Editing Atlantic cod (section)

===Response to changing temperatures===
Swimming and physiological behaviours change in response to fluctuations in water temperature. [[Respirometry]] experiments show that heart rates of Atlantic cod change drastically with changes in temperature of only a few degrees. A rise in water temperature causes marked increases in cod swimming activity. Cod typically avoid new temperature conditions, and the temperatures can dictate where they are distributed in water. They prefer to be deeper, in colder water layers during the day, and in shallower, warmer water layers at night. These fine-tuned behavioural changes to water temperature are driven by an effort to maintain homeostasis to preserve energy. This is demonstrated by the fact that a decrease of only {{convert|2.5|C-change|0}} caused a highly costly increase in metabolic rate of 15–30%.<ref name=Claireaux>{{cite journal|last=Claireaux|first=G|title=Physiology and behaviour of free-swimming Atlantic cod (Gadus morhua) facing fluctuating temperature conditions|journal=Journal of Experimental Biology|year=1995|volume=198 | issue = 1|pages=49–60|doi=10.1242/jeb.198.1.49|pmid=9317317|url=http://jeb.biologists.org/content/198/1/49.short|access-date=27 October 2013|display-authors=etal|doi-access=free|bibcode=1995JExpB.198...49C}}</ref>