jay

transcript

  • [20:15 25/02/2005] <@craig> Good evening everyone! Welcome to Live, Fishchat!
  • [20:16 25/02/2005] <@craig> Tonight is a special treat, as it always is, Russ will be speaking for us on the topic of Fish Sensory Systems..
  • [20:17 25/02/2005] <@craig> So without further adieu, Russ take it away, we are late enough as it is. :-D
  • [20:18 25/02/2005] <+russ> Thanks Craig. I needed to find out how to spell 'adieu' :-D
  • [20:18 25/02/2005] <+russ> Good evening folks. Welcome back to the Friday evening moderated chat presentations. Thank you for allowing me once again to participate. These presentations, presented in 2018real-time2019, offer you great information that you can immediately interact with.
  • [20:19 25/02/2005] <+russ> The subject matter and topics of past presentations have been excellent and have been well received. Hopefully, with the aid of hobbyist volunteers and other featured presenters, we can explore additional subject matters surrounding this great hobby of aquarium fishes.
  • [20:20 25/02/2005] <+russ> For my humble contribution tonight, I will be continuing on a methodical path of presentations I had started last year. I started with you, the hobbyists, and the advantages of being a member of or starting a local aquarium club. Then, factors affecting non-growth in fishes, the essence of filtration, feeding habits of fishes, setting up and maintaining hospital and quarantine tanks, and establishing a protocol when things ap
  • [20:21 25/02/2005] <+russ> Tonight I am going to talk about fish physiology. In particular, the sensory systems. Since fish physiology, in general, is way beyond the scope of an hour chat session, I had to divide this up into two parts. I hope I can present this in a easy to understand manner.
  • [20:22 25/02/2005] <+russ> Sensory systems (Part One)
  • [20:22 25/02/2005] <+russ> VISION:
  • [20:23 25/02/2005] <+russ> Its really not necessary to try to review that whole link now. It will will be there for a while:-)
  • [20:25 25/02/2005] <+russ> While we focus light by changing the shape of our lens, a fish eye will focus by changing the position of the lens, much the same way a camera lens focuses. Back and forward. When a fish eye is in a relaxed position (lens being in the forward position), near objects are in focus. Retracting the lens back towards the retina allows distant objects to become in focus.
  • [20:27 25/02/2005] <+russ> Because both the quality and quantity of light is so different underwater, fishes have also evolved the widest range of visual pigments than any other vertebrate. There are two major visual pigment components in the fish eye. These are called the opsin and a chromophore. Differences in the opsin determine which wavelengths of light are absorbed. The pigment undergoes a change that sends and electrical impulse to the brain, wh
  • [20:28 25/02/2005] <+russ> Because of the different depths of the water regions, and turbidity of other water regions different wavelengths travel through the water and fishes residing in those different regions have adapted optimal wavelengths into different degrees of sight sensations. Because fish eyes contain cones, they can distinguish colors and use this feature to distinguish objects against a variety of backgrounds.
  • [20:29 25/02/2005] <+russ> ......
  • [20:29 25/02/2005] <+russ> HEARING AND EQUILIBRIUM:
  • [20:30 25/02/2005] <+russ> A little background in underwater sound is in order to explain how fishes are affected and react. I think we talked a little about this a few months ago in a Q & A on another chat presentation. Molecules are closer together in water than they are in air. This results in acoustical energy being transferred from molecule to molecule at a faster rate. Sound travels almost 5 times faster in water than in air. There are near and
  • [20:32 25/02/2005] <+russ> A general consensus for determining the boundary of a near-field effect and far-field effect is about one sixth of the wavelength from a sound source. Acoustical characteristics are different in air and water. Because of this, land vertebrates are almost always exposed to far-field acoustical sounds, while fish are exposed to both.
  • [20:33 25/02/2005] <+russ> Please bear with me. It is important to get a basic understanding of acoustical ranges and characteristics and how our fish are capable of handling this in their underwater domain.
  • [20:33 25/02/2005] <+russ> Majority of sounds generated in either air or water is reflected back into that medium at the air-water interface. What this basically means is that generating a sound that stays above the water surface will probably not be detectable by the fish. An object generating sound that is connected in some way at or below the water2019s surface, can be detected by fish within acoustical range.
  • [20:34 25/02/2005] <+russ> ....
  • [20:34 25/02/2005] <+russ> INNER EAR:
  • [20:34 25/02/2005] <+russ> There are two sound detection systems in fishes. This is the inner ear and the lateral line.
