Big fish, but not from around here

I want to talk in more detail about invasive fish later. Probably when my Con Bio guys start looking at exotics. But here's an interesting study looking at the way in which introduced fish species have increased the average size of fish assemblages. The exotics are bigger than the natives by a full 12 cm - that's a ton. I guess it makes sense - we've been moving fish around, deliberately or not, for thousands of years. And I suppose, on average, the one's that we move around are bigger than the ones we don't.

Goes without saying that the introduction of large fish, in abundance, can seriously alter ecosystem function. Many of the introduced big guys are top predators, like largemouth bass (Micropterus salmoides) or the butterfly peacock bass (Cichla ocellaris) pictured above. Exotic detritivores like carp also have significant impacts on energy flow in aquatic systems.

We're already knew that invasive species will be one of the prime concerns for biology in the 21st Century. Doesn't help matters when those introductions are the bullies on the block.