If you look at the marsh next to the Saquatucket Harbor in Harwich Port, Mass than you will notice that a lot of its grass is missing! This grass has been slowly disappearing for decades. With help from the National Science Foundation, Dr. Bertness studies this critical ecosystem. Marshes protect our coastal environment by nurturing a complex web of plants and animals, and serving as a critical storm barrier.
This ecosystem is being thrown out of balance, according to Bertness who's currently researching a possible link between overfishing and the death of all New England salt marshes. The marshes are being overrun by purple marsh crabs. This is because the purple marsh crabs main predators are being over fished.
Bertness sets up experimental stations all over Cape Cod. At each field station he tethers purple marsh crabs to sticks, offering an easy meal for hungry blue crabs. In addition he sets up predator traps to get a good idea of the number of blues at the stations. He is finding that the marsh grass was the healthiest where the purple marsh crabs are getting eaten. He see's this same trend throughout the cape. Marshes erode while the purple marsh crabs eat the grass away. Bertness is calling this a halo effect.
"People like fishing and they like salt marshes, and they don't understand that there's a pretty tight linkage between the healths of both of them," says Bertness. "Salt marshes are such an important nursery ground habitat for both recreational and commercial fisheries that it's in their best interest to understand these linkages."
I think that this is a very interesting topic and it is great that Bertness figured out the problem. Salt marshes are important to a lot of environments and we need to keep them around.
