Integrated Marine Archaeological Research on a Japanese Shipwreck Site in Gorontalo Province,

Nia Naelul Hasanah Ridwan1, Gunardi Kusumah1, Semeidi Husrin1, Try Altanto1, Ilham1, Hadi Sofyan1, Aprizon Putra1, Herlina² 1Research Institute for Coastal Resources and Vulnerability Ministry of Marine Affairs and Fisheries ²Bandung Institute Technology E-mail: [email protected]

Abstract

Gorontalo is "The Hidden Paradise" and is one of the youngest provinces in Indonesia. It is home to a Japanese shipwreck site from World War II located at Leato Beach. Recently this shipwreck site began to be known amongst SCUBA divers. However, it has not yet been protected by law and has not been utilized optimally. This Japanese shipwreck site in a depth of 25-50 m along with the diversity of coral reefs and other marine life is a potential marine resource that can be developed as a shipwreck diving spot in Gorontalo that could accelerate the economic prosperity of local communities. Integrated marine archaeological research in 2014 conducted by Ministry of Marine Affairs using underwater archaeological approaches to find out the shipwreck's condition and site significance. Collecting hydro-oceanographic data (, currents, waves), sedimentation, water quality, supporting ecosystem data and bathymetry analysis have also been carried out in this study in order to determine the site's physical environmental conditions and to identify the factors of vulnerability that threaten the site. The results of this study are expected to provide information on site conditions and the types of vulnerabilities which can be used as the basis of the coastal zone management as well as the basis for its sustainable preservation and development efforts. The results of this study can also provide input to the preparation of regional spatial plans, the regional tourism development master plan, and the master plan of development zone of marine and fisheries in Gorontalo.

Keywords: Marine Archaeological Research, Japanese Wreck, Site Preservation, Economic Prosperity, Local Community, Gorontalo.

Introduction In accordance with Law No. 1/2014 on Amendment of Law No. 27/2007 on Management of Coastal Areas and Small Islands which is the concept of Indonesian marine affairs sustainable development, in accordance with the Ministerial Decree of Marine Affairs and Fisheries No. 17/2008 on Conservation Areas in Coastal Areas and Small Islands which mandates the need for identification of potential and vulnerabilities related to sustainability and resource management in coastal and small islands as well as the optimization of resource utilization that can support national marine conservation program of Ministry of Marine Affairs and Fisheries, and noticed the Law No. 11/2010 on The Protection of Cultural Heritage, and by taking into account the priorities and direction of marine affairs development in Indonesia, hence the Research Institute for Coastal Resources and Vulnerability, Ministry of Marine Affairs and Fisheries sees the need to carry out research on valuable historical-archaeological sites of sunken ship in Gorontalo Province which can be designated as a Maritime Conservation Area and marine tourism destinations, along with analysis of potential vulnerabilities to the changes of the surrounding physical environment and the threat of human disturbance.

Gorontalo, one of the youngest province in Indonesia with nicknamed "The Hidden Paradise", has a real marine and coastal resources that potential to be developed. Besides rice, coconut, and corn cultivation, Gorontalo is also exporting tuna and cultivating seaweed. However, another potential which has not been utilized optimally is the richness and the beauty of Gorontalo's underwater world. Despite located along the Equator and called as "Paradise on the Equator", Gorontalo is the real center for marine biodiversity with many different species of endemic marine life. At this time Gorontalo's local governments started developing a number of point locations in coastal and small island for beaches, diving and marine tourism such as Olele rural tourism village, Traffic Jam Diving Spot, and Bitila Island. Meanwhile, not far from the city center, there is a point location of Japanese ship sinking during World War II, which, according to Fadel Muhammad, the previous Minister o Marine Affairs and Fisheries, if well developed in the future this shipwreck site can be a world-class dive spots (Allen, 2006).

