Stimulating investment in pearl farming in ... - World Fish Center

Suitability of Habitats for Growth of Black-Lip and Silver-Lip Pearl Oysters Final, June 2008location of corals reefs in PNG is limited (Huber 1994). Over one half of the coastline andsurrounding islands appear to be fronted by coral reefs (Quinn and Kojis 2000). All reeftypes are represented, but fringing and barrier reefs are the most common. The followingdescription of reef and lagoon habitats is based on the information presented in Wells andJenkins (1988).The Western Province of the mainland is characterised by numerous patch reefs withextensive seagrass beds. There are two major embayments, Port Moresby Harbour andBootless Inlet. The headlands between these bays are bordered by narrow (less than 100 mwide) fringing reefs. There are also large barrier reefs in the Port Moresby area. The coralassemblages on the steep leeward back-slopes of the barrier reefs and on the near verticalflanks of island fringing reefs facing deep channels and passes with strong currents arediverse and profuse. Bootless Bay has a diverse range of habitats including mainland andisland fringing reefs, mangroves, seagrass beds, soft bottom assemblages, patch reefs and awell developed barrier reef (Maniwavie 2000). The Papuan Barrier Reef is situated about 5km off the south coast and stretches for 563 km from just west of Port Moresby to theLouisiade Barrier at about 151° E. This reef has four major and numerous small channels.Near Port Moresby, it encloses a lagoon which has an opening in the north-west and thereare fringing reefs and barrier reefs in the south-east, where the lagoon narrows.On the northern side of the mainland, fringing reefs with large coral cover and speciesdiversity occur between Condor Point in Madang Province and East Cape. There is also afairly continuous fringing and barrier reef between Condor Point and Cape Ward Hunt insouthern Morobe. The reef crest is this area lacks rubble and large boulders. Thedevelopment of offshore shoal reefs is limited by the steeply-shelving seabed. The easterncoast south of Lae is fringed by reefs and there are numerous offshore islands within 50 kmof the coast that have reefs. The islands in the Fly and Longuerue Groups are surroundedby fringing reefs which have a similar structure to those on the mainland. The growth ofreefs within Huon Gulf is limited by sediment inputs from the Markham River. The coastbetween Cape Arkona and Finschhafen is lined by fringing reefs, except around rivermouths. There is a small atoll, Tami, with three elevated limestone islets situated in theocean approximately 10 km off Finschhafen. The lagoon is about 18 m deep, has a sandybottom, but there is little coral growth below a depth of 10 m. The fringing reefs betweenFinschhafen and Madang are generally less than 100 m wide and lack a well-defined lagoon,except at some sites. There is a double barrier reef around and 10 km to the north ofMadang inside which there are hundreds of small reef islands and depths down to 50 m.Hansa Bay, to the north of Madang, the site of the last major reefs south of the two largestrivers in PNG (Ramu and Sepik), has a discontinuous fringing reef. During the rainy season,the water within Hansa Bay is often reduced in salinity, muddy and rich in organic materialdischarged from the Ramu and Sepik rivers. In the dry season, the current comes from thesouth-east and brings clear water, short swell and strong waves to the reef. Laing Island,the only emergent portion of the north-south aligned reef within the bay, has a small (400 x200 m) lagoon along its western shore and is surrounded by a well-developed fringing reef.Milne Bay Province covers an area of approximately 265,000 km 2 and encompasses theextreme southeastern tip of mainland Papua New Guinea and the extensive offshore areaimmediately to the east. The province includes three major mainland districts: the 130-kmlong stretch of the south coast between Samarai and Orangerie Bay, Milne Bay proper, andGoodenough Bay, lying immediately northward, and the adjacent southeastern part ofCollingwood Bay. The province also encompasses the Papuan Island Group to the eastwhich comprises the Trobriand Islands and associated Lusancay Reefs, d’EntrecasteauxIslands, Muyua and the reefs and islands in the Louisiade Archipelago (Wells and JenkinsThe Ecology Lab Pty Ltd – Marine and Freshwater Studies Page 16