  • [20:35 25/02/2005] <+russ> Fish do not possess a outer or middle ear, but do possess an inner ear. This is made up of a series of ducts and chambers containing sensory hairs lined alone the inside of these interconnected chambers and pathways. The inner ear also plays an important part in maintaining a fish2019s equilibrium. The upper portion is responsible for sound detection, while the lower portion of the ear deals with gravity and equilibrium. Fis
  • [20:36 25/02/2005] <+russ> Because fish and their surrounding water is about the same density, sound waves will move through a fish2019s body at almost the same amplitude and frequency as they would through the water. Hmmm. So, if that is the case, then how can a fish detect sound?
  • [20:39 25/02/2005] <+russ> Not all swim bladders are created equally. Not all rest entirely within the main body cavity of a fish. There are a variety of shapes and sizes that can vary with different fish species. In some species, the bladder has a projection that extends through the skull and presses against the inner ear. Mormyrid species have separations of the swim bladder that is enclosed in the skull and in constant contact with the inner ear.
  • [20:40 25/02/2005] <+russ> Not the entire swim bladder...just a seperate section
  • [20:41 25/02/2005] <+russ> ....
  • [20:41 25/02/2005] <+russ> EQUILIBRIUM:
  • [20:43 25/02/2005] <+russ> .....
  • [20:44 25/02/2005] <+russ> LATERAL LINE SYSTEM:
  • [20:44 25/02/2005] <+russ> The lateral line system is unique to fishes (except gobies) and amphibians when in their aquatic stage. The way this system works is similar to the way the inner ear works by means of sensitive hair cells enclosed in a cupula. Movements of these cells which have been acted upon by a stimuli, cause changes in the frequency of impulses that are sent to the brain.
  • [20:45 25/02/2005] <+russ> Two types lateral line sensors (receptors) are located within the skin or below the skin. Some fishes have only one type while many advanced fishes have exceptionally developed lateral lines. The lateral line channels or canals extend along the longitudinal plane extending out along the flanks of the fish and even up into the head region.
  • [20:46 25/02/2005] <+russ> Although there are similarities in basic functions of the inner ear and lateral line, the primary function of the lateral line system is the detection of water movement and particle displacement from low frequency vibrations in water movement. Fishes with lateral lines can still function to a degree with the loss of a inner ear by responding to low frequency vibrations.
  • [20:46 25/02/2005] <+russ> Fishes can utilize their lateral line sensitivity to detect movements in water with poor visibility and can also detect objects and boundaries. This is accomplished by detecting the bow waves as the fish swims. This would be important in a aquarium where the fish can detect the glass sides
  • [20:48 25/02/2005] <+russ> Many fish species also utilize their lateral line senitivity to detect prey. Many times large mouth bass seem to gulp something that attracts their attention, then ask questions latter.
  • [20:49 25/02/2005] <+russ> The lateral line is also important to schooling fish behavior in several species. Tests have shown that when the vision of some species of schooling fish was blocked, they still managed to maintain their place within the group. Active species of fish have more lateral line canals beneath their skin with the reasoning being that the extra canals and tissue act as a buffer from external water wash and environmental noises.
  • [20:49 25/02/2005] <+russ> ...
  • [20:50 25/02/2005] <+russ> That pretty well ends (although not inclusively) my presentation for this evening. I have edited this from a prior presentation I had made to a aquarium society about twelve years ago. References that I have used then were from Freshwater Fishes of the World (Sterba), Introduction to Fish Physiology, Smith, L.S., Hearing and Sound Communication In Fishes, Tavolga, W. N., Comptons Encylopedia, and Britanica On-line, and frien
  • [20:50 25/02/2005] <+russ> Part 2 (next Friday) will be on Chemoreception (Olfactory functions and taste).
  • [20:51 25/02/2005] <@Jessica> thank you russ :-D
  • [20:51 25/02/2005] <@craig> Thanks Russ. :-)
  • [20:52 25/02/2005] <+russ> Your very welcome:-)
  • [20:52 25/02/2005] <@craig> I'm just going to open the floor for general discussion of the topic..
  • [20:52 25/02/2005] <@craig> Let the free for all begin..
