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At least 901 records · Page 50Linked to original sources

USGS2012

Passage probabilities of juvenile Chinook salmon through the powerhouse and regulating outlet at Cougar Dam, Oregon, 2011

Cougar Dam near Springfield, Oregon, is one of several federally owned and operated flood-control projects within the Willamette Valley of western Oregon that were determined by the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service in 2008 to impact the long-term viability of several salmonid stocks. In response to this ruling, the U.S. Army Corps of Engineers is looking for means to reduce impacts to salmonids, including improving downstream passage of juvenile salmonids at Cougar Dam. This study of juvenile Chinook salmon ( Oncorhynchus tshawytscha ) passage at Cougar Dam was conducted to inform decisions about potential improvements for downstream fish passage. The primary objective of the study was to estimate route-specific passage probabilities of yearling Chinook salmon at Cougar Dam. The study was conducted using fish from a nearby hatchery surgically implanted with radio transmitters and passive integrated transponder (PIT) tags and released near the entrance of a temperature control tower through which all water going through the dam must pass. Water passing through the temperature control tower may be routed through a penstock to a powerhouse with two Francis turbines, or to a spillway-like structure called the regulating outlet. Secondary objectives of the study were to estimate the probability that fish enter a bypass at a non-federal facility downstream, and to estimate dam-passage and in-river fish survival. Dam operating conditions during the study included an average forebay elevation of 1,580 feet (National Geodetic Vertical Datum of 1929) and an average of 48.2 percent of the total dam discharge of 1,106 cubic feet per second passing through a regulating outlet opening of 1.25 feet. Dam passage probability was greatest at night (0.8741 standard error [SE] 0.0265) and primarily through the regulating outlet (0.8896 SE 0.0617 day; 0.9417 SE 0.0175 night). The joint probability of entering the bypass at Leaburg Dam and being detected at the PIT system within the bypass was 0.0755 (SE 0.0363), but some fish were known to pass the PIT system undetected, indicating that the true probability of entering the bypass was underestimated. The estimated survival of fish passing through the temperature control tower, through the dam, and to a site at a bridge over the South Fork of the McKenzie River 3.9 kilometers downstream was 0.3680 (SE 0.1322) for fish passing through the powerhouse, and 0.4247 (SE 0.0440) for fish passing through the regulating outlet. The estimated in-river survival through the 37.3 kilometers from the bridge to a site at Leaburg Hatchery on the McKenzie River was 0.5857 (SE 0.2227) for fish that had passed through the powerhouse, and 0.4537 (SE 0.0551) for fish that had passed through the regulating outlet.

Oregon↗

USGS1980

Preliminary report on the geology of the continental slope adjacent to OCS Lease Sale 55, eastern Gulf of Alaska: Petroleum resource implications

Forty samples of Tertiary and Cretaceous outcrop or suspected outcrop were dredged along the 250-km-long northwest-trending continental slope between long 138°00' W. and 142°30' W. These samples, from water depths of 3,150 m to 200 m, combined with seismic reflection data, identify seven rock units in apparently normal stratigraphic position. From oldest to youngest they are: Unit A: Hard graywacke, argillite, and possible intrusive rocks of inferred Late Cretaceous age that crop out in the eastern part of the slope and probably underlie much of the Fairweather Ground. Unit B: At least 900 m of sandstone, conglomerate, shale, and subordinate basaltic volcanic rocks west of Yakutat Seavalley between 142° W. and 143° W. that is not dated but is probably of late Paleocene to early Eocene age. Unit C: 1,300 m of basaltic flow and pyroclastic rocks with associated clastic marine sedimentary rocks that makes up much of the rugged lower slope throughout the area. This sequence is largely, or entirely, of early Eocene age. Unit D: Up to 2,100 m of early and middle Eocene sandstone, conglomerate, siltstone, and tuffaceous organic-rich shale that partly overlies, and partly intertongues with, the volcanic unit. Unit E: 800 m of early to late Eocene and early Oligocene(?) organic-rich shale, tuffaceous shale, siltstone, and sandstone that partly intertongues with, and partly overlies units C and D. Unit F: 300+ m of siltstone, at least in part of late Oligocene age, that crops out locally along the upper slope where it unconformably overlies Unit E. Unit G: Up to 2,000 m of late Cenozoic (middle Miocene? and younger) clastic sedimentary rocks including abundant glaciomarine deposits that unconformably overlie all the older units. The early Tertiary sequence sampled on the continental slope differs strikingly in lithology and structure from coeval rocks exposed onshore or penetrated in unsuccessful exploratory wells on the adjacent mainland. Units B, D, and E include abundant source rocks that have undergone a thermal history resulting in local generation of hydrocarbons. Sandstones from Units D and E locally have secondary porosities up to 31 percent and permeabilities to 36 md. Seismic reflection data indicate that the sequence with the most favorable source and reservoir potential (Units B, D, E) dips northeastward beneath OCS Lease Sale 55 where it could be a favorable exploratory target if involved in suitable traps. Young anticlinal folds are not present, but other important traps are likely to include drape structures, horsts, and faults within the early Tertiary sequence and pinchouts, fault traps, or combination structural/stratigraphic traps along the northeastern margin of the early Tertiary basin.

