March 26, 2002
Dear sent to numerous agencies and organizations listed at the end of the letter:
The Montana Chapter of the American Fisheries Society is writing to ask for your support and participation in efforts to control exotic aquatic nuisance species in Montana. Some species have already become established in Montana (e.g. salt cedar or Tamarisk and the New Zealand mud snail) while others are likely to invade the state in the near future (e.g. zebra mussels and Eurasian Milfoil).
Of
the currently invading species, the Montana Chapter AFS is particularly
concerned about the New Zealand mud snail (NZMS).
This prolific snail was first found in the Madison River in 1994 and has
reached densities of 300,000/sq/
meter within Yellowstone National Park.
It has since been
detected in all major drainages in the Park and downstream in the Madison River
below Quake Lake. A disjunct
population has been documented in Darlinton Ditch outside of Three Forks,
near the mouth of the Madison River.
Because of it�s
high densities, the snail has the potential to outcompete native benthic
macroinvertebrates for food and space. In
1998, in the Madison River near West Yellowstone on Highway 191, the mudsnails
comprised 70% of all aquatic invertebrates.
The snails, unfortunately, are a poor source of food for fish, whose
digestive fluids cannot digest the snail shells to get at the nutritious soft
tissue inside. Studies in New
Zealand showed that brown trout extract less than 2% of the energy available
from ingested NZMS. While rainbow
trout can extract almost 20%, other mollusks with unbroken shells yielded 38-67%
of the energy available.
The reproductive biology of the NZMS is quite interesting, but
problematic. They
reproduce by cloning, therefore a
single
NZMS can
start a new population. In fact,
very few male NZMS have been found in North America, and all populations
in the
western US are entirely female and of a
single
genotype.
NZMS are characterized as �born pregnant� because developing
embryos can
be detected
in larvae as they are released from
the parent.
The
Montana Chapter is concerned that our public natural resource agencies have not
made enough effort to understand the threat that is posed by this snail. With this letter, we are urging all agencies to initiate
efforts to document the distribution and abundance of this snail, and then take
actions to slow or reduce its numbers where needed.
Specifically, we
would like your
agency to immediately require
all field personnel
to perform visual
inspections for the presence of NZMS as a part of every field activity. In
addition we are requesting that you instruct all personnel to collect samples of
suspect snails and transmit them to the proper investigators for identification.
People already working on the mudsnail issue in Montana include Dr. Billie Kerans(406-994-3725) and Dr. Dan Gustufson (406-994-2771) at Montana State University in Bozeman and Pat Clancey with Montana Fish, Wildlife and Parks in Ennis (406-682-7807). They can be contacted to obtain information about the habits, identification, and chemical control of this species. Dr. Gustufson, in particular, has agreed to field calls or inquiries related to mud snail identification. The Montana Fish, Wildlife and Parks has started an Aquatic Nuisance Species Task Force, and we see this as an appropriate forum which can be used to organize and coordinate a mudsnail inventory. We encourage your agency or company to join this task force if you have not done so already. Tim Gallagher with MFWP is the contact with the Task Force and can be reached at 406-444-2448. With a coordinated effort, we feel that we can minimize the damage that may come from the presence of the mudsnail in Montana.
Sincerely,
Pat Clancey
President, Montana Chapter
cc: Jan Sensibaugh, MDEQ
Bud Clinch, MDNRC
Chris Hunter, MFWP
Ralph Peck, MDOA
Joel Marshik, MDOT
Kate Walker, USFS
Mark Wilson, USFWS
Mick Shea, Ron Snyder, USCOE
Susan Kelly, BOR
Matt Millenbach, BLM
Leo Marnell, Glacier Ntl. Park
John Varley, Yellowstone Ntl. Park
Mark Reller, BPA
Sean Cross, CSKT
Brent Mabbott, PPL Montana
Joe Dos Santos, AVISTA
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