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There is good news and bad news. The good
news is that there does not appear to be a lot of nonindigenous species in the
eastern part of the Gulf. The bad news is that we may not have really looked.
No marine organism, once established, has
ever been successfully removed or contained. The following list is how
introduced species can affect native species and habitat.
The first animals were things such as
shipworms (Mollusks) and gribbles (Isopods). With such a long history of boats
travelling to the Caribbean, who really knows what is or is not native.
This is a list of likely sources of
marine introductions. These are generally considered unintentional.
These methods of introduction are
considered to be intentional. Mariculture and aquarium releases are very
These are the kinds of organisms that can
are introduced into US waters. But because some of the introductions took
place so long ago. We cannot be sure if some species are indeed introduced.
The term we use for those is cryptogenic.
Very simply, no marine plants have been
successfully introduced into Florida coastal waters.
These occasional single introductions of
fish have no significant effects.
Again, an occasional introduction of a
single fish should have significant effects.
This shad is native to the Mississippi
River drainage and to the freshwaters of northern Florida.
A young threadfin shad.
More work needs to done on the marine
invertebrates of Florida. We only know of a few introductions.
The green mussel was brought to our
attention just this past August. It has been found in 3 power plants but not
in any significant numbers in Tampa Bay. But, USGS plans to survey the Bay
Several green mussels with a sea cucumber
Green mussels are from a family of edible
mussels and have been sold as a mariculture product since 1972. We do not know
if they are being cultured anywhere in the US yet. If there is money to be
made at it, it will not be long before someone in the US will be trying it.
A very small green mussel. At this size
you can see why they are a problem at power plants. They grow to about 4-5
inches. They prefer warm tropical waters and a salinity of at least 16 parts
Perna viridis from Tampa Bay, Perna
viridis from Trinidad, and Perna perna from Texas. All exotic to where these
Perna viridis from Trinidad. They are
lining the coastline of this small Caribbean island. They can also be found in
Venazuela. Could that be the source of the Tampa Bay green mussels? We don’t
know yet, but DNA sequencing could provide the answer.
A website for purchasing Perna
canaliculus. A native to New Zealand which has been observed live at Chiese
markets in the U.S. But it has not been collected from open waters.
Another website, this one in Texas
selling green mussel only we don’t know what species. Another source for new
Green mussels from a source in Bangladesh
selling them over the Internet..
Culturing Perna viridis in Palau,
Micronesia. China is the largest supplier of edible mussels, the US is 12th.
Perna canaliculus (Greenshell mussel from
New Zealand). It is sold as a remedy for arthritis worldwide. Has been seen in
Chinese markets in the US.
The native range of Perna perna in Africa
and South America. In the US it can be found along the Texas Gulf coast. The
native range of Perna viridis is from India to China. In the US it has been
discovered in Tampa Bay.
We also need to detect changes in species
composition over time. Determine probable areas of endemicity, dispersal
tracks, and timings of introductions. Pinpoint sources of current and future
invasions and identify species potentially involved. To an area already so
disturbed by man, exotics put a lot of pressure on the delicately balanced
community of native species that may be barely hanging on.
Large ship in Tampa Bay, Florida
One crab was introduced for a commercial
fishery, but it did work. Another, the saber crab, has been found in
tributaries of Tampa Bay. A few species of barnacles and isopods are
nonindigenous and occurred as long as 100 years ago. Did they impact any
native species? We don’t know.