I usually by gulf shrimp that I have to devein. I run a knife along the back, through the shell and part of the flesh, and pull out the black vein that runs along the back. But when I turn the shrimp upside down, there appears to be another black vein running along the underside.
Does this need to be removed too? It looks as full of crud as the vein running along the back.
If I do remove it, I will likely have to split the shrimp in two lengthwise, not desireable.