This Japanese shipwreck site has not been investigated yet. The absence of research and identification of potential vulnerabilities and the lack of awareness of the central and local governments as well as general public in protecting and managing this shipwreck site needs serious attention so that it can be protected presently and later can be utilized as a potential underwater tourist destination that is useful for society. Therefore, our research started this year is perceived quite important and urgent. The results of this study will be expected to provide information regarding the shipwreck site significance and other coastal resources surrounding the site that can be used as the basis of the zoning arrangement of the coastal region, the basis for ongoing preservation efforts and the scientific basis for future development as an eminent underwater cultural heritage sites and excellent tourist destination in Gorontalo. Identification of resources and its vulnerabilities related to coastal resources sustainability and the optimization efforts of resources utilization are expected to support the national marine conservation programs and programs of local governments on the development of potential marine tourism of the region, as well as to support the management of Tomini Bay region which is the follow up of the signing Memorandum of Understanding on May 13, 2009 between the Governor of Gorontalo with the Minister of Marine Affairs and Fisheries in the framework of joint management of coastal resources of Tomini Bay. This study will also be one of the efforts to support the government's program through science- based recommendations (scientific support) that is given to local governments and other stakeholders in Gorontalo who will be the manager of this shipwreck site and the parties that directly interact with the the region.

Japanese shipwreck is now becoming known dive sites and has attracted a number of people to dive at that location. However, the protection and management has not been unnoticed by the central and local governments and only dive tourism operators who have taken advantage of the shipwreck site. The big interest of dive tourism operators shows that the Japanese shipwreck can be considered to have a huge potential to serve as the next shipwreck dives spot for tourist in Gorontalo. This site can be developed into such USAT Liberty Wreck at , , SS Yongala in 's Great Barrier or USS Arizona in Pearl Harbor USA. Indonesian Marine Board (2012) explained that the economic policy direction of marine tourism sector should be encouraged to be developed to improve the tourist development of the archipelago which is capable to keep the integrity of the national culture. In addition, the preservation of shipwreck sites and the development of marine tourism should be able to provide employment opportunities for local communities and must be managed sustainably (http://www.dekin.kkp.go.id/index.php).

Research Location The study conducted on Japanese shipwreck which is administratively located in Leato Village, Kota Selatan District, The city of Gorontalo, Gorontalo Province. Its position lies in Tomini Bay at Gorontalo Waters. Japanese shipwreck location is not too far from the beach which is 50 - 70 m, so as to reach the location of this wreck, the divers could walk and simply to do beach entry for descending. The nearest river to the shipwreck site location is Bone River which is in distance 2 km. The size of underwater research area is about 100 x 50 m.

Fig 1. Japanese Shipwreck Site Location

Scope and Methodology This multidisciplinary research was done in order to obtain data and a complete profile of shipwreck site and its environment for the development of science related to underwater cultural heritage, marine ecosystems, and also to document the existing shipwreck site before it ruined and lost due to natural processes and human activities. Experts involved on this research consists of a wide range of expertise and disciplines, namely maritime archeologist, physical oceanographers, marine geologists, marine and fisheries experts, coastal resource management specialists, GIS specialists, marine tourism specialist, geodetic experts, specialists, marine ecosystems experts, and underwater photographer. While the equipment used in this research, are: 1 camera Canon EOS 5D Mark III and underwater housing Nauticam Canon NA-5DMK lll, 1 camera Olympus SP560UZ with Ikelite underwater housing, 3 cameras and housing Canon G12, Singlebeam Echosounder, Fishfinder, 8 sediment traps, Multiparameter Instrument TOA-DKK, Water Quality Checker, Master Valeport, GPS, Compass, bottle sample, Nansen Bottle, roll metre 100 m, and diving gear.

The research activities include literature study and secondary data collection in the form of: archived data of shipwreck and maritime culture remains in the local area, the local historical data, meteorological and climatology data, regional biophysical data including biodiversity and ecosystems, socio-economic and cultural aspect of local communities, central government and/or local government policy; oceanographic data, water quality data, geographic data region, as well as the basic maps such as thematic maps and bathymetry maps and the Spatial Plan of Gorontalo province; pre-survey (May); coordination with the relevant agencies; consultation with expert from university and underwater construction experts; and field survey (June and September). Field survey activities include diving on shipwreck site to take complete documentation with photos and video; installation and removal of 8 sediment trap at shipwreck site and at the mouth of the river; bathymetry/underwater topography survey (500 x 500 m) in the vicinity of the wreck site; hydro-oceanographic measurements (waves/currents, weather, tidal); water sampling at the surface and at depths (10, 20, 30, and 40 m depth); measurement of seawater quality in-situ at 14 stations consisting of physical parameters (, salinity, pH), chemical parameters (nitrates, nitrites, ammonia, biochemical demand (BOD), total dissolved oxygent (DO), and others, the quality of water (brightness); observation of ecosystems and coastal profiles, observation of the coral reefs and marine life conditions, observation the position of river and the discharge water river to examine sedimentation; interviews with the local residents and agencies about the historical background of the site; data processing and analysis of bathymetry, data analysis and modeling of hydrodynamics (waves, currents, and tides), analysis of the rate of sedimentation, water quality analysis, GIS analysis, sketching shipwreck, and making photogrammetry and videogrametry of Japanese shipwreck site.

