7805

• UCREFRP Catalog Number: 7805
• Author: Colorado River Wildlife Council.
• Title: Minutes, Colorado River Fish & Wildlife Council.
• USFW Year: 1988.
• USFW - Doc Type: July 9, 1988.
• Copyright Material: NO

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Status of Grass Carp
Mike Hatch provided the report. At the April 1987 council meeting, -the
council adopted a policy for importation of triploid grass carp into the
Basin; however, they expressly noted the bylaw to consider any import into
the Basin as an introduction of a new species and therefore, any introduction
would need to receive unanimous approval by the Council. The Council, then,
has a policy for introduction and management of grass carp under certain
rules and regulations which they suggest each state adopt, but still prohibit
all forms including the triploid from being introduced without unanimous
approval.
This year all states were made aware of the wide proliferation in the basin
of the diploid grass carp from a fish and wildlife service seizure of
shipping records of one supplier from the south central United States. From
this information it was understood that Arizona had about twenty illegal
importers of grass carp in which between eighty and eighty-five ponds were
stocked with diploids. In response, Arizona has granted the illegal
importers and holders a hundred and twenty days to respond if they want
assistance from the department in eradicating the illegal fish. The illegal
importers have up to two years to purge their waters of the diploids without
penalty of law. New Mexico discovered four illegal imported diploid stocks
and they granted a period of amnesty in which other unknown importers would
have a chance to make activities known without legal action. Most of the
introduction occurred in golf course ponds. Utah also discovered several
illegal importations, in particular, in the southern part of the state.
. California discovered the same thing and have already proceeded with the
process of eradicating the diploids and are probably seventy-five percent
complete. Likewise, Nevada at the moment is in the process of eradicating
all populations of grass carp which they have discovered through the Fish and
Wildlife Service action or otherwise.
. Research during the last five or more years concerning the sterility of
triploids are nearly conclusive that triploids are functionally sterile. The
females will produce rudimentary ovaries but very little egg production.
Likewise, triploid males are capable of producing spermatozoa, although the
eggs from a normal diploid female fertilized with a triploid male rarely
result in embryos and those embryos have not survived. Recent studies
. concerning triploid crosses induced by gonadotrophic hormone have resulted in
less than 0.5% survival to hatch. The lack of fertility coupled with the
very special reproductive requirements of the species negates their reproduc-
tion in at least most habitats that they would be introduced to, especially
if the recently approved guidelines from the council are followed.
. Wyoming and Colorado both allow triploid grass carp into non-Colorado Basin
portions of state. Arizona recently faced legislative pressure challenging
their authority to manage grass carp in Arizona and were defeated in some
efforts to retain jurisdiction. They now have a grass carp policy very
similar to the one by the council. With this, they assess a $100 fee on an
annual basis. California presently prohibits grass carp in the state with
the exception of the Imperial and Coachilla Valleys. In fact, in this
location, a hatchery operated by canal operators is producing triploid grass
carp. Nevada Wildlife Department recommended a policy for private use of
triploid grass carp adopting many of the special conditions in the Colorado
Wildlife Council policy, but the Nevada Wildlife Commission did not approve
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