Good morning everyone, it’s very nice to be here and take part in this meeting. I admit was not familiar with this organization in the past and I’m especially glad of course that the organization is interested in the invasive species issue.  I’m sure some to many of you have dealt with invasive species up-close and personal and probably wish the issue would go away. So do I.

Just as background, according to Dr. James Carlton, an expert in exotic introductions, no systematic studies have been done on the nonindigenous marine invertebrates of Florida. Because Tampa is a busy shipping port, it would be advantageous to systematically examine the exotics there and around the the rest of the coast of Florida as well.  I’m sure you are well aware of how important it is to have baseline data so you have something to compare new data or data collection in the future to.

Again according to Dr. James Carlton, no marine organism, once established, has ever been successfully removed or eradicated in the US. New introductions can cause problems for native species such as predation, competition, disturbance, and diseases and parasites.  There now may be an exception, an exotic sabellid worm which was devastating abalone population on the West Coast.  A localized population was eliminated below the detection level by eliminating the intermediate host.

This is the mussel we are talking about, Perna viridis.  It is aptly named the green mussel and is in the family Mytilidae along with other edible mussels that we are more familiar with like the blue mussel Mytilus edulis that you see on restaurant menus.

There are 3 species of Perna worldwide.  Shell color can be variable in them all.  They all used to be geographically isolated, location was used to tell them apart.  Location of a specimen can no longer be used to identify them because they are being moved around the world.  Although you can loosely identify them by shell color and shape, the best scientific method to identify them from each other is by genetics. 

The green shells showed up in Tampa, they were unfamiliar to biologists here and never seen in the US before. The natural range of Perna viridis extends from the Persian Gulf east to the South China Sea.  The natural range of Perna perna is Africa and South America.

The red shaded circles represent populations that we are aware of in the Caribbean region which are located in Trinidad (1990), Venezuela (1993), and Jamaica (1998).

Tampa is a large port where millions of gallons of ballast water are dumped in port every year. Much of the shipping traffic (~43%) comes from Gulf of Mexico and Caribbean regions including the northern coast of South America. Only a negligible amount (~1.5%) of shipping traffic comes from the home range of Perna viridis. 

Other mussels in the area besides Perna viridis (Tampa Bay), include Perna viridis (Trinidad), Perna perna (Texas).  All the mussels from Trinidad (~30) had a distinct green outer margin.  Virtually all the green mussels collected from Tampa Bay had entirely green shells.  The brown mussel here is entirely brown and has a much thicker shell.  The green mussel shells have been very thin in comparison.

According to the literature, these are some of the conditions where green mussels live in their native range. The temperature is 26-32 C.  The LC50 is 10 and 36 C after 2 weeks exposure (50-96).  Salinity is 27-33 ppt but can tolerate 20 ppt for short durations. Marc Blouin has documented even lower salinity measurements where green mussel exist in the Alafia River. The temperature and salinity tolerances vary somewhat in the literature.    I do not know how many eggs are produced.

Perna viridis collected from TECO Gannon Station's intake tunnels October 13, 1999. Over 150 specimens were collected.  Sizes ranged from

Our first survey in November 1999 just 3 months after we were made aware of there presence. We weren’t really sure where to begin looking.  So we decided to look in Old Tampa Bay because we already knew they must be in Hillsborough Bay, that’s where the power plants were. The first green mussel revealed itself to us on the bottom of this buoy out in the middle of the bay.

Next we decided to start looking at the bridges in the bay.  This I-275, the Howard Frankland Bridge over Old Tampa Bay.

Here are a few more gaping open.  Also you may notice that the mussel inhabit structures that are exposed at low tide.

This is a good example where you can clearly see them intertidally.  These mussel are attached the the concrete bridge pilings.

We also examined the structures that help mark the center of the bridge where large boats can pass under it.  They are made up concrete with wooden fenders.

This mussel we attached to the underside of the wooden fenders at the underpass.  As you can see they are pretty well covered with barnacles and exposed out of the water.

This is Mote Marine Laboratory's west intake pump from the New Pass dock, Sarasota Bay August 3, 2000. Bay water goes through this pump and is distributed to the lab. One Perna viridis was found.  It was 7.6 mm (0.30 inch).  The east pump had nine P. viridis ranging from 1.2 to 4.0 mm (0.05 to .16 inches).  The east pump was last cleaned April 19, 2000. Here you can see the fouling of Mote Marine Laboratory's west intake system discharge expansion collar from the New Pass dock, Sarasota Bay. On August 3, 2000 two Perna viridis collected ranged from 26.9 to 38 mm (1.06 to 1.50 inches).

This is the 1000 ft. pier (shore to 1/4 of the length) at Ft. Desoto Park, St.Petersburg.  July 29, 2000, specimens were found on the on the 3rd and 4th support piling from shore, on the "low" profile jetty directly to the north of the pier, and on the "high" profile concrete rubble farther north of the pier.  The furthest south I have personally seen them was on the fishing pier in Venice.

