Jason G. Romine

Potential Effects of Changes in Temperature and Food Resources on Life History Trajectories of Juvenile Oncorhynchus mykiss

Abstract Increasing temperatures and changes in food resources owing to climate change may alter the growth and migratory behavior of organisms. This is particularly important for salmonid species like Oncorhynchus mykiss, where some individuals remain in freshwater to mature (nonanadromous Rainbow Trout) and others migrate to sea (anadromous Steelhead). Whether one strategy is adopted over the other may depend on the individuals growth and size. In this study, we explored (1) how water temperature in Beaver Creek, a tributary to the Methow River, Washington, may increase under four climate scenarios, (2) how these thermal changes may alter the life history trajectory followed by O. mykiss (i.e., when and if to smolt), and (3) how changes in food quality or quantity might interact with increasing temperatures. We combined bioenergetic and state-dependent life history models parameterized for O. mykiss in Beaver Creek to mimic baseline life history trajectories. Based on our simulations, when mean water t...

Carbon Dioxide as a Tool to Deter the Movement of Invasive Bigheaded Carps

AbstractNonnative bigheaded carps are established in the Mississippi River and there is substantial concern about their potential entry into the interconnected Laurentian Great Lakes. While electrical barriers currently exist as a preventative measure, there is need for additional control mechanisms to promote barrier security through redundancy. We tested the effectiveness of infused carbon dioxide gas (CO2) as a tool to influence the movement and behavior invasive bigheaded carps, namely Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix, as well as native Bigmouth Buffalo Ictiobus cyprinellus, Channel Catfish Ictalurus punctatus, Paddlefish Polyodon spathula, and Yellow Perch Perca flavescens in an experimental pond. Individuals were monitored with acoustic telemetry before, during, and after CO2 addition to the pond. We noted distinct changes in fish behavior following CO2 addition. Each species except Paddlefish maintained farther distances from the CO2 infusion manifold relative to ...

Identifying when tagged fishes have been consumed by piscivorous predators: application of multivariate mixture models to movement parameters of telemetered fishes

BackgroundConsumption of telemetered fishes by piscivores is problematic for telemetry studies because tag detections from the piscivore could introduce bias into the analysis of telemetry data. We illustrate the use of multivariate mixture models to estimate group membership (smolt or predator) of telemetered juvenile Chinook salmon (Oncorhynchus tshawytscha), juvenile steelhead trout (O. mykiss), striped bass (Morone saxatilis), smallmouth bass (Micropterus dolomieu) and spotted bass (M. punctulatus) in the Sacramento River, CA, USA. First, we estimated two types of track statistics from spatially explicit two-dimensional movement tracks of telemetered fishes: the Lévy exponent (b) and tortuosity (τ). Second, we hypothesized that the distribution of each track statistic would differ between predators and smolts. To estimate the distribution of track statistics for putative predators and smolts, we fitted a bivariate normal mixture model to the mixed distribution of track statistics. Lastly, we classified each track as a smolt or predator using parameter estimates from the mixture model to estimate the probability that each track was that of a predator or smolt.ResultsTracks classified as predators exhibited movement that was tortuous and consistent with prey searching tactics, whereas tracks classified as smolts were characterized by directed, linear downstream movement. The estimated mean tortuosity was 0.565 (SD = 0.07) for predators and 0.944 (SD = 0.001) for smolts. The estimated mean Lévy exponent was 1.84 (SD = 1.23) for predators and -0.304 (SD = 1.46) for smolts. We correctly classified 90% of the Micropterus species and 72% of the striped bass as predators. For tagged smolts, 80% of Chinook salmon and 74% of steelhead trout were not classified as predators.ConclusionsMixture models proved valuable as a means to differentiate between salmonid smolts and predators that consumed salmonid smolts. However, successful application of this method requires that telemetered fishes and their predators exhibit measurable differences in movement behavior. Our approach is flexible, allows inclusion of multiple track statistics and improves upon rule-based manual classification methods.

Short-Term Response of Subadult White Sturgeon to Hopper Dredge Disposal Operations

Abstract The effect of dredged-material disposal operations on the behavior of seven white sturgeon Acipenser transmontanus (50–101 cm fork length) was examined by analysis of the movements and depth use of these fish before, during, and after a series of hopper dredge disposal operations in the lower Columbia River. Analyses of fish locations showed that 12 flow-lane disposal operations within a 24-h period had minimal effect on subadult white sturgeon behavior; six of the seven fish showed slight attraction to the disposal area during disposals, and one fish increased its distance from the disposal area. The core area for all fish combined shifted toward the disposal area during disposals. In the 24 h after completion of the disposal operations the fish core areas shifted back toward those areas occupied before the disposals. The rates of movement, depths used, and diel movement patterns of the white sturgeon showed little change over all periods, suggesting that natural behaviors were not altered durin...

Evaluation of a floating fish guidance structure at a hydrodynamically complex river junction in the Sacramento–San Joaquin River Delta, California, USA

Survival of out-migrating juvenile Chinook salmon (Oncorhynchus tshawytscha) in the Sacramento–San Joaquin River delta, California, USA, varies by migration route. Survival of salmonids that enter the interior and southern Delta can be as low as half that of salmonids that remain in the main-stem Sacramento River. Reducing entrainment into the higher-mortality routes, such as Georgiana Slough, should increase overall survival. In spring 2014, a floating fish-guidance structure (FFGS) designed to reduce entrainment into Georgiana Slough was deployed just upstream of the Georgiana Slough divergence. We used acoustic telemetry to evaluate the effect of the FFGS on Chinook entrainment to Georgiana Slough. At intermediate discharge (200–400m3 s–1), entrainment into Georgiana Slough was five percentage points lower when the FFGS was in the on state (19.1% on; 23.9% off). At higher discharge (>400m3 s–1), entrainment was higher when the FFGS was in the on state (19.3% on; 9.7% off), and at lower discharge (0–200m3 s–1) entrainment was lower when the FFGS was in the on state (43.7% on; 47.3% off). We found that discharge, cross-stream fish position, time of day, and proportion of flow remaining in the Sacramento River contributed to the probability of being entrained to Georgiana Slough.

Acoustic tag detections of green sturgeon in the Columbia River and Coos Bay estuaries, Washington and Oregon, 2010–11

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Using broad landscape level features to predict redd densities of steelhead trout ( Oncorhynchus mykiss ) and Chinook Salmon ( Oncorhynchus tshawytscha ) in the Methow River watershed, Washington

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