Alaska↗

USGS2010

Coastal circulation and sediment dynamics in Maunalua Bay, Oahu, Hawaii: Measurements of waves, currents, temperature, salinity, and turbidity: November 2008-February 2009

High-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity were made in Maunalua Bay, southern Oahu, Hawaii, during the 2008–2009 winter to better understand coastal circulation, water-column properties, and sediment dynamics during a range of conditions (trade winds, kona storms, relaxation of trade winds, and south swells). A series of bottom-mounted instrument packages were deployed in water depths of 20 m or less to collect long-term, high-resolution measurements of waves, currents, water levels, temperature, salinity, and turbidity. These data were supplemented with a series of profiles through the water column to characterize the vertical and spatial variability in water-column properties within the bay. These measurements support the ongoing process studies being done as part of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program’s Pacific Coral Reef Project; the ultimate goal of these studies is to better understand the transport mechanisms of sediment, larvae, pollutants, and other particles in coral reef settings. Project Objectives The objective of this study was to understand the temporal variations in currents, waves, tides, temperature, salinity and turbidity within a coral-lined embayment that receives periodic discharges of freshwater and sediment from multiple terrestrial sources in the Maunalua Bay. Instrument packages were deployed for a three-month period during the 2008–2009 winter and a series of vertical profiles were collected in November 2008, and again in February 2009, to characterize water-column properties within the bay. Measurements of flow and water-column properties in Maunalua Bay provided insight into the potential fate of terrestrial sediment, nutrient, or contaminant delivered to the marine environment and coral larval transport within the embayment. Such data are useful for providing baseline information for future watershed decisions and for establishing guidelines for the U.S. Coral Reef Task Force’s (USCRTF) Hawaiian Local Action Strategy to address Land-Based Pollution (LAS-LBP) threats to coral reefs adjacent to the urbanized watersheds of Manualua Bay. Study Area Maunalua Bay is on the south side of Oahu, Hawaii, and is approximately 10 km long and 3 km wide. The bay is flanked by two large, dormant craters: Koko Head to the east and Diamond Head to the west. Rainfall in the watersheds that drain into Maunalua Bay ranges from more than 200 cm/year at the top of the Ko‘olau Range that borders the northwestern part of the bay to less than 70 cm/year to the east at Koko Head. Seven major channels flow into the bay, and all but one have been altered by engineering structures.

Hawaii↗

USGS2021

Genetic analysis of red lionfish Pterois volitans from Florida, USA, leads to alternative North Atlantic introduction scenarios

The red lionfish Pterois volitans is a successful invasive predator across the western North Atlantic, Caribbean, and Gulf of Mexico. The southeast coast of Florida (USA) has been identified as the original introduction location, but genetic analyses including Florida lionfish have yet to investigate introduction scenarios. Here, we assessed the potential lionfish invasion pathways using 1795 sequences from previously published mitochondrial D-loop sequences (n = 1558) and new samples (n = 237) from 6 locations: The Bahamas, Florida Keys, northwest Florida, North Carolina, Panamá, and southeast Florida. None of the assessed Florida lionfish (n = 394) contained the H05-H09 D-loop haplotypes found in The Bahamas, North Carolina, and Bermuda (the Northern Region), indicating that Florida was not the source for these haplotypes. Assessing the mitochondrial population structure, the Florida east coast lionfish grouped with the Caribbean/Gulf of Mexico, as opposed to the Northern Region. To further explore connectivity and invasion pathways, 14 nuclear microsatellite loci were multiplexed on lionfish collected from 15 locations (n = 394). As found in other nuclear lionfish studies, the analyses identified a lack of population structure likely due to founding effects and/or inbreeding in aquaculture brood stocks. Together, the significant haplotype differences and H01-H04 haplotypes refute Florida as the sole source of red lionfish introduction. The results of this study support alternative invasion scenarios, in which Florida was colonized as a secondary introduction site or by individuals from the Northern Region. Understanding invasive species’ population boundaries and dispersal patterns informs local control efforts and management planning for future invasive species introductions.

Florida↗

USGS2012

Changing Arctic ecosystems--research to understand and project changes in marine and terrestrial ecosystems of the Arctic

Ecosystems and their wildlife communities are not static; they change and evolve over time due to numerous intrinsic and extrinsic factors. A period of rapid change is occurring in the Arctic for which our current understanding of potential ecosystem and wildlife responses is limited. Changes to the physical environment include warming temperatures, diminishing sea ice, increasing coastal erosion, deteriorating permafrost, and changing water regimes. These changes influence biological communities and the ways in which human communities interact with them. Through the new initiative Changing Arctic Ecosystems (CAE) the U.S. Geological Survey (USGS) strives to (1) understand the potential suite of wildlife population responses to these physical changes to inform key resource management decisions such as those related to the Endangered Species Act, and (2) provide unique insights into how Arctic ecosystems are responding under new stressors. Our studies examine how and why changes in the ice-dominated ecosystems of the Arctic are affecting wildlife and will provide a better foundation for understanding the degree and manner in which wildlife species respond and adapt to rapid environmental change. Changes to Arctic ecosystems will be felt broadly because the Arctic is a production zone for hundreds of species that migrate south for the winter. The CAE initiative includes three major research themes that span Arctic ice-dominated ecosystems and that are structured to identify and understand the linkages between physical processes, ecosystems, and wildlife populations. The USGS is applying knowledge-based modeling structures such as Bayesian Networks to integrate the work.

