Boats with barnacles begat other boats with barnacles

Yesterday, I spent the better part of an hour underwater cleaning my props of barnacles.

What is interesting in this particular case is that in my entire term of owning this boat I have NEVER had this many barnacles on my boat. Particularly, the props are absolutely covered to the point that I could not get above 1600 rpm despite cleaning the props over Memorial Day weekend.

I keep my boat in what is supposed to be fresh water but it has turned brackish over the years. Recently, two of my friends have purchased boats that came from an entirely salt water environment. One boat is right next to mine and the other is across the dock.

Over Memorial Day weekend I rafted up with my friends boat and I cleaned his hull while we were in the GOM. His boat was covered in barnacles as well while mine had only a few after sitting more than 6 months without a cleaning.

Is is possible that their boats brought the barnacles? Heck, even my fresh water hose that was hanging in the water at my dock has barnacles.

In our area there are years with more barnacles than others. This year seems like it will be a bumper crop. There are also some boats that seem to grow more barnacles than others. Not really sure why.

But I have some theories. First, I wonder if they all "spawn" (or whatever it's called) at the same time. If so, perhaps boats that get in before the spawning cycle starts get covered with barnacles, while later arrivals don't. At least, that's how it seemed this year.

Also, presumably, the amount of suspended nutrients in the water will have a direct effect on the population of these filter-feeders. Changes in agriculture practices shoreside, runoff from rains, water temperature, and probably other factors will impact this. Those could differ from year to year.

As far as I know, barnacles are salt water creatures. Maybe I'm wrong, but my assumption was that they wouldn't survive in fresh water for any length of time. Let me know, maybe I'll plan a trip up one of the rivers for a few days this year.

I keep my boat in a large river (Merrimack) which is usually brackish water, but due to a 9 foot tide, the salinity in my area fluctuates quite a bit. During years of low river flow (last year was one) we get more barnacles - and I did. This year there has been a lot more rain and I know a lot more outflow from the river. So it will be interesting to see if there are fewer barnacles than last year.

My area includes the Cape Fear River, which is mostly fresh water. A little bit of salt depending on rain and tides, enough to kill cypress trees. Boats moored up at Bennett Bros STILL get barnacles. Apparently they need salt, but not much.

I'd be a little aggravated if a boat moored next to me covered in the things. The spawn come from somewhere, and having a bunch arrive next door can't help.

The short answer is no. Being close to other boats with barnacles will have no direct effect on the barnacle load on your boat. Barnacles have a planktonic stage that lasts several days at least. There will be several tide changes and moving current that disperses the organisms over a wide area. They then seek a suitable substrate for the "sessile" stage. The bigger issue is "suitable substrate". It's important to remove the calcareous base plate when you clean your boat. It's a nice spot for succeeding generations of barnacles to land. Oh and BTW, certain species of barnacles have a pretty wide tolerance to low salinity water.

We are always in salt water and we have our props and running gear sprayed with Pettit running gear anti fouling spray, works great, might want to go that way.