Salary
Average Salary: $72,000
Expected Lifetime Earnings: $3,005,856
This one's tough—not as tough as defeating the great White Whale, but definitely up there. The salary all comes down to the type of vessel you're captaining.
Who's your employer? How big is your ship? How many crew members are under your command? What's your ship doing? How long are you at sea, on average? Do you own the ship? Are you carrying fish, passengers, iPads, or an arsenal of advanced weaponry (hopefully not all at the same time)?
As remarked in the opening section, most of us probably associate the idea of "captain" with the top officer aboard a U.S. Navy ship. Naval (and Coast Guard-al) officers' salaries are determined by Congress, so pay-wise they don't have the same concerns as merchant sailors, cruise line officers, and charter captains. Their pay isn't contingent upon how many enemy ships they sink (thankfully, that's not really how war works).
If you're talking about all captains averaged together, the salary you can expect is somewhere in the high $70,000s range (source). Some, of course, will make more—the top ten-percent earn over $100,000 per year.
However, many more will earn less, especially if the salary is tied to fish caught or field trips taken. A lot of the pay for the blue-collar captains comes from the amount of seafood you can catch and sell, or how many paying customers you can take out to point their smartphones at some humpback whales.
On a more positive note, provided he or she owns the boat, the captain still gets to set prices—meaning all those field trips of fussy elementary students can pay an extra "service charge" for the privilege.