Echo Sounder Theory; About Biomass - Simrad ES70 - REFERENCE MANUAL REV A Reference Manual

Simrad ES70
When you use an echo sounder there are some basic knowledge that you may find it
useful to possess.
Topics
• About biomass on page 204
• About TVG gain on page 205
• About dynamic range and display presentation on page 206
• About output power on page 207
• About pulse duration on page 207
• About bottom slopes on page 209
About range selection on page 210
•
• About bottom lines on page 211

About biomass

Provided that you use an ES70 with a split beam transducer, or have a valid biomass
license on a single beam transceiver, you will have access to the
pane.
This biomass value is an indicator to how much fish you currently have in the current
echogram, or in the zoomed area. Every single fish will emit an echo, and the sum
of all these registered echoes are presented as a number. Smaller organisms such as
plankton will also emit echoes, but these are so weak that they will hardly influence on
the total biomass.
ES70 records all the targets from the smallest plankton to the largest whale, and provides
these findings as a number. For all practical purposes this number will provide you with
information about the fish abundance to allow you to decide if it pays off to start fishing.
You must also consider if this number is a result of large amounts of plankton or bait, or
if there is real fish below the keel. The number provided to display fish abundance is
relative, and after some use your experience will be a valuable factor when the decision
is made.
204

Echo sounder theory

information
Biomass
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