Arctic↗

USGS2019

Stratigraphic cross sections of the Niobrara Interval of the Upper Cretaceous Cody Shale in the Bighorn Basin, Wyoming and Montana

The Bighorn Basin is one of many structural and sedimentary basins that formed in the Rocky Mountain foreland during the Laramide orogeny. The basin is nearly 180 miles long, 100 miles wide, and encompasses about 10,400 square miles in northern Wyoming and southern Montana. The basin is bounded by major basement uplifts that include the Pryor uplift on the northeast, the Beartooth uplift on the northwest, the Bighorn uplift on the east, and the Owl Creek uplift on the south. The northern margin includes a zone of faulting and folding referred to as the Nye-Bowler lineament. The western margin is formed by volcanic rocks of the Absaroka Range. Many important conventional oil and gas fields producing from reservoirs ranging in age from Cambrian through Tertiary have been discovered in this basin. In addition, an extensive unconventional overpressured basin-centered gas accumulation may be present in Cretaceous strata in the deeper parts of the basin. It has long been suggested that various Upper Cretaceous marine shales, including the Cody Shale, are the principal hydrocarbon source rocks for many of these accumulations. With recent advances and success in horizontal drilling and multistage fracture stimulation, there has been an increase in exploration and completion of wells in these marine shales in other Rocky Mountain Laramide basins that were traditionally thought of only as hydrocarbon source rocks. The stratigraphic cross sections presented in this report were constructed as part of a project carried out by the U.S. Geological Survey to characterize and evaluate the undiscovered continuous (unconventional) oil and gas resources of the Niobrara interval in the lower part of the Upper Cretaceous Cody Shale in the Bighorn Basin. These cross sections were constructed using borehole geophysical logs from wells drilled for oil and gas exploration and production. The stratigraphic interval extends from the upper part of the Frontier Formation to the middle part of the Cody Shale. The datum is the base of the “chalk kick” marker bed, a distinctive resistivity peak or zone in the lower part of the Cody Shale. A gamma ray and (or) spontaneous potential log was used in combination with a resistivity log to identify and correlate units. Marine molluscan index fossils collected from nearby outcrop sections were projected into the subsurface to help determine the relative ages of the strata and aid in correlation.

Montana, Wyoming↗

USGS2013

A step decrease in sediment concentration in a highly modified tidal river delta following the 1983 El Niño floods

Anthropogenic activities in watersheds can have profound effects on sediment transport through river systems to estuaries. Disturbance in a watershed combined with alterations to the hydro-climatologic regime may result in changes to the sediment flux, and exacerbate the impacts of extreme events (such as large-magnitude floods) on sediment transport. In the San Francisco Estuary, suspended sediment has been declining over the past 30 years as a result of declining sediment supply, contributing to dramatic changes in the ecology and geomorphology of the estuary. However, the decline has not been gradual. Recent observations of an abrupt decrease in suspended sediments in the San Francisco Bay have been explained by a model that suggests that the step change has occurred due to exceedance of a sediment regulation threshold that triggered the change from a sediment transport regime to a supply-limited system. We investigated structural changes in the historical record of total suspended solids (TSS) concentration measured in the upper estuary to verify the model predictions. TSS in the upper estuary exhibited an abrupt step decrease in 1983 corresponding to the record-high winter and summer flows from the 1982 to 1983 El Niño event. After this step change, TSS concentrations had a significant declining trend despite subsequent near-record high flows. The abrupt change in TSS followed by the declining trend provides evidence for the hypothesis of sediment supply limitation in the San Francisco Estuary.

California↗

USGS2026

Phytoplankton responses to experimental nitrogen and phosphorus loading in the eutrophic and colored Caloosahatchee River, Florida

The Caloosahatchee River, located in southwest Florida, is a eutrophic and colored river that flows from Lake Okeechobee westward into its estuary and the Gulf of America. Cyanobacterial harmful algal blooms (HABs) are a documented problem along this freshwater-to-marine waterway where nutrient enrichment has been identified as a key factor in bloom occurrence but has not been experimentally tested in the river. This study is the first to test the effects of inorganic nutrient loading on phytoplankton assemblages in the Caloosahatchee River and the effects of different nutrient sources on phytoplankton dynamics at different times of the year. Three independent, in situ experiments were conducted to test the effects of daily, incrementally increased ammonium, nitrate, and phosphate loading on phytoplankton at different times of the year (summer, fall, winter). Over the 72-hour enclosure period, phytoplankton abundance metrics (cell concentration, chlorophyll- a , and phycocyanin), dissolved oxygen, and pH increased, and fluorescent dissolved organic matter and turbidity decreased in all treatments and controls. Increased phytoplankton abundance metrics relative to controls were observed after 72 hours of exposure to elevated ammonium and nitrate in summer and only ammonium in winter, suggesting periodic nitrogen limitation; however, no treatment effects on phytoplankton assemblage structure in terms of resemblance and diversity metrics were found. Increases in total cell concentrations were driven by elevated growth rates of already dominant taxa but not sufficiently to form a visible bloom. Cyanobacteria consistently dominated the phytoplankton, particularly Aphanocapsa and Merismopedia , whereas the common HAB-forming Microcystis maintained consistently low abundance. This study provides new information on the ecology of phytoplankton assemblages in the Caloosahatchee River and could be used by water resources managers to evaluate strategies for controlling cyanobacterial HABs in the river.

