Sea sponge or seaweed?

Day 171 - I often wonder are these sea sponges that are washed up on the shoreline or is it some kind of seaweed, and if they are sea sponges are they the same as the ones that you can buy in a shop

[Margaret Brown]

You got me there but it is a nice capture.

[KoalaGardens🐨]

ooooh it's fascinating

[mittens (Marilyn)]

So interesting looking.

[Judith Johnson]

No idea, but very interesting

[Mags]

How intriguing!

[Carole Sandford]

Interesting!

[bkb in the city]

Very interesting

[Diana]

Such a fascinating find and great close up. No idea what it could be.

[Dione Giorgio]

Great find and capture. Although I have never seen anything like this I think they must be a bunch of seaweed.

[Lou Ann]

It doesn’t really look like a sponge to me. Of course I have no idea what it is, though. 😊

[Michelle]

@craftymeg @koalagardens @mittens @busylady @marlboromaam @carole_sandford @bkbinthecity @ludwigsdiana @sangwann @louannwarren Thank you everyone for the lovely comments

[Sue Cooper]

It's neither Michelle, it's whelk egg cases. I can't claim any credit for knowing this, I asked Chris, he studied marine and fresh water biology at uni so he's supposed to know these things 😂

[Lou Ann]

@susiemc ah ha!

[Michelle]

@susiemc Amazing thank you for the information, your never too old to learn! @louannwarren Thank you for the comments