Beam Reach

A 2011 quest to identify sound-making fish

The How Stuff Works web site has published a fun investigation of low frequency sounds that were troubling Florida home owners:

http://videos.howstuffworks.com/science-channel/5080-discoveries-fish-mating-calls-video.htm

It turns out the sounds are made by the black drum to attract mates during spawning events.  By “drumming” their sonic muscle — the fastest muscle known in vertebrates — against its swim bladder about 200 times per second, it generates a sound akin to a heartbeat.  According to the abstract of Jim Locascio’s doctoral thesis (advised by David Mann at the University of South Florida), the black drum sounds are surprisingly loud:

Source level estimates averaged 165 dB RMS re: 1 microPa (SD=1.0) (n = 1,025). Call energy was concentrated in the fundamental frequency (94 Hz) and first two harmonics (188 Hz and 282 Hz).

At Beam Reach, one of our 2011 resolutions is to identify the source of a variety of grunts and groans that we often hear in the Salish Sea.  We suspect many of them come from fish like rockfish and midshipmen, but we’re still narrowing down the list of soniferous (sound-producing) fish of the Pacific Northwest.

If you know about local fish (or other marine animals besides mammals) that make sound, or if you have recorded mysterious sounds that you suspect may be fish, please let us know in the comments.  For the curious, here are some “mystery” sounds recorded in the Salish Sea — some of which may be coming from marine fish — while listening to the live hydrophone network we help run.  One to listen for is a “chorus” of fish calls that often occurs in temperate waters within a couple hours of dusk or dawn.