I think you all have made a pretty good case as to how the world is being cross pollenated with just about every type of organism. Terestrial plants, animals, reptiles, birds, bugs, fungus, virus, bacteria and desease are being transported daily around the globe by shipping, trade, of fresh food stuffs, grains, plants and pets. and our favorite sea critters too. Yup the ships that carry them transport millions of gallons of live organism laden water from distant oceans, rivers and lakes to every point of the globe and then discharge them daily. nearly all the cargo ships that sail up the chesapeake or delaware bay each day, lighter their load of ballast water in the lower bay. and take on our waters on the way out again. its been going on since man first started to walk about with his stuff.
It’s not an arguement i wish to win. Yup the world is going through a rapid species migration that will make new local winners and losers everywhere. In the long run, it will all settle out to a new stable biosphere. but in the short term, the age of mankind, it may be unpleasant. especially when the effects of global warming are tossed on top of all this stress. and don’t forget all the chemicals, and medications and hormones we consume and then flush down the loo. Yup, there are much bigger forces at work than just our tanks.
Dude…Don’t drink the water!!!