fish finders: fish id or arc

[Psandherr]

i just got a new fish finder mounted on my boat it is a lowrance 4x pro

I have had several people tell me to turn the fish id off and just read the arcs. Why is that?

love to hear your opinions

 

[joed]

Re: fish finders: fish id or arc

That is how how I use mine. I just like to see the raw uneditted data so I can make my own determinations. I believe the fish ID cuts out some of the data that can be useful.

 

[Georgesalmon]

Re: fish finders: fish id or arc

I use both. I agree that some data may be lost using fish ID. When I am targeting fish using techniques such as bottom jigging walleye I use the raw data (arches). When I'm trolling I use the fish ID feature as I am not trying to so directly target fish, just looking for depth and if anything is there at all. I can just glance at the display once in a while and make sure I'm at the right depth and location. I like the feature that displays the depth of the fish in little numbers alongside the fish picture also.

 

[dingbat]

Re: fish finders: fish id or arc

Fish ID is a useless feature to give inexperience people someone to look at while they’re boating.

Fish ID doesn't know the difference between a fish and a stick if the stick walked up and hit it in the head. Actually, more a hindrance than help since they typically don't recognize or filter out the little details that can make a difference.

Between the sensitivity of my unit and my experience with using it, I can tell you what species of fish the unit is marking. If you’re lucky enough to have a good unit, you’ll find that each species of fish gives off a distinctive return. Some by their shape, others by the colors in the return.

FWIW: Ever notice how out of scale the arches are?

 

[bruceb58]

Re: fish finders: fish id or arc

Fish ID is pretty much useless as fas as I am concerned. I never turn it on.

 

[Jlawsen]

Re: fish finders: fish id or arc

The reason you turn it off is because it will mark things that are not fish. The arches rairly lie and you can tell a lot about the fish by the way an arch is formed. I can tell the difference between a trout and a Tui Chub just by the way the arch forms and how the fish stack up in the water column.

 

[bruceb58]

Re: fish finders: fish id or arc

FWIW: Ever notice how out of scale the arches are?

So what is the reason for that? I always figured it was due to a very wide cone angle picking up a fish that was far away and as the boat passed over it it would be closer(top of the arc). I would think that the deeper the fish, the more variation in the arc there would be.

 

[Jlawsen]

Re: fish finders: fish id or arc

The arch can be disproportionate to the actual fish size because either the boat or the fish is moving. Multiple pings of over a moving object will make it appear larger.

 

[J_48_Johnson]

Re: fish finders: fish id or arc

Also, the partial arcs on the screen are from fish either swimming into or out of the sonar as you pass over them. They are right at the very edge of it as they get "read" for the lack of a better term.

 

[dingbat]

Re: fish finders: fish id or arc

So what is the reason for that? I always figured it was due to a very wide cone angle picking up a fish that was far away and as the boat passed over it it would be closer(top of the arc). I would think that the deeper the fish, the more variation in the arc there would be.

The arch is the result of the fishe’s higher density skeletal structure. How is it possible for the arch to extend outside the body of the fish?

See post #12
http://forums.iboats.com/showthread.php?t=474468

The arches you see on the screen of the more popular FF is indeed a software driven "feature". The arching phenomenon does exist, but the size is comparison to the outline of the fish is very small. You would not be able to see them without enhancement. It takes a very large fish, high up in the water column, for the arch to be large enough to be seen without zooming in on the object.

