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Claws for Alarm

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Published on: Aug. 20, 2013

sources, often the same food eaten by fish species such as basses, goggle-eye, trout, and catfish. This leaves less food for fish, translating to slower fish growth, fewer numbers of fish, and less-productive fisheries. Because the production of most fisheries naturally varies, subtle changes caused by invasive crayfishes can go undetected or be mistakenly blamed on other factors.

Overpopulated invasive crayfish also reduce or eliminate aquatic plant beds that are important habitats for fish food organisms such as insects, smaller fishes, and spawning and nursery habitats for sport fishes such as smallmouth bass, largemouth bass, goggle-eye, and sunfishes. The process of destroying these plant beds also muddies waters, leading to less-productive fisheries and poorer water quality for all who enjoy these systems.

The Economic Pinch

Crayfish invasions are not only bad news for aquatic ecosystems and fisheries, but they can affect local and regional economies. U.S. anglers spent about $22 billion on fishing trip food, lodging, transportation, and associated costs in 2011. State governments haven’t yet conducted research to measure widespread eco;nomic effects of crayfish invasions. However, a recent Notre Dame University study focusing on only one Wisconsin county affected by crayfish invasions provides insight. Researchers estimated economic losses directly tied to the degraded or altered fisheries in that county were more than $1.5 million annually! We must also consider the amount of money that conservation agencies are forced to spend on addressing these invasions, money that otherwise would be directed to managing our natural resources.

Hitchhikers and Transplants

So how are invasive crayfish moving around and expanding their ranges? Baitbucket introductions, or live release of leftover bait by anglers, is widely considered the primary pathway for invasive crayfish in the U.S. Other known pathways in;clude transport by the aquaculture industry and live releases by hobby aquarists and even school teachers. Recent surveys reveal that release of live fishing bait is a serious problem. A significant percentage of anglers admitted to baitbucket introductions in Wisconsin/Michigan (12 percent), Missouri (40 percent), and Maryland (69 percent).

Unfortunately, once crayfish invasions have taken hold, it is nearly impossible to eliminate them. The key to managing crayfish invasions is proactive prevention of introductions. Most states, including Missouri, prohibit the release of live crayfish into natural waters. In addition, many natural resource agencies, including the Department of Conservation, and nongovernmental organizations have started or increased campaigns to educate the public about invasions.

In a perfect world, these educational efforts would prevent future crayfish introductions. However, natural resource agencies have learned that they must combine education efforts with some amount of regulation.

The Department has been gathering input and working closely with a diverse group of stakeholders, including bait shop dealers, hatchery owners, conservation organizations, university scientists, and anglers. The Department also collected information online and provided periodic updates and presentations to the Conservation Commission. Information gained from all stakeholders will be used in order to ensure the right balance of regulations for all involved. The engagement of citizens and stakeholders has been crucial to this regulation review process.

The invasive crayfish problem is large, growing, and causing real dam;age to treasured aquatic resources throughout the U.S. and Missouri. People transporting and releasing live crayfish into new water bodies is one cause of this problem, and it is an illegal act in Missouri. Natural resource agencies can’t be everywhere at all times to enforce regulations and educate those who might introduce these invaders. Part of the solution lies with the public. The thought of a favorite fishery or neighborhood stream being invaded should be enough to cause most of us to speak up and help educate fellow resource users and other members of our communities. Only together do we have a chance of protecting our valuable waterways and fisheries from this rapidly growing threat.

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