Red abalone collecting and marine water temperature during the Middle Holocene occupation of Santa Cruz Island, California

Central place foraging and shellfish processing on California’s Northern Channel Islands

“…Except for the latest date, which is associated with a less dense midden lens, the rest of the occupation of these sites ended by 4560-4140 cal BP (2r range; CA-SRI-50, Unit 1, 30-40 cmbs). This places the occupation of these sites within the Middle Holocene and within the general range of dates for the formation of red abalone middens on the NCI (Braje, 2010;Braje et al, 2007Braje et al, , 2009Glassow, 1993Glassow, , 2013Glassow et al, 1988Glassow et al, , 1994Glassow et al, , 2008Glassow et al, , 2012Jazwa et al, 2013a;Kennett, 1998Kennett, : 462, 2005. The red abalone midden sites span nearly the entire range, particularly at CA-SRI-109, which produced dates ranging from 5870 to 4420.…”

“…Historically, red abalones prefer to live in subtidal environments in southern California, but will live in intertidal regions in cooler areas during periods of cooler water (Raab, 1992). Glassow (1993Glassow ( , 2013Glassow et al, 1988Glassow et al, , 1994Glassow et al, , 2008Glassow et al, , 2012also Hubbs, 1967;Raab, 1992;Salls, 1992) argued that red abalone middens on Santa Cruz Island dating between 6300 and 5300 cal BP were related to cooler sea surface temperatures during this interval (Kennett, 2005: 66;Kennett et al, 2007: 354). He also suggested that the comparatively low human population densities during this period would have limited the depletion of stocks of abalone and other large gastropods from over-predation by island inhabitants, while the later expansion of human populations may have had deleterious effects on these high-ranked resources (Glassow, 2013).…”

“…The measurement of oxygen isotopes (d 18 O) in shell carbonate is a well-established technique for determining sea surface temperature (SST; see Glassow et al, 1994Glassow et al, , 2012Jazwa et al, 2012;Jew et al, 2013aJew et al, , 2013bJones and Kennett, 1999;Kennett, 2005;Kennett and Voorhies, 1996;Killingley and Berger, 1979;Shackleton, 1973;Thakar, 2014). Oxygen isotope ratios in shell contain information about the physical and chemical environment at the time of their growth.…”

“…All dates were calibrated in OxCal 4.1 (Bronk Ramsey, 2009) using the most recent marine calibration curve, Marine13 (Reimer, et al, 2013 whether the shell was collected during a period when SST was increasing or decreasing, and the rate of change, to better associate it with a time of year. Recently, several researchers argued that even more samples should be taken to characterize season of collection more accurately (e.g., Glassow et al, 2012;Jew et al, 2013aJew et al, , 2013bEerkens et al, 2014;Thakar, 2014). We selected two samples from each shell to maximize the number of levels and sites that could be tested with our limited funding and to maintain consistency with previous studies for the sites analyzed (e.g., Kennett, 1998Kennett, , 2005Jazwa et al, 2012).…”

A Test of Ideal Free Distribution Predictions Using Targeted Survey and Excavation on California’s Northern Channel Islands

“…The relationship between environmental and sociopolitical change has been an important topic of research on the NCI (Arnold 1992a(Arnold , 2001aArnold and Graesch 2004;Arnold and Tissot 1993;Braje et al 2007;Erlandson and Jones 2002;Jazwa et al 2012;Jazwa and Perry 2013;Kennett and Kennett 2000;Kennett et al 2007Raab and Larson 1997;Glassow et al 2012). In parallel, there have been several attempts to generate high-resolution records for sea surface temperature (Arnold and Tissot 1993;Kennett 2005;Kennett and Kennett 2000;Pisias 1978) and drought (Raab and Larson 1997) in the Santa Barbara Channel region.…”