The sperm of one sea urchin species cannot bind to the eggs of a different sea urchin species. This exemplifies what type of reproductive isolating mechanism
This is due to Gametic isolation/ incompatibility.
What is Gametic incompatibility?
It is a type of barrier where fertilization does not takes place even when the gametes (sperm and egg) come in contact with each other.
In this, the gametes of different species are not able to recognize each other.
A chemotactic molecule resact from the egg jelly of sea urchin species is specific for the sperms of that species and is not able to attract sperms of other species towards itself.