Besides conducting survey, in the field the team has also conducted focus group discussion was attended by 22 agencies and relevant stakeholders in Gorontalo Province. The team also gave a public lecture at University of Gorontalo to disseminate research activities and to publish the preliminary research results as well as to raise awareness and concern of the community, local government, students and also young people about the importance of research, protection and management of historic shipwreck and other marine and coastal resources in their area.

History of Shipwreck The sunken ship in Leato Beach likely is a Japanese cargo ship which sunk during World War II when the Japanese invaded Indonesian territory in between 1942 - 1945. The ship suspected to be sail from Gorontalo port, but on her way she was on fire so that the ship moved back to the port again. In this incident, there were no casualties because the ship did not sink immediately after burned, she was stranded on the Leato beach for about a month until then she drowned. Mr. Gani Paja (80 years old) who was born in 1930 in Leato Village, is the only alive witness who knows and sees the ship himself shortly before she sank. At that time, he was still sitting in 3rd grade of elementary school (approximately in age of 10 or 11 years) so it can be ascertained that the ship was sunk in the Japanese colonial era. He stated that the crew of the ship amounted to 6 people, the ship sailed from Gorontalo Port and would come out of the Tomini Bay. On her way was about to exit the harbor, there is a fire on the ship, so the ship turned the direction towards the mainland. He also stated that the ship damaged by bombing and then drowned.

Ms. Pino Karim (63 years old) said that the ship named "Kaisumaru" was carrying copra, wood, and rattan from the region outside the city of Gorontalo, and then got burned on the beach Leato. Other information states that in Gorontalo area there are many gold mines, and today still operates and is managed by the local community. The hill which is located just behind the beach is also a gold mine that has been operated since colonial period. It is also known that nearby the shipwreck site, at the edge of Leato cape, the community believe that there is a warehouse which has function as a gold repository built by the Japanese. The warehouse was found by someone who was once employed as Romusha (forced labour in Japanese occupation era). However, that storage area then became feared due to people who went there never returned. Of those information, some residents believe that the cargo of this Japanese shipwreck is actually gold and not copra or wood. However, the local people also believe that the ship's cargo had been salvaged long ago so at present no longer exist on this shipwreck site. Another resources stated that the ship caught fire because she was attacked by local people under the command of Gorontalo's hero, Nani Wartabone.

Shipwreck Condition Currently, the position of the Japanese shipwreck on the slope seabed is reversed just off the wall in 50 meters of water. The ship material is carbon steel. The structure of the ship which bearing the load is the starboard side. The right part of the ship (portside) is seen to be hanging. There is also a ship part with holes in the portside. This hole was probably because of a bomb or hit the reef. we can see the intact propeller at 26 meters depth with the shape which is still clearly visible. Two-thirds of the hull leans on a rocky outcrop, falling at a 14- degree angle, until the hull buckles horizontally with the stern resting on the seabed. The wreck is almost level, tilting only slightly seaward. The bottom of the stern hull is heavily sprinkled with whips that look purple gorgonian. About midway of a large fragment in the ship's portside provides access at 44 meters. The bow is almost completely exposed with two decks clearly evident. This bow lies at a depth of 47-51 meters above sea level. The fragments of ship's masts and anchors can be found at a depth of 15 meters.

