Best camera for shooting fish pictures that will last on the boat?

[Choupique]

No definitely not; SLRs are available in a few quality levels:
Crop Frame sensors are the most comon SLRs available from $400 for basic plastic made cameras with simpler processors (canon rebels) and focus systems to higher end semi-professional crop frames built for sports, action, and telephoto uses in the $1500 range that offer some weatherproofing (canon 60d , canon 7d). Then there are full frames that offer better low light capabilities, noise reduction with less available light (iso performance) and are generally excel in portait and landacapes, with more advanced dust and moisture sealing (canon 6d, canon 5diii) $2k-3.5k.

I would invest in a good fast lens (or two) with Image Stability in the telephoto, and a mid range camera body as you will most likely have plenty of light for 90% of your shooting. Get a 17-50mm f2.8 for shooting anglers in the boat and a 70-300mm for shooting those bills tailwalking in the spread behind the boat.