Florida↗

USGS2012

Tectonic setting of the Yukon-Koyukuk basin and its borderlands, western Alaska

The Yukon-Koyukuk basin of western Alaska is composed of an arcuate belt of Jurassic and Early Cretaceous subduction-related volcanic and plutonic rocks (Koyukuk terrane) flanked by deep subbasins filled with mid-Cretaceous terrigenous sedimentary rocks. The basin is bordered on three sides by metamorphosed Proterozoic and Paleozoic continental rocks (Seward, Arctic Alaska, and Ruby terranes) and is separated from the metamorphic borderlands by a narrow, highly tectonized belt of oceanic crust and mantle rocks (composite Angayucham-Tozitna terrane). The oceanic and mantle rocks, which dip inward beneath the basin and are thrust outward onto the borderlands, are divided into three separate thrust panels: (1) a structurally lowest panel (Slate Creek) composed of phyllite and metagraywacke of probable Devonian age, (2) a middle panel (Narvak) composed of imbricated basalt, chert, and gabbro of Devonian to Early Jurassic age, and (3) a structurally highest panel (Kanuti) composed of gabbro and peridotite of probable Middle and Late Jurassic age. The three thrust panels appear to represent a reversely stacked sequence that progresses from continental slope deposits in the lower panel to cumulus and mantle peridotites in the upper. Metamorphic mineral K-Ar ages from garnet amphibolite on the sole of the upper panel suggest that the upper panel was emplaced on the middle panel in the Middle to Late Jurassic. Subsequent accretion of all three panels to the continental rocks of the borderlands occurred in the latest Jurassic and Early Cretaceous, synchronous with arc volcanism within the basin. Arc volcanism waned and the accretionary phase ended in the middle of Early Cretaceous time. Uplift and erosion of the metamorphic borderlands and the obducted oceanic rocks began in late Early Cretaceous and was accompanied by the rapid filling of two flanking subbasins with turbiditic sediments. In the latest Early Cretaceous and early Late Cretaceous, shallow marine and nonmarine conglomerates were deposited around the margins of the basin, and a prograding delta was built out from the southeast margin of the basin across the turbiditic subbasins and the remnant volcanic arc. In the Late Cretaceous, western Alaska was subjected to strong east-west compression which severely deformed both the Yukon-Koyukuk basin and the borderlands. Several widespread magmatic episodes in the mid- and Late Cretaceous and in early Tertiary transgress the basin boundaries and stitch together the accreted arc and oceanic terranes and the continental borderlands.

Journal of Geophysical Research Solid Earth↗

USGS2005

GIS compilation of data collected from the Pulley Ridge Deep Coral Reef region

Pulley Ridge is a chain of drowned barrier islands that extends almost 200 km in 60-90 m water depths (Fig. 1). This drowned ridge is located on the Florida Platform in the southeastern Gulf of Mexico about 250 km west of Cape Sable, Florida (Jarrett and others, 2005). These islands formed during the early Holocene marine transgression approximately 12,000 - 14,000 years before present, and were then submerged by sea level rise and preserved near the outer edge of the Florida Platform. The southern portion of Pulley Ridge is the focus of this study. This area hosts zooxanthellate scleractinian corals, green, red and brown macro algae, and a mix of deep and typically shallow-water tropical fishes. This largely photosynthetic community is unique in that it thrives with less than 5% of the light typically associated with shallow-water reefs with similar fauna. Several factors help to account for the existence of this unique deep-water community. First, the underlying drowned barrier islands provide both elevated topography and lithified substrate for the establishment of the hardbottom community. Second, the region is commonly bathed by the Loop Current, which brings relatively clear and warm water to this area. Third, the ridge's position on the continental shelf places it within the thermocline which provides nutrients to the reef during upwelling (Halley and others, 2003). The USGS has made two proposals to resource managers for the designation of marine protected areas based on the geophysical and photographic data in this report. The proposals describe areas that may require some regulatory protection of marine life utilizing the sea floor (Fig. 1). The first proposal is that the area of greatest hermatypic coral cover (Fig. 1) is considered for future management actions and designated a Habitat Area of Particular Concern (HAPC) by the Gulf of Mexico Fishery Management Council. HAPCs are identified on the basis of habitat level considerations: The importance of the ecological function provided by the habitat. The extent to which the habitat is sensitive to human-induced environmental degradation. Whether and to what extent development activities are or will be stressing the habitat. The rarity of the habitat type. The second proposed area is for Coral Essential Fish Habitat (CEFH, Fig. 1). CEFHs are defined as "those waters and substrate necessary to corals for spawning, breeding, feeding, or growth to maturity." The following definitions are provided for clarification: waters is defined as "aquatic areas and their associated physical, chemical, and biological properties that are used by corals" substrate means "sediment, hard bottom, structures underlying the waters, and associated biological communities" necessary means "the habitat required to support a sustainable population and the managed species' contribution to a healthy ecosystem" spawning,breeding, feeding, or growth to maturity covers the full life cycle of a species. The CEFH shown in Figure 1 is the greatest coral cover in the region as determined by the bottom photo and video transects acquired during this study. This report presents the geophysical and photographic data that were collected to describe the surficial and shallow subsurface geologic framework of the area where these deep-water corals are known to occur. The data types include multibeam bathymetry, sidescan-sonar imagery, images of high-resolution seismic-reflection profiles, and bottom photographs. In addition, the tracklines for the seismic data, locations of bottom photographs and camera drifts, and tracklines along which submersible and remotely operated vehicle (ROV) observations were made are contained in the GIS files accompanying this report. Unfortunately, video footage from the camera drifts, submersible, and ROV cruises is not available on this DVD due to the quantity of data. The bottom photograph data set has been previously published (Cross and others, 2004), however it is included in this publication in an effort to integrate the varying data sets in one location. This integration is accomplished through the GIS data included on this DVD.

