Possible Clues:

• Small boat danger
• Ocean current moving the same way as the wind
• Type of current produces change with fish heading north
• Danger for small watercraft
• It goes whichever way the wind blows
• Water current with the wind
• It moves along with the wind
• Small-boater's concern
• River connection houses 500 for one of those windy types going with the flow
• Small craft danger