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years ago I was working in Pennsylvania at a U.S. Fish and Wildlife Service laboratory working on lake trout and
Atlantic salmon restoration projects.
While I was there I was
aware that we had a laboratory in Florida that worked on exotic species but was really sure what that meant. I had my
own work to do so I went on about my business. And then while on a visit to Florida to
learn about the sturgeon restoration going
on here, I learned a little more about exotics. About 6 months after the visit
to Gainesville I applied for
and accepted a job at the Gainesville laboratory and now exotics are all I do. I first started by
documenting occurrences of exotics, that was, and still is the kind of information the
government wants to compile. The lab had started to compile a list of exotic fishes in the US
before I got there. When I arrived I began to keep track of where the zebra mussel was spreading. Now we are trying to compile documentation of any aquatic organism that
is outside of its historic natural range. Originally our laboratory was established to test whether
exotics could serve good uses such
as biocontrol of aquatic weeds and algae with tilapia. In some cases research
has unfortunately been
responsible for a few introductions.
the US Congress recognized the problem and had their own staff compile a report. This is very good report but it
stated that information on harmful nonindigenous species was scattered, obscure, and highly
variable in quality and scientific rigor.
The effects of many
species have never been studied. With poor documentation as the report stated, the magnitude of the problem
has probably been underestimated. So we
are doing are part to help
improve the knowledge base of at least the aquatic end of the exotic spectrum.
Some species like the African honey bee,
the fire ant, and more recently the West Nile virus are a human health risk.
While others like the Melaleuca tree and the zebra mussel threaten widespread disruption of
ecosystems by displacing native plants and animals.
first introductions probably occurred over 500 years ago with the earliest
European settlers. These most
likely were ship hull fouling an boring organisms. Things like barnacles and shipworms.
Mollusks, crustaceans fish,
plants, sponges, etc.
But because of the possibility of
introductions 500 years ago, it is difficult to determine what is native to the region’s marine
waters and what is not. We refer to
these species as cryptogenic.
is actually some anecdotal information from ancient times about how they stocked carp and goldfish. From this graph
it appears that fish introductions actually peaked worldwide in the 1960s. Either they ran out of new
species to stock or they were
happy with what they have. Recent introductions mostly for a human food source
now seem to be a lot of clams,
mussels, and crustaceans such as shrimp and crayfish.
majority of species have been introduced into only a few countries. Eighty-six
percent of the species
introduced have been recorded from 10 countries or less. This graph is read for example the first column means that 29 countries have
only had 1 species introduced,
6 countries have had only 2 species introduced and so on. I am concerned with the farthest bar to the right that
says 1 country has had 70 foreign species of fishes introduced in it and that happens to be the
US. Canada falls out at 17 foreign
species, Mexico with 33, and
Hawaii with 45 species of foreign fish.
of Nonindigenous Aquatic Species Introduced into the US. This includes interbasin transfer within the US.
are almost as many ways for introductions to occur as there are introductions.
But here is a list of the most
well-known and documented. I found one example of shipping water very interesting. Several years ago 3000 Pacific oysters were
shipped from California to
Woods Hole. The shipment had 2
certificates stating the oysters were
parasite and disease free. That was all
well and good but only 10% of the shipment
was checked which I believe is standard. After arriving at Woods Hole, the oysters were washed and the water saved.
There was a total of 29 species of algae, diatoms, protozoans, and invertebrates detected in the water
the oysters were shipped in.
truly is a global problem. The Russians are have problems in the Caspian Sea
with exotic jellyfish where
one bay was nearly solid with them. And
in China, largemouth bass are
becoming a problem as a result of stocking.
of Nonindigenous Aquatic Species in the US by Pathway of Introduction
is a short list of pathways which could lead to the introduction of exotic
organisms. I don’t want to forget to mention the rate
of introductions steadily increase as commerce
and free-trade increase as well. New
pathways for the possible introduction are
Percentages of All Aquatic Species in the US Introduced from
scientists believe there are characteristics which help a species survive in a
new environment. Here is one list.
large comprehensive study has been undertaken yet like those done in San Francisco Bay and Chesapeake Bay.
we know about Florida. Fish are mostly freshwater species.
