INTEGRATIVE STUDIES ON ENVIRONMENTAL, NUTRITIONAL, AND TECHNOLOGICAL DRIVERS OF PHYSIOLOGY AND PASSAGE PERFORMANCE IN ANADROMOUS FISH

Rikeem Kamal Sholes

Anadromous fish populations face mounting anthropogenic threats that span environmental, nutritional, and physical domains. This dissertation integrates four studies examining key drivers of physiology and passage performance in anadromous fish, with a focus on improving conservation and hatchery management outcomes.Chapter One reviews the existing literature on the effects of aquaculture sound on fish development, physiology, and behavior. Anthropogenic noise from pumps, generators, and other hatchery equipment can alter embryonic development, damage sensory structures including the inner ear and lateral line, elevate stress hormone levels, suppress immune function, and disrupt critical behaviors such as predator avoidance and schooling. These findings highlight that unmitigated noise in aquaculture facilities poses a significant but often overlooked threat to the fitness of captive-reared fish. Chapter Two presents an experimental study evaluating the effects of noise on the development, behavior, and return rates of hatchery-reared Chinook Salmon (Oncorhynchus tshawytscha). Juvenile salmon were reared under three noise conditions, Quiet (noise-abated), Ambient hatchery noise, and continuous white noise (150 dB re 1 μPa), and in two rearing habitats. While morphometric measures and sensory organ development showed limited differences among treatments, fish exposed to chronic white noise exhibited significantly lower adult return rates compared to quiet- and ambient-reared fish, demonstrating that hatchery soundscape management can meaningfully influence long-term survival outcomes. Chapter Three investigates the role of dietary vitamins A and D in the growth, sensory development, and swimming performance of hatchery-reared Chinook Salmon. Approximately 20,000 fry were reared on five diet treatments varying in vitamin A and D concentrations. Fish fed reduced vitamin D exhibited significantly lower condition factor, and the high vitamin D group showed fewer vertebral compressions, while no significant differences were observed in lateral line neuromast counts, inner ear hair cell density, or swim performance. These results suggest that refining micronutrient levels in hatchery diets may reduce skeletal abnormalities and improve overall fish condition. Chapter Four describes the development and deployment of a novel, low-cost infrared monitoring system for enumerating Pacific Lamprey (Entosphenus tridentatus) passage at a Lamprey Passage Structure at Warm Springs National Fish Hatchery. The Raspberry Pi-based system used infrared breakbeam sensors to trigger targeted video capture and was accessible remotely, providing reliable passage data across four years of operation. This technology offers a versatile and scalable tool for monitoring lamprey at small dams and hatcheries where conventional methods are impractical. Collectively, these studies demonstrate that environmental noise, dietary composition, and passage infrastructure are critical yet modifiable factors affecting anadromous fish fitness and conservation.

INTEGRATIVE STUDIES ON ENVIRONMENTAL, NUTRITIONAL, AND TECHNOLOGICAL DRIVERS OF PHYSIOLOGY AND PASSAGE PERFORMANCE IN ANADROMOUS FISH

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