Project number:
1995-041
Project Status:
Completed
Budget expenditure:
$143,482.00
Principal Investigator:
Anthony Hart
Organisation:
Department of Primary Industries and Regional Development (DPIRD) WA
Project start/end date:
28 Jun 1995
-
22 Oct 1999
Contact:
FRDC
1. To determine growth rates of pearl oysters in the Lacepede Channel and Exmouth Gulf areas
2. To utilize the existing and new knowledge of time lags between spatfall and recruitment to the fishery and the period of vulnerability to fishing to carry out analyses of possible environmental influences on recruitment
Final report
ISBN:
0-7309-8426-5
Author:
Anthony Hart
Final Report
•
1999-09-20
•
856.74 KB
1995-041-DLD.pdf
The pearling industry is Australia’s most valuable aquaculture industry, generating approximately $187 million in 1997 (source: ABARE 1997). The oysters used to culture pearls are derived almost entirely from wild stock shell, rather than hatchery produced stock as occurs in other major pearling industries. Fisheries WA has been conducting a variety of studies on wild stocks of pearl oysters since 1989 to provide the knowledge-base necessary to evaluate their status and set quotas. Most of these studies have focused on stocks in the 80 Mile Beach and Lacepede Channel areas, which provide about 80% of the annual wild stock quota. Catch rates in these areas have shown a major upswing in recent years, with the 1993 catch rate being 70% higher than the 10 year average (1983-1992). The increases in catch rate are believed to arise primarily from a major increase in recruitment, rather than any increases in diver or vessel efficiency. The recent period over which catch rates have increased corresponds with a prolonged El Nino lasting 4 years. Examination and analysis of environmental and catch data over past years may provide a better understanding of possible environmental influences on pearl oyster recruitment. However, in order to determine the appropriate time lags between environmental effects at the time of recruitment as spat, and recruitment to the fishery, it was necessary to further develop an understanding of growth in other areas of the fishery.
