Temporal trends in prehistoric fishing in Palau, Micronesia over the last 1500 years

Abstract Previous research at the Chelechol ra Orrak site in Palau, Micronesia suggested that fishing may have declined prehistorically over the past two thousand years. Here we discuss the analysis of an additional suite of archaeofish remains recovered from the site that significantly expands the size of the previous assemblage, providing a more robust interpretation of prehistoric fishing in the archipelago. Results indicate that although all phases of occupation show diverse and relatively equitable exploitation of fish taxa, there are statistically significant changes in fishing over time when feeding guild (general ecological niche) is considered. In addition, the number of fish remains declines by an order of magnitude between early (1400-1240 BP) and later (1290-720 BP and 500-0 BP) occupation phases. Although various factors may be responsible for this dramatic decrease, it is generally correlated with settlement changes and possible increasing agricultural production in Palau. Thus, a decline in the overall importance of fishing may account for the changes observed in the archaeofish assemblage over time. Keywords: fishing, prehistoric, Chelechol ra Orrak, Western Caroline Islands, Pacific ********** The analysis of archaeofish remains from prehistoric sites in the Pacific is critical for examining a range of issues, including subsistence strategies, capture technologies, human impacts, and how these changed over time (e.g. Allen 1992, 2002; Butler 1988, 2001; Leach and Boocock 1993; Leach and Davidson 2001; Morrison and Addison 2009). In a previous paper, Fitzpatrick and Kataoka (2005) reported the first stage of analysis of fish remains recovered from the Chelechol ra Orrak site in the northern Rock Islands of Palau, Micronesia. Their analysis of 922 identified fish specimens from two test units dating back to around ca. 2000 BP suggested that inhabitants were procuring taxa from a wide variety of marine environments, particularly near shore and lagoonal habitats, and that fishing decreased over time. However, the reasons for this were unclear. Since that time, additional analysis has augmented the identified archaeofish assemblage nearly threefold for a total of 2604 identified specimens, allowing for a better assessment. Dating to ca. 1400-0 BP, this substantially larger assemblage supports a more robust interpretation of early subsistence strategies in Palau and 1 changes that occurred in fish exploitation in the northern part of the archipelago. Here, we expand our quantitative approach to include investigation of sample diversity, evenness and archaeofish density, statistical support for observed temporal trends, and consideration of fish feeding guilds. This last method is used to explore large scale patterning in human fishing strategies. Together these multiple lines of evidence indicate significant changes in fish taxa targeted by Chelchol ra Orrak residents along with a decline in the overall importance of fishing over time. Archaeological background Palau is located roughly 600 km east of the southern Philippines and about the same distance north of New Guinea (Figure 1). The archipelago is comprised of several hundred islands of varying geological origin (volcanic, coral reef and atoll, and uplifted limestone) which stretches approximately 160 km northeast/southwest, is 25 km across at its widest point, and has a land area of around 400 [km.sup. 2]. Archaeological research indicates that Palau was probably first settled sometime between 3300-3000 BP (see Fitzpatrick 2003a; Clark 2005; Liston 2005; Clark et al. 2006). One of the oldest sites recorded in Palau is the Chelechol ra Orrak rockshelter located on the small limestone island of Orrak just off the southeast tip of the larger island of Babeldaob (Figure 1) which dates from between ca. 3000-2700 BP to the historic period (Fitzpatrick 2003a; Fitzpatrick and Nelson 2008). Archaeological investigation at the site began in 2000 (Test Units 14) with additional fieldwork in 2002 and 2007 (Test Units E2/S1, E3/S1, E2/$2, E1/S4, and E1/S5, shown in white on Figure 2). …