Possible Clues:

• Well-armed predator?
• Army animal?
• One bit of work, or eight, for the autumn?
• Well armed for autumnal work
• Sea creature finding surface caught in fix, heading off
• Work after a short month in the autumn getting seafood
• A month to work on American swimmer
• Sea creature caught at surface in river briefly
• After a month's work, one is well armed and in depth
• Sea creature with tentacles