Hi Everyone!

I do not fish but this is an interesting application of
technology.
Shabbat Shalom,
Jacob

A Fish Caught With Hook, Line and Sonar

By James Gorman
New York Times - Technology
July 24, 2003
http://www.nytimes.com/2003/07/24/
technology/circuits/24howw.html?8cir
 
Using sonar to help catch fish may seem unfair, but sonar evolved 
for hunting, at least in bats. They were pinging moths on nightly
search-and-destroy missions eons before World War II destroyers 
hunted enemy submarines. 

Bats have not changed their tactics recently (nor have whales and 
dolphins, which also use underwater sound for a variety of reasons), 
but biological evolution is slow. Technological evolution, 
as everyone knows, is rapid and unpredictable and can result in 
high credit-card balances. A variety of sonar species have evolved 
since World War II and filled unoccupied niches in science and 
bass fishing. 

Scientists developed side-scan sonar to map the ocean floor, 
hunt for the Titanic and find ancient sea trade routes in the 
Mediterranean by looking for discarded wine jugs, or amphorae. 
In this technique, shaped waves of sound are sent out from a 
small assembly called a towfish that is towed on the surface 
behind a ship. Returning echoes are amplified, digitized and 
sent up a cable, usually to a scientist's laptop computer. 
This kind of sonar can identify features as small as a 
centimeter wide.

In medicine, echocardiograms and sonograms have become familiar 
ways to map the inside of the body with sound. 

Both of these technological genera involve increasingly sensitive, 
expensive and sophisticated instruments. In fishing, technological 
evolution has followed its other common course - the smaller, 
better, cheaper path of all consumer electronics. 

As a consequence, it's not just commercial fishing boats or 
professional bass anglers who use fish finders. Every boat with 
a fishing rod in it seems to have one. 

If all you have is a rowboat, there are fish-finder models for 
not much more than $100. Hand-held fish finders with the 
sound-producing transducer on a cable have been marketed. 

Obviously, someone had to develop the fish-finder wristwatch, 
or rather, wrist receiver, since it doesn't tell time. Techsonic 
Industries, a maker of a variety of fish finders, has created 
the Humminbird Smartcast, in which a small towfish shaped like 
a child's bath toy is cast into the lake on a fishing rod as 
if it were a lure or a bobber. In fact, it can be used as a 
bobber, although it is probably better when used just for 
reconnaissance, to find a good spot.

This sonar sensor, a little bundle of electronics sealed in 
plastic, turns on only when it is in the water. Then it sends 
out sound waves, receives the echo and transmits what it has 
found on one of two possible radio frequencies (in case you're 
standing next to another angler with the same kind of fish 
finder). You check the screen on your wrist to view the depth 
of the water, the shape of the bottom and, if you are lucky, 
little fish-shaped blobs.

All fish finders are fickle. The little fish shape is not always 
a fish; sometimes it's debris in the water. Fish finders all 
require some getting used to, and in my experience, they all 
go haywire for mysterious reasons at unpredictable times. 

By these standards, the Smartcast, which can be purchased for 
about $90, was pretty good. I tried it on a lake near my home. 
First I cast it out from a dock where people often catch fish. 
Sure enough, it showed me the bottom, picked out fish in only 
one place (false positives are a real problem with fish finders) 
and was easily comprehensible. 

This is a minimalist fish finder, which in many ways is a blessing. 
Anglers who buy it are likely to be looking simply for depth or 
an underwater structure and a few fish. They probably don't need 
bells and whistles like "two input ports for digital Multimedia 
cards for recording, storing, reviewing and editing your sonar 
graphs and G.P.S. trip details" that come with a $1,255 model 
from Lowrance.

The wrist receiver does have its limits. It has to be in the 
line of sight of the sensor without any obstructions, including, 
as the instructions mention, your wrist. Sometimes this means 
standing in an awkward position as you view the screen, hold your 
fishing rod and reel in the sensor as you investigate a stretch 
of bottom. The Smartcast's range is about 75 feet, and it works 
up to a depth of 100 feet.

I walked around the lake checking spots. I made a few desultory 
casts with a fly rod, but few fish were near shore, and the ones 
I did mark had sought out spots that required casts into the wind. 

I have a couple of thoughts for improvements. Perhaps some of the 
new telephone/camera/MP3 player/palmtop/Web browser/e-mail devices 
could also serve as a receiver for the remote sensor. Then it 
would be as if the fish were calling in. With some voice software, 
the sensor could even deliver instructions in a sultry voice: 
"Hi, Jim, these look like white perch. Try bouncing a grub along 
the bottom."

Meanwhile, I can't help but imagine the fish hiding in deep water 
behind rocks like submariners in a World War II film, sweating, 
smoking cigarettes and listening to the pings.