Pomacea canaliculata channeled
applesnail – SA Daphnia
lumholtzi – AF, AA
Cipangopaludina chinensis Chinese
mysterysnail -AS Marisa
cornuarietis, giant rams-horn
snail – SA
Melanoides tuberculatus, red-rim
melania – AF, AS
Hemichromis letourneauxi –
African jewelfish AF - south Florida
Oreochromis aureus - blue
Tilapia mariae – spotted tilapia
Monopterus albus - swamp
Xiphophorus helleri – green
Ctenopharyngodon idella – grass
Pterygoplichthys disjunctivus -
vermiculated sailfin catfish SA
Asian clam is very common in Florida, you many not know it’s an exotic. We are not
sure how it got but it first was discovered in the Pacific Northwest in the
1920s and is spreading
throughout the country. It was originally thought that it would not survive the warm southern temperatures based on the
temperatures of its native waters, but it’s doing quite well everywhere.
If there’s one thing that helps a species to survive in a new environment is its ability to adapt --
genetic plasticity. The African clawed
frog is a common pet store
item and it is established in south Florida along with the Cuban tree frog that came in accidentally in shipping
are not many marine fishes which have been introduced. Here is one: Scatophagus argus. Scat, Seahorse Key (Gulf of Mexico),1992,
Asia, Aquarium release.
Little impact if any.
Cromileptes altivelis. Another
is the Panther grouper, Found a couple time in Coffee Pot Bayou, from the South Pacific, probable
monodon, Asian tiger
shrimp, Captured in Florida from aquaculture escapes in South Carolina, not established.
spectabilis - sabre crab.
This crab came from the western Gulf of Mexico
in the 1930s on imported cedar logs, found in the Tampa region.
serrata. The serrate
swimming crab is from the Pacific, intentionally introduced in the 1990s to create a new fishery but did
hellerii. An Indo-Pacific
crab on east coast of Florida. Ballast
armatus. Green porcelain
crab. This crab is native to the tropical Atlantic, Bahamas, and Caribbean, may have come with
shipments of seed clams and is established.
are 3 barnacles considered not native to Florida, B. amphitrite, B.
reticulatus and B. trigonus.
have two mammals in Florida. The nutria
has been documented but the capybara I have
mostly heard through personal communication of local residents. Myocastor
coypus denude a lot of of marsh habitat.
viridis group. Discovered
in 1999 by TECO, a probable ballast water introduction, well established, edible where it is legal
collected this specimen last Monday. I
noticed a large amount of reproduction this year. I did not see
this the year before. I think this
species is just getting started, perhaps.
not forget about plants, a plant like Hydrilla has had huge impacts her in
Florida as you I’m you’re
aware of. Millions of dollars are spent
every year in Florida to control it
and . . .
hyacinths. The situation with plants
both aquatic and terrestrial far outweighs the problems with most of the animals. Exotic insects may be
the exception there. The western US has has some real bad
terrestrial plants such as leafy spurge, yellow star thistle, and salt cedar. The National Park
Service is extremely concerned there.
are relatively new invaders of which both occur in Florida. Minima is native to central America and molesta to South
America. Minima can be found in most region of Florida except the far west panhandle. Molesta is the more
invasive of the two and was discovered
in SW Florida near Naples.
has chocked off several large rivers in Asia.
We knew this was a bad one and now
it’s here in the US.– Giant Salvinia from the water garden trade
is list of several plants closely associated with the aquarium trade. It is
pretty well documented that
hydrilla and parrot’s feather came from aquaculture, more specifically the aquarium trade.
are several Great Lakes invaders and might do well in Florida if they get
here. Most of us are familiar with which the zebra mussels spread.
