Do Artificial Reefs Work
The desire for fish to be close to a solid object on the seabed has long been recognised by fishers. Fish aggregation devices and artificial reefs as a means of manipulating and exploiting fish stocks have been in use for centuries in various parts of the world.
However, only in recent decades have investigations been mounted to gain a better understanding of how artificial reefs work and what effect they have on fish behaviour.
The majority of recreational fishing activity in South Australia occurs in Gulf St Vincent and Spencer Gulf adjacent to the major population centres.
The seafloors in these regions generally are broad featureless expanses of sand, fringed by seagrass beds. From experience, recreational anglers found that the best fishing and the most desirable fish in gulf waters can usually be found around natural reefs, ledges, shipwrecks or any anomalies on the seabed.
During the early 1970s, it was considered that the placement of artificial reefs adjacent to the metropolitan area and a number of rural communities would improve recreational fishing opportunities and provide economic benefits. The then Department of Fisheries embarked on a program of installing a number of large artificial reefs to achieve this goal.
The reefs were constructed by using tetrahedron shaped tyre modules and redundant government owned barges and dredges which were sunk at various sites in upper Spencer Gulf and adjacent to the Adelaide metropolitan coastline. As a result of this program, South Australia has the largest number of officially endorsed artificial reefs in Australia.
It was hoped that the organised installation of artificial reefs would enhance recreational fishing in two ways. Firstly, they would increase the total habitat available for the production of target species, thereby increasing the total potential catch. Secondly, artificial reefs would provide superior fishing locations by concentrating target species in greater numbers than natural areas.
However, more recent research on the effect of artificial reefs on fish populations brings these motives into question. Whether artificial reefs actually contribute to increasing the population of a particular fish species is arguable. Studies in tropical waters have concluded that increased production, if any, caused by artificial reefs was small when compared with the increased stock availability. In other words, in these situations, the artificial reefs acted primarily as aggregating devices and, therefore, they could potentially have detrimental effects on fish stocks.
Since 1993, PIRSA Fisheries has taken the conservative approach and discouraged the construction of any additional artificial reefs in State waters. There is enough available evidence to suggest that the construction of any new reefs would increase the potential for species such as snapper and King George whiting to be taken without actually enhancing stocks of these species.
The concept for constructing artificial reefs as a means of enhancing recreational fisheries is now considered questionable by fisheries managers if we are to maintain fish stocks at sustainable levels.
Further research is needed into the effects of artificial reefs on the availability of fish and the ecology and productivity of the marine ecosystem in South Australian waters before any future reef building projects should be considered.
However, only in recent decades have investigations been mounted to gain a better understanding of how artificial reefs work and what effect they have on fish behaviour.
The majority of recreational fishing activity in South Australia occurs in Gulf St Vincent and Spencer Gulf adjacent to the major population centres.
The seafloors in these regions generally are broad featureless expanses of sand, fringed by seagrass beds. From experience, recreational anglers found that the best fishing and the most desirable fish in gulf waters can usually be found around natural reefs, ledges, shipwrecks or any anomalies on the seabed.
During the early 1970s, it was considered that the placement of artificial reefs adjacent to the metropolitan area and a number of rural communities would improve recreational fishing opportunities and provide economic benefits. The then Department of Fisheries embarked on a program of installing a number of large artificial reefs to achieve this goal.
The reefs were constructed by using tetrahedron shaped tyre modules and redundant government owned barges and dredges which were sunk at various sites in upper Spencer Gulf and adjacent to the Adelaide metropolitan coastline. As a result of this program, South Australia has the largest number of officially endorsed artificial reefs in Australia.
It was hoped that the organised installation of artificial reefs would enhance recreational fishing in two ways. Firstly, they would increase the total habitat available for the production of target species, thereby increasing the total potential catch. Secondly, artificial reefs would provide superior fishing locations by concentrating target species in greater numbers than natural areas.
However, more recent research on the effect of artificial reefs on fish populations brings these motives into question. Whether artificial reefs actually contribute to increasing the population of a particular fish species is arguable. Studies in tropical waters have concluded that increased production, if any, caused by artificial reefs was small when compared with the increased stock availability. In other words, in these situations, the artificial reefs acted primarily as aggregating devices and, therefore, they could potentially have detrimental effects on fish stocks.
Since 1993, PIRSA Fisheries has taken the conservative approach and discouraged the construction of any additional artificial reefs in State waters. There is enough available evidence to suggest that the construction of any new reefs would increase the potential for species such as snapper and King George whiting to be taken without actually enhancing stocks of these species.
The concept for constructing artificial reefs as a means of enhancing recreational fisheries is now considered questionable by fisheries managers if we are to maintain fish stocks at sustainable levels.
Further research is needed into the effects of artificial reefs on the availability of fish and the ecology and productivity of the marine ecosystem in South Australian waters before any future reef building projects should be considered.
- Page URL: http://www.pir.sa.gov.au/fisheries/recreational_fishing/artificial_reefs/do_artificial_reefs_work
- Page Last Modified: November 8, 2011