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December 2001 Volume XII Issue 10 Abridged Edition |
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Exotic InvasivesDump and Clean Your Boat Between Paddles by Tom Todd (with excerpts from NH DES and other sources) We are the migrate gypsies of the paddling world. We carry our boats from place to place, launching them on many bodies of water. As such we can easily be the Typhoid Mary of the water world. As the world shrinks, the threat to our waterways by exotic plants and animals is increased. We want to make sure that we don't become a carrier for transporting these exotic invasives from place to place.
Other plants and animals are just beginning to get a foothold here and we should attempt to avoid being the ones who contribute to spreading them.
Exotic invasives crowd out native plants, and scientists are worried that decline in the health of native species may lead to less biodiversity. That is, fewer species of plants may lead to a more fragile habitat for other creatures. For example, several lakes and ponds in our region are threatened by Eurasian milfoil. The speedy growth of milfoil threatens native water plants and also cuts down on the amount of sunlight reaching the pond bottom. Submerged plants, fish and other aquatic life, may be affected. It grows so thick that it is difficult paddling through it.[2]
Adult and juvenile mussels are transported by waterfowl and by attachment to boat hulls, crayfish and turtles. Large stage mussels (veligers) can be transported in anglers' bait bucket water and boat engine cooling water. Similar to other introduced non-native species such as milfoil,these exotic mussels can reproduce rapidly because natural predators are not present to keep the population in check.[6] As of January 1, 1998, the sale, distribution, importation, purchase, propagation, transportation, or introduction into NH of exotic aquatic weeds is prohibited. The following is a list of prohibited exotic aquatic species in New Hampshire:
What you should do:
Learn to identify these exotic invasives. NH DES has a two page identification pamphlet that you can down load and print at: http://www.des.state.nh.us/wmb/exoticspecies/fourteen.pdf References:
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I think we are all familiar with Purple Loosestrife: an erect (1-2m),
perennial herb with a square, woody stem and opposite or whorled leaves.
Purple loosestrife flowers from July through August in New Hampshire, and
is named for its bright purple flower that spikes from the top of the
plant. One plant may grow as an individual stalk or as several stalks
clumped together. Purple loosestrife is native to Eurasia. It was
originally introduced to eastern North America in the early to mid 1800's.
This invasive plant was probably accidentally introduced via ship ballast
or brought over for use as an ornamental plant.[0,1] Loosestrife is so
established now that it will be impossible to eradicate it.
Exotic aquatic plants, such as milfoil and fanwort, have been a problem
in New Hampshire lakes and ponds since the mid-1960s. Variable milfoil, by
far the most wide-spread exotic aquatic plant in NH, was first found in
Moultonborogh Bay in Lake Winnipesaukee. From there it has spread to
infest 38 waterbodies. Fanwort, water chestnut, Eurasian milfoil, purple
loosestrife, and common reed are also problematic species in this state.
[0]
Eurasian Milfoil is just beginning to hit NH and VT but has not hit
Maine. Once introduced to a lake (usually by boats) it grows and spreads
very quickly, ultimately ruining valuable shore front property. Mountain
Pond in Brookfield and the Connecticut River in Charlestown are the only
two locations of this plant in New Hampshire. However, Eurasian milfoil
can be found nearby in a number of waterbodies in Vermont and
Massachusetts. This plant is typically found in alkaline (hard) water,
while New Hampshire tends to have soft water. Learn to identify the
plants. Please inform NH DES if you see this plant. 603-271-3503 [3,4]
In July 1998, the NH Department of Environmental Services (DES)
confirmed reports that the exotic aquatic plant water chestnut has
infested the Nashua River in Nashua. Water chestnut can completely cover
the surface of a water body and cause ecological hardship to native plants
and animals. Fishing and boating can become extremely difficult as
well.[5]
Not all the exotic invasives are plants. One of the most problematic is
the Zebra Mussel. The mussel is expected to infest most areas of North
America within the next few years. During the summer of 1993 the zebra
mussel was discovered in Lake Champlain, Vermont. In 1998, the mussel was
found in East Twin Lake, Connecticut. With infestations to the south and
west, it is anticipated that their arrival in New Hampshire is just a
matter of time.
