Very simple--umpires wear blue uniforms.
a blue berry bush
'Blue filming' is apparently a 'street term' for spotting in-process filmmaking in local areas. The term could come from the notion that 'blue' is slightly illegal or shady.
its baseball because you run around bases and you play with a ball
There isn't really a "blue" Wiemaraner it is used as a term for the wiemmy's Blue like coat such as a Blue Russian there coat is a type of Gray but it looks in a way blue. This goes the same for Whimmy's although some look more gray then blue.
In the navy, when a boat lost its captain, blue flags would be hung above the deck. When returning to land a blue banner would be stretched out across the length of the boat.
the tools of ignorance refer to the catchers gear
The term "blue moon" is used when something very rare happens, the most common usage of this term is "Once in a blue moon".
The term refers to policemen
From folks who aren't thinking about what they are saying (most aren't really talking about the blue backed little fish). "Blue Herring," is a lazy spoken reference to the Blue Heron; a large and graceful, crane-like marsh bird found through out North America .
Yes, all of the Nintendo handhelds come in a blue version.
The term greasers come from their greasy hair
From the old days of Baseball. If a game was rained out, the patrons were affered a voucher to attend another game for free.