Perna viridis (Linnaeus, 1758) Asian Green Mussel In Duval Co., Florida

Perna viridis (Linnaeus, 1758) Asian Green Mussel

    This exotic species was first discovered in Florida during July of 1999 when divers from the Tampa Electric Company (TECO) were performing routine maintenance on the cooling water intake pipes at one of its power generating stations in Tampa Bay and found that the screens on the pipes were partially clogged with the mollusks. Since the initial discovery, prevailing currents have spread the mussels southward along the southwest Florida, and only four years after their initial discovery, the mussels had spread to northeast Florida.

    The species made its first appearance in northeast Florida during early 2003 when Dr. W. Henry McCullagh found a moderate number of living adult Perna viridis (Linnaeus, 1758) stranded along with benthic green algae, to which the mytilids were attached, at Crescent Beach, St. Johns Co. [image].  Later during the third week or March, an additional stranding of live specimens was discovered by Ms. Betty DeMarco on Atlantic Beach, Duval Co. - some 50 miles north of the initial discovery by Dr. McCullagh. Subsequently on 7/28/2003, Bill Frank found the species living in numbers on the granite boulders of the south St. Johns River jetty at Mayport Naval Station in Duval Co. [see report]. In the ensuing years the species has colonized a portion of the St. Johns River and associated waterways (shown below).

    Under optimal conditions, Green Mussels can grow to a length of nearly 6 inches and are native to the Indian Ocean and Southwest Pacific. It appears likely that the species was transported to Tampa Bay in the ballast water of commercial shipping with the Tampa port being the 11th busiest in the country. According to the U. S. Geological Survey, this is the first known infestation by this species in the United States although previously the species has been recorded in the Western Hemisphere from the waters off Trinidad (1990) and nearby Venezuela (1993).

    The map above depicts the locations where the Asian Green Mussel has thus far been found living in Duval County, Florida. Empty shells have also been found on the open Atlantic beach both north and south of the St. Johns River entrance (numbers 1 and 2 below). The species spread up the St. Johns River since their initial discovery in 2003 may be related to increased salinity as a result of less than normal precipitation - especially during 2007.



Date Found

South St. Johns River Jetty at Mayport Naval Station (Atlantic Ocean) [site image] 7/28/2003

North St. Johns River Jetty at Huguenot Memorial Park (Atlantic Ocean) [site image] 7/31/2003

Shore armoring, southern end of Little Talbot Island State Park (Ft. George River) [site image] 6/22/2005

Floating Docks at public boat ramp, Mayport Village (St. Johns River) [site image] 1/13/2007

Floating dock at Sisters Creek Marina (Sisters Creek) [site image] 1/8/2008

Floating dock at Palms Fish Camp and Boat Ramp (Clapboard Creek) [site image] 1/11/2008

Floating dock at Browns Creek Fish Camp (St. Johns River at Browns Creek)

[site image] 1/24/2008

Floating dock at Ft. Caroline National Memorial (St. Johns River)

[site image]


Arlington Lions Club boat ramp floating docks/fishing pier (St. Johns River)

[site image]



Back Page Two