THE NEKSELØ FISH WEIR AND MARINE RESERVOIR EFFECT IN NEOLITHIZATION PERIOD DENMARK

ABSTRACT The Nekselø Wickerwork provides an unusually solid estimate on the marine reservoir age in the Holocene. The basis for this result is a 5200-year-old fish weir, built of hazel wood with a brief biological age of its own. Oysters settled on this construction. They had lived only for a short number of years when the fence capsized and was covered in mud and the mollusks suffocated. Based on the difference in radiocarbon (14C) age between accelerator mass spectrometry (AMS) samples of oyster shells and wood, respectively, the marine reservoir age for this site is estimated to 273 ± 18 14C years. Re-evaluations of previously produced data from geological and archaeological sites of Holocene date in the Danish archipelago indicate marine reservoir ages in the same order as that of the Wickerwork. Consequently, we recommend the use of the new value, rather than the ca. 400 14C years hitherto favored, when correcting for the dietary induced reservoir effect in radiocarbon dates of humans and animals from the Late Mesolithic and Early Neolithic periods of this region.

“Coyote Broke the Dams”: Power, Reciprocity, and Conflict in Fish Weir Narratives and Implications for Traditional and Contemporary Fisheries

This article examines the social and political implications of the geographically widespread and cross-cultural oral narratives related to the releases of salmon into the rivers of the Pacific Northwest through the destruction of weir-dams. Key themes in these narratives provide insights into indigenous concepts of reciprocity and authority, which in turn reveal dimensions of social organization and intercommunity interactions from a new perspective. These narratives explicitly foreground the inevitable tensions between communities that relied on salmon and also sought to prioritize their own interests, seeking exclusive use of weirs, occasionally to the detriment of other groups. This study illustrates how these narratives convey episodes of contradictory interests, exploitation, social struggle, reconciliation, and a moral charter for communities over a broad area. The analysis also highlights how the messages of these narratives are just as pertinent today as they were in the past.

Effects of a fish weir on the structure of the macrobenthic community of a tropical sandy beach on the Amazon coast

The present study investigated the effects of a fish weir, a fixed trap used by artisanal fisheries, on the intertidal macrobenthic infauna of a macrotidal sandy beach on the Amazon coast. Biological and sediment samples were collected from within the weir and at five points of increasing distance (10 cm, 50 cm, 1 m, 2 m, 5 m and 50 m) from the external portion of the trap. The sediments from the weir and at 10 cm were dominated by mud, with a gradual decline in fine grains, water content and organic matter with increasing distance from the weir to 50 m (control). Taxon abundance and richness were significantly higher in the weir and at 10 cm than at the other sampling points. There was a trend of decreasing density and richness of the infauna from the weir to 1 m (which was a point of transition between the muddy and sandy sediments), after which the biological descriptors tended to increase once again. A shift was also observed in the dominant trophic groups, with a decrease in the abundance of the deposit feeders with increasing distance from the weir. By contrast, predators were more abundant at the points further from the weir. Our results indicate that fish weirs alter the associated sedimentary habitats, due to the increased protection from the action of waves and currents, with a micro-scale (from a few centimetres to 1–2 m) influence on the local macrofauna.