Project Overview
Assignment 1
Assignment
2
ecological
analysis
Assignment
3
management
recommendations
References
SUPPLEMENTAL
INFORMATION
Chinese mitten
crab:
picture #1
picture
#2
Glossary:
catadromous
Assignment 2
Assignment 3
Invasion of
Europe
picture #3
picture #4
Oriental lung
fluke:
Paragonimus
westermanii
Establishment in San
Francisco Bay
Undersireable
Outcomes
Table 1a.
Management
Model
Figure
1a
Regulations
Table 1b
Regulations
Table 1b
Oriental lung
fluke:
Paragonimus
westermanii
Management
Overview
Figure 1b
Project
Overview
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Assignment 1
Assignment 2
ecological
analysis
Assignment 3
management
recommendations
References
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Chinese mitten crabs
(Eriocheir sinensis) -
a threat to Washington State waters?
Management Model
Robyn
Draheim, Jamie
Goen, Florian
Wegelein
Assignment 1
May 4, 1998
SMA 510:
Ecological Concepts for Decision Makers
Introduction
Management
Problems
Management
Goals
Table 1:
Undesirable outcomes of mitten crab
populations
Management
Actions and Regulations
Figure 1a:
Chinese Mitten Crab Management Model
Table 1b:
Vectors and regulations
Assumptions
Summary
Figure 1b:
Overview of Chinese Mitten Crab Management
References
Introduction
The Chinese mitten crab (Eriocheir sinensis H.
Milne-Edwards, 1854), a catadramous burrowing species native
to Korea and China, is listed in the Washington State
Aquatic Nuisance Species Management Plan (unpub. working
draft 1998) as "one of four [freshwater] species
pose[ing] the greatest threat to Washington's
environment and economy."
The goals of this three-part term project are to 1.)
identify the management structure and regulations currently
in place, 2.) evaluate the ecological assumptions inherent
in the management model, and 3.) make recommendations for
institutional changes and further scientific research.This
first assigment proposes to isolate the management problem,
identify the goals of the current management, and describe
the management model conceptualizing the specific management
practices and associated regulations.
Management
Problems
The Chinese mitten crab is an aqautic nuisance species
notorious for its invasion of Europe in the early 2Oth
Century. In the 1930's the mitten crab population in Germany
exploded, over-ran stream banks, swarmed through city
streets and caused extensive damage to dams, levees and
riverbanks (Slack 1996). Concern for the potential damage
their burrows could cause, as well as fears of a human
health hazard from the parasite Paragonimus
westermanii (an Oriental lung fluke) led to a ban on the
importation of mitten crabs into California in 1987 (Section
671(h)(2) Title 14 CCR) (Horwath 1989). In 1989 the United
States (US) Fish and Wildlife Service listed the Chinese
mitten crab as an "injurious species" (50 CFR 16.13) making
its importation, capture and possession a serious crime.
Despite these two bans on the import of mitten crabs they
still became successfully established in San Francisco Bay
(Carlton and Cohen 1997, Halat and Resh 1996).
The introduction of mitten crabs into San Francisco Bay
brings the threat of invasion closer to Washington State
waters. With mitten crabs now established in three global
transportation centers (China, Europe and San Francisco),
the risk of ballast water introductions has increased
significantly. In the summer of 1997 a fisherman in the
Columbia River caught a mitten crab off of a pier, although
no other sightings have been reported as far north (Seattle
Times 1998). In addition, the demand and potential
blackmarket for live mitten crabs is growing. Shipments of
live animals have been confiscated at airports in Los
Angeles, San Francisco and Seattle, and several petitions
have been submitted to the California legislation to allow
mitten crab aquaculture (Cohen and Carlton 1997), suggesting
that intentional introductions and smuggled shipments of
live specimens could become more important introduction
vectors.
Management
Goals
Current management of mitten crabs is aimed at
reducing the threats of physical destruction, fishery damage
and health hazards associated with the introduction of the
Chinese mitten crabs into US waters, by limiting their
dispersal. The potential, undesirable outcomes of a mitten
crab infestation of Washington State are detailed in
Table 1a.
Management
Actions and Regulations
To achieve the management goal, the maintenance of the
current mitten crab-free status of ecosysytems (and
industries) in Washington State waters, management actions
focus on the introduction and spread of mitten crabs in
estuarine and fresh waters. The Chinese mitten crab
management model (Figure
1a) demonstrates the potential introduction vectors and
the pathways that existing regulations address.
Vectors through which the Chinese mitten crab can enter
Washington waters include ballast water dumping, importation
of live seafood, contaminated shipping / packing materials,
shipment of scientific specimens, intentional illegal
release, or natural dispersal. Introductions through ships'
ballast water and illegal importation of mitten crabs as
live seafood pose the highest risk for spreading the crab
into Washington State's waters. There are few regulations
that address, either directly or indirectly, the
introduction of Chinese mitten crabs. Table
1b. describes in more detail both the primary and
secondary vectors, the management actions which address
them, and the agencies charged with their oversight.
Washington State is in the process of reviewing a proposed
management plan which would act as a framework to deal with
impending or currently invading nonindigenous species,
including the mitten crab, but it has not yet been
implemented.
Assumptions
There are assumptions inherent in the management model
that should be acknowledged.
- Current ballast water regulations deal only with
introductions from foreign sources, ignoring the
potential for ballast water introductions from San
Francisco.
- Vectors listed in Table
1b. that are not addressed by management actions are
assumed to be non-existent.
- Management goals and actions do not address the
impacts of established mitten crab populations.
- Finally, although health hazards associated with the
Oriental lung fluke are a part of management goals, the
model assumes that the only vector for the importation of
the fluke is infected Chinese mitten crabs.
Summary
The desired outcome of the management actions is to
reduce the threats posed by the Chinese mitten crab to human
health, fisheries, and riverbanks by preventing their
introduction into Washington State waters. For an general
overview of the management goals, actions and environmental
outcomes, refer to Figure
1b.
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