Abstract
Objective
Construction of Fort Peck Reservoir on the Missouri River, Montana, resulted in the creation of the Fort Peck Dredge Cuts (Dredge Cuts), a complex of flooded borrow pits (total area = 219 ha) located immediately below the dam that has become inhabited by 33 fish species, including the Paddlefish Polyodon spathula. We summarized information on growth and size at age at recovery of Dredge Cuts Paddlefish in relation to other Yellowstone–Sakakawea stock Paddlefish tagged and recovered in the Montana and North Dakota recreational snag fisheries. We also summarized the life history of the Dredge Cuts Paddlefish taken in the 2021–2023 bowfisheries and compared the life history of the Dredge Cuts stock component taken by bowfishing with that of the larger Yellowstone–Sakakawea stock component.
Methods
Paddlefish were jaw-tagged and recovered over a period of more than 30 years at fisheries in Montana and North Dakota. Recovered tagged fish, as well as fish taken from bowfisheries from 2021 to 2023, were compared for growth with other Paddlefish of the Yellowstone–Sakakawea stock with von Bertalanffy growth curves (length versus age and weight versus age).
Results
Partial exchange of fish occurs between the Dredge Cuts and both the Montana and North Dakota snag fisheries, depending on river flows. Nevertheless, the size at age and ultimate size of Dredge Cuts fish was significantly less in length and weight than for fish rearing in Lake Sakakawea, the Missouri River main-stem reservoir where most Yellowstone–Sakakawea Paddlefish feed.
Conclusions
This stock component and its unusual bowfishery has led to the Dredge Cuts Paddlefish being viewed as a distinct harvest management unit with a distinct harvest season and tag system from other Yellowstone–Sakakawea stock Paddlefish. The number of bowfishers and their take should be monitored and any large expansion of the fishery avoided until more is known about the Dredge Cuts Paddlefish stock discreteness, abundance, exploitation rates, movements, and spawning success.