Florida↗

USGS2020

Kelp forest monitoring at Naval Base Ventura County, San Nicolas Island, California: Fall 2018 and Spring 2019, fifth annual report

Introduction Kelp forests and rocky reefs are among the most recognized marine ecosystems and provide the primary habitat for several species of fishes, invertebrates, and algal assemblages (Stephens and others, 2006). In addition, kelp forests have been shown to be important carbon dioxide sinks (Wilmers and others, 2012) and are an important source of nearshore marine primary production (Duggins and others, 1989). These highly dynamic ecosystems are extremely variable, and both top-down and bottom-up ecological controls drive this rich trophic environment. Giant kelp ( Macrocystis pyrifera ) forests and the species that inhabit these ecosystems are influenced by several environmental conditions, such as wave exposure, water temperature, water clarity, bottom depth and composition, species composition, and the density of kelp and other algal assemblages (Schiel and Foster, 2015). However, in addition to “normal” variability, kelp forests can undergo extreme regime shifts from kelp canopy forested areas to barrens characterized by high densities of urchins and encrusting coralline algae (Harrold and Reed, 1985). San Nicolas Island (SNI), outermost of the California Channel Islands, is home to a diverse group of terrestrial and marine organisms and includes kelp bed and rocky reef habitats ( fig. 1 ). The SNI kelp forests not only provide food and shelter for fishes and invertebrates within the habitat, but also they support higher trophic level consumers such as marine birds and several marine mammal species including the southern sea otter ( Enhydra lutris nereis) , a major predator on sea urchins and other marine invertebrates. Owing to concern about the vulnerability of the California population, the U.S. Fish and Wildlife Service (USFWS) translocated 140 southern sea otters from the central California coast to SNI between 1987 and 1990. Although only approximately 14 translocated otters are thought to have remained at SNI (U.S. Fish and Wildlife Service, 2012), their population at the island has increased and is currently greater than 120 individuals (Hatfield and others, 2019). Sea otters are a natural part of the kelp forest ecosystem, but their presence has implications for community dynamics as they repopulate a region from which they were extirpated in the 19th century. At SNI, sea otters have been concentrated mostly around the west end of the island, with some use of the south side and very little, but expanding, use of the northeast side. An ecosystem shift from urchin dominated to kelp dominated, that occurred at a site at the west end of the island in the early 2000s, though initiated by sea urchin disease, was likely facilitated to some degree by sea otter foraging (Kenner and Tinker, 2018). These ecosystems also are the target of many fisheries, including urchin and lobster. Urchin fisheries, which target the larger red sea urchin, may release the smaller but more mobile purple sea urchin from competitive control (Dayton and others, 1998). Lobster fisheries may release purple sea urchins from predatory control (Lafferty, 2004). Owing to the distance from the mainland, however, SNI kelp forests and reefs have been somewhat protected from the degree of harvest and other anthropogenic impacts experienced by the southern California mainland. Invasive species are another issue, and there are a few invasive subtidal macroalgae of concern in southern California waters. Although the brown alga Sargassum muticum has been established at the island for decades, S. horneri has only recently been seen at SNI and, so far, the invasive kelp Undaria pinnatifida and the green alga Caulerpa taxifolia have not been observed there. Sargassum horneri , in particular, has demonstrated a capability to outcompete native kelps at some of the other Channel Islands but it is unclear what indirect effects it may have on community structure (Marks and others, 2015). Because the surrounding kelp forests fall within the management boundary of the SNI Integrated Natural Resources Management Plan (INRMP; U.S. Navy, 2015), USGS works with the Navy to provide surveys of this ecologically important ecosystem that inform natural resource managers of trends in the population abundance of particular species. In addition, long-term surveys allow for an understanding of potential changes in species diversity and community composition as a result of trophic or other interactions. The U.S. Geological Survey (USGS) implemented a kelp forest monitoring program for the U.S. Navy at San Nicolas Island in 2014, building on sites and methods established by USFWS scientists in 1980 ( appendix 1 ). This report focuses on data collected during sampling expeditions to these sites in fall 2018 (October 2–5) and spring 2019 (April 3–6). Together they will be herein referred to as year 5 because, although the trips were made in different calendar years, they were approximately 6 months apart and were conducted under the fifth year of this contract. The previous sampling year (fall 2017 and spring 2018) is referred to as year 4. The year 5 data are compared with data collected during eight trips from fall 2014 through spring 2018. Differences in counts between these expeditions can result from seasonal factors, stochastic variation, or sampling error, but temporal comparison can reveal population trends. Where appropriate, long-term data collected during the 33 years prior to the implementation of these slightly revised protocols will be presented in order to lend some context to the observations reported here. Genus and species names used in this report are those currently recognized as valid in the Integrated Taxonomic Information System (ITIS.gov). Upon first use, the name recognized as valid by the World Register of Marine Species (WoRMS; marinespecies.org) is shown in brackets if different. The exception is Sargassum horneri which does not show up in any discernable form in ITIS.gov.

