Fishing, Subsistence Change, and Foraging Strategies on Western Santa Rosa Island, California

2020 ◽  
Vol 85 (3) ◽  
pp. 591-608
Author(s):  
Christopher S. Jazwa ◽  
Terry L. Joslin ◽  
Douglas J. Kennett

Shifting from shellfish collecting to fishing as a primary coastal foraging strategy can allow hunter-gatherers to obtain more food and settle in larger populations. On California's northern Channel Islands (NCI), after the development of the single-piece shell fishhook around 2500 cal BP, diet expanded from primarily shellfish to include nearshore fishes in greater numbers. During the Medieval Climatic Anomaly (1150–600 cal BP), settlement on the islands condensed to a small number of large coastal villages with high population densities supported largely by nearshore fish species including rockfishes, surfperches, and señoritas. Faunal data from five sites on western Santa Rosa Island (CA-SRI-15, -31, -97, -313, and -333) demonstrate an increase in nearshore fishing through time. We argue that demographic changes that occurred on the northern Channel Islands were accompanied by changes in subsistence strategies that were related in part to risk of failure when attempting to acquire different resources. As population density increased, the low-risk strategy of shellfish harvesting declined in relative importance as a higher-risk strategy of nearshore fishing increased. While multiple simultaneous subsistence strategies are frequently noted among individual hunter-gatherer communities in the ethnographic record, this study provides a framework to observe similar patterns in the archaeological record.

2021 ◽  
pp. 1-13
Author(s):  
Kristina M. Gill ◽  
Todd J. Braje ◽  
Kevin Smith ◽  
Jon M. Erlandson

There is growing evidence for human use of geophytes long before the advent of agriculture. Rich in carbohydrates, geophytes were important in many coastal areas where protein-rich marine foods are abundant. On California's Channel Islands, scholars have long questioned how maritime peoples sustained themselves for millennia with limited plant resources. Recent research demonstrates that geophytes were heavily used on the islands for 10,000 years, and here we describe geophyte and other archaeobotanical remains from an approximately 11,500-year-old site on Santa Rosa Island. Currently the earliest evidence for geophyte consumption in North America, our data extend geophyte use on the Channel Islands by roughly 1,500 years and document a diverse and balanced economy for early Paleocoastal peoples. Experimental return rates for a key island geophyte support archaeological evidence that the corms of blue dicks (Dipterostemon capitatus) were a high-ranked staple resource throughout the Holocene.


Author(s):  
Poppy M. Jeffries ◽  
Samantha C. Patrick ◽  
Jonathan R. Potts

AbstractMany animal populations include a diversity of personalities, and these personalities are often linked to foraging strategy. However, it is not always clear why populations should evolve to have this diversity. Indeed, optimal foraging theory typically seeks out a single optimal strategy for individuals in a population. So why do we, in fact, see a variety of strategies existing in a single population? Here, we aim to provide insight into this conundrum by modelling the particular case of foraging seabirds, that forage on patchy prey. These seabirds have only partial knowledge of their environment: they do not know exactly where the next patch will emerge, but they may have some understanding of which locations are more likely to lead to patch emergence than others. Many existing optimal foraging studies assume either complete knowledge (e.g. Marginal Value Theorem) or no knowledge (e.g. Lévy Flight Hypothesis), but here we construct a new modelling approach which incorporates partial knowledge. In our model, different foraging strategies are favoured by different birds along the bold-shy personality continuum, so we can assess the optimality of a personality type. We show that it is optimal to be shy (resp. bold) when living in a population of bold (resp. shy) birds. This observation gives a plausible mechanism behind the emergence of diverse personalities. We also show that environmental degradation is likely to favour shyer birds and cause a decrease in diversity of personality over time.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Monique Ladds ◽  
David Rosen ◽  
Carling Gerlinsky ◽  
David Slip ◽  
Robert Harcourt

Abstract Physiology places constraints on an animal’s ability to forage and those unable to adapt to changing conditions may face increased challenges to reproduce and survive. As the global marine environment continues to change, small, air-breathing, endothermic marine predators such as otariids (fur seals and sea lions) and particularly females, who are constrained by central place foraging during breeding, may experience increased difficulties in successfully obtaining adequate food resources. We explored whether physiological limits of female otariids may be innately related to body morphology (fur seals vs sea lions) and/or dictate foraging strategies (epipelagic vs mesopelagic or benthic). We conducted a systematic review of the increased body of literature since the original reviews of Costa et al. (When does physiology limit the foraging behaviour of freely diving mammals? Int Congr Ser 2004;1275:359–366) and Arnould and Costa (Sea lions in drag, fur seals incognito: insights from the otariid deviants. In Sea Lions of the World Fairbanks. Alaska Sea Grant College Program, Alaska, USA, pp. 309–324, 2006) on behavioural (dive duration and depth) and physiological (total body oxygen stores and diving metabolic rates) parameters. We estimated calculated aerobic dive limit (cADL—estimated duration of aerobic dives) for species and used simulations to predict the proportion of dives that exceeded the cADL. We tested whether body morphology or foraging strategy was the primary predictor of these behavioural and physiological characteristics. We found that the foraging strategy compared to morphology was a better predictor of most parameters, including whether a species was more likely to exceed their cADL during a dive and the ratio of dive time to cADL. This suggests that benthic and mesopelagic divers are more likely to be foraging at their physiological capacity. For species operating near their physiological capacity (regularly exceeding their cADL), the ability to switch strategies is limited as the cost of foraging deeper and longer is disproportionally high, unless it is accompanied by physiological adaptations. It is proposed that some otariids may not have the ability to switch foraging strategies and so be unable adapt to a changing oceanic ecosystem.


Author(s):  
Bill Angelbeck

The concept of modes of production has been a constructive way to analyze state societies in archaeological history. Yet the utility for archaeologists working with non-state, or anarchic societies, can be quite generalized, mainly useful for broad temporal scales of analysis. To apply to non-state societies, I reorient modes of production from historical epochs to the microscale, evaluating the seasonal shifts of activity throughout the annual round. For complex hunter-gatherers, such as the Coast Salish of the Northwest Coast, modes of production shifted constantly season by season as they adjusted their subsistence strategies toward the availability of varied resources. In so doing, they implemented distinct means of production and varying relations of production to harness those resources most effectively. Some involved small-scale formations, with dispersed families (egalitarian and autonomous), while others involved corporate multi-family groups (hierarchical with ranks of authority), for instance, to process fish during annual salmon runs. In this way, Salish individuals engaged different modes of production throughout the year, each varying in levels of autonomy, which they often pursued. By focusing modes of production into particular modes, we can track the microscale revolutions that occur within broader historical epochs.


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