Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

Abalone stocks exist as a large number of metapopulations or sub-stocks each with peculiar growth and mortality characteristics. Hence different populations respond differently to exploitation through fishing. The sustainability of this fishery is linked to effective management of these meta-populations. For this reason, abalone catch and effort data should be collected on as fine a spatial scale as possible.

South Australia's catch and effort data is collected on the finest spatial scale of any abalone fishery in Australia. However, to date, analysis of the fine scale components of the data has been superficial simply as a result of the lack of tools to rapidly summarize and present data visually. Spatial and temporal analyses of these data will assist in the assessment of how individual sub-stocks have responded to fishing.

Across South Australia there are 35 abalone fishers fishing 7 different Total Allowable Catches (TAC's) on two species across 196 reporting areas. While the complexity of the data has to date precluded comprehensive analysis it also offers the potential for powerful insights into the dynamics of the fishery after more than 10 years of quota management.

In all fisheries, levels of catch and catch rates are two indicators used to attempt to evaluate and assess the response of stocks to exploitation through fishing. Declines in catches or catch rates are often interpreted as indicators of recruitment or growth overfishing and similarly increases in catches and catch rates may be interpreted as providing evidence that stocks are being sustained in the face of fishing or may even be under-exploited. 

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

One of the main objectives of fisheries management is to ensure the sustainability of fished stocks. To reach this objective scientists have to adequately assess the status of fished populations with quantitative models of the fishery systems. Most of these models require estimates of population parameters such as growth rates, mortality rates and catchability (the proportion of the population caught by a single vessel each day). Most of these parameters are unique for each stock; unfortunately they are not easily estimated because marine organisms are inherently difficult to observe and study. Estimation is generally done through statistical analysis of catch data, either from the fishery or from research surveys.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

The Peel-Harvey Estuary in south-western Australia covers an area of ca 136km2. The natural entrance channel at Mandurah is ca 5km long and opens into the north-western corner of the circular Peel Inlet, which occupies an area of ca 75km2. The south-western corner of the Peel Inlet in turn opens into the elongated Harvey Estuary, which has an area of ca 56km2. The Serpentine and Murray rivers discharge into the north-eastern corner of the Peel Inlet, which the Harvey River discharges into the southern end of the Harvey Estuary.

The discharge of nutrients into the Peel-Harvey Estuary from agricultural land and piggeries during the 1970s and 1980s resulted in the development of massive growths of macroalgae in Peel Inlet and prolific seasonal grows of the toxic blue-green algae Nodularia spumigena in the Harvey Estuary. In 1994, an artificial channel was opened between the northern end of the Harvey Estuary and the ocean at Dawesville in order to increase the amount of water exchanged between the estuary and the ocean, and thereby facilitate the flushing of nutrients out to sea, and to raise salinities in the Harvey Estuary to levels that would restrict the germination and growth of the blue-green algae.

The aim of this study on the Peel-Harvey Estuary was to determine the influence of the Dawesville Channel on such features as the migratory patterns, abundances, size compositions and distributions of the blue swimmer crabs and western king prawns, the species composition of the fish fauna, and the abundances, distributions and commercial catch of the main commercially-fished species. Relevant biological data were thus collected for crustaceans and fish in the Peel-Harvey Estuary between March 1995 and July 1998, i.e. post-Dawesville Channel, and compared with data collected for the same sampling sites in periods between July 1979 and April 1988, i.e. pre-Dawesville Channel.

Our results demonstrate that the blue swimmer crab and western king prawn are now present in far greater numbers and for far longer periods in the Harvey Estuary than was the case prior to the construction of the Dawesville Channel.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.

By world standards Australia has not developed a significant marine finfish fanning industry. One of the principal constraints has been the absence of suitable technology for Australian species. This technology is currently being developed in a number of research facilities in temperate regions of Australia.

There are currently several companies intending to farm marine finfish in Western Australia. The species intended for culture (snapper and black bream) have medium level prospects for price and markets. An urgent need exists for the development of technology suitable to culture a high priced market driven species, such as the WA dhufish reported here, to support the endeavours of this fledgling industry.

Information was obtained during the course of this project for WA dhufish for fish capture, growth rates, fish health, egg production and larval requirements.

Keywords: fish culture; aquaculture development; aquaculture techniques; egg production; larval development; Glaucosoma hebraicum; WA dhufish; jewfish.