Friday, March 22, 2013

Squid really can hear!

Our first candidate for hearing test
Busy couple of days! Yesterday, we finalized our setup with a few calibrations and including getting Kakani's particle image velocimetry (PIV) system running. This system uses a laser and small particles in the water to measure the hydrodynamic flow and swimming movement of animals. In this case, squid. We also dissected a large "veined" squid specimen. The animal was 47 cm mantle length, and over a meter in total length (from the tip of the tentacles to the end of the body). That's a big squid!  We examined precisely how and where to place the electrodes for the hearing tests.

Loligo forbesi (the "veined" squid) specimen over 1 m total length.
Today, we worked with our nice, accommodating Loligo forbesi squid. First we started out with Kakani's PIV work recording with her high-speed camera the movement particles around the squid as it moved in our large glass tank.  The animal was the sedated (another interesting procedure we defined for squid) and move to our hearing test tank. Aran then inserted the electrodes and starting measuring the squid's neurological responses to sound!  It heard from 80-500 Hz, very similar to our inshore squid species in Woods Hole. This is the second audiogram (hearing test) of any squid species, the first for L. forbesi, and the first for a pelagic squid species. 

Even after 13 years of doing this, I am always impressed when we can pack up a portable, neurophysiology (or laser) system. Ship everything thousand of miles, and they get amazing new data on previously unexamined or poorly understood species. Pretty exhilarating stuff.

Our squid friend during the hearing test. The blue circle is the speaker. The yellow and white cables are the neurophysiology sensors.

 After the tests, we placed the animal back into its holding tank. We hope to try some pressure-temperature-acceleration tag fittings on it later today or tomorrow. It really is an accommodating squid. We're also planning on squid fishing tomorrow, if the weather improves.
Stay tuned, we'll keep you posted!

No comments:

Post a Comment