 

[Psandherr]

Re: fish finders: fish id or arc

so for a basic unit with a small screen and gray scale would fish id be better

 

[fishndirk]

Re: fish finders: fish id or arc

It really doesn't matter iether way. Dingbat and some of the others are right on with this. A "fishfinder" is only called that because it misleads people into thinking their going to "find" fish. Although some of those "blips" you see on your screen may actually be fish, this is not the intended purpose of this type of equipment. Keep in mind, this is not a rifle with a scope on it; your not going to spot a fish on your screen and drop a jig right on his head. Fishfinder is just a cool name for them, I prefer to call it a sonar because it refers to the actuall intended purpose of them. They are there to help you know these things: how deep it is, bottom structure, transition zones, thermal clines, water temp, ect...knowing these things and the habbits of the fish you are after will help you "find" the fish, not those cool little blips on your screen

 

[Psandherr]

Re: fish finders: fish id or arc

It really doesn't matter iether way. Dingbat and some of the others are right on with this. A "fishfinder" is only called that because it misleads people into thinking their going to "find" fish. Although some of those "blips" you see on your screen may actually be fish, this is not the intended purpose of this type of equipment. Keep in mind, this is not a rifle with a scope on it; your not going to spot a fish on your screen and drop a jig right on his head. Fishfinder is just a cool name for them, I prefer to call it a sonar because it refers to the actuall intended purpose of them. They are there to help you know these things: how deep it is, bottom structure, transition zones, thermal clines, water temp, ect...knowing these things and the habbits of the fish you are after will help you "find" the fish, not those cool little blips on your screen

That makes perfect sense and i should have thought of it sooner. Of course you cant use a fish finder to find fish only the cover that they would be in.

Thanks for the insight

 

[fishndirk]

Re: fish finders: fish id or arc

That's exactly right, you got it. Fish move, the bottom of the river doesn't.

 

[rivermouse]

Re: fish finders: fish id or arc

I got a harbor freight fish finder, I cant seem to figure it out,,,Should I throw it in the trash? I cant afford another one right now.

 

[foodfisher]

Re: fish finders: fish id or arc

Three sharks w/ramoras and a lone remora Just had to.

 

[Jlawsen]

Re: fish finders: fish id or arc

Fishndirk nailed it. The term fishfinder is a marketing ploy only. The truth is that it's just a fathometer that's been adapted for us. It does use sonar by bouncing a signal off the bottom and then calculating the time it takes for that signal to be heard back. Fishfinders have different degrees of sensitivity and if you have a fairly good unit you can adjust that sensitivity and the frequency to see things that get in the way of the signals destined for the bottom.

My Lowrance HDS 8 standard sonar is highly tuneable and I can adjust the sensitivity so that I can see fish arches and not all the other clutter or I can adjust it so that I can see the thermocline and use that instead of looking for arches. There is also a point of compromise where you can see both the thermocline and the fish and this is where most basic fish finders are going to be set.

Lowrance also has structure scan sonar that uses much higher frequencies to produce a very accurate picture of the bottom. It's not a fish finder although if you train you eyes well enough you can see fish. Humminbird has side/surface scan that is probably more effective at seing fish in and around the depths of the thermocline. Of course the thermocline feeders are not every fish and may not be what your fishing for. That's why I went with the Lowrance HDS and use both structure scan and standard sonar to give me an "excellent idea" (pivotal phrase) of where I should be fishing and at what depth.

Other factors such as surface temp and oxygen levels factor in because the natural food of the fish that you're going after will change colors depending on that. It's critical to know that info on lakes but not such a big factor on rivers and almost unimportant in Saltwater.

Given all that, you can see that there's no way a fishfinder can accuratel choose between a fish and clutter. It may be 25% correct though and that may be enough if you learn to use the other factors well. I don't use the Fish ID function on my units if for no other reason than it's wrong 75% of the time.

 

[Mark_VTfisherman]

Re: fish finders: fish id or arc

Not sure why this was moved as I interpret this thread as a fishing question not an electronics question. But I digress.

There are a lot of assumptions made in this thread. dingbat makes some good points. But I have thoughts after covering the thread:

That makes perfect sense and i should have thought of it sooner. Of course you cant use a fish finder to find fish only the cover that they would be in.

All depends on what kind of fish and what kind of water you are fishing. Not all fishing is in cover.

I use sonar to find fish all the time! I NEVER use fish ID as it obscures everything useful and makes my good resolution pointless if all I am getting is fish symbols. I use sonar to find fish when open water salmon trolling, and open water or off-structure oriented roaming walleye for example.

