Humminbird Side Imaging Forums

General => General Discussion => Topic started by: 1fireball on July 14, 2014, 07:29:20 AM

Title: plankton bloom and why it affects sonar at night?
Post by: 1fireball on July 14, 2014, 07:29:20 AM

Can someone explain why it affects my sonar at night on fresh water lakes?

Title: Re: plankton bloom and why it affects sonar at night?
Post by: Humminbird_Greg on July 14, 2014, 10:09:19 AM

Welcome to the Humminbird Side Imaging Forums 1fireball.

Because plankton (including zooplankton), when in dense enough clouds, can reflect sonar.
Plankton rises to the surface of the water to feed at night as it is safer to do so.

Can you post a Screen Snapshot of this for me please?

Title: Re: plankton bloom and why it affects sonar at night?
Post by: 1fireball on July 14, 2014, 10:29:02 AM

I will get a screenshot next time out.
It was a full moon night and it happened two nights in a row.
My friend Dieter Melhorn is the one who told me what it was.
The screen looked like a lake turning over...like so much trash floating it filled the 2d sonar with lines. You could not desensitize it enough to still see arches underneath.