers were present at the point where the duct joined the oesophagus. Occlusion of the pneumatic duct may be through the contraction of either of these types of fibers.The term "Gasspuckreflex" as originally used by Franz described the loss of gas from the swimbladder of physostomes in response to decompression. The authors suggest this term be reserved for this passive loss of gas, and not applied to fright-induced gas loss, resulting from active contraction of the bladder wall.This publication has 3 references indexed in Scilit:
- Gas Spitting by Alarmed Fish Disturbs Their Hydrostatic EquilibriumScience, 1962
- The Swimbladder and the Vertical Movements of Teleostean FishesJournal of Experimental Biology, 1951
- The Origin of the Landlocked Habit in SalmonProceedings of the National Academy of Sciences, 1932