Post-feeding Thermotaxis and Daily Vertical Migration in a Larval FishNature (1988)
Many aquatic animals make daily vertical migrations, typically ascending into warm shallow strata for the night and descending to cooler, deeper layers of lakes or oceans for the day. Although some organisms may migrate to avoid predation1–3 researchers have also suggested that daily migration is a thermoregulatory strategy allowing ectotherms to lower their metabolic rates in cold, deep waters, thus conserving energy4,5. Tests of this hypothesis, however, have been equivocal6–8. Here we suggest an alternative hypothesis: that fish ascend into warmer water after feeding to stimulate digestion, thereby allowing greater feeding and growth. We tested this hypothesis using the Bear Lake sculpin (Cottus extensus) which feeds on the bed of the lake during the day, and at night migrates into the water column where temperatures are 10 °C warmer. The warmer temperatures promoted digestion and allowed the fish to feed and grow three times faster than if they had remained in the cold hypolimnion. Thus, daily vertical migration in this species is an adaptation allowing them to exploit thermal gradients in their environment9 to maximize energetic intake.
Citation InformationWayne A. Wurtsbaugh. "Post-feeding Thermotaxis and Daily Vertical Migration in a Larval Fish" Nature Vol. 333 (1988) p. 846 - 848
Available at: http://works.bepress.com/wayne_wurtsbaugh/175/