  • [20:53 25/02/2005] <@craig> I'll have to wait for next week before I ask the questions that I wanted to bring up, since you will be covering them then. :-)
  • [20:53 25/02/2005] <@Jessica> thank you russ, i'm not sure if anyone will have any questions oafter that
  • [20:54 25/02/2005] <Kimrin> well I do
  • [20:54 25/02/2005] <Kimrin> :D
  • [20:54 25/02/2005] <@JP> Ask 'em! :-D
  • [20:54 25/02/2005] <+russ> Good thing I didn't do the extra long version :-D
  • [20:54 25/02/2005] <@craig> Don't be shy Kim, go! :-D
  • [20:54 25/02/2005] <@Jessica> go! ladyo :-D
  • [20:55 25/02/2005] <Kimrin> so assuming ther's no physical vibration basicaly our fish shouldn't be able to hear sounds that originate outside the aquarium?
  • [20:56 25/02/2005] <+russ> That is correct....unless the actual sound wave is generated at the air-water interface...more...
  • [20:56 25/02/2005] <+russ> Borrowed example, but its a good one....
  • [20:57 25/02/2005] <+russ> Imagine you and another person in a boat on the water, talking to each other.
  • [20:57 25/02/2005] <+russ> Fish will not be able to detect those sound waves....
  • [20:57 25/02/2005] <Kimrin> yap! right above the water
  • [20:57 25/02/2005] <Kimrin> I mean yep
  • [20:57 25/02/2005] <+russ> Now, imagine you dropping a pop can in the bottom of that same boat....
  • [20:58 25/02/2005] <+russ> Fish will be able to detect that:-)
  • [20:58 25/02/2005] <Kimrin> ahhhhh
  • [20:58 25/02/2005] <@JP> So, all these talks I have with the fish accomplish nothing?
  • [20:58 25/02/2005] <@craig> Talk louder. :-D
  • [20:58 25/02/2005] <+russ> They can see you perfectly:-)
  • [20:58 25/02/2005] <Kimrin> you'll have to tap them out in morse code
  • [20:58 25/02/2005] <@JP> I think Joe can read lips. ;-D
  • [20:58 25/02/2005] <@Jessica> lol
  • [21:00 25/02/2005] <@craig> There was a discussion on the boards some time back about stereos and loud music....
  • [21:00 25/02/2005] <@craig> Sustained vibrations from a loud sound source, detrimental or not?
  • [21:01 25/02/2005] <Kimrin> the bass can cause physical vibration
  • [21:01 25/02/2005] <+russ> yep....majority of those sound waves that were bieing produced were probably picked up by the lateral line senses in a bunch of fish
  • [21:02 25/02/2005] <+russ> they would most likey have to have been lower than 200Hz
  • [21:02 25/02/2005] <@craig> To what effect though?
  • [21:03 25/02/2005] <@craig> Is there a general dulling of the senses or...?
  • [21:03 25/02/2005] <+russ> a lot of research on this subject has been difficult to test because of extraneous noise sources
  • [21:04 25/02/2005] <+russ> dulling of the senses? No...more like a hieghting of the senses
  • [21:05 25/02/2005] <@craig> Can or is there something with fish that is like us... You go to a concert and listen to LOUD music for 2 hours, after you leave, there is a period where hearing isn't what it normally is..
  • [21:05 25/02/2005] <@craig> Same with fish?
  • [21:05 25/02/2005] <+russ> Fish have it tough, lets face it. An ich outbreak is bad, but stress on a fish that has to contend with having their senses blown out of proportion is a bummer
  • [21:07 25/02/2005] <Kimrin> what about dolphins and whales I wonder?
  • [21:07 25/02/2005] <+russ> Craig I guess that could go back to the various stress levels in a fish that Sully and I talked about in other presentations..
  • [21:07 25/02/2005] <+russ> If it is acute and sustained, becomes a chronic problem, then the fish can be lost
  • [21:08 25/02/2005] <@craig> I guess that was what I was getting at when I mentioned the "concert noise" theory..
  • [21:09 25/02/2005] <@craig> For the record, I don't buy into everything being a "stress" source for our fish.. Neither does Sully.
  • [21:09 25/02/2005] <+russ> vibrations and wave particle disruptions will eventually dissipate.
  • [21:10 25/02/2005] <+russ> Either do I.
  • [21:10 25/02/2005] <@craig> This will be much more fun next week after you cover the sense of smell. :-D
  • [21:11 25/02/2005] <+russ> But there is something to be said for generations of pond/tank bred fishes, compared to newer caught arivals.
  • [21:11 25/02/2005] * @craig is trying desperately to keep the cart behind the horse. ;-)
  • [21:11 25/02/2005] <+russ> :-D
  • [21:11 25/02/2005] <@craig> Agreed Russ, I see it here with my various fish off spring..