The length of ship is about 50 meters. The length of ship started from the tip of the broken bow to stern is 45 m, broken bow falling apart and has a length of about 8 m, width of the central part of ship is 10-12 m, width of the rear (stern) is 8 m (sideboard to sideboard), the height of the middle draft is 8 m. Overall integrity of the ship is approximately 60 %, while the part that broke out is around 30 %. Because the position of the ship was tilted upside down, then there is a part of the ship which is totally embedded into the seabed about 30 %, partially broken, and 20 % collapsed to the ocean floor. Compartments or passanger deck is collapsed onto the ground. The long and oblique cargo crane is still clearly visible, located near the bow. The parts of the ship which still visible among them are: the complete blade propeller, complete sharp propeller, bottom flat toward the center of the stern is still complete and can still be recognized. Bilge keel is only at left side half but the right side is still ¼ recognizable, no rudder found, broken bow is still recognizable, but has been separated. The engine room is still there and can be said to be still intact, located at the bottom of the propeller at a depth of about 43 m. Regarding the marine life group level, 30 % of the ship was overgrown with corals, 10 % hard coral and 20 % soft coral.

Fig 2. Shipwreck Condition

Fig. 3. Shipwreck Condition

Fig. 4. Plan Section of Japanese Shipwreck

Sea Environment Conditions Average depth at shipwreck site location is 25 m and maximum depth is 51 m. Average horizontal visibility is 15 - 20 m, average vertical visibiility is 15 m. Minimum water temperature is 24° C and maximum water temperature is 30° C. Bottom contour is drop off and slope meanwhile the bottom composition are silt, , and rock. Diving in this area is seasonal, it is quite challenging during May to October because the wind which blows from the South establishes high waves, but in November to April the sea tends to relax and very pleasant. For water quality, which consists of six parameters temperature, salinity, , DO, pH, and conductivity were measured directly with the using mulitparameter. The results showed that in general, Gorontalo waters have excellent water quality. Seabed forms is slope with angle of seabed is 20⁰. The maximum current at shipwreck site is 0.5 knot and the height of wave is 0.5 m at survey time.

1. Conditions Tomini Bay waters, particularly Gorontalo waters are very rich in biodiversity. This, can be seen from the number of diving spots in the city of Gorontalo. However, the oceanographic characteristics in this area has not been widely studied. Related to the research activities conducted by Research Institute for Coastal Resources and Vulnerability on the potential vulnerability of the shipwreck sites in Gorontalo Province, the oceanographic studies are absolutely necessary to provide the data to support the research on the existence sites.

Located in the Northeast of Tomini Bay, the underwater biodiversity of Gorontalo waters are very rich and well-known. Nutrient-rich waters of Gorontalo are related to the water circulations (currents) in Tomini Bay which are influenced by the surrounding oceans such as the Moluccas Sea and Celebes Sea. Investigations on the characteristics of oceanography (i.e. tides and currents) in the area were carried out by the measurement of tides and numerical simulation of hydrodynamics using MIKE21 from DHI. Tides of Gorontalo waters were measured started from 7 May 2014 until 17 June 2014 (~40 days) using an automatic tide gauge “Tide Master” from Valeport. The device was deployed in the Ferry Harbour of Gorontalo (00 29,813 N dan 123 04,283 E) and measured automatically the tides every 15 minutes (Fig. 5).

0.8

98.6%98.6% represented akurasi 0.6

0.4

0.2

0 Elevation (m) -0.2

-0.4 data prediction

-0.6 04/05 09/05 14/05 19/05 24/05 29/05 03/06 08/06 13/06 18/06 Days in May/June 2014

Fig. 5. Data and Prediction of Tides in Gorontalo Waters

Table 1. Tidal Constituent of Gorontalo Waters

Tidal constituents Frequency (cph) Amplitude (m) Phase (deg) Q1 0.0372185 0.0258 245.94 O1 0.0387307 0.1125 255.27 NO1 0.0402686 0.0131 225.54 K1 0.0417807 0.1969 250.77 J1 0.0432929 0.0101 293.89 N2 0.0789992 0.0272 74.33 M2 0.0805114 0.2316 112.57 L2 0.0820236 0.0130 124.25 S2 0.0833333 0.1473 171.07 MK3 0.1222921 0.0127 330.59 M4 0.1610228 0.0126 335.47 MS4 0.1638447 0.0102 17.19

The collected tidal data was analysed using “Least-squared method” of T-Tide (Pawlowicz et al., 2002) to derive the tidal constituents and to determine other characteristics of the tides in the region. The tide in Gorontalo waters is Mixed Predominantly Semi Diurnal or it has 2 times high and low tides in one day with different magnitudes. The dominant tidal constituents are shown in Table 1. Constituents of O1, K1, M2 and S2 are the main tidal constituents representing more than 80% of measured tidal signals. Based on the derived constituents, tidal prediction of the region can be done as shown in Fig. 5. The represented tidal prediction covers 96.6% of the measured data.

