Blackwaterkatz
bait shad
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Posts: 64
My big cat50+ Blue Catfish, 30# Flathead, 18# Channel
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« Reply #75 on: September 04, 2008, 12:45:00 PM » |
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Hey Michael, I just read something that pretty much confirms what I felt in my head: Unlike most other fish, in which the air-bladder is a simple parchment-like sac, gars have air-bladders which serve as efficient lungs to supplement their gills in aerating their blood. These air-bladders are spongy, richly supplied with blood vessels, and have a connection with the throat through which air is exhaled and inhaled when they come to the top of the water and "break" the surface, as they frequently do. The makeup of their air bladder (which is what the sonar signal actually reads) is denser than that of many fish, which could explain why they show up on screen the way they do, while a catfish has a large bladder, but not as dense, or maybe not as large as the longnose gar. ???? |
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« Last Edit: September 04, 2008, 12:45:49 PM by Blackwaterkatz »
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Tommy
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catfishrus
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« Reply #76 on: September 05, 2008, 04:31:34 PM » |
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Tommy, dad got on a big school of stripers once on the lower lake under a big school of gar by accident. He wasnt catching much but spotted these gar on top so he decided to see if he could catch one ...well he started catching stripers under them on a crank bait. Ive seen them by the acres on top in the lower lake under calm water conditions and I feel sure you have also. Just thought I would tell you about that in case you ever run across a school of gar. You never know whats feeding under them.
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Blackwaterkatz
bait shad
Offline
Posts: 64
My big cat50+ Blue Catfish, 30# Flathead, 18# Channel
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« Reply #77 on: September 06, 2008, 03:59:15 AM » |
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I have seen that, Michael, but I don't often target stripers. A biologist/guide coworker also mentioned the same thing to me yesterday. Thanks.
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Tommy
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Gottafish
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« Reply #78 on: September 06, 2008, 11:55:09 AM » |
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You're also only going to get the most pronounced arches when a fish is directly under the boat. The arch is caused because the fish is "further away" from the transducer when the echo is first returned. As you move closer to the fish, it gets closer to the transducer so the depth reading is shallower on screen, then as you move away from it, the reading gets deeper again.
Fish that are off to the side of the boat will show a much flatter arch because the distance from the transducer doesn't change as much.
It's also a good idea to think of your arches as the number of feet "away from the transducer" as opposed to "depth". In otherwords - if you mark a fish at 20 feet - it's 20 feet away from the transducer, not 20 feet deep. The reason for that is, if you mark a fish off to the side of the boat at "20 feet" it is actually shallower in the water column. How deep actually depends on the cone angle of the transducer.
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catfishrus
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« Reply #79 on: September 06, 2008, 01:58:43 PM » |
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Scott you trying to give away some more raffle tickets?  Just kidding you but I know thats what your question was about for the raffle tickets a while back. Im not sure I really understand that but I get the point. I could see it more with a really wide angle cone or really deep water. |
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Gottafish
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« Reply #80 on: September 07, 2008, 02:50:46 AM » |
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LOL, that's why I am trying to stress it because it's a bit difficult to grasp. Here's a little experiment - Hang a string from your ceiling (I'm assuming its an 8 foot ceiling) until it touches an object on the floor. Now consider that string the "path" of the echo from the transducer to the object that you would read on your depth finder. You depth finder would tell you that the object was at 8 feet right?
Now move the object 2 feet to the side. The 8 foot string no longer touches it because it's further away from the point on the ceiling (the transducer). Let's say it takes a 9 foot string to touch the object now (no I'm not doing any math). Your depth finder would now tell you the object is at 9 feet, when it's really at a depth of 8 feet...
The principle is the same on the water. Only fish "directly" under the transducer will be "accurately" recorded at the depth they're in. The further away from the transducer they get, the deeper they will be recorded relative to the depth they're actually at. That's also the reason for arches.
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Blackwaterkatz
bait shad
Offline
Posts: 64
My big cat50+ Blue Catfish, 30# Flathead, 18# Channel
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« Reply #81 on: September 07, 2008, 03:06:56 AM » |
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Thanks for posting the info, Scott. I've read that before in some of the stuff when I was really trying to learn the sonar. A lot of people that use them don't fully understand how it all works, and I'm still learning, too. Oddly, when I made the trip to James River in March of 2006, things just seemed to really start falling into place for me as far as interpreting the sonar images, and I try to learn something new on almost every trip.
