Geology topics

Andrew P. Matala

Publications and source records attributed to Andrew P. Matala.

3 recordsLinked to original sources

USGS2021

Adult sockeye salmon responses to transplanting upstream of an impassable dam

The Yakama Nation manages a program for reintroducing Sockeye Salmon Oncorhynchus nerka upstream of Cle Elum Dam in the Yakima River basin. The program involves transplanting of a mix of adult Sockeye Salmon from two middle Columbia River donor stocks, Lake Wenatchee (WEN) and Osoyoos Lake (OSO), with the goal of establishing a self-sustaining population in the basin. In 2017, a subset of the transplanted population was radio-tagged and monitored to assess stock-specific responses to transplanting, including downstream entrainment at Cle Elum Dam (“fallback”) and prespawn mortality. Tagged fish were active during the first two weeks after release: some fish moved upstream into the Cle Elum River and then returned to the reservoir; other fish moved downstream and passed Cle Elum Dam. Movement within the study area diminished during August but increased in September when fish began migrating up the Cle Elum River for spawning. A greater proportion of WEN fish (76.3%) were detected entering the river compared to OSO fish (53.9%). The hazard ratio from a multistate analysis of fish behavior indicated that WEN fish were nine times more likely to enter the river than OSO fish. The WEN fish also initiated upstream movement three weeks earlier than OSO fish. We found that 27.0% of all tagged fish were lost to the spawning population through fallback (20.7%) and prespawn mortality (6.3%). Fallback and pre-spawn mortality occurred for a greater percentage of OSO fish (26.9% and 7.7%) than WEN fish (15.3% and 5.1%) but these differences were not statistically different. These results provide foundational information from the early phase of a reintroduction effort. Continued monitoring will be required as Sockeye Salmon evolve to conditions upstream of Cle Elum Dam, and results from these efforts will provide valuable insights for this reintroduction effort and others in river systems with similar characteristics.

Washington↗

USGS2017

Restricted gene flow between resident Oncorhynchus mykiss and an admixed population of anadromous steelhead

The species Oncorhynchus mykiss is characterized by a complex life history that presents a significant challenge for population monitoring and conservation management. Many factors contribute to genetic variation in O. mykiss populations, including sympatry among migratory phenotypes, habitat heterogeneity, hatchery introgression, and immigration (stray) rates. The relative influences of these and other factors are contingent on characteristics of the local environment. The Rock Creek subbasin in the middle Columbia River has no history of hatchery supplementation and no dams or artificial barriers. Limited intervention and minimal management have led to a dearth of information regarding the genetic distinctiveness of the extant O. mykiss population in Rock Creek and its tributaries. We used 192 SNP markers and collections sampled over a 5‐year period to evaluate the temporal and spatial genetic structures of O. mykiss between upper and lower watersheds of the Rock Creek subbasin. We investigated potential limits to gene flow within the lower watershed where the stream is fragmented by seasonally dry stretches of streambed, and between upper and lower watershed regions. We found minor genetic differentiation within the lower watershed occupied by anadromous steelhead ( F ST = 0.004), and evidence that immigrant influences were prevalent and ubiquitous. Populations in the upper watershed above partial natural barriers were highly distinct ( F ST = 0.093) and minimally impacted by apparent introgression. Genetic structure between watersheds paralleled differences in local demographics (e.g., variation in size), migratory restrictions, and habitat discontinuity. The evidence of restricted gene flow between putative remnant resident populations in the upper watershed and the admixed anadromous population in the lower watershed has implications for local steelhead productivity and regional conservation.

Washington↗

USGS2016

Climate variables explain neutral and adaptive variation within salmonid metapopulations: The importance of replication in landscape genetics

Understanding how environmental variation influences population genetic structure is important for conservation management because it can reveal how human stressors influence population connectivity, genetic diversity and persistence. We used riverscape genetics modelling to assess whether climatic and habitat variables were related to neutral and adaptive patterns of genetic differentiation (population-specific and pairwise F ST ) within five metapopulations (79 populations, 4583 individuals) of steelhead trout ( Oncorhynchus mykiss ) in the Columbia River Basin, USA. Using 151 putatively neutral and 29 candidate adaptive SNP loci, we found that climate-related variables (winter precipitation, summer maximum temperature, winter highest 5% flow events and summer mean flow) best explained neutral and adaptive patterns of genetic differentiation within metapopulations, suggesting that climatic variation likely influences both demography (neutral variation) and local adaptation (adaptive variation). However, we did not observe consistent relationships between climate variables and F ST across all metapopulations, underscoring the need for replication when extrapolating results from one scale to another (e.g. basin-wide to the metapopulation scale). Sensitivity analysis (leave-one-population-out) revealed consistent relationships between climate variables and F ST within three metapopulations; however, these patterns were not consistent in two metapopulations likely due to small sample sizes ( N = 10). These results provide correlative evidence that climatic variation has shaped the genetic structure of steelhead populations and highlight the need for replication and sensitivity analyses in land and riverscape genetics.

Columbia River Basin↗