California↗

USGS2015

California State Waters Map Series — Offshore of Salt Point, California

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Salt Point map area is located in northern California, about 110 km north of San Francisco and 50 km south of Point Arena. The map area includes three California Marine Protected Areas: the southern portion of the Stewarts Point State Marine Reserve, the Salt Point State Marine Conservation Area, and the Gerstle Cove State Marine Reserve. The coast and shoreline are rugged and scenic, characterized by rocky promontories, steep bluffs capped by bare to forested marine terraces, kelp-rich coves, and nearshore rocks and pinnacles. The largely undeveloped onshore part of the map area is used primarily for grazing and recreation. U.S. Highway 1 extends along the coast through the map area, passing through Salt Point State Park, Kruse Rhododendron State Natural Reserve, and Stillwater Cove Regional Park. Sandy beaches are uncommon, present only in relatively protected coves. The seafloor in the map area extends from the shoreline to water depths of about 90 to 100 m. The nearshore to inner shelf area (to water depths of about 50 to 60 m) typically dips seaward about 1.0° to 1.5° and is underlain by bedrock and sand-sized to coarser grained sediment. The midshelf, underlain predominantly by muddy sediments, slopes more gently (less than 0.5°). Surficial and shallow sediments were deposited in the last about 21,000 years during the approximately 125-m sea-level rise that followed the last major lowstand associated with the Last Glacial Maximum, at which time the entire Offshore of Salt Point map area was emergent and the shoreline was about 20 km west of the present-day shoreline. Tectonic influences that impact the shelf morphology and geology in the map area are related to local faulting, folding, uplift, and subsidence. The onshore part of the map area is cut by the northwest-striking San Andreas Fault—the right-lateral transform boundary between the North American and Pacific tectonic plates with an estimated slip rate of about 17 to 25 mm/yr in this area. The region between Fort Ross and Point Arena, west of the San Andreas Fault, is the known as the “Gualala Block” on the basis of its distinctive geology. The Gualala Block consists of a thick, discontinuous Upper Cretaceous to Miocene stratigraphic section, however, only the submarine fan deposits of the Paleocene and Eocene German Rancho Formation are exposed along the coast in the Offshore of Salt Point map area. The German Rancho Formation also forms all of the rugged seafloor bedrock outcrops in the map area. The western boundary of the Gualala Block lies 3 to 5 km offshore, perhaps at the shore-parallel Gualala Fault. High-resolution seismic-reflection data reveal shallow folding and faulting in inferred upper Pleistocene strata along the Gualala Fault trend, suggesting this structure is now or has been recently active. The last ground rupture in the map area occurred during the devastating great 1906 California earthquake (M7.8, 4/18/1906), thought to have nucleated on the San Andreas Fault about 100 kilometers to the south offshore of San Francisco. Circulation over the continental shelf in the map area is dominated by the southward-flowing California Current, the eastern limb of the North Pacific Gyre. Associated upwelling brings cool, nutrient-rich waters to the surface, resulting in high biological productivity. The current flow generally is southeastward during the spring and summer; however, during the fall and winter, the otherwise persistent northwest winds are sometimes weak or absent, causing the California Current to move farther offshore and the Davidson Current, a weaker, northward-flowing countercurrent, to become active. Throughout the year, this part of the central California coast is exposed to four wave climate regimes: the north Pacific swell, the southern swell, northwest wind waves, and local wind waves. The north Pacific swell dominates in winter months, with wave heights at offshore buoys ranging from 2 to 10 m and wave periods ranging from 10 to 25 s. During summer months, the largest waves come from the southern swell, generated by storms in the south Pacific and offshore Central America. Characteristically, these swells have smaller wave heights (0.3 to 3 m) and similarly long periods (range 10 to 25 s). Northwest wind waves affect the coast throughout the year, while local wind waves are most common from October to April. These two wind-wave regimes typically have wave heights of 1 to 4 m and short periods (3 to 10 s). Potential marine benthic habitats in the Offshore of Salt Point map area include unconsolidated continental shelf sediments, mixed continental shelf substrate, and hard continental shelf substrate. Rocky-shelf outcrops and rubble are considered to be promising potential habitats for rockfish and lingcod, both of which are recreationally and commercially important species.

