I was going to say Red Tide!! But looks like your husband knew! Are you on the Atlantic side? I'm in Sarasota visiting my parents and they said the Atlantic side had it bad this year. About 5 yrs ago I was down here & we went down to Venice to some beach known for gathering shark's teeth & the red tide was so bad, I almost passed out as my airway was closing up. My parents did not believe how sick I got so fast - they thought I was over-reacting
It is horrid - I can't imagine what that could do to a little yorkie if they were sensative to it.