Sunday, October 5, 2008

Porcupine fish (carcass)

One of the beachcombing finds that I have wanted to write about is this: the porcupine fish or globe fish. I saw one carcass on the South Cottesloe shore on 21 September and another on the Penguin Island shore on 27 September.

This is the one I found on the South Cottesloe shore. About 12-15 cm in length I think. Since the body was still soft to touch (with a stick of course, even if the spines are said to be non-venomous) , it probably had not been on the shore for very long before I found it.

What caught my attention were the teeth or jaw with the small mouth. It reminded me of babies. But babies don't use their mouths to crush sea urchins and shellfish :)

I read about the fish later and learnt that the porcupine fish has two fused teeth, thus the family name "Diodontidae". The teeth of the upper and lower jaws are fused together. I couldn't find the other jaw/tooth.

In the place where I expected to find the eye, I saw only a whitish tissue.

The spines didn't look so bony as I previously thought.

A week later, I saw another dead porcupine fish that was washed ashore on the Penguin Island.

Again, the eye's gone!?

I tried to look for the teeth but couldn't find them.

Unlike the flesh of the fish which is toxic, the spines of the fish are not. These spines usually lie flat on the body. But when the fish inflates its body with water and blows up like a balloon, the spines will stick straight out. I read that a daring predator that eats a porcupine fish may find the eaten spiny ball wedged up in its throat. Not really a funny situation because apparently, this will kill both of them.


Mosura said...

Some nice detailed shots there. I'm glad I'm not the only person who photographs dead fish :-)

Tsun-Thai Chai said...

Ha ha ha. Dead fishes are fine. At least they don't swim away when you try to get a few close-ups.

Denis Wilson said...

Hi Chai
I didn't quite understand the fused teeth business. Surely upper and lower jaws are separate?
Surely there must be a small lower jaw, with a row of teeth, or a single fused tooth?
If not, how do they eat?

The thought of a predator eating one of those things is a nasty image. Serves them right, if they are that stupid.
A nice post. Always good to end with more questions than answers.

Tsun-Thai Chai said...

Hi Denis,

I know the lower jaw has a single fused tooth, but I couldn't find it. Maybe I didn't look carefully enough.