Chiaki Katagiri

Advanced maritime adaptation in the western Pacific coastal region extends back to 35,000-30,000 years before present.

Significance Moving into oceanic islands after c. 50,000 years ago was a remarkable step forward in the history of worldwide expansion of modern humans. However, the developmental process of Pleistocene maritime technology remains unclear. So far, the only secure sources of information for such discussions were the Indonesian Archipelago and northern New Guinea as steppingstones from the Asian continent to Australia. This article reports a successful maritime adaptation that extended from ∼35,000 to 13,000 years ago on a small island environment in the southern Japanese Archipelago. The new evidence demonstrates a geographically wider distribution of early maritime technology that extended north to the midlatitude areas along the western Pacific coast. Maritime adaptation was one of the essential factors that enabled modern humans to disperse all over the world. However, geographic distribution of early maritime technology during the Late Pleistocene remains unclear. At this time, the Indonesian Archipelago and eastern New Guinea stand as the sole, well-recognized area for secure Pleistocene evidence of repeated ocean crossings and advanced fishing technology. The incomplete archeological records also make it difficult to know whether modern humans could sustain their life on a resource-poor, small oceanic island for extended periods with Paleolithic technology. We here report evidence from a limestone cave site on Okinawa Island, Japan, of successive occupation that extends back to 35,000−30,000 y ago. Well-stratified strata at the Sakitari Cave site yielded a rich assemblage of seashell artifacts, including formally shaped tools, beads, and the world’s oldest fishhooks. These are accompanied by seasonally exploited food residue. The persistent occupation on this relatively small, geographically isolated island, as well as the appearance of Paleolithic sites on nearby islands by 30,000 y ago, suggest wider distribution of successful maritime adaptations than previously recognized, spanning the lower to midlatitude areas in the western Pacific coastal region.

Discovery of Iron Grapnel Anchors in Early Modern Ryukyu and Management of Underwater Cultural Heritage in Okinawa, Japan

The Yarabuoki underwater site contains seven iron grapnel anchors and Early Modern Okinawan ceramic jars and is dated to the 16th–19th centuries. The site lies at a depth of 12–32 m off the western coast of Ishigaki Island in Okinawa, Japan. Based on underwater archaeological and broadband multibeam surveys, as well as historical research of the artefacts and Early Modern Ryukyuan shipping, we discuss the possible anchor and vessel types in Ryukyu and Eastern Asia in Early Modern times. We also discuss the efficacy of low-cost ROV for assisting surveys in shallow-water environments and the value of educational programmes for promoting the management and conservation of underwater cultural heritage.

Observation support system of an ROV for underwater archaeology

In this paper, we propose an observation support system of a Remotely Operated Vehicle (ROV) for underwater archaeology. In general, it is difficult for unskilled users to drive an ROV for underwater observation because a camera mounted on an ROV always moves due to external disturbances and objects easily move out of the field of view (FOV) of the camera. Once an object is out of the FOV, users cannot easily find out it again. The observation support system is used to help unskilled users to drive an ROV. To realize the proposed system, object detection based on image processing is a key component. We apply the SURF (Speeded Up Robust Features) algorithm to detect archaeological objects, and investigate the performance of the algorithm using video images recorded by our ROV in an underwater archaeological site.

Early Metal Age interactions in Island Southeast Asia and Oceania: jar burials from Aru Manara, northern Moluccas

New evidence from the rockshelter site of Aru Manara, on the island of Morotai, in the northern Moluccas, East Indonesia, suggests an earlier than previously assumed date for extensive interactions between this area of Southeast Asia and the wider Pacific. Shared mortuary customs and associated ceramic grave goods, along with other practices such as megalithic traditions, appear to start in the Late Neolithic, but become more widespread and consolidated in the Early Metal Age. Excavations at Aru Manara show that the northern Moluccas may have figured prominently in the newly established network of interaction evidenced at this time, making it an important location in the spread and dispersal of people and culture throughout Island Southeast Asia and into Oceania.

A basic experiment for image-based position measurement of objects at sea

This paper presents an image-based position measurement of underwater objects using a low-cost maritime mobile robot with a monocular camera. Visual recognition of distant underwater objects is possible in the water with high transparency, for example, in the coastal sea area of Okinawa prefecture, Japan. In this paper, we apply the proposed method to estimate the position of an old anchor that is at a deep of 30 [m] and is estimated to be hundreds-of-years-old in an archaeological site in Ishigaki Island. We explain the measurement principle of the proposed method and the developed system. Moreover, we describe the experiment conducted off the coast of Ishigaki Island and show the experimental results of the proposed method.