Study Proposes to Help Save Migratory Fish

Colleagues at the University of Nebraska-Lincoln conducted a study in order to offer fish the same protection as migratory birds.

Freshwater fish swim through thousands of miles of water during their migration systems each year and need some help in reaching their destination safely. Migratory birds are protected by the federal Migratory Bird Treaty Act of 1918, and state collaboration and federal oversight span borders and encompass large conservation efforts in migratory flyways, but fish do not have that kind of protection. There are fisheries in each state that create a patchwork of protection and spotty data on things like habitat, range and population numbers—data that can show researchers and managers how different species are faring or where they're moving. But for the most part, it is difficult for researchers to successfully track freshwater fish and know how far they travel or where they travel to.

In order to understand fish movements, Brenda Pracheil and her colleagues at the University of Nebraska-Lincoln and the Nebraska Game and Parks Commission analyzed a database kept by the Mississippi Interstate Cooperative Resource Association (MICRA), an organization of 28 state natural resource offices. MICRA was formed in 1991 to address the lack of federal oversight of the nation's fish. For their study, published this month (October 2012) in the journal Fisheries, Pracheil's team focused on the American paddlefish. The paddlefish is a perfect case study because of its global importance in the lucrative caviar industry, and because no one can seem to agree on the health of paddlefish populations.

For example, in Ohio paddlefish are listed as "threatened" and are off-limits to both commercial and sport fishermen. But on the other side of the Ohio River in Kentucky, paddlefish are commercially harvested for caviar. That bipolar approach to managing a shared resource is the cause of conflict and concern. Not only might a sensitive fish population be overharvested, but fishermen can get tangled up in the different approaches of state and federal agencies. Earlier this year, some Kentucky fishermen anchored one end of their nets to the Ohio side of the river in pursuit of paddlefish. The problem, the study's authors contend, is that state fisheries managers are trying to work within a certain framework. With migratory fish, no one knows where they should be, when they should arrive, or how many to expect.

Getting a handle on whole-system fish movements and population numbers is crucial to preserving freshwater fish species, the Wisconsin researcher argues. A September report in the journal BioScience found North American freshwater fish populations were going extinct at an alarming and accelerating rate. Pracheil worries that the paddlefish is no exception and that its status as a sought-after commercial fish will only make things worse. Pracheil says centralized oversight and management on a species-range scale and protected corridors of "swimways" might begin to provide some answers and help provide more insight to the migration of freshwater fish in order to better protect them.

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