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Tommy
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Jerry9497
flathead catfish
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Posts: 293
My big cat67blue 25flathead 12channel
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« Reply #82 on: September 07, 2008, 11:07:43 AM » |
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it would seem to me that if I were in 40 foot of water and a fish was 20 foot beside the boat and on the bottom then it would mark my fish at a depth greater than 40. but that does not occur on my sonar.
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gone fishing, please leave a message
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Blackwaterkatz
bait shad
Offline
Posts: 64
My big cat50+ Blue Catfish, 30# Flathead, 18# Channel
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« Reply #83 on: September 07, 2008, 12:43:06 PM » |
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Nor on any other sonar, Jerry. From the link http://www.hightechfishing.com/lowrancetutorial.html You may want to follow the link and view the explanatory pics. Maybe this will help you, but the article is really worth reading in its entirety.
Critical Concept # 1 : The transducer is the “eye” of the sonar.
This is more true than most people realize. The transducer is an unblinking eye which views the water below your boat in a full 360º. Frontward, right, left, backwards, and all around. The actual view of the transducer is similar to a “fisheye view” where the closest point is directly below the transducer, and falls away on all sides. In referencing the lake bottom, what is forward, behind, or to either side of the transducer is increasingly farther away than what is directly below.
If a Sonar actually displayed every bit of every signal it transmitted and received it may appear like the following Illustration. Here it is more readily seen how what is forward rises to the transducer and what is behind falls away. At the point in which the actual bottom is closest, is determined to be the actual depth under the transducer and this contour is only charted when directly below the transducer. So even though structure or suspended targets may return echoes long before directly below the structure and bottom chart until the closest the transducer.
While you may begin to pick up the slightest echo returns from suspended targets which are farther away than the bottom, they do not chart on the screen until they are closer than the bottom as no details are plotted below the bottom contour line. The shape and strength of an echo arch can provide clues to where it is located relative to the center or nearest point of the transducer.
The peak of the arch does not indicate depth… It indicates only the exact range from the transducer to something which returns an echo [/size][/size] |
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« Last Edit: September 07, 2008, 12:45:02 PM by Blackwaterkatz »
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Tommy
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Gottafish
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« Reply #84 on: September 07, 2008, 03:27:34 PM » |
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That's correct Jerry, you would not mark that fish. It's buried in the bottom return.
Good link Tommy, I don't think I've seen that one before.
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Doug158
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« Reply #85 on: September 07, 2008, 03:56:44 PM » |
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All excellent info thanks Guy's  |
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Jerry9497
flathead catfish
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Posts: 293
My big cat67blue 25flathead 12channel
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« Reply #86 on: September 07, 2008, 04:05:04 PM » |
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I read it, I guess my sonar is not as smart as I gave it credit for. I rarely try to park on a fish anyway.I usealy go up current or wind from it and drift the area or scatter my rods out in the area when anchored.
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gone fishing, please leave a message
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Doug158
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« Reply #87 on: September 07, 2008, 05:17:43 PM » |
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I usually just fish structure unless I am running and gunning in the stumpfield then I am looking for fish in and around the structure  |
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Gottafish
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« Reply #88 on: September 08, 2008, 04:03:05 AM » |
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Some, noted catfishermen claim they can park over a "specific" fish and catch it. Specifically because Sonar's aren't as "smart as we thought" (I like that comment ), I don't believe it for a second. That's also why the little "fishy" symbols are nothing more than "more junk on the screen"...Sorry Jim |
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« Last Edit: September 08, 2008, 04:04:14 AM by Gottafish »
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bigcatwannabe
flathead catfish
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Posts: 415
My big cat53 lb blue, 41 lb flathead, 20 lb channel
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« Reply #89 on: September 08, 2008, 02:55:04 PM » |
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ive done everything you guys said and looked at the tutorials, but my lowrance x86 doesnt show arches, just blobs, i mean it marks all the fish, i catch baitfish with it all the time, but it just doesnt show arches like all the others ive seen, any suggestions
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pat
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