These are Lido Beach jetties on the Gulf on Mexico, Sarasota, Florida, on September 21, 2000.  Two Perna viridis collected from the southern jetty ranged from 27.3 to 42.9 mm (.39 to 1.67 inches).  These specimens were found in the outer edge of the jetty which receives high wave energy and sandblasting.  They showed irregular growth and coloration.  On October 5, 2000 one P. viridis was found on the south jetty. It was 39 mm (1.53 inches). This is Lido Beach, north jetty rocks on the Gulf on Mexico, Sarasota, Florida, September 21, 2000.  Five Perna viridis collected here ranged from 12.5 to 18.0 mm (0.49 to 0.70 inches).  They were collected in high energy intertidal zone which experiences sandblasting.  All were collected in "protected crevices or tidal pools on the rocks - all in areas receiving the most wave impact.

Here is a close up of the "high" profile concrete rubble and its position to the shore line north of the 1000 ft. pier at Ft. Desoto, St. Petersburg July 29, 2000.  This area receives high energy waves and experiences "sandblasting" .  This is where very irregularly shaped and colored Perna viridis specimens were found in the intertidal zone (some fairly high up in the intertidal zone).

This is a close up of Perna viridis growing on the "high" profile concrete rubble (north of the1000 ft. pier at Ft. Desoto, St. Petersburg, July 29, 2000) in the upper intertidal area growing among oysters, barnacles and algae.  This is an area of high wave energy, "long" periods of exposure to air, and constant sandblasting.

They were attached very firmly by their byssus and were difficult to remove by hand.  This is what they look like just having been removed.  Some were nearly completely covered with barnacles.  I have some literature that mentions this fouling in their native range.

Here are two mussels showing the mass of byssal threads that are used to to attach themselves to a substrate.

This appears to be a ripe female as their ovaries become this bright orange color.  Males gonad appear white when ripe.  But it becomes difficult to distinguish the sexes when not near spawning.

The highest growth rate recorded in an aquaculture situation was 10.6 mm per month in Singapore (Cheong and Chen (1980). Preliminary growth rate in Tampa Bay (Apollo Beach) was estimated to be 7.2 mm per month (Ingrao).  Out in the Bay, preliminary data shows in to be closer to 5.8 mm per month (Benson et al.).  The literature makes mention of a case where a mussel reached 300 mm. This mussel from Tampa Bay was 109.8 mm and was estimated to be about 15 months old suggesting that it may have settled about September 1998.

To sum up where we have found green mussels, all the symbols represent a location where green mussels were collected.  The difference between symbols is simply who collected them, which includes USGS, FMRI, Mote Marine Lab, TECO, and the US Coast Guard. We have found them as far north as Johns Pass in St. Petersburg and as far south as Boca Grande outside Charlotte Harbor.  We don’t know the complete range as mussels were collected as the outermost sites we sampled. Blue dots are Mote Marine collections.

This is Debi collecting Perna viridis from the intake pipes at TECO's Gannon Plant, October 13, 1999. Over 150 specimens were collected.  Sizes ranged from 6 to 63 mm (.24 to 2.48 inches). This is one of the mussel found inside the power plant last August 1999.  Small mussel ~20 mm such as these were gravid at the time they were collected.  This mussel was probably about 2 months old.

Mote Marine Laboratory's west intake pipe from the New Pass dock, Sarasota Bay August 3, 2000. No specimens clearly visible on the outside of the intake pipe.  The inside of the intake end of this pipe was scraped approximately 6 inches in. One 1.7 mm (0.07 inch) Perna viridis was found.  It was beige with golden concentric zig-zag markings.

Green mussels may have remedial properties for helping some common ailments as rheumatoid arthritis and osteoarthritis. 

Green mussel are edible and are consumed in great numbers in Southeast Asia and South Pacific Islands.  Will this help keep their numbers in check?  Maybe where harvesting is legal.  But Tampa Bay will always be a source for recruitment of young since harvesting is illegal there.

I found several seafood market with websites advertising green mussels for sale.  I know you can’t read this, but the next to last item on this list has green mussels selling for $2.95 per pound.  It does give the species name of course, so you can’t be sure exactly what you’re buying.

This is green mussel culture in Thailand where they grow on bamboo poles stuck in the bottom.  Cotton rope supposedly makes the best substrate when hung from floating rafts.

Perna viridis have been sold in the aquaculture industry since at least 1972.  They have been shipped to other islands in the South Pacific to start an aquaculture industry there.

To summarize : They were first discovered in a Tampa area power plant July 1999. 

Of course everyone wants to know how far could they spread and survive.  The dark red represents areas of coastlines where I believe green mussel can overwinter.  The pink areas are less suitable based solely on their temperature tolerance.  They have already survived temperatures as low as 12oC in Tampa Bay last winter.

Unfortunately, they are too well established to eradicate on Florida’s west coast.  The only way we can attempt to control them is by not spreading them intentionally or unintentionally. There is much interest already by commercial fisherman to harvest green mussels where it’s legal for human consumption.

This is another species to be on the lookout for along the Atlantic coast.  Currently, it is found in the Chesapeake Bay area since 1998. It feeds on other mollusks such as oysters.