Maui Time (Pictures) -2

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London Lad

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Most people have buoyancy at the surface i.e. they tend to float. As they swim down buoyancy decreases and at some point becomes negative, they start to sink.

As a general rule (but not always) the leaner you are the less buoyancy you have and the fatter you are the more you have.

When scuba diving you wear weights to make it easier to swim down and a buoyancy compensation jacket that you can add air too in order to establish 'neutral buoyancy' at the depth you wish to stay at.

Some people who are very lean or densely muscled have a natural negative buoyancy and can scuba without weights.
 

Kiessling

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Ah ... ok, thanx. This means that when you go too deep you actually have to crawl back up as you lost buoyancy on the way down (if you don't where the magic suit, that is).

Fat that I am, I probably won't need anything to help me back up :green:
Not that I ever intend to go deeper than 2 meters or so.

I knew the stuff about bublle sin the blood stream and the lung thing, they teach us this in medical school. They didn*t teach us the bouyancy thing though.

bernie
 

London Lad

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Being fat I have to work to swim down and can't swim deep enough (holding my breath) to get negative buoyancy so I always ascend without much effort.

My girlfriend being much leaner gets negative after only about 2 meters down and descends easily but has to work to swim up.

(She also looks better)
 

McGizmo

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Bernie,
I don't know how fish, cetacea, turtles and other sea creatures handle the buoyancy issues but I believe they have a number of methods. I read recently where some dolphin or whales were autopsied and found to have suffered possibly from the bends! The speculation was that the underwater testing of the Navy with their ULF gear may have sent the animals too deep and then possibly too quickly to the surface. :green:

I swam down for one visit with the frogfish today and in the image below you can see he had hopped off my hand and was doing a banked turn.

DSC_4000.jpg


It seemed well adept at achieving neutral buoyancy as it had no mass perception while in my hand.

DSC_4001.jpg


In the profile shot below that I got yesterday, you can see just how large his mouth is and a feel for where his jaw is. When a hapless fish goes for its dangling "bait" the fish is all mouth when it lunges!!

DSC_3974.jpg
 

Kiessling

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I like the little fellow. He has style :D

Yepp, fish do have some sort of bladder. But dolphins aren't fish :nana: ... or so they say. I say they have fins and are underwater, so they are fish :D
 

McGizmo

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I believe fish handle it differently than mammals and the sea turtles who take on air at the surface and need to deal with the compression of this air as they dive down. I can recall seeing deep sea dwelling rock fish brought to the surface that had their bladder or something blown up like a balloon and bubbled out of their mouth. Compression and decompression are not trivial for the locals or visitors I would imagine. Probably much less of an issue if you or the animal doesn't have any gas or gas chambers within the body...

London Lad,

We await pics so we can be the judge.... :nana:
 

McGizmo

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is that fish using his fins to hold himself up on the coral? He looks like a stretchy toy...

Yes,
That's what I find so cool about the frog fish and even the leaf scorpion fish to a lesser extent. Although their fins can and do function as control surfaces and means of propulsion in swimming, most of the time, they are used as hand and feet to secure them in a stationary and still position on the reef even with strong currents and surges. they also form their fins and even body to blend in to the form of the reef and disguise their presence. If you do a search on frogfish on YouTube, you can find some examples of them eating. Here's one for example. They are also called angler fish because they can stick out a "lure" with an amorphis blob that will bring small fish and shrimp in close thinking they have found a meal when in fact they are the meal.
 

bshanahan14rulz

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ah yes, the angler fish! I did a very thorough investigation and report on them in the 4th grade. Well, not so much thorough investigation as "look at this cool-lookin fish! it has a glowy thing too!" Even at that age, light instantly added a certain amount of interest to anything.

Anyways, I was thinking it looked kind of familiar, but that family of fish is huge.
 

McGizmo

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I tried to interest him in a Sapphire today but he said he has his own technique for night fishing (I suspect he sleeps)

DSC_4075.jpg


There were a pair of squid just off the beach today.

DSC_4058.jpg
 

Data

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I looked at that and was wondering if you see any cuttlefish around? Also I did a Yahoo Answers lookup:

Cuttlefish VS Squid?
We are in Thailand and have just visited the fish market.
We thought we knew the difference but can anyone tell us how to tell the difference between squid and cuttlefish. How do we know what we have bought. We thought it was squid but now not sure... thanks

Best Answer - Chosen by Asker
A squid's body is much more slender than a sepia or cuttlefish. The eyes are also set more to the side of the head. When cleaning a squid there is a clear bone called the quill, it looks like plastic and is very thin. A cuttlefish is broader in width, it's eyes are placed more towards the front of the face, they have a certain scowl look to them. When cleaning they have a much harder calcified bone in them. Save the ink sack, if your making a tomato sauce for pasta, open the ink sack in the sauce for the last minute of cooking. It imparts a delicious flavor and your friends will look at your dish in bewilderment :) However, cooking and taste of the two are almost identical.
Have fun...


Cheers
 

RocketTomato

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Fascinating! Those squid are something else. I thought they were deep sea creatures and would never come near shore.

Here's an interesting page I found for any cephalopodophiles out there.
 

McGizmo

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I would guess this pair were 7-8" long.

DSC_4057.jpg


DSC_4067.jpg


Below is a shot of one I took early this year:

Squid_088.jpg


They really are amazing creatures to watch hover and then jet off! I don't see them very often and have seen more tiny babies than this size. A number of years ago, I think I did see a pair of cuttle fish while snorkeling. They were more into hovering and had undulating "skirts" for want of a better term. I wouldn't claim that I could tell the difference between a cuttle fish or squid. I think the squid here have much larger eyes though. :shrug:
 

gsxrac

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Yes,
That's what I find so cool about the frog fish and even the leaf scorpion fish to a lesser extent. Although their fins can and do function as control surfaces and means of propulsion in swimming, most of the time, they are used as hand and feet to secure them in a stationary and still position on the reef even with strong currents and surges. they also form their fins and even body to blend in to the form of the reef and disguise their presence. If you do a search on frogfish on YouTube, you can find some examples of them eating. Here's one for example. They are also called angler fish because they can stick out a "lure" with an amorphis blob that will bring small fish and shrimp in close thinking they have found a meal when in fact they are the meal.

I think this is the first time ive heard of a frogfish but they look to be some cool creatures! Found another video on the tube that shows one using his "fins" to walk across the ocean floor instead of swimming! Just a guess but are these fish not a migrating species and is that why you were able to find the little guy again?
 
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