Paleogeographic changes drove prehistoric fishing practices in the Cambaceres Bay (Tierra del Fuego, Argentina) during the middle and late Holocene

ZANGRANDO, FRANCISCO ; PONCE, JUAN FEDERICO; VANELLA, FABIÁN A.

Environmental Archaeology

Maney Publishing

Lugar: Aberdeen; Año: 2015

1461-4103

Since 1920s, the Cambaceres bay area (Beagle Channel, Tierra del Fuego, Argentina) has been the focus of archaeological studies, including extensive field surveys (Lothrop 1928: 182-184; Bjerck 2014) and excavations (Piana et al. 2000, 2012; Orquera and Piana 1999, 2000a; Briz et al. 2009; Zangrando 2009a; Alvarez et al. 2013). As a result, the distribution of archaeological sites is well known in that place and the excavations allowed developing temporal analyses of the settlement system and subsistence of hunter-gatherer populations from 8000 BP until historic times. One of these studies focused on subsistence activities of hunter-gatherers at the Imiwaia I site (located in the Cambaceres Interior Bay) during middle and late Holocene (Zangrando 2003, 2009a). The Cambaceres Bay area is located within a drumlin field assigned to the Last Maximum Glacial (Rabassa et al. 1990). After removal of the ice, the Beagle channel was occupied by a proglacial lake since 9400 BP (Rabassa et al. 1986) and the irregular relief generated by the drumlin field would have led to the formation of lagoon environments and peatlands in depressed areas (inter-drumlins areas). Prior to 7900 BP, the marine environment in the vicinity of Beagle Channel (Rabassa et al. 1986) was fully installed with a sea level located at least 30 m below the present sea level, taking into account the bathymetric thresholds located in Mackinlay and Murray Channels (Bujalesky 2011). The current coastal configuration was acquired at around 7000 cal BP (Borromei et al. 2013). At present, Cambaceres Interior bay has a semi-enclosed configuration and the subtidal substrate is muddy; the Macrocystis pyrifera ecosystem is absent inside the bay. The water salinity is lower (~26? Vanella 2013, personal communication) than in open waters of the Beagle Channel (~32?). The euryhaline conditions in the interior of the bay lead to a different composition of the fish fauna to that observed in open waters and characterized by a greater abundance of Patagonian blenny (Eleginops maclovinus) and silversides (Odontesthes sp.).The exploitation of marine resources by hunter-gatherers is evidenced through the archaeological sequence of the Beagle Channel region, starting approximately 6400 BP. The zooarchaeological assemblages include bone remains of pinnipeds, terrestrial mammals (principally guanaco), birds and fish. From 1500 BP, fish became one of the most represented resources in the archaeological record until the last hunter-gatherer occupations of the region. Fishing intensification is evidenced in the Late Holocene both by a significant increase in the representation of coastal taxa as an increase in the diversity of pelagic fishing (Zangrando 2009a; 2009b).Zooarchaeological evidence from the Imiwaia I site shows a different pattern to this regional trend in terms of temporal variation in the exploitation of coastal fish. While in later occupations of that site pelagic fishing was clearly important, few remains of coastal fish were recovered. In order to explain the fishing pattern in this particular area, special attention was given to the possibility that changes in coastal geomorphology along the Holocene might have impacted on the subsistence activities of hunter-gatherers. In this paper we present an analysis base on an interdisciplinary research carried out in the area, mainly focusing on the geomorphological and ichthyoarchaeological studies.