ObjectivePopulations of eastern Brook Trout Salvelinus fontinalis face threats from several sources, such as habitat fragmentation, climate change, and competition with introduced salmonids. As a native species, understanding how these populations will respond to disturbances is paramount to their management and effective conservation. A population's ability to respond to disturbance, its resilience, is influenced by several factors. One such group of factors is population genetics.MethodsWe calculated population resilience metrics based on transient dynamics using population projection matrix models. Long-term demographic data from 23 headwater stream Brook Trout populations were used to parameterize models. Genetic data were collected, and genetic indices were calculated. Partial redundancy analysis was then used to evaluate relationships between resilience metrics and genetic indices.ResultInbreeding coefficient, rarefied allelic richness, pairwise genetic differentiation (FST), and effective population size were all found to be important variables in predicting resilience.ConclusionOur results suggest that genetic isolation may increase the demographic resilience in Brook Trout through faster generation times and higher juvenile survival, but this likely comes at the cost of increased extinction risk and truncated size structures. Genetic indices can provide insight into gene flow between populations, thus the relationship between population connectivity and resilience. Given the importance of connectivity to population resilience, restoring and maintaining movement corridors could affect resilience in headwater Brook Trout populations. Understanding the ability of a population to respond to disturbance, its resilience, is incredibly important in ecology and fisheries management. Many factors go into resilience, and this study explores how genetics can affect resilience in eastern Brook Trout populations and why genetics alone might not tell the whole story of a population's resilience.Impact statement

Examining variation in fish populations over time is strengthened when climatic variations are understood and incorporated into analyses. We used a 18-year brook trout (Saivelinus fontinalis) data set with samples across a similar to 4800 km(2) spatial area in the Central Appalachian Mountains, combined with PRISM climate data at the HUC-12 subwatershed level to investigate temporal trends of each. We found significant increases in air temperature (p <.01) with no significant trends in precipitation across time, including no trends in changes in variation of temperature and precipitation also. Extreme rainfall events (# of days above 95% percentile for total daily precipitation in a year) and consecutive dry days (cumulative # of consecutive days with <3 mm precipitation in a year) were also examined arid produced no significantly changing trends over time. Using random forests, seasonal climate variables identified as changing over time explained 35.1% of the variability in young-of-the-year brook trout abundance over the 18-year monitoring period. The same procedure explained 25.1% of the variability in juvenile abundance and only 5.1% in adult abundance. Variable selection following random forest generation illustrated significant effects for winter and spring precipitation (both negative on young-of-the-year abundance. Spring degree days and spring precipitation both had significant negative effects on juvenile abundance. Random effects for stream and year explained a maximum of 27.7% and 10.8% of the variation in abundance across all models. A significant, positive interaction between spring degree days and precipitation was also identified, lending support to the important balance between temperature and flow in these systems that is critical to brook trout persistence. This work provides long-term evidence to help understand the dynamics of these sentinel headwater fish populations as they experience a changing climate.

In the central Appalachian Mountains, Brook Trout Salvelinus fontinalis are a popular target of anglers, but given the remoteness of many of these systems traditional creel methods of evaluating angling effects are impractical. We used a combination of angler and fish survey sampling methods to determine the sizes and numbers of fish harvested. Fish harvest information was reported by anglers, trout size structures were determined by electrofishing, and angler effort was identified via surveys and remote camera sampling in six streams in West Virginia. On average, anglers retained 3.7 +/- 0.2 fish (mean +/- SE) >= 170 mm TL per trip. Between March 13 and May 29, we estimated that anglers harvested from 0.1 to 2.3 +/- 0.3 fish per 100 m in the six streams. Applying these harvest rate estimates to Brook Trout > 170 mm TL, densities in 25 headwater streams in West Virginia yielded a mean of 14.5 angler-days to deplete harvestable-sized fish in these streams. Anglers appeared knowledgeable of local fish populations and focused greater effort on streams with larger populations of harvestable-sized fish. While Brook Trout populations in low-productivity streams may be particularly sensitive to harvest, anglers appear to use them less often. However, in low-productivity streams where fewer harvestable-size fish occur, anglers may still have noticeable effects on mortality through postrelease stress on abundant smaller-sized fish. This study identifies the localized effects that a small subsection of anglers may have on remote populations of sensitive fish and should be carefully considered as a way to understand more widespread effects on popular sport fishes that exist in remote areas.

In this chapter we outline and update Missouri's Paddlefish (Polyodon spathula) experience, including efforts to culture the species and the use of those fish in its fishery management program for reservoirs. The Osage River, historically one of the nation's premier Paddlefish rivers, underwent major habitat alterations in the twentieth century, including the construction of two major mainstem reservoirs (Lake of the Ozarks and Harry S. Truman Lake), resulting in the loss of nearly all natural spawning habitat for the Paddlefish. In response, the Missouri Department of Conservation (MDC) began a program of artificial propagation for the species at Blind Pony Hatchery (BPH) in the 1960s. Early propagation developments in Missouri and elsewhere included research on early life history, feeding, and improving growth rates. In the early 1970s, the MDC determined that a Paddlefish population could be established in Table Rock Lake and supplementation could build and maintain harvestable populations in Lake of the Ozarks and Harry S. Truman Lake. As of 2019, these three reservoirs support quality Paddlefish fisheries and are known globally for their harvest potential. Even though Paddlefish propagation in Missouri has been fruitful, additional efforts through collaboration with other entities and states are underway to continually improve success. Through collaboration, unique intricacies in culture and stocking techniques have surfaced that should be implemented as propagation and restoration programs commence around the world. To this end, Paddlefish propagation has been successful and will continue to play a role in restoring, maintaining, or creating Paddlefish fisheries.

Large-river fishes (e.g., sturgeons [Acipenseridae] and Paddlefish Polyodon spathula) that inhabit reservoir systems are potentially unable to sense environmental cues that elicit typical life history behaviors. These cues can be masked by altered hydrology and temperature regimes. In many reservoirs throughout North America, Paddlefish populations are potentially affected by these unnatural conditions. In an attempt to understand and identify the potential mechanisms that limit Paddlefish reproduction in reservoir systems, we selected Harry S. Truman Reservoir (Truman Lake), Missouri, as our study area of focus. This population is supplemented by stocking, and although anecdotal evidence of potential natural reproduction exists, spawning has never been documented. We implanted ultrasonic transmitters into 113 reproductively mature Paddlefish, and the movements of these fish were tracked over 2 years. Paddlefish migratory behavior was significantly related to water temperature and gauge height, and differences in movement behaviors existed between sexes. Spring aggregations were located in the riverine portion of the Osage River, and embryos and larvae were sampled in 2015 and 2016 near said aggregations. Using acoustic telemetry and egg mats, we acquired evidence suggesting that the Truman Lake Paddlefish are spawning. Our technique can likely be applied to determine spawning locations for Paddlefish inhabiting other large reservoirs.