I always thought that the seahorse was the symbol for cross dressing transvestites, so you would think that the jocks would have it on their badge as well.
I've never seen a Seahorse. I've never seen Newcastle win a major trophy. That's the only link I can see.
Its because all geordies are Asexual. We can reproduce without the need to shag one of the many ogres from the area and change our gender at any time.