Does anyone know about how to maintain a healthy lifestyle as a Fisheries Observer

Hello! I will be starting a full-time fisheries observer position in the Northeast in roughly a month. The trips will be between 10-12 days long, with a maximum of 5 days off in between trips. I was a PSO on a seismic vessel before this, and I was able to walk endlessly around the helipad and work out in the gym.

The fishing vessels were significantly smaller; since I'll be spending easily 2/3 of every month on the boat, I wanted to see if anyone had any advice for keeping up with exercise or various health practices. I want to get a sense of how creative I'll have to be.