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  • Aquatic Invasions! A Menace to the West : Crayfish Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    Crayfish are one of the most threatened groups of animals in the world. About 45 percent of North American crayfish species are considered to be at risk of extinction. However, a few crayfish species are among the world's most invasive freshwater organisms. Taking into consideration that invasive crayfish are the...
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    500 different species of crayfish in the world, a handful of them have been introduced to the west

  • Aquatic Invasions! A Menace to the West : American Bullfrog Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    The American Bullfrogs are a highly reproductive aquatic species that are native in central, eastern United States and Southeastern Canada. This species was first introduced to western America as a food source (frog legs!); since then it escaped aquaculture ponds and have spread widely. Bullfrogs lay up to 20,000 eggs...
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    ., weighing up to one pound. It has been cultivated globally for its edible legs and has been introduced and

  • Aquatic Invasions! A Menace to the West : Nutria Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    The nutria is a large, semi-aquatic rodent native to South America. Nutria were introduced to the United States for their fur. After a boom in nutria ranches during the 1930s, the animals escaped or were released from fur farms in the Pacific Northwest, Louisiana and other states, where theyare now...
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    introduced to the United States for their fur. They are often mistaken for beavers but can be distinguished

  • Aquatic Invasions! A Menace to the West : Asian Carps Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    Asian carps—fish in the Cyprinid family—have been part of our culture for centuries. We use them as ornamental aquarium fish (goldfish and koi) and food fish, and to help keep aquaculture ponds clean. However, when Asian carps escape into natural waterways, they can cause big problems for human health, the...
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    were initially introduced to benefit the aquaculture industry in the Midwest; grass carp were

  • Aquatic Invasions! A Menace to the West : Knotweed Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    Knotweeds are a group of closely related invasive plants from Asia. Knotweeds are very tall plants that can grow to over three meters with bamboo-like hollow stems and heart-shaped or lance-shaped leaves. They spread quickly and form tall, dense thickets. They dominate stream banks, sides of roads, gardens, and other...
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    out native plants and alters wildlife habitat. These attrac­ tive perennials have been introduced as

  • Aquatic Invasions! A Menace to the West : Colonial Tunicates Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    What ancient animal in modern times has a primitave spinal cord that may resemble the first vertebrates on earth, spends most of its life stuck to a boat or rock, produces an exoskeleton made of cellulose and is more associated with plants than animals? Tunicates are marine invertebrate filter feeders...
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    harmful to the harbors or bays that the organism is introduced to. Another major vector of introduction

  • Biological invasion of a fishery by a space competitor: dynamic optimisation of the control program

    Creator:
    Fresard, Marjolaine and Boncoeur, Jean
    Abstract:
    This paper deals with the control of an invasive species, void of market value, and acting as a space competitor for a native valuable harvested species. The paper presents a theoretical bioeconomic model describing the interacting dynamics of the two stocks. In the model, control variables are the levels of...
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  • Aquatic Invasions! A Menace to the West : Caulerpa Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    Caulerpa taxifolia is a type of invasive seaweed that can thrive in temperate waters.
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  • Aquatic Invasions! A Menace to the West : Hydrilla and Brazilian Elodea Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    Hydrilla and Brazilian elodea are invasive aquatic plants that occupy freshwater habitats. While hydrilla is native to Asia, Africa, and eastern Australia, and Brazilian elodea is native to South America, both plants are invasive to North America. Because these plants are related and both have pointed green leaves that whorl...
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    South America. They were typically introduced Hydrilla stands can become so thick that ducks and other

  • Aquatic Invasions! A Menace to the West : New Zealand Mudsnail Species Guide

    Creator:
    Siemens, Tania
    Abstract:
    New Zealand mudsnails are a highly invasive species of freshwater mollusk of the family Hydrobiidae, also known as spring snails. Their ability to clone themselves and maintain high reproductive rates allows them to rapidly spread throughout the western United States. Some estimates indicate that one female can clone and produce...
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    a diet of mudsnails. How they got here and spread The New Zealand mudsnail was introduced to the