Monday, September 21, 2009

(Codium fragile)*: dead man's fingers

Photographs taken by ScienceNrrd on 9.20.09
Click on photo to enlarge


Listening to the Nantucket waves lapping at the shore and noticing the amazing ocean life around me, I spied a beautiful cluster of seaweed called Codium fragile ssp. tomentosoides, or ‘dead man’s fingers’.  It is a particularly stunning variety, beckoning in its gracefulness as the ocean tumbles over it, back and forth.  I did some research, hoping to find interesting facts about this flora undulating about like mermaid hair.  It turns out that, beautiful as it is, it is actually a rather destructive species of weed. Native to the pacific waters near Japan, it was introduced to the US in NY from Europe in 1957. It is found in subtidal zones along most of the Eastern US coastline, from NC to Canada, in shallow waters and permanent tidepools. The seaweed attaches to almost any available hard surface, increasing maintenance labor for aquaculturists and reducing productivity of their cultured species.

When established in shellfish beds, wave action can carry the algae along with its host shellfish away from their normal habitat. Because of this, it has earned the nickname ‘oyster thief’.  Their dense benthic beds make mobility difficult for fish, lobster, and other marine organisms, and its ability to regrow rapidly from small fragments enables it to outcompete indigenous algaes such as kelp beds and eelgrass, primary habitats of many invertebrates and fish.  As a result, it can cause major upheaval to the local subtidal community composition and structure, and thereby, its function. The algae can be washed ashore in large amounts during storms, littering beaches. Take a stroll along the shoreline at an East Coast beach, and you might see some.  It is at once captivating and destructive in its beauty.


*In proper form, scientific names of organisms are typed in italics or underlined when written.  As this blog's format does not allow for either in the blog post title, I have put the scientific name in parentheses.