Mosquitoes?
Short answer: No.
Long answer: No. I'm sure they are there but I have never seen one.
- Biting flies? Yes, like horseflies but those mostly on the eastern shores where more livestock are around.
- Gnats? Yes but, again harmless though at times a nuisance.
- Mud dauber wasps? Plenty but, they'll generally leave you alone. Do the same and no problem.
- Tarantula Hawk wasps? Yes but again, leave them alone. Setting anchor once there were flowering bushes at water's edge with probably 100 of those huge things in them. Don't stumble into that or you'll regret it.
- Spiders? yes. A lot directly proportional to the gnat population it seems.. Harmless except for the funnel webs hidden onshore.
- Scorpions? Yes. I've only seen them onshore.
- Poisonous snakes? Sure. Just be careful around dawn and dusk. Sometimes with heavy monsoons they can be put awash in the lake looking for any dry higher ground like a boat.
- Rodents with Hantavirus? Unfortunately yes. Keep trash secured and don't touch any carcasses or droppings of rodents. Lysol is supposed to kill it I think.
- Speaking of trash, Heckle & Jeckle will be out and about looking for a tasty meal or just chunks of your upholstery
- Pesky little fish that hang out around your swim ladder? Yes. Sometimes you have a couple of small fish around that like to bite freckles or moles or anything they see on you. Pesky little devils.
We can save the discussion of all the Indonesian Pythons that have been let loose in the southern end of Lake Powell in recent years for another day. That would be way too much to digest all at once.
Check 6,
Goblin