Marine Resources Assessment for the Marianas Operating ... - SPREP

AUGUST 2005 FINAL REPORT
Dedicated artificial reefs are currently found in two locations of the study area: Agat Bay, Guam and Apra
Harbor, Guam (Figure 2-11). In 1969, 357 tires were tied together and scattered over a 465 m 2 area in
Cocos Lagoon (Eldredge 1979). In the early 1970s, a second reef consisting of 2,500 tires was also
placed in Cocos lagoon (Eldredge 1979). These tire reefs disintegrated and no longer serve as artificial
reefs (Davis personal communication). In 1977, a 16 m barge was modified to enhance fish habitat and
was sunk in 18 m of water in Agat Bay. Fish abundance has increased with time, and herbivorous and
carnivorous communities have thrived (Eldredge 1979). In Apra Harbor, the “American Tanker,” a 90+ mlong
concrete barge, was sunk in 1944 at the entrance of the Apra Harbor to act as a breakwater
(Micronesian Divers Association, Inc. 2005). In 1944, the 76th Naval Construction Battalion (SEABEES)
built the Glass Breakwater which forms the north and northwest sides of Apra Harbor (Thompson 2005).
The enormous seawall is made of 1.5 million m 3 of soil and coral extracted from Cabras Island
(Thompson 2005). The Glass Breakwater is the largest artificial substrate in the Marianas.
To date, no additional artificial reefs have been established in the study area. The passage of tropical
cyclones and typhoons have probably damaged and/or displaced the reefs placed in Cocos Lagoon
(Gutierrez personal communication). The installation of artificial reefs around Guam is currently prohibited
(Gutierrez personal communication).
2.7.8.2 Shipwrecks
Many shipwrecks are found within the study area including grounded vessels and military wreckage
(Figure 2-11). Vessels have probably wrecked upon the shores of the Mariana Islands since Spanish
galleons sailed to these islands during the seventeenth century. There is abundant WWII-era wreckage
(including sunken ships, airplanes, and tanks) along the shores of the Marianas that resulted from the
battles of Guam, Tinian, and Saipan (Commonwealth of the Northern Mariana Islands Coastal Resources
Management 2001). Many of the shipwrecks along the shorelines of the study area have become popular
dive sites (see Section 5.4 for more information on dive site locations). The groundings of ships can also
create numerous hazards for navigation or the environment including the formation of large scars through
seagrass beds or coral reefs, blockage of entry into ports or harbors, and the release of engine oil and
fuel into the surrounding waters (NOAA 2004b).
As of October 2003, Lord et al. (2003) documented 117 abandoned vessels along the coast of Guam.
Most of the vessels (80) were found in water depths greater than 12 m; the other vessels were
abandoned in water depths shallower than 12 m. There are seven general locations where vessels were
documented in shallow water (12 m or less) along the coast of Guam: Piti Channel (two longliners, six
sailing vessels, three landing crafts, one tug, and one barge), Outer Piti Channel (three barges, one
freighter, one landing craft), Outer Apra Harbor (four barges), Inner harbor of Piti Channel (one sailboat),
Sasa Bay (one sailboat), Hagåtña Boat Basin (six sailing vessels), and Cocos Lagoon (1 sailboat) (Lord
et al. 2003). Shipwrecks of interest along Guam include the Cormoran, a German gunboat scuttled in
Apra Harbor during World War I (WWI) to prevent it from falling into enemy hands (Rock 1999; Hanauer
2001). Lying next to the Cormoran in Apra Harbor is the Tokai Maru, a 134 m long Japanese freighter
sunk by a Navy submarine during WWII. Also located in Apra Harbor are a tanker and a “junkyard”
comprised of bulldozers, pieces of the oceanliner Cariba, and other scrap (Rock 1999; Hanauer 2001).
Located off of Cocos Island at the southern tip of Guam is the wreck site of a seventeenth century
Spanish galleon (Hanauer 2001).
A total of 55 abandoned vessels are known along the coasts of Saipan, Rota, and Tinian (Lord et al.
2003). Ten of the vessels are found in water depths greater than 12 m. At Saipan, Lord et al. (2003)
documented nearshore abandoned vessels in the general area off Tanapag (two longliners, 27 barges,
one cabin cruiser, one cargo vessel, one trawler, one freighter). Lord et al. (2003) found four abandoned
vessels in the Tinian Harbor: two freighters, one fishing boat, and one yacht. At Rota Island, there were
five abandoned vessels along the western coast (one fishing vessel, three U.S. military M-boats, and one
tugboat) (Lord et al. 2003). Forty-five percent of the abandoned vessels encountered in shallow water
(less than 12 m water depth) were potential navigation threats (Lord et al. 2003). Fourteen of the
2-44