The Comprehensive Sturgeon Research Project is a multiyear, multiagency collaborative research framework developed to provide information to support pallid sturgeon recovery and Missouri River management decisions. The project strategy integrates field and laboratory studies of sturgeon reproductive ecology, early life history, habitat requirements, and physiology. The project scope of work is developed annually with cooperating research partners and in collaboration with the U.S. Army Corps of Engineers, Missouri River Recovery-Integrated Science Program. The research consists of several interdependent and complementary tasks that engage multiple disciplines. The research tasks in the 2011 scope of work emphasized understanding of reproductive migrations and spawning of adult sturgeon, and hatch and drift of larvae. These tasks were addressed in three hydrologically and geomorphologically distinct parts of the Missouri River Basin: the Lower Missouri River downstream from Gavins Point Dam, the Upper Missouri River downstream from Fort Peck Dam and including downstream reaches of the Milk River, and the Lower Yellowstone River. The research is designed to inform management decisions related to channel re-engineering, flow modification, and pallid sturgeon population augmentation on the Missouri River, and throughout the range of the species. Research and progress made through this project are reported to the U.S.

Diagram showing the Sturgeon Information Management System that accommodates and integrates multiple disparate data types by using a suite of software to accommodate various data formats and the demand for near real-time updates .

Fragmentation of the Yellowstone River is hypothesized to preclude recruitment of endangered Scaphirhynchus albus (pallid sturgeon) by impeding upstream spawning migrations and access to upstream spawning areas, thereby limiting the length of free‐flowing river required for survival of early life stages. Building on this hypothesis, the reach of the Yellowstone River affected by Intake Diversion Dam (IDD) is targeted for modification. Structures including a rock ramp and by‐pass channel have been proposed as restoration alternatives to facilitate passage. Limited information on migrations and swimming capabilities of pallid sturgeon is available to guide engineering design specifications for the proposed structures. Migration behavior, pathways (channel routes used during migrations), and swimming capabilities of free‐ranging wild adult pallid sturgeon were examined using radiotelemetry, and complemented with hydraulic data obtained along the migration pathways. Migrations of 12–26% of the telemetered pallid sturgeon population persisted to IDD, but upstream passage over the dam was not detected. Observed migration pathways occurred primarily through main channel habitats; however, migrations through side channels up to 3.9 km in length were documented. The majority of pallid sturgeon used depths of 2.2–3.4 m and mean water velocities of 0.89–1.83 m/s while migrating. Results provide inferences on depths, velocities, and habitat heterogeneity of reaches successfully negotiated by pallid sturgeon that may be used to guide designs for structures facilitating passage at IDD. Passage will provide connectivity to potential upstream spawning areas on the Yellowstone River, thereby increasing the likelihood of recruitment for this endangered species.

Oxytetracycline (OTC) immersion treatments were evaluated at the Waterville State Fish Hatchery (Waterville, Minnesota) for producing fluorescent marks on larval Northern Pike Esox lucius otoliths. A pilot marking trial conducted with 7‐d‐posthatch (dph) larvae resulted in poor mark efficacy and prompted further investigation on the treatment of younger larvae and modification of the treatment by use of osmotic induction to promote better mark formation. Northern Pike treated within 24 h post‐hatch had significantly higher mark efficacies and marked otolith intensities than did Northern Pike treated at later life stages. Similar to the pilot marking trial, immersion of 7‐dph fry in OTC solution resulted in poor mark efficacy, in which only 38% of the inspected fry possessed visible marks and most of the marks that were visible appeared faint. Simple immersion of newly hatched fry in OTC solution resulted in 91% marking success, and 65% of the visible marks appeared either clear or intense. The poorer mark efficacy on 7‐dph fry suggests that differences in mark formation were more dependent on contemporaneous physiological processes than on otolith size. Osmotic induction prior to OTC immersion had a much weaker effect on mark intensity than did age‐class of treatment in the study. Received November 12, 2013; accepted March 30, 2014