Difficult problem (Score 1)

This one is kind of a tough one to tackle. First of while a single crab can lay hundreds of thousands of eggs at a time, ober 98% of the young will never survive. This is because when they hatch, crabs go through a neoplanktonic period. This means that the larva just drift around like little bits of plankton. This makes them prey to larger fish and perhaps even some zooplankton. Whether or not they can reach as far south as Gibraltar is unclear to me. They seem to be a very cold water type creature. I don't think that King crab have spread down to say Washington or Oregon (at least I haven't heard of it happening). This can be because of diffences in water temperature, or perhaps because of the direction of the currents which might prevent to larva from drifting that far. One of the things that we learn in the introductory level oceanography is that whenever a species in introduced, you run into some major problems. Once you reach the 400 level courses then the discussion becomes a little less black and white in some cases. There is a very small train of thought that in some cases, an introduced species can increase biodiversity in an ecosystem. One of the things that can happen when a species in introduced is that not only does that environment change, but also the species itself changes. I believe down in Oregon, a species of copepod from the western pacific had been introduced. It's moving up the Columbia river and is actually out performing the indigenous species. However you start to notice that there are some differences between this new species when it first arrived to the its present form, probably from cross breeding. Once we start moving into even smaller organisms, things get a lot more complicated. One of the things that we learned in Special Topics Ocean Biology is that the ocean is full of viruses that can create lateral gene transfer in organisms which can lead to the developement of new species.