California↗

USGS2024

Pathology of tissue loss in three key gorgonian species in the Mediterranean Sea

The Mediterranean is known for its marine biodiversity, especially gorgonian forests. Unfortunately, these are experiencing rapid declines due to climate change, manifested by repeated marine heat waves resulting in mass mortality events since the early 1990 s. To better understand why gorgonians are declining, more systematic approaches to investigate the exact causes are needed, and pathology may aid in this goal. We described gross and microscopic pathology of tissue loss in three key gorgonian species in the Mediterranean region, Paramuricea clavata , Eunicella cavolini , and Leptogorgia sarmentosa , that were all experiencing various degrees of acute to subacute tissue loss characterized by exposed axial skeleton sometimes partly colonized by epibionts and thinning of adjacent tissues. The most significant variety of lesions was seen in P. clavata followed by L. sarmentosa and E. cavolini. For all species, dissociation of gastrodermal cells was the dominant microscopic lesion followed by necrosis of the gastrodermis. Ciliates invading gastrodermis and associated with necrosis of polyps were seen only in E. cavolini. Epidermal tissue loss was seen only in L. sarmentosa , while P. clavata was distinguished by a prominent inflammatory response and unidentified dark round structures within the tentacle epidermis and gastrodermis with no host response. Further work to understand the cause of death in gorgonians is needed, particularly to elucidate the role of ciliates and environmental co-factors or infectious agents not visible on light microscopy, as well as applications of additional tools such as cytology.

Journal of Invertebrate Pathology↗

USGS1980

Makah Formation — A deep-marginal-basin sequence of late Eocene and Oligocene age in the northwestern Olympic Peninsula, Washington

The Makah Formation of the Twin River Group crops out in a northwest-trending linear belt in the northwesternmost part of the Olympic Peninsula, Wash. This marine sequence consists of 2800 meters of predominantly thin-bedded siltstone and sandstone that encloses six distinctive newly named members--four thick-bedded amalgamated turbidite sandstone members, an olistostromal shallow-water marine sandstone and conglomerate member, and a thin-bedded water-laid tuff member. A local unconformity of submarine origin occurs within the lower part of the Makah Formation except in the central part of the study area, where it forms the contact between the older Hoko River Formation and the Makah. Foraminiferal faunas indicate that the Makah Formation ranges in age from late Eocene (late Narizian) to late Oligocene (Zemorrian) and was deposited in a predominantly lower to middle bathyal environment. The Makah Formation is part of a deep-marginalbasin facies that crops out in the western part of the Olympic Peninsula, in southwesternmost Washington and coastal embayments in northwestern Oregon, and along the central part of the coast of western Vancouver Island. On the basis of limited subsurface data from exploratory wells, correlative deep-marginal-basin deposits underlie the inner continental shelf of Oregon and the continental shelf (Tofino basin) along the southwestern side of Vancouver Island. Directional structures in the Makah Formation indicate that the predominantly lithic arkosic sandstone that forms the turbidite packets was derived from the northwest. A possible source of the clastic material is the dioritic, granitic, and volcanic terranes in the vicinity of the Hesquiat Peninsula and Barkley Sound on the west coast of Vancouver Island. Vertical and lateral variations of turbidite facies suggest that the four packets of sandstone were formed as depositional lobes on an outer submarine fan. The thin-bedded strata between the turbidite packets have characteristics of basin-plain and outer-fan fringe deposits.

Washington↗

USGS2016

Was everything bigger in Texas? Characterization and trends of a land-based recreational shark fishery

Although current assessments of shark population trends involve both fishery-independent and fishery-dependent data, the latter are generally limited to commercial landings that may neglect nearshore coastal habitats. Texas has supported the longest organized land-based recreational shark fishery in the United States, yet no studies have used this “non-traditional” data source to characterize the catch composition or trends in this multidecadal fishery. We analyzed catch records from two distinct periods straddling heavy commercial exploitation of sharks in the Gulf of Mexico (historical period = 1973–1986; modern period = 2008–2015) to highlight and make available the current status and historical trends in Texas’ land-based shark fishery. Catch records describing large coastal species (>1,800 mm stretched total length [STL]) were examined using multivariate techniques to assess catch seasonality and potential temporal shifts in species composition. These fishery-dependent data revealed consistent seasonality that was independent of the data set examined, although distinct shark assemblages were evident between the two periods. Similarity percentage analysis suggested decreased contributions of Lemon Shark Negaprion brevirostris over time and a general shift toward the dominance of Bull Shark Carcharhinus leucas and Blacktip Shark C. limbatus . Comparisons of mean STL for species captured in historical and modern periods further identified significant decreases for both Bull Sharks and Lemon Sharks. Size structure analysis showed a distinct paucity of landed individuals over 2,000 mm STL in recent years. Although inherent biases in reporting and potential gear-related inconsistencies undoubtedly influenced this fishery-dependent data set, the patterns in our findings documented potential declines in the size and occurrence of select large coastal shark species off Texas, consistent with declines reported in the Gulf of Mexico. Future management efforts should consider the use of non-traditional fishery-dependent data sources, such as land-based records, as data streams in stock assessments.