The data from the measurement of tide was used for the validation of hydrodynamic simulation of Gorontalo waters using Mike21 from DHI. The simulation was conducted for 40 days or similar to the duration and the time of tide measurements. The tides for boundary conditions of the model were taken from NAO.99b tidal prediction system (Matsutomo et al., 2000). The model domains were divided into two regions. The larger region includes the entire Tomini bay where the smaller region covers only the Gorontalo waters (Fig. 6). The bathymetry data of Tomini Bay (large region) was taken from GEBCO gridded bathymetry data (www.gebco.net) while the bathymetry in smaller area (Gorontalo waters) was from direct field measurements in 2014.

Fig. 6. The Bathymetry of Hydrodynamic Simulation Covering Tomini Bay and Gorontalo Waters

Fig. 7 shows the simulation of current in Gorontalo waters without wind. Around the shipwreck location, nearshore currents are stronger than offshore current due to the fact that the bathymetry in the area has a steep slope (Fig. 8) and the geometry of the coastline causing steeper elevation gradient in the area. Stronger currents circulations around the shipwreck may have provided better nutrient exchange in the area where materials (nutrients) from the river mouth in the North-east are transported to the South-east (towards shipwreck location) and back. The maximum current speed simulated in the model is 0.74 m/s. Strong currents in the area may threaten the existence of the shipwreck to slide down into deeper waters since it is located at a very steep slope as shown in Fig. 8. In general, the bathymetry measurement result shows a fairly steep bathymetry conditions and only within a distance of less than 500 m from the beach. Even at a distance of about 100 m from the mouth of the river, the ocean depths may reach more than 200 m.

Fig.7. Simulation of Currents in Gorontalo Waters during Spring Tides

Fig. 8. 3D Bathymetric Conditions at Japanese Shipwreck Site

2. Seawater Quality Seawater quality measurements carried out at 14 stations point as shown in Fig. 9 Measurement of the quality of seawater at a certain depth Gorontalo waters performed 2 times, using measuring instruments and TOA Multiparameter Quality Checker. Seawater quality data of Gorontalo Waters obtained by direct measurement (in-situ) and measurements of seawater from taken seawater samples. In-situ measurements madewithin the surface, whereas the seawater sampling done on into 10 - 40 m. From Table 2, it appears that a significant difference only visible at the point of measurement at station 4 (4-1 and 4-2). This clearly shows how high the effect of the influx of fresh water to the sea from the river. The temperature at the surface is apparently a few degrees cooler. Turbidity is much higher than other points while salinity and conductivity are much lower. Nevertheless, the general condition of seawater in Gorontalo categorized good when referring to the Seawater Quality Standards for Marine Tourism and for Marine Life according to the Decree of the Minister of Environment No. 51/2004. These results also show that the existence of Bone River and its material has not significantly give negative impact on the seawater condition where the shipwreck is located. However, the current modeling of the water circulation in this area needs to be carried out especially in two different seasons to describe the actual conditions at a particular time span.

Fig. 9. The Measurement Stations of Seawater Quality Sampling at Surface and a Certain Depth surrounding the Shipwreck Site

Table 2. Seawater Quality at Surface

Physical Parameter of Sea Chemical Parameter of Sea Water Water Station Dissolved Turbidity Conductivi Temperature (°C) pH Salinity (‰) Oxygent ᵟt (NTU) ty (mS/cm) (mg/L)

