Hello Friends,

In this article we will be looking at another invasive species and studying both its nature and effects upon the environment. This invasive species is the green crab (Carcinus maenas). Listed among the world?s most destructive invasive species, the green crab has spread around the world and can be found in Australia, South Africa, South America and both the eastern and western seaboards of North America. The green crab, in its native region, grows anywhere from 2.4 to 3.5 inches. However, as is the case with many invasive species, can grow up to 4 inches wide in regions where it has been introduced.

One of the key advantages that has led to the success of the green crab multiple regions throughout the world has been its adaptability. The green crab can generally survive in most protected coastal areas around the world. The green crab is also a ferocious predator which makes it destructive upon the environment which it enters. The green crab has a tendency to prey upon clams and other small crustaceans. Throughout North America, the green crab has preyed upon native clam populations.  An example of the harm caused by green crabs comes in form of the feeding habits of the crab in California. The green crab prefers to feed upon the native clams in the region, thus resulting in an opportunity for the invasive clam, the amethyst gem clam. This provides insight into the fact that in an ecological system, everything is interconnected. The ecological harm caused by the green crab is an amplified by influencing the populations of another invasive species.

The effect of the green crab is also a very real one. The green crab not only causes a harm to the ecological system as shown above, but also the economic system. The green crab has been notoriously infamous for causing harm to the commercially viable clams, scallops and even small and young crabs and fish. The green crab through both outright preying on these species and outcompeting them for resources, has led to the decline of a diverse range of aquatic species. This has led to the decrease of the commercial and recreational fisheries in many regions in the eastern waters off the coast of North America – costing millions of dollars.

In this article, we will also look at the measures that are taken to control the numbers of the destructive invasive species. Firstly, in the past there have been a very direct approach taken in Massachusetts to decrease the populations of the invasive species – a bounty levied upon the species. However, more measures have been taken also. The introduction of other species has been undertaken in the regions affected by the green crab in order to outcompete them. However, this is always risky measure, as the introduced species has the risk of becoming even more destructive than the green crab. AS the green crab continues to cause havoc upon the North American ecosystem, the hunt is on for alternative approaches to control and contain this problem. Scientific studies are now underway in order to discover how to deal with this alien predator. Maybe we, the next generation, can come up with some innovative ideas which can ultimately help us combat this problem and restabilize broken habitats.

photo credits: dfo-mpo.gc.ca