Harry: I don’t even like the term invasives. They don’t invade.
George: They do. They’re here. To stay.
Harry: They don’t invade. Particularly fish. How do they invade any place? Someone has to put them into the water, particularly fresh water fish.
George: You’re not saying that’s a good thing.
Harry: Sometimes it’s a good thing, sometimes it a bad thing. Depends on the species.
George: When is it a good thing?
Harry: Well, a great fish is crappie. What can anyone say negative about crappie? They grow big, taste good, and are easy to catch.
George: Wait a minute. They have been illegally introduced in more than 300 Maine waters, where they’ve displaced native fish. There is only so much fish food in the water.
Harry: I don’t know what they’ve displaced.
George: They’ve mostly displaced brook trout. But let’s talk about rainbow trout – the most invasive fish in the world. I read a book about this.
Harry: Rainbow trout are not invasive. The only way those rainbows got anywhere is because man put them there. That’s not an invasion.
George: Well, I’ll give you that, or at least agree they didn’t invade on their own. But the result is the displacement of native fish. And I agree sometimes that is ok. For example, warmer waters have resulted in the loss of native brook trout, and we’ve been able to create other fisheries there like rainbows. But you are not going to tell me northern pike have been a good thing.
Harry: Yes, I am. Pike are a boon for ice fishing. They are the centerpiece of winter ice fishing tournaments, a truly huge fish.
George: And they’ve wiped out landlocked salmon and brookies in many places – including my favorite, Long Pond in Belgrade. Long Pond is now full of nonnative fisheries including pike, walleye, crappie, and bass.
Harry: Well, landlocked salmon are not native to Long Pond. Originally they were only in four Maine lakes. So they are an invasive species, by your definition.
George: Let’s stick to bass. Bass are a nonnative species, stocked in some waters by DIF&W and in others by anglers, and very invasive. So I guess your point there is well made. Some invasives are ok. But they are still invasives Harry.
Harry: How can they be invasive? We put them in lots of places.
George: You helped them invade! Let’s look up the definition of invasives.
Harry: Here is the definition. “Tending to spread very quickly; undesirable and harmful.”
George: Sounds like northern pike to me, but I have to agree, not smallmouth bass or rainbow trout. So I guess what I am saying is that to be invasive, you’ve got to be something we don’t like.
Harry: That’s exactly it. It’s not a scientific meaning, it’s a value. And what one person likes, another might dislike.
George: Yes, wild turkeys would be a good example. You and I love them – or at least we love to shoot them. Others find them a terrible nuisance. Farmers hate them.
Harry: So, who gets to decide what is invasive and what is welcomed as a new species.
George: Good question. We have laws against introducing invasive species, and a list of those species that are already here – at least for plants. Maine has never seemed to care a whole lot about the spread of invasive fish. But we’ve gone crazy over invasive plants.
Harry: The fine for introducing invasive fish is $10,000, but we’ve been unable to catch or prosecute anyone.
George: Hey, they are right on top of goldfish. The Fish and Wildlife Department kills goldfish wherever they’re found.
Harry: As if goldfish are going to be a real problem.
George: Yes they will. They crowd out other species.
Harry: No they don’t. The rabid invasives people went nuts over purple loosestrife and said it would take over the state’s marshes.
George: And it did.
Harry: No it didn’t. Show me a place that has happened. And I haven’t heard any concern about lupine.
George: Well, how are you defining rabid invasives people? Are these people from away?
Harry: These are people who are inclined to fight any new species, even those of value. They worry about anything that comes along. Once upon a time people went nuts about the introduction of English sparrows.
George: Well, now you’ve got me. I love the new birds that are showing up, especially the Sand Hill Cranes we’ve been seeing in central Maine. I hope they continue to invade.
Harry: And how about turkey vultures? Are they crowding out other species?
George: No, they’re feasting on road kill, cleaning up our roads, and that is exactly how and why they arrived – following the Interstate with its many road-killed creatures. I95 is a buffet for turkey vultures.
Harry: So, are they invasive.
George: Yes, but we’re ok with some invasives. Especially you. A lot of folks don’t know you came here from Boston. And I for one am glad you did!
Harry: My point is that some invasives are good, many are having no impact, some have significant value.
George: And some are really really bad Harry.
PHOTO: a native brook trout that I caught recently on a river that has no invasive species in it!