St 1 29.9 6.6 8.16 29.5 4.63 4.98 20.2 St 2 29.9 4.88 8.19 32.9 3.19 4.81 20.1 St 3 29.8 1.1 8.17 31 4.6 5.24 19.1 St 4-1 27.6 10 8 15 1.02 5.24 1.27 St 4-2 26.4 12.1 7.92 14.6 0.29 5.32 0 St 5 29.2 3.6 8.12 25.2 3.89 5.03 15.2 St 6 29.6 3.9 8.17 28.5 4.34 5.29 16.3 St 7 29.5 2.8 8.18 32.4 4.82 5.18 19.7 St 8 29.7 0.9 8.19 33.8 5.02 5.33 20.9 St 9 29.5 0 8.18 33.3 4.95 5.97 20.6 St 10 29.2 0.2 8.18 30.6 4.61 5.28 18.7 St 11 29.2 1.1 8.16 28.7 4.23 5.2 17 St 12 29.4 0.2 8.16 29.9 4.46 5.14 17.6 St 13 28.9 2.9 8.18 28.5 4.35 5.16 13.7 St 14 30.3 19.6 8.18 32.1 4.59 5.43 19.6 Sea Water 6.5-8.5 Quality Natural Natural (changes may Standards for (changes may occur 5 NTU (changes may occur < 5% - > 5 mg/l - occur Marine 2°C) seasonal average salinity) < 0.2 unit pH) Tourism Natural Natural (changes may occur < Sea Water (changes may occur 7-8.5 5% seasonal average Quality 2°C) (changes may < 5 NTU salinity) - > 5 mg/l - Standards for Coral, Seagrass: 28- occur Coral, Seagrass: 33- Marine Life 30°C < 0.2 unit pH) 34‰ Mangrove: 28-32°C Mangrove: up to 34‰

Table 3. Water Quality at the Depth

Physical Parameter of Sea Chemical Parameter of Sea Water Water Station Temperature Turbidity Conductivity Dissolved pH Salinity (‰) ᵟt (°C) (NTU) (mS/cm) Oxygent (mg/L)

st 1-0 m - 4.4 8.14 32.2 4.87 5.5 20.8

st 1-10 m - 0 8.13 29.6 4.51 5.49 18.6 st 1-20 m - 0 8.14 31 4.69 5.82 19.7 st 1-30 m - 0 8.14 32.7 4.94 5.59 21 st 1-40 m - 0 8.04 32.7 4.94 5.33 21.2 St 2-0 m - 3.7 8.13 32.5 4.92 5.49 20.9 St 2-10 m - 0 8.15 32.6 4.95 5.53 21.3 St 3-10 m - 2.7 8.18 32.4 4.9 5.47 20.9 St 4-10m - 3.4 8.18 32.6 4.93 5.48 21.1 St 5-10 m - 3.8 8.19 32.9 4.97 5.51 21.3 St 6-10 m - 0 8.2 33 4.99 5.56 21.5 St 7-10 m - 1.9 8.18 32.2 4.9 5.53 20.9 St 8-10 m - 0 8.21 32.8 4.95 5.47 21.2 St 9-10 m - 1.5 8.2 31.8 4.85 5.61 20.8 St 10-10 m - 0 8.2 32.6 4.96 5.6 21.5 St 11-10 m - 1.2 8.19 32.5 4.94 5.43 21.3 St 12-10m - 0.9 8.19 32.6 4.95 5.62 21.3 St 13-10 m - 2.6 8.25 32.4 4.91 5.47 21.1 St 14-10 m - 2.4 8.19 32.4 4.92 5.55 21.2 Sea Water Natural Quality 6.5-8.5 (changes may occur Standards for - 5 NTU (changes may occur - > 5 mg/l - < 5% seasonal average Marine < 0.2 unit pH) salinity) Tourism Natural (changes may occur Sea Water 7-8.5 < 5% seasonal Quality < 5 - (changes may occur average salinity) - > 5 mg/l - Standards for NTU < 0.2 unit pH) Coral, Seagrass: 33- Marine Life 34‰ Mangrove: up to 34‰

