Talk:Indonesian fishermen jailed for fishing offences in Australian waters

What is trochus shell? And why would I want two tonnes of it? -Edbrown05 20:36, 7 January 2006 (UTC)

Good point. Trochus shell is used in the manufacture of high quality buttons, beads and trinkets. There is no Wikipedia entry on trochus shell. Here are some llinks in the hope somebody will one day write an entry…

New Research To Help Trochus Stocks – November 2001: [1] Department of Fisheries, Government of Western Australia In 2001, the current global demand for trochus shell is estimated at about 7,000 tonnes annually, worth about A$50 – $60 million. In Australia, trochus is found in Queensland and in Western Australia, (WA).

In WA trochus are found on coral reefs of the Buccaneer and Bonaparte Archipelagos in the Kimberley and offshore at Rowley Shoals, Browse Island, Scott Reef, Seringapatam Reef, Ashmore Reef and Cartier Island.

There is a strong worldwide demand for trochus shell. Most of the shells collected in the Kimberley region are currently sold through Perth at a wholesale price of about $9.50 per kg.

Some of the Aboriginal groups are value-adding this product by polishing trochus shells for ornaments which sell for $20 to $50 a piece. Recent interest has also been expressed on the processing and export of trochus meat which is known to fetch a high price in Japan…

Farming Trochus “Trochus niloticus (Mollusca: Gastropoda) is commonly known as the topshell or trochus shell and by various names in the countries where it occurs naturally. It is a large, conical-shaped, marine gastropod (snail) of shallow tropical reefs that can attain a size of over 120 mm, measured across the base. The shell of trochus has external mottled red-green and white bands and a thick inner layer of mother-of-pearl (nacre), which makes it valuable for manufacture of jewellery and buttons for highlypriced garments…”

Natural Habitat Adult trochus inhabit intertidal and shallow (less than 5 m depth) areas of tropical coral reefs that receive strong wave or tidal action. In the King Sound Region they are often found on hard reef surfaces dominated by short algae rather than corals or other attached invertebrates. They are also found around the edges of boulders within the intertidal zone, avoiding areas covered with sand or mud (Nash, 1985). Trochus do not usually occur on sandstone reefs if these lack the three-dimensional matrix structure typical of coral reefs.

General Biology Trochus are mainly herbivorous and have separate sexes. However, males and females cannot be distinguished from external shell characteristics, but sex ratios in the wild are close to 1:1. Size at sexual maturity varies with location, being in the range of 50 – 70 mm. This is reached in two to three years and individuals are known to live for up to 12 years, but growth rates also vary with location (Nash, 1993). In WA, adults attain about 100 mm base shell diameter in about five years and their growth rate slows to below one millimetre per month. From – Department of Fisheries, Government of Western Australia: [2]

ABC News: [3] Fisheries WA: [4] Fisheries of Queensland: [5]

Surveys of Trochus, Holothuria, Giant Clams and the Coral Communities at Ashmore Reef, Cartier Reef and Mermaid Reef, Northwestern Australia, 2003 http://www.aims.gov.au/pages/research/marine-surveys/nw-aus-surveys-2003/index.html

Queensland Department of Primary Industries and Fisheries http://www2.dpi.qld.gov.au/fishweb/2564.html

CRC Reef Research Centre: Fisheries of Queensland’s East Coast – Trochus http://www.reef.crc.org.au/research/fishing_fisheries/statusfisheries/harvesttrochus.htm

{{editprotected}} Australia should be wikilinked to Australia. Not sure, but Indonesian should probably be [[Indonesia|Indonesian]]