Cercopagis is a small crustacean
also spreading quickly to all the Great Lakes and the Finger Lakes of New York State. It’s native to the Caspian
region of Eurasia. The snail, a native of New Zealand, is also in the Snake River system in Idaho and is
doing well, hundreds of thousands
per square meter. They have spread into Yellowstone Park probably unknowingly by fisherman. The state of
Montana has closed small isolated areas to fishing where the snail is found to keep it from spreading.
two species both from Asia are really taking off in the Mississippi and Ohio
river drainages. One bighead taken from the upper Ohio River
was 47 pounds, possibly a world
record. Animals seems to grow larger in
a new environment without factors such as
predation and diseases acting on them. The carp are mainly feed on
phytoplankton and algae. Therefore, they may be competing with the
native paddlefish and other organisms
depending on algae such as mussels.
dalmatinum in the northern Gulf of Mexico in 2000. Native to Atlantic and Pacific but not the Gulf. It is suspected
that a weather event or change in the Gulf currents brought this jelly to the northern Gulf. Has a potent sting to many.
spotted Jellyfish. Was found in the northern Gulf of Mexico in 2000. It is suspected that a weather event or
change in the Gulf currents brought
this jelly to the northern Gulf from the Caribbean. Gets to 20 inches across.
to Mediterranean, Hawaii
to the western tropical Atlantic late 1960s / early 1970s
recently, primary Atlantic concentration in southern Caribbean
venosa. Introduced from
Europe into the Chesapeake Bay several years ago. It
feeds on shellfish such as oysters which all know is an important industry
sinensis. From Asia, a
probable ballast water introduction into San Francisco Bay. They travel mimes and miles upstream
to spawn in fresh water. This species really
took off in central California but its number have dropped now. The state was pulled dump truck loads of them from water
pumping stations so critical to California’s irrigation systems.
maenas. This is an old
introduction from Europe into the northeastern US, but recently into the northwestern coast of US.
There is fear that it will compete with the native crabs that are a valuable commercial commodity. A more recent introduction to the northeast is the Japanese shorecrab, Hemigrapsus sanguineus.
is one main problem of how exotics can impact us. Here are some zebra mussel attached to the submerged portion of
an outboard motor. The larvae can be pumped into the engine’s cooling system and
cause problems if they are allowed to settle
and grow there.
propeller. Here you can see a little better how they might tend to cause problems.
are green mussels with barnacles covering one of the bridge pilings over Old Tampa Bay from last year. With the way they
attach, they could cause structural damage
to the integrity of the concrete over time.
bridge piling in Tampa Bay. The green
that you see are this year’s
reproduction of green
mussels. Each bridge piling on all three bridges was cover on all fours sides.
Some a little heavier than
mussels are also attaching to navigation aids.
In parts of Asia where they are not
native, the weight of the mussels can actually sink the buoys. In the great lakes, zebra mussels were sinking buoys there
Mote Marine in Sarasota, a few green mussels were found in a water intake at
Economic Impacts all come done
to dollars and cents.
Mechanical cleanup is
Biocontrol is expensive
Pesticides are expensive
Herbicides are expensive
Costs usually passed onto consumers and taxpayers
Degradation of host
Displacement of natives
Extinction of natives – out west this
a problem with several of the rare desert fishes. Aquarium species are being reared in the
warm thermal springs.
Hybridization with natives
be honest, it’s very difficult to control organisms once they get established.
For the future, prevention is
the best method of control and why it is so important. Getting laws changed and new ones passed is extremely difficult because
each segment of this trade has
a lobby that fights any regulation on their industry. I believe that
discovering new pathways and
eliminating them may have possibilities of slowing down the flow of new organisms.
Boiga irregularis - Native to Indonesia,
New Guinea, Australia - 13,000/sq. mi. in forest on Guam
easy to buy anything on line these days and there is no way to get it all
inspected. There’s simply not
•Elevate the issue in DOI agencies to get
•Attain an adequate level of survey /
inventory activity to monitor invasive species
•Develop better methods to assess status and
•Increase efforts in areas with many invasive
species and in high biodiversity
•Identify new “hotspots” and gaps in
What can you do as educators to
Educate people about impact
Elevate local invasive species
issues to governments and public.
What can the public do?
Clean and dry boating and
Do not empty bait bucket
Do not empty livewell
Do not purchase known invasive
animals and plants. Many are still for sale.
What can you and the public
Learn to identify exotics
Learn which waters are
Learn the laws concerning
prohibited species which is not easy.
is very import than we teach people not to release their pets. Some other
options may be to give to
someone else, the pet store may take it back and resell it. To euthanise an aquatic pet use can freeze
you scholarly types here is some recommended reading.