There ain't no cover out there! I am looking for bait, and arches that indicate fish at certain depths. I also sometimes lower (at varying depths up to it's full 60' length) an electronic water temp sender and check temps at varying depths and choose which arches to target if that information gets my attention. I have marked arches while fishing and suddenly adjusted lure depth based on the depth of the arch and often this results in a fish being caught. It is not a fish-finder, as pointed out. It is a sonar I use to help me find fish.

so for a basic unit with a small screen and gray scale would fish id be better

Fish ID is never better. It is a waste of good sonar technology. You want to see the results of you echoes, not the results of what the software is deigned to interpret for you. As far as gray scale sonar: I use a 480x480 grayscale sonar. It doesn't show those huge marks dingbat mentioned. Only occasionally for probably the reason(s) other posters mentioned. I do not like color sonar- yet. I like HDS and "scan" units and think they are pretty cool tools but I don't want one. Just give me sonar! And think about this: it takes three pixels to display a color, while only ONE pixel to display "black." So my 480x480 is 480x480 pixels resolution on-screen. However, take your color 640x640 and you get only ~213x213 effective pixel resolution.

Grayscale is better for general purposes. Structure scan I suppose has usefulness for bass or maybe some saltwater fishing. But as a troller for walleye and salmon and steelhead mostly my 480x480 helps me find fish. That, and it seems all the color units show those huge arches. My grayscale shows smaller, thinner arches. Often when walleye fishing I can predict the size of a fish if it hits as I have seen enough arches at "x" feet deep which were followed by a hooked fish that I now know what to expect.

....you can adjust that sensitivity and the frequency to see things that get in the way of the signals destined for the bottom....

Well, it is more than a fathometer. Most of what we enjoy for sonar today came out of technology originally brought "to the next level" during WWII with submarines. We have more tech on our boats today in that little box on the dash than the military did on warships in the 70s.

 

[dingbat]

Re: fish finders: fish id or arc

I do not like color sonar- yet. I like HDS and "scan" units and think they are pretty cool tools but I don't want one. Just give me sonar! And think about this: it takes three pixels to display a color, while only ONE pixel to display "black." So my 480x480 is 480x480 pixels resolution on-screen. However, take your color 640x640 and you get only ~213x213 effective pixel resolution.

Each color pixel is made up of three liquid crystal color cells. The display resolution on color LCD panel is no different than a monochrome screen.

BTW: Unlike the old days, increasing the resolution on an LCD display only makes things smaller. It has no bearing whatsoever on what you can see on the screen. 320 x 240 (QVGA)is more than enough for even a 6" display

 

[Mark_VTfisherman]

Re: fish finders: fish id or arc

Each color pixel is made up of three liquid crystal color cells. The resolution on a 480 x 480 ? (no such video standard) color LCD panel is no different than on a monochrome screen.

BTW: Unlike the old days, increasing the resolution on an LCD display only makes things smaller. It has no bearing whatsoever on what you can see on the screen. 320 x 240 (QVGA)is more than enough for a 6" display

OK. So then I have a follow up question: are the "pixels" different sizes on a color display unit?

A Lowrance factory rep at a show mentioned that the grayscale units offer better definition than color units, and posters on another forum have mentioned this as well. As far as the arches being smaller- compared to my old sonar, I can see bait sometimes (in water under 30' and the depth set at 30 feet) that is discernible on my 480, whereas the old unit would show solid black for bait clouds or single black blocks for scattered bait if it showed bait at all. In clear water I have watched 2" minnows under the boat actually read on the sonar screen. That never happened with the old unit. Usually it would mark nothing. The 480 shows nice arches like old printouts I have seen from (now ancient) graphs that printed on paper.

Anyway, really would like to know more on the color vs. grayscale issue. Most color units I have seen are no where near as "crisp" in displaying echo returns as the 480x480 unit is. That info certainly isn't in the sonar tutorial on Lowrance's website.

Thanks, dingbat.