Say What?

What exactly can marlin “hear”? As I started to dive into this topic, I immediately hit a roadblock. No one has been able to keep a billfish alive in captivity, so unfortunately, unlike some other penned species such as tuna, no studies have been conducted on what and how marlin hear. ¶ This inquiry brings on another question: What do billfish hear down there, and how are sounds perceived? Ironically, this is the same question I began asking as I was putting together a piece on raising fish, and what we can do to turn our own vessels into fishy boats.

Have you ever run over a mark on your screen that looked like a nice marlin sulking in the depths and wondered what it is that actually brings it up to investigate your pattern? Presumably, if the mark is deeper than 20 fathoms, we can assume that the fish is deep enough where sight alone would make little or no difference in raising them to the surface. So it must be sound that sparks their interest, right? Well, maybe.

My first order of business was to speak with marine scientists and experts in the field, and read as much on the study of fish hearing as I could find. The research led to some interesting discoveries that better illuminated a picture of what these animals might be hearing deep down in the dark water column. It also brought to question what techniques we might tweak in our trolling efforts for marlin.