Historical clue formulations

• Reason not to go swimming in the ocean — 2020-12-05
• Colorful beach sighting — 2018-09-28
• Potential beach closer — 2012-01-07
• Dangerous algal bloom — 2006-11-09
• Shellfish contaminant — 2006-07-28
• Dangerous ocean phenomenon — 2005-06-23
• Shellfish contaminant — 2002-07-27
• Recurring marine phenomenon — 1996-01-21