Fig. 10. Graphic of Seawater Quality at Surface

Fig. 11. Graphic of Seawater Quality at the Depths

3. Sedimentation Characteristics, Climatology, Physiography and Geology Regional

Rainfall in this region were approximately 11 mm to 266 mm per year. In general, the air temperature in Gorontalo average at 32⁰ Celsius during the day, while at night 23⁰ Celsius. Air humidity is relatively high with average around 79.9%. Geographically, the city of Gorontalo is located between 000 28 '17 "- 000 35' 56" North Latitude (NL) and the 1220 59 '44 "- 1230 05' 59" East Longitude (EL). In physiographic point of view, Gorontalo can be devided into four major Physiographic zones, namely Zone-Boliohuto Telongkabila Northern Mountains, Interior Plateau Zone Paguyaman-Limboto, Southern Mountains Zone Bone- Tilamuta-Modello, and Coastal Plain Zone Pohuwato (B.Brahmantyo, 2010).

The sediment transport that effect the Gorontalo Waters was influenced by processes in the Interior Plains Paguyaman-Limboto. This plateau is a hollow structure that is thought to be controlled by normal faulting. In Plain Paguyaman to Limboto Lake, according to the Tilamuta Geological Map Sheet (Bachri, et al., 1993), at Kala Pleistocene, once a vast lake. In fact, before the Plio-Pleistocenen periods, the hills around Lake Limboto is a shallow sea with coral reefs, such as the Marine Park Tourism Olele which formed at 2 million years ago. In Physiographic, it can be said that the general morphology of Gorontalo is a rugged mountainous area, except in the Alluvial Plain of Interior and Coastal Plain. The boundaries of mountains stretching to the beach. Beaches on both in the north to the Celebes Sea, and in the south to the Tomini Bay, only narrow beaches or rocky. Steep relief is very prone to landslides or rock falls. Erosion will be very sensitive if change occurs on the forest area with steep slopes. Sedimentation in a coastal environment occurs because there is a high supply of sediment from the coastal environment. A very high sediment load supply that causes sedimentation comes from land that was carried out to sea through rivers flow.

Bone River near the shipwreck site is one of the major rivers in Gorontalo Province and also flows past the city of Gorontalo, this river is the largest means of sediment transport to the Gorontalo Waters, except for the sediment movement that controlled by the hydrodynamics of the sea. Upstream areas located in District Pinogu, Bone Bolango Regency, which is still an area of Nani Wartabone Forest Protected Areas and downstream areas is located in Talumolo Village Gorontalo. Based on the river flow, flow velocity and width of streams, Bone River is included in the classification of a large river. Bone River has river runoff discharge ranged from 40.28 m3 / s to 143.90 m 3/s (Pantolay A. et al., 2013).

To determine the value of the rate of sedimentation around the mouth of the Bone River and sedimentation characteristics around the shipwreck site, 5 sediment traps has been installed around the mouth of Bone River downstream and 3 sediment traps has been installed around the shipwreck. From a total of 8 sediment traps, only 4 sediment traps is successfully lifted; 2 from the river and the others from shipwreck site, while the rest have been lost, probably swept away by the river flow and the disruption of the surrounding population. The result of literature study shows that Leato Waters do not have sedimentation problems that could threaten the waters and its coastal ecosystems. Sediment from the river have moderate to fine grain size with gray to black color while from the sea around the site has a very fine grain size, and colored dark gray to light and the sediment trap also managed traped some living organism on the bottom of the sea. Based on lab analysis, the sediment type in shipwreck site is silt, meanwhile the sediment transport from the river is huge and the sediment transport around the shipwreck is small. It could be interpreted that the river sediments does not have a direct affect to the shipwreck locations which could disturb the sites. Preliminary results will be followed by calculating the rate of sedimentation and the effect on the current conditions of the sedimentation rate.

Fig. 12. Sediment Sampling Location at Shipwreck Site

4. Marine Life and Coral Reef Condition Marine life around the Japanese shipwreck are varied and some of which are unique. Various types of fish and other marine life that may found easily surrounding the shipwreck are Cattle fish, Trevallies, Snapper, Fussilier, Sweetlips, Butterfly, Cardinal, Angelfish, Grouper, Damselfish, Anthias, Batfish, Wrasse, Parrot, Surgeon, Trigger, Box, Puffer, Gobies, Moray eels, Eels, Scorpion, Blennies, Yellow-mask angelfish (Pomacanthus xanthometopon), Hawksbill turtle (Eretmochelys imbricata), Goatfish, Coleman’s coral shrimp (Vir colemani), Humphead parrotfish (Bolbometopon muricatum,) cat fish, abalone, and so on. Meanwhile, coral reef e.g patchy and submerge coral reef condition found at this location could be said to be excellent such as Salvador Dali sponges (Petrosia lignosa), Purple gorgonians and bubble coral. Sponges dominate Gorontalo’s underwater sphere, thus divers start calling Gorontalo as the sponge capital of the world. Gorontalo is the only area in Indonesia where the bizarre pattern sponge (Petrosia lignosa), later be well-known as Salvador Dali sponge, is exist.

