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This document is a government generated Section 106 report consisting of a historic property inventory and an assessment of adverse effects associated with the A5 Powerline Replacement Project. The purpose of the document is to compile any prior or current studies performed in support of the A5 Powerline replacement project as a single Section 106 report. This report provides the information needed by the California State Historic Preservation Officer to concur on the project findings and determinations for individual resources as presented by the Vandenberg Air Force Base Cultural Resource Manager. The report specifically examines project impacts and/or avoidance strategies for twenty-seven archaeological sites; CA-SBA-592, -702, -775, -776, -1779, -2086, -2569H, -2570, -2571, -2883, -2884, -2885, -2886, -2887, -2888, -2889, -2894, -3213, -3215, -3232, -3348, -3376, -3527H, -3552H, -3560H, -3747, -3748.

A proxy record of sand beach accretion for the past 10,000 years has been assembled from radiocarbon dates on the Pismo clam, Tivela stultorum, in archaeological sites along the southern California coast. When this record is compared with numerous climate proxies, it appears that El Nino–Southern Oscillation (ENSO) controls on wave climate and sediment flux have acted upon regional geomorphology at different sea levels to either accrete or erode the Holocene beaches of southern California. Tivela dates from the Santa Maria coast indicate that perennial sand beaches built by 9000 years ago in response to abundant riverine sediment contained by the natural groin at Point Sal, wave sheltering by the massive headland of Point Buchon, and Early Holocene El Nino events. On the western Santa Barbara coast, sand beaches were forming by 7000 years ago in response to high sand fluxes from the Santa Ynez Mountains to the many small littoral catchments, possibly aided by high local rates of uplift. Decline of these sand beach habitats 5000–4000 years ago coincides with increased El Nino-driven wave energy. In accord with slowing in sea-level rise ca. 6000 years ago, sand beaches were most widespread in the period 6000–5000 years ago on Estero Bay, the western Santa Barbara coast, and west of Point Dume. However, Tivela dates first appear 5000 years ago in the Oceanside and Silver Strand littoral cells of the San Diego region. This lag coincides with the Middle Holocene shift to a more variable climate and modern periodicity in El Nino events that increased sediment supply to the southern coast. The ontogeny of the littoral cells provides timelines for modeling coastal evolution with implications for sand beach ecology, prehistoric human coastal adaptations, and coastal planning for future climate change.

Shell beads have long been a topic of interest in North American Pacific Coast archaeology. Studies by Gifford (1947), Gibson (1975, 1976, 1987, 1992), King (1974, 1978, 1990), Macko (1984), Bennyhoff and Hughes (1987), Arnold (1992a), Arnold and Munns (1994), and Arnold and Graesch (2001) have established the temporal sensitivity of shell bead assemblages in California and explored their socioeconomic importance among several groups on the coast and in the interior. Somewhat less attention has been directed toward elucidating shell bead production techniques (but see Arnold and Graesch, 2001; Macko, 1984). Here, we experiment with an often reported but unusual drilling technique attributed to the coastal Chumash, among others, for the manufacturing of Pismo clam (Tivela stultorum) tube beads. We also place Tivela stultorum bead manufacturing in a broader cultural and manufacturing context, including implementing systematic Moh's hardness testing of Tivela and nine other widely used shell species. Ethnographic, archaeological, and experimental evidence suggests that Tivela tube beads were among the most labor-intensive and valuable of the many bead types made and used by Native Californians.

Scope-for-growth is an integrative measure of physiological processes occurring in the organism and, as such, provides information on organism-environment functional interactions. The physiological responses necessary to calculate the scope for growth were measured in different salinity-temperature combinations in adult Pismo clam, Tivela stultorum, of different sizes. Parallel box plot and multiple regression equation, represented by surface responses, show that the Pismo clam has a positive scope-for-growth in all salinity-temperature combinations. However, a greater energy portion for both somatic growth and reproduction was obtained at 110% sea water at 21°C and in smaller sizes. This knowledge is useful in cultural practices aimed at obtaining clam "seeds" under laboratory conditions so as to restock naturally occurring banks.

As modern humans grapple with the repercussions of their extensive environmental impacts, archaeologists are increasingly looking toward the past to understand the nature and extent of prehistoric human impact on the environment. Many researchers rely heavily on archaeological correlates of resource intensification as a proxy measures of resource depletion, a profound and often catastrophic human impact. However, the traditional conceptualization of the archaeological correlates of shellfish intensification disregards a large amount of species-specific variation. This paper presents archaeomalacological data from Santa Cruz Island, California. The shell midden deposits CA-SCRI-480 contain a high density of Tivela stultorum (Pismo clam). Statistical analysis of the shellfish assemblage reveals significant variation in both the size and quantity of Pismo clam that people collected through time. This paper investigates this unique patterning with due consideration of the natural ecology and life history of the species and illustrates species-specific deviation from the traditional archaeological correlates of shellfish intensification. Increased collaboration with ecologists and biologists can help refine models of intensification when necessary in order create more sophisticated understanding of prehistoric human–resource interactions.

