Southern blue-fin tuna. (Image from http://www.thewe.cc)
I was very intrigued by a research brief that recently ran in New Scientist magazine on the cause for daily deep-diving behavior in southern blue-fin tuna. According to the un-bylined brief, these top-predator fish descend deeply like clock-work, penetrating the depths at almost exactly 30 minutes before sunrise and again 30 minutes after sunset. Apparently scientists differ over the reasons behind this behavior. Some say that the tuna make rapid descents to keep track of their prey. Others suggest diving rids the fish of pesky parasites. But a recent study interprets their behavior more complexly. A researcher from the University of Tasmania in Australia is lead author to a paper published in Behavioral Ecology and Sociobiology that concludes the tuna dive regularly to calibrate and fine-tune their internal compasses at the precise time of day when they can get the clearest reading possible. (more…)