Fig. 13. Marine Life Around Shipwreck

Site Preservation

For the interest of Japanese shipwreck site protection and preservation in Gorontalo, the local government may immediately assign the site as an underwater cultural heritage site under the protection of Gorontalo provincial regulations, Cultural Heritage Protection Law, and the Law on Coastal and Small islands Management, hence its sustainability may be ascertained. Although the shipwreck site must be researched, protected and preserved, archaeologists and the government are obliged to deliver and present the existence of of this shipwreck site before the general public.

In addition to widely publicize to the public, in the framework to improve the welfare of local communities, the government can also utilize and develop this underwater site for enjoyment or recreation as a marine tourism destination. The type of tourist dives that can be performed at this location are and shipwreck diving. However, to note that this site is recommended only for experienced divers due to the depth of site location. Thus, this shipwreck which located at a depth of 25 - 51 m naturally could limit the number of divers because only experienced divers can access this shipwreck site. It is also beneficial for the preservation of the shipwreck as the inexperienced beginners divers who usually tend to be less cautious and may cause a variety of damage, both the ecosystem and shipwreck damage, may prohibited for diving in this location. Therefore the rulemaking of diving activities and limiting the number of divers is definitely necessary. With the ban for beginners to dive at this location, it may reduce the damage and preserve the shipwreck site little longer.

Monitoring and surveillance of the site condition and its surrounding ecosystem should be done periodically by the local government so that if there is a destruction or conditions that endanger the site preservation as well as the safety of the tourists may soon be known. In carrying out the monitoring, the local government may request the assistance of local divers or the dive guide of diving centers in Gorontalo. Thereby in the implementation of its preservation, the local communities are taken into account so it is expected that it can increase their sense of belonging and their willing to keep protecting and preserving the existence of this Japanese shipwreck site.

The research result on site condition, site significance, and environment condition is expected to be used as the basis of the coastal zone management as well as the basis for shipwreck site's sustainable preservation and development efforts. Based on our recommendation, the local government could prepare the regional spatial plan and enact the regional marine tourism development master plan and the master plan of development zone of marine and fisheries in Gorontalo.

Conclusion and Recommendation Tidal in Gorontalo waters tend to be a predominantly mixed diurnal with 1.3 m pairs. The condition of seawaters in the city of Gorontalo is in good condition and to meet the seawater quality standards that exist set by Indonesian Ministry of Environment. The bathymetry condition in which the shipwreck located revealed a high vulnerability to gravity that may cause the shipwreck will be slipping into the deeper waters. Hydrodynamics modeling is needed to see the effect of circulating currents and waves in the waters around the wreck. Legal safeguards should be done immediately, while the central and local governments should start to prepare the site preservation efforts to maintain its sustainability. Local communities and the general public can be engaged to participate in preserving and monitoring the shipwreck site to protect it from damage both by human and natural factors. DEiving and marine tourism regulation in this location should be prepared as soon as possible by the local government.

Acknowledgment We would like to thank to Mr. Abilawa Setyadi (marine specialist from Yalagada Surya, Co), Mr. Oki Refianto (underwater photographer), Kusbian Indradi & Muhidin (Gorontalo Office of Marine Affairs and Fisheries), Albertinus Kaligis (Gorontalo Office for Cultural Heritage Preservation), Noldi & Yunan (Aqua Diving Center), Syahar & Supriyadi (Directorate of Monitoring and Surveilance of Marine and Fisheries Resources), Tika Nurhasanah (Bandung Institute of Technology), Agency of Sea Transportation Gorontalo, and thanks to another local government of Gorontalo and related institutions.

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