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Sexual reproduction was invented by organisms that lived in the sea or in brackish or fresh water. When conjugation and fusion were fashionable, the watery environment was no problem. But when gametes came into being, allowing the advantages of greater mobility and fecundity, the vagary of currents and other hazards called for new strategies. One of the best ways to have enough progeny for the species to survive was to produce a redundancy of eggs and sperm. This is common in marine animals. A cod will lay up to 8 million eggs, though usually fewer, which float on the surface of the sea. A Pismo clam produces about 15 million eggs a year. There could be 100 trillion eggs spawned by the clams along less than 10 miles of beach, and if they all matured into legal-size clams and were laid end to end, they would encircle the earth 300,000 times. But only a small fraction of a percent of the eggs ever become mature clams. An annual census showed that in 1 year, only 33,000 clams resulted from 120 trillion eggs.

Sea otter, Enhydra lutris, predation had no detectable effect on abundance and size distribution of deep-burrowing bivalve prey in the Elkhorn Slough, California, USA. Up to 23 otters were present for 6 mo of the study period (March 1984 through April 1985). This is in contrast to previous studies of sea otter predation, especially on the shallow-burrowing Pismo clam Tivela stultorum, which can be found along the wave-exposed coast near the slough. The deep-burrowing clams Tresus nuttallii and Saxidomus nuttalli made up 61% of the prey taken in the slough, and are more difficult for otters to excavate than Pismo clams. The occurrence of foraging otters was highest in an area where the two bivalve prey were extremely abundant (∼18 individuals m−2). However, the otters did not selectively prey on the largest clams available within the study sight, but foraged preferentially in a patch of smaller individuals where bivalve burrow depth was restricted by the presence of a dense clay layer. This foraging strategy maximized the amount of prey biomass obtained per unit volume of sediment excavated. Our findings suggest that in soft-sediment habitats deep-burrowing bivalves may be more resistant to otter predation than shallower burrowers.

A Pismo clam, Tivela stultorum, census was conductedin January 1976 on selected southern California beaches.Effort and catch information was collected throughclamer interviews. Estimates for January 17 on beachessampled were 3,296 clammer-hours, 2,170 clammers, and10,739 legal clams (4.5 inches or larger) harvested.Clams were collected for age and growth studies.Samples of clams from the Long Beach to Newport Beach pierarea demonstrate the fastest growth rates of any Pismoclams reported in the literature. Clams begin to be recruited to the fishery at age 40 months. (14pp.)The 1974 year class was the largest on beachessampled. Recruitment to the fishery will be poor for the1976-77 and 1977-78 seasons and clamming will be dependenton large older clams.

A Pismo clam, Tivela stultorum, survey was conductedin January 1977 on selected southern California beaches.Effort and catch information was collected through clammer interviews. Estimates for the two day survey were 1,596clammers spending 2,506 hours to take 6,139 clams. Comparisons were made between the 1977 survey results andprevious surveys.Clams were collected for length and age studies. Complianceto the 4.5-inch (114.3 mm) minimum size limit appeared to be good. (15pp.)

Sea otter foraging along Monterey Bay beaches and at Atascadero State Beach has precluded recreational Pismo clam fisheries at six major clamming beaches. Outside the sea otter's foraging range Pismo clam stocks are yielding good catches; apparently the stringent controls on the recreational fishery is adequate to maintain the State's Pismo clam stocks. Clammer interviews at Orange and Los Angeles County beaches and at beaches near Pismo Beach and Morro Bay and in Monterey Bay revealed the clam stocks to be on a healthy, sustainable yield basis. Exceptionallylarge numbers of small 1.5 to 3.5 inch Pismo clams were reported at all clam beaches surveyed north of Pt. Conception indicating good year class survival in recent years. Sea otters forage dense Pismo clam beds by moving along a "front", progressively foraging from one beach to the next, reducing the clams to low levels before moving on. Some sea otters continue to forage throughout the areas previously depleted by the larger aggregate moving northward, thus the large numbers of sublegal clamsin the 1.5 to 3.5 inch size group in these intertidal and shallow subtidal areas are not expected to reach legal size in numbers sufficient to develop a recreational fishery. In Monterey Bay about 60,000 Pismo clams were removed or killed by human activity in the April 1974 to March 1975 period. A rough estimate of the Pismo clams consumed by sea otters during this same period in Monterey Bay is over 500,000 clams. (51pp.)