First things first, call the jury number they gave you on the paperwork and ask about how to postpone service. Chances are you will need to show some sort of financial/family hardship by you actually doing your civic duty. The fall striper bite is probably not on the courts list of "pardonable" items
Grand jury duty is a pretty time intensive, it can be tough. For regular jury service often times a phone call is enough (depending on who you talk to at the jury pool). They have the ability to delete your name and toss it back into the jury pool within the next three months you will be called again. As a lawyer I wouldn't pick you as a juror knowing you wanted to fish.
btw-bring up the capital murder point and run it by them...can't hurt