  • [21:11 25/02/2005] <Kimrin> oh, yes! I'm sure tank bred are much more durable so to speak than wild caughts
  • [21:11 25/02/2005] <+russ> I'll drop a little crumb, then table Part 2.....
  • [21:12 25/02/2005] <+russ> Smell definately affects the either gulp, fight, or flight response;-)
  • [21:13 25/02/2005] <+russ> there are sounds generated in a tank that fish do not encounter in a farm pond or natural setting
  • [21:15 25/02/2005] <@craig> I'll have to wait until next before I comment further, there are some observations that I have, that need the sense of smell and touch together.. :-D
  • [21:15 25/02/2005] <@Jessica> what a concept, fish need sight, hearing, touch and smell together ;-D
  • [21:15 25/02/2005] <+russ> Fish, in the wild can detect the bow wake of other fish. In a tank of limited proportions and several different shapes and sizes of fish, it could get a little noisy in there:-)
  • [21:17 25/02/2005] <@craig> Which I can attest to Russ... I see more "natural" behavior in the 210, even though its not a large body of water, its does afford room to play.
  • [21:17 25/02/2005] <+russ> Plants and other structure can help counter other fish species 'noise' and act as an extra buffer....more...
  • [21:17 25/02/2005] <@craig> (Hint: Save your pennies and buy a BIG tank..)
  • [21:18 25/02/2005] <@Jessica> lol
  • [21:18 25/02/2005] <+russ> fish, however, can become a little too comfortable with this and be lax in their primary senses of detecting danger;-)
  • [21:19 25/02/2005] <@craig> I can tell you story after story of my clown loaches and how they react to movement......
  • [21:20 25/02/2005] <@craig> Initially the first reaction on their part is flee, but if you stand there and stay still, they will get curious and come back out, to watch you..
  • [21:20 25/02/2005] <+russ> With all this stuff about vibrations, and frequencies, and waves, you can get a little better understanding abouot, when Dan referrs to fish 'talking' to one another and not being able to understand each other.
  • [21:21 25/02/2005] <@craig> That is a can of worms in itself. :-D
  • [21:21 25/02/2005] <+russ> :-D
  • [21:21 25/02/2005] <Kimrin> do fish make noises????
  • [21:21 25/02/2005] <+russ> yes
  • [21:21 25/02/2005] <@craig> Yes.
  • [21:21 25/02/2005] <Kimrin> I would think that they communicate with one another more by color and body posturing
  • [21:21 25/02/2005] <Kimrin> they do!!!!???!
  • [21:21 25/02/2005] <@Jessica> click click click
  • [21:22 25/02/2005] <Kimrin> oh yeah, I forgot about that?
  • [21:22 25/02/2005] <@craig> Click, click click goes the clown loach..
  • [21:22 25/02/2005] <@craig> Or in the case of big ones... Pop, pop, pop..
  • [21:22 25/02/2005] <+russ> Do you know what fish are actually doing when they 'flash' at each other. Like two male White clouds?
  • [21:22 25/02/2005] <Kimrin> what?
  • [21:22 25/02/2005] <@craig> White clouds its a mating display..
  • [21:22 25/02/2005] <+russ> NO, JP, they are not wearing raincoats:-D
  • [21:23 25/02/2005] <Kimrin> yes I know that
  • [21:23 25/02/2005] <Kimrin> that's visual, not sound
  • [21:23 25/02/2005] <@craig> Same to be said for cherry barbs..
  • [21:24 25/02/2005] <@craig> Kim, yes, there are many fish that produce sound, most of which the human ear can not detect..
  • [21:24 25/02/2005] <+russ> They are generating pressure on each other's lateral lines. The one who can't stand it anymore, breaks away from the mock battle:-)
  • [21:24 25/02/2005] <Kimrin> I was reading a post on another board somewhere, he was talking about a pleco that got stuck in a peice of decor
  • [21:24 25/02/2005] <+russ> b r b
  • [21:25 25/02/2005] <@craig> I don't have any direct references at hand, but Google will bring up hits that you can use for research..
  • [21:25 25/02/2005] <Kimrin> ???!! back to the clouds...wow!
  • [21:25 25/02/2005] <Kimrin> that's amazing
  • [21:26 25/02/2005] <Kimrin> but about that pleco....guy had to take him out of the tank to get him out of the decor and he said he was squeaking!
  • [21:26 25/02/2005] <@Jessica> yeah
  • [21:26 25/02/2005] <@craig> As for what Russ is talking about, we can experience much the same thing. Think about this, move your hand through water, can you feel the pressure of the wave that is produced? Yep, you can, so can the fish, there is also a noise produced, but we don'thave the senses to detect it.
