Geology topics

Steve Rubin

Publications and source records attributed to Steve Rubin.

3 recordsLinked to original sources

USGS2019

Seasonal use of a nonnatal marine basin by juvenile hatchery chinook salmon

Information on the movement patterns of fishes is essential for managers that are making critical resource decisions. We examined the frequency of a keystone species, Chinook Salmon Oncorhynchus tshawytscha that migrated from different marine basins to the Nisqually River estuary, which lies within the southernmost marine basin (hereafter, “South basin”) in Puget Sound (Washington, USA). Hatchery‐reared juvenile fish were sampled by using beach seine, lampara seine, and fyke nets to determine seasonal trends in frequency, habitat use, and the influence of different capture methods. The captured fish originated from three marine basins, nine Puget Sound rivers, and fourteen hatcheries. The data revealed a consistent pattern showing that most of the tagged fish (72%) were from the nearby Nisqually River (in the South basin), but fish from more northerly marine basins (hereafter, “Outbasin”) were also common. Although the majority of the tagged fish (99%) that were captured during April and May were originally released into rivers adjacent to the South basin, 90% of the fish that were captured in August and September had originated from rivers adjacent to Outbasin locations (up to 130 km distant). A comparison of sampling methods showed that the beach seine produced 27% Outbasin fish compared with 53% that were obtained with the lampara seine. The analysis of habitat use suggested that during June and July, more Outbasin fish (>40%) were captured in delta flats and nearshore habitats than in estuarine emergent marsh habitat (26%). Release location (river basin), but not distance, appeared to be an important factor that influenced the percentage of Outbasin fish that were captured in the South basin. However, it appeared that the fish that were released at light weights and early dates were more likely to be captured. Information on the movement of juvenile salmon to a nonnatal marine basin may help to increase our understanding of features of life history and survival, and it has application elsewhere, as many marine species are artificially propagated, released in large numbers, and have the potential to use nonnatal habitats.

Washington↗

USGS2019

Impacts of suspended sediment on nearshore benthic light availability following dam removal in a small mountainous river:In situ observations and statistical modeling

The 2011–2014 removal of two dams from the Elwha River, WA, delivered ~ 19 Mt of sediment to the marine environment, creating an opportunity to study the sensitivity of a coastal ecosystem to large-scale sediment input. Macroalgae, the primary habitat-forming species in the nearshore, disappeared from the region. It was hypothesized that this mortality event was caused by a reduction in benthic light availability due to increased turbidity. To investigate this connection, nearshore processes and benthic light availability were monitored at 7 locations along the 10-m isobath in 2016 and 2017. The primary driver of light attenuation was suspended sediment, with measured chlorophyll-a and CDOM concentrations contributing < 15% to observed attenuation values. A Bootstrap-aggregated Regression Tree was trained to predict attenuation from the in situ data. Light attenuation was impacted by both sediment transport in the river plume, represented in the model by fluvial suspended sediment load and tidal current direction, and subsurface resuspension, represented by wave height and bed shear velocity. The models were used to hindcast light availability during the dam removal. Total daily benthic light availability was below the 1–2 mol photons/m2/day threshold for macroalgae growth consistently in 2013 and seasonally in 2012 and 2014, supporting the hypothesis that reduced light availability caused the mortality event. Light availability increased in 2016–2017 as the annual sediment load decreased, and macroalgae were concurrently observed in the region. Predicting benthic light availability over event, tidal, and seasonal timescales by accounting for both near-surface and subsurface attenuation will improve management strategies designed to limit ecosystem damage during sediment delivery events.

Washington↗

USGS2008

Needs Assessment and Scoping Study for Sinking Ships as Diving Sites in Puget Sound

BACKGROUND There is growing interest in starting a program to sink ships in Puget Sound to create one or more underwater dive sites. Experience in other parts of the world has indicated that sunken vessels are highly popular with divers and could provide a basis for increased recreation and attraction of out-of-state divers with attendant economic benefits to the State. The Washington State legislature reviewed this possibility during the 2006 session and determined that more information is required before the legislature could determine if this activity is feasible or desirable. The legislature directed several State agencies to undertake a preliminary study of the feasibility. The Washington Department of Fish and Wildlife (WDFW, lead State agency) in turn asked U.S. Geological Survey to conduct the study.

Open-File Report↗