Swimways: Protecting Paddlefish through Movement-centered Management

ABSTRACT

Attempts to mitigate lack of formal interjurisdictional paddlefish management have been made in the United States through the Mississippi River Interstate Cooperative Resource Association (MICRA). We used 1988–2009 data from the MICRA paddlefish (Polyodon spathula) stock assessment database—a database containing mark-recapture and biometric information on more than 30,000 individually marked wild paddlefish and more than 2 million hatchery origin paddlefish—to estimate survival and movement across large and potentially biologically relevant spatial scales. Paddlefish frequently moved between political jurisdictions with differing conservation strategies and harvest regulations and showed differences in survival parameter estimates throughout their range. We argue that the degree of interjursidictional movements, spatially variant survival rates, and conservation concerns associated with paddlefish necessitate more cohesive interjurisdictional management. Based on criteria used to establish flyways for migratory bird management, we offer swimways as a potential spatial configuration for biologically relevant management units.

RESUMEN

La Asociación Interestatal de Recursos Cooperativos del Río Mississippi (AIRCRM) ha hecho intentos para mitigar la falta de manejo inter-jurisdiccional del pez espátula en los EEUU. Se utilizó información sobre evaluación de los stocks de pez espátula (Polyodon spathula) contenida en la base de datos de AIRCRM para el periodo 1995–2009, la cual contiene información biométrica y de marca-recaptura de >30,000 peces espátula marcados individualmente y de >2 milliones de especímenes provenientes de cultivo, con el fin de estimar la supervivencia y movimiento a escalas espaciales amplias y con potencial biológico relevante. El pez espátula frecuentemente se mueve entre jurisdicciones políticas que difieren en cuanto a sus estrategias de conservación y regulaciones de captura, y muestra diferencias en sus parámetros de supervivencia a lo largo de su ambito geografico. Se argumenta que el grado de movimiento inter-jurisdiccional, el cambio espacial en las tasas de supervivencia y las preocupaciones de conservación asociadas a esta especie, demandan de un manejo inter-jurisdiccional con mayor cohesión. Sobre la base de criterios usados para establecer corredores de vuelo para el manejo de aves migratorias, aquí se muestra un corredor de nado como una potencial configuración espacial para unidades de manejo biológicamente-relevantes.

ACKNOWLEDGMENTS

We thank J. Fontaine and A. Tyre for comments and discussion that was valuable in the construction of this article; B. Elkington and J. Grady for providing MICRA database support; R. Holland, K. Pope, K. Eskridge, D. Martin, and J. Lyons for reviewing early drafts of this manuscript; and states that have voluntarily contributed to the MICRA database over the years. Funding was provided through Federal Sport Fish Restoration F-75-R, the Nebraska Environmental Trust, the University of Nebraska-Lincoln School of Natural Resources, a University of Nebraska Foundation Maude Hammond-Fling Graduate Fellowship to B.M.P., and Hatch Act funds through the University of Nebraska Agricultural Research Division, Lincoln, Nebraska, to M.A.P. and L.A.P.

Notes

^aSurvival as time- and basin-specific (S_B*t ) or time constant (S_B ), recapture probability as time constant and basin-specific (ρ_B ), and movement as time- and basin-specific (ψ_B*t ) or time constant (ψ_B ).