  • [21:26 25/02/2005] <@Jessica> they hiss at you
  • [21:27 25/02/2005] <Kimrin> eeeeeek!! hissing?
  • [21:27 25/02/2005] <@Jessica> yup
  • [21:27 25/02/2005] <Kimrin> great, now I'mm scared of my fish :D
  • [21:27 25/02/2005] <@Jessica> it's faint, but the plecs and banjo catfish hiss at you if you pick them up.. they dont like it much :-D
  • [21:27 25/02/2005] <@craig> Kim, I have a common pleco I am going to have to move soon, wanna come by and help? :-D
  • [21:28 25/02/2005] <@Jessica> his hissing will be louder, though
  • [21:28 25/02/2005] <Kimrin> I'll stand behind you and hold the big stick
  • [21:28 25/02/2005] <@Jessica> lol
  • [21:28 25/02/2005] <@craig> He won't hurt you, get you wet and scare the begeezus out of you? Yes, but hurt you intentionally, no. :-D
  • [21:29 25/02/2005] <Kimrin> :) how do you know it won't be intentional lol!
  • [21:32 25/02/2005] <+russ> back:-)
  • [21:32 25/02/2005] <@craig> Getting back to the subject at hand tho, fish can "feel" you coming after them as well as see you..
  • [21:33 25/02/2005] <@craig> My move your hand inthe water thing comes into play there too..
  • [21:33 25/02/2005] <+russ> yep
  • [21:33 25/02/2005] <+russ> you will be able to hear the sound that is being produced above the surface, but not below
  • [21:34 25/02/2005] <@craig> Even a net moving in water produces a small pressure wave in front of it.
  • [21:34 25/02/2005] <+russ> If it is a small ne in a very big tank. Otherwise it cn generate a pretty hefty one:-)
  • [21:34 25/02/2005] <Kimrin> well yeah...
  • [21:35 25/02/2005] <@Jessica> you can feel that pressure wave or something similar in a swimming pool with your hands, and you are nowhere close to as sensitive as the fishies
  • [21:35 25/02/2005] <+russ> thats correct
  • [21:36 25/02/2005] <+russ> However...
  • [21:36 25/02/2005] <Kimrin> that's why I can't catch em
  • [21:36 25/02/2005] <@craig> And to some extent hear it, if your head is under water and the source of the wave is close enough to jar the inner ear..
  • [21:37 25/02/2005] <+russ> A fish with a Weberian system is somewhat similar to our own ear
  • [21:37 25/02/2005] <+russ> Craig wins a beer on that one:-)
  • [21:38 25/02/2005] <@craig> I've spent too much time with my fishies. :-D
  • [21:39 25/02/2005] <@Jessica> lol
  • [21:39 25/02/2005] <+russ> With the sense of vision and lateral line, coupled with the inner ear, a fish is very aware of its surroundings:-)
  • [21:39 25/02/2005] <@craig> Either that or I am smart, but I'll go with the time spent with fish thing. ;-D
  • [21:39 25/02/2005] <+russ> thats how one becomes fish-smart:-)
  • [21:40 25/02/2005] <@craig> I'm just fish lucky, fish smart is mom, she knows fish..
  • [21:41 25/02/2005] <@craig> And the fish know her too..
  • [21:41 25/02/2005] <@craig> She can walk abruptly up to the 210 and the loaches don't move an inch, let anything else move by and they scatter..
  • [21:42 25/02/2005] <+russ> b r b
  • [21:42 25/02/2005] <Erin> Goodnight folks.
  • [21:43 25/02/2005] <@Jessica> good night erin
  • [21:43 25/02/2005] <@JP> Take care, Erin. :-)
  • [21:43 25/02/2005] <@craig> I'm trying to bring this in line with the discussion.. :-D
  • [21:55 25/02/2005] <@craig> Not that I want to break up the party, but since things seem to have wound down here, lets move this back to the other side? :-)
  • [21:55 25/02/2005] <Erin> Before I hit the sack maybe you guys can give me some snail egg advice?
  • [21:56 25/02/2005] <+russ> Keep them moist? :-)
  • [21:56 25/02/2005] * @Jessica points at other channel
  • [21:56 25/02/2005] <Kimrin> Yeah, i think mine dried out
  • [21:56 25/02/2005] <@craig> Russ, again thanks.. See ya next week and I will be on time then. ;-D

 

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