Hook Rust Test --- 14 MONTH UPDATE

[treysdaddy]

Since I have been fishing BTB, I've always told people that the hooks I leave in sharks will rust out pretty quickly after being exposed to saltwater. I've always wanted to do an experiment to see how long it will actually take. Since I had to get some saltwater today for the aquarium, I picked up some extra for my little experiment. I used 2 16/0 mustad circle hooks. They are both in a small aquarium with constant water flow delivered by a pump. On one of the hooks I sanded off a small section of the plating thinking that this would make them start to rust quicker. I used a dremel tool for the sanding. It took me about 15 seconds to do it.

These are the 2 hooks. If you look closely at the hook on the left, you can see the small place where I sanded the plating off.


This is the setup -- a 2.5 gallon aquarium with a pump.


After only 4 hours, take a look at the rust already forming on the sanded section.

[iFish]

Interesting, I've also wondered about that. Will be watching for an update.

[texnomad]

The body fluids will add to the corrosion rate also. My guess is something in the two year range.

[Earth's End Kayaker]

Absolutly great experiment!

I have been wanting to debunk
the fact that it takes a short while
for this oxidation to occur enough to
to free from the unfortunate fish's mouth.

Please post results...

Thanks for posting.

Best regards,
EEK

[treysdaddy]

I hadn't thought about the oxygen level in my experiment tank. The best thing I have to simulate the oxygen-rich gulf is to add an aquarium airstone with pump. I did that this morning. I think it will take about a month to significantly corrode enough to break.

At the end of this, if it turns out that sanding a spot of the coating on a hook helps it corrode faster, I'd be willing to do that. I already mash the barbs down on every hook to give it a shot at falling out, which I think a lot do. I've caught a lot of sharks and haven't ever caught one with a hook in its mouth. I've heard of a few. I still don't think that a hook in a shark's mouth hurts its quality of life, but I would be willing to take an extra step to help it go away.

[peterpan]

That's impressive!

I've heard on spawning season the male sharks like the glitter of piercing on the females shark mouth! Turn them on! Kidding!

[BrandonFox]

There was a thread on Extremecoast that lasted over a few years of a guy who did this experiment off his dock. Might be worth looking up, very interesting. I'd be happy to see your results!

[kippears]

Thanks for the post, very interesting, definitly keep us informed of the progress.

Also where do you buy those hooks from?

[richg99]

I think it is great that someone would take the time to do this type of test....and then to share the results with us. Thank you! regards, Rich

[Johninaustin]

The hooks don't rust out, the sharks flesh festers and turns soft so they fall out. Happens within a day or two.

[treysdaddy]

The hooks don't rust out, the sharks flesh festers and turns soft so they fall out. Happens within a day or two.

Great, now I'm going to have to figure out how to fit a shark in that 2.5 gallon tank so I can test that.

[HtXfisherMan8706]

Me, you and probably about 500 others on this site have waned to do this to really back up theory. Glad u took the time to do it. Can't wait to see the results

[texnomad]

I did some looking around on the internet. The expected corrosion rate for uncoated steel in seawater is 3 to 5 mm per year. That leads me to think that most hooks will be gone in about a year at the most. Stainless Steel hooks would be a lot longer. I personally never have used stainless hooks and three years ago started using barbless hooks. Maybe this is good information.

[Jolly Roger]

The hooks don't rust out, the sharks flesh festers and turns soft so they fall out. Happens within a day or two.

This happens on the inside of the shark's mouth. Kinda a way to get rid of bones, stingray barbs and gafftop fins that get stuck in the sharks mouth. Shark eat some sharp crap.

If the hook is through the outer skin in any way, then it will have to wobble the hole out large enough to fall out. Rusting of the hook can help this process, stomach acids come into play, etc.... Hooks coming out is a combination of many factors, but overall they do not stay in long no matter where they are located. Sharks have evolved eating fish and sea creatures with sharp defense mechanisms, overall leaving a hook in a large predator is not that damaging to there long term health. An exhausting fight has much more of a chance of killing them compared to leaving in a hook.

[treysdaddy]

I decided to keep on going with the test just to see how long it took in my controlled conditions. I added the airstone to add some oxygen, but it made such a mess that I quit using it shortly thereafter. Four months later, everything is a lot uglier and the rust spot is really rusty, but still strong. I predict another 4 or 5 months from now, I will be able to twist the hook apart. We will see in a few months...

You can see the rusty spot on the sanded hook getting really rusty...


Here's the aquarium in it's not so pristine condition.

[DX2]

Great study but I would think that the salt levels would decrease after a week or so unless your adding new water weekly. This would also slow down the corrosion rate .......

[treysdaddy]

Great study but I would think that the salt levels would decrease after a week or so unless your adding new water weekly. This would also slow down the corrosion rate .......

Freshwater evaporates from saltwater so I replace any evaporated water with fresh. I learned this from keeping saltwater aquariums over the years. I had no idea that it worked like that.

[lildave40]

Great experiment bill.

[HtXfisherMan8706]

Awesome!!!! I have been wondering about this experiment haha.

[xmatador2000]

This is a great experiment! Two thumbs up! Actually, water evaporates while salt stays in the aquarium. If you are not adding freshwater, there would be less water with the same amount of salt resulting in a higher level of salinity.

[rod dawg]

Only difference I can see is the yellow pencil added next to the fish tank.

[Old Skool Hookers]

X2 on what Jolly Rodger said about the stress put on sharks fighting them. They can not be revived like other fish.

On the hook experiment, I would assume it could be an accurate experiment if the salinity levels would be the same from the ocean to the tank. Just my $0.02

[Earth's End Kayaker]

Hey Treysdaddy,

How is this experiment coming along?....just cuious??

EEK

[treysdaddy]

We are right at 10 months now. I'm keeping it going until I can break the rusted hook in two with my hands, or until the pump dies from rust.

So far, there is tons of caked rust on the hook that I sanded the coating off. There is still no flex at all to the hook. The unsanded hook is discolored, but not rusted at all. The whole tank has a brownish tint to it, but the pump is still going strong. I'll take some pics soon.

[Wolfman57]

Interesting post. Sounds like you may create life in this tank before the hook rusts out!