Bioenergetics, Exercise, and Fatty Acids of Fish

The bioenergetic aspects of pentachlorophenol poisoning andexercise in fish are discussed. When cichlids are exposed to0.2 ppm of pentachlorophenol, the intake of food was increasedand energy losses were also increased. Growth was decreased.The cost of specific dynamic action was higher and the costof exercise was increased above the cost of similar exercisein nonpoisoned controls. In salmon swimming to exhaustion at52 cm/sec fatty acids 18:1, 16:0, and 16:1, and at 59 cm/secfatty acids 22:6, 18:2, and 20:4 suffered the greatest depletion.At 52 and 59 cm/sec, respectively, average exhaustion timeswere 1141 and 398 minutes; the equivalents of distance traveledwere 26.0 and 12.7 miles; the loss in lipids, 54 and 10 mg;and the average weight losses, 830 and 480 mg per salmon. Totalcaloric losses calculated from the data on lipid and weightlosses were approximately 1118 and 566 calories. Calculatedfrom the data of Brett (1964) on O₂ consumption, caloric losseswere estimated at only 344 and 188 calories. The differencebetween observed values and values calculated from the dataof Brett may lie in the duration and severity of the exercise.Brett collected his data on O₂ consumption on the basis of atmost two hours at high velocity. Possibly when maximum effortis involved each succeeding mile and each succeeding hour ismore difficult and more costly to the salmon.