I'll add to the military option.
I know a guy who went into the coast guard when he was younger. I think did it for ten years, then was doing some seasonal fisheries work for the Forest Service and also going to school part time.
He was about 40 when I met him several years ago and was determined to get a hatchery job when he finished his schooling. I really didn't think he was going to be able to get in being later in life, but he was able to land a Federal hatchery Job, I think he gets preference because of the military. He bounced from a couple of Midwest hatchery jobs, but finally came back to his home state and is working as a Federal Fisheries Technician now.