This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

This document is the final report of research undertaken in FIRTA project 87/81 and in FIRDTF project 89/60. The results reported in the disease prevention segment (FIRTA 87/81) build upon the experience derived from six years of previous FIRTA supported investigation of pearl oyster mass mortalities. The application of preventative measures recommended by these studies and the resulting reduction in the occurrence of such mortalities has helped enable the pearl culture industry to achieve its current economic status as Australia's most lucrative aquaculture industry (the 1989 production figure is in excess of $80 million), and ranking it third in value of production after the rock lobster and prawn fisheries.

This account also reports the findings from research into methods for the on-growing of hatchery propagated pearl oyster spat. Since pilot scale quantities of spat, to facilitate this segment of the project, were not available until the summer of 1987/88 and pearl oysters take slightly longer than a year to grow to a commercially usable size/ the completion of the on-growing segment (FIRTA 87/81) was funded by a further one year grant (FIRDTF 89/60).

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.

A three year study of the pearl oyster Pinctada maxima in Western Australia was carried out to provide basic biological data and to develop an understanding of the status of the stock. Aspects examined were:

1. The location of stocks within Western Australia, both geographically and by depth.
2. The population characteristics of the stocks, with emphasis on growth rates and fishing mortality rates.
3. The reproductive status, which mcluded an examination of the reproductive cycle over a large part of the range of P. maxima in Western Australia and an assessment of the genetic status of pearl oyster stocks across northern Australia.
4. The measurement of recruitment, using both spat collectors and surveys of the abundance of naturally occuring spat.
5. The further development of the fishery logbook to provide more detailed data on the operations of the fishing fleet and an understanding of fishing fleet behaviour and technology which allow a proper interpretation of catch-effort data.

The study found that the core area of stock location within Western Australia is that currently fished by the pearl oyster fishery. Some stocks of possible commercial significance were located in deeper waters (20+m depth) off the Pilbara coast. However, the stocks located in the waters off the northern Kimberiey coast were very limited and unlikely to be of commercial significance. It is likely that stocks also exist in deep water (35+m), offshore from the core Eighty Mile Beach fishing area, as this depth range was fished in the early history of the fishery. However, stocks at these depth are outside the scope of the modem fishery because of the safety requirements of the industry.