Texas↗

USGS2017

Shelf evolution along a transpressive transform margin, Santa Barbara Channel, California

High-resolution bathymetric and seismic reflection data provide new insights for understanding the post–Last Glacial Maximum (LGM, ca. 21 ka) evolution of the ∼120-km-long Santa Barbara shelf, located within a transpressive segment of the transform continental margin of western North America. The goal is to determine how rising sea level, sediment supply, and tectonics combine to control shelf geomorphology and history. Morphologic, stratigraphic, and structural data highlight regional variability and support division of the shelf into three domains. (1) The eastern Santa Barbara shelf is south of and in the hanging wall of the blind south-dipping Oak Ridge fault. The broad gently dipping shelf has a convex-upward shape resulting from thick post-LGM sediment (mean = 24.7 m) derived from the Santa Clara River. (2) The ∼5–8-km-wide Ventura Basin obliquely crosses the shelf and forms an asymmetric trough with thick post-LGM sediment fill (mean = 30.4 m) derived from the Santa Clara and Ventura Rivers. The basin is between and in the footwalls of the Oak Ridge fault to the south and the blind north-dipping Pitas Point fault to the north. (3) The central and western Santa Barbara shelf is located north of and in the hanging wall of the North Channel–Pitas Point fault system. The concave-up shape of the shelf results from folding, marine erosion, and the relative lack of post-LGM sediment cover (mean = 3.8 m). Sediment is derived from small steep coastal watersheds and largely stored in the Gaviota bar and other nearshore mouth bars. Three distinct upper slope morphologies result from a mix of progradation and submarine landsliding. Ages and rates of deformation are derived from a local sea-level-rise model that incorporates an inferred LGM shoreline angle and the LGM wave-cut platform. Post-LGM slip rates on the offshore Oak Ridge fault are a minimum of 0.7 ± 0.1 mm/yr. Slip rates on the Pitas Point fault system are a minimum of 2.3 ± 0.3 mm/yr near Pitas Point, and decrease to the west across the Santa Barbara Channel. Documentation of fault lengths, slip rates, and rupture modes, as well as potential zones of submarine landsliding, provide essential information for enhanced regional earthquake and tsunami hazard assessment.

California↗

USGS1979

Makah Formation--a deep marginal basin sedimentary sequence of Late Eocene and Oligocene age in the northwestern Olympic Peninsula, Washington

The Makah Formation of the Twin River Group crops out in a north-west-trending linear belt in the northwesternmost part of the Olympic Peninsula, Wash. This marine sequence consists of 2,800 meters of predominantly thin-bedded siltstone and sandstone that encloses six distinctive members. The named members include four packets of thick-bedded amalgamated turbidite sandstone, an olistostromal shallow-water marine sandstone and conglomerate member, and a thin-bedded water-laid tuff member. A local unconformity of submarine origin occurs within the lower part of the Makah Formation except in the central part of the study area, where it forms the contact between the older Hoko River Formation and the Makah. Foraminiferal faunas indicate that the Makah Formation ranges in age from late Eocene (late Narizian Stage) to late Oligocene (Zemorrian Stage) and was deposited in a predominantly lower to middle bathyal environment. The Makah strata are part of a deep marginal basin facies that crops out in the western part of the Olympic Peninsula, in southwesternmost Washington and coastal embayments in northwestern Oregon, and along the central part of the coast of western Vancouver Island. On the basis of limited subsurface data from exploratory wells, correlative deepmarginal-basin deposits underlie the inner continental shelf of Oregon and the continental shelf (Tofino Basin) along the southwestern side of Vancouver Island. Directional structures in the Makah Formation indicate that the predominantly lithic arkosic sandstone that forms the turbidite packets was derived from the northwest. A possible source of the clastics is the dioritic, granitic, and volcanic terranes in the vicinity of the Hesquiat Peninsula on the west coast of Vancouver Island. Vertical and lateral variations of turbidite facies suggest that the four packets of sandstone were formed as depositional lobes on an outer submarine fan. The thin-bedded strata between the turbidite packets have characteristics of basin-plain and outer-fan fringe deposits.

Washington↗

USGS2000

Revision of middle Proterozoic Yellowjacket Formation, central Idaho, and revision of Cretaceous Slim Sam Formation, Elkhorn Mountains area, Montana

The Yellowjacket Formation is restricted to the strata originally assigned to it by Ross (1934). The Yellowjacket, the conformably overlying Hoodoo Quartzite, and succeeding unnamed argillaceous quartzite unit form a genetically related sequence that lies in a structural block delimited on the northeast by the Iron Lake fault. Directly northeast of the fault, strata currently assigned by others to the lower subunit of the Yellowjacket are correlated with the Apple Creek Formation in the Lemhi Range. Mapping in the western part of the Lemhi Range shows that the Apple Creek Formation lies depositionally above the Big Creek Formation and that no rocks of the Yellowjacket-Hoodoo unnamed unit stratigraphic sequence are present. In contrast, in the area of the Yellowjacket mapped by Ross (1934) and the area directly northeast of the Iron Lake Fault, the Big Creek Formation is absent, even though it is 2,700 m thick in the Lemhi Range. These data indicate that the Iron Lake Fault juxtaposed the Yellowjacket-Hoodoo-unnamed unit sequence against non-Yellowjacket strata to the northeast. The Upper Cretaceous Slim Sam Formation of the Elkhorn Mountains area is revised. Strata of the lower part are correlated with the regionally recognized marine Telegraph Creek Formation and the overlying marine to marginal marine Eagle Sandstone. Only lower strata of the Eagle are present in the study area and they are preserved discontinously. The nonmarine volcanic and volcaniclastic rocks of the upper part of the Slim Sam as originally defined retain the name Slim Sam Formation. These rocks, mainly of sedimentary origin, are genetically related to the Elkhorn Mountains Volcanics. The lower contact of the Slim Sam (restricted) is unconformable above the Eagle Sandstone or more commonly above the Telegraph Creek Formation. The upper contact is conformable with the Elkhorn Mountains Volcanics.

Idaho, Montana↗