Book reviews
Artificial Habitats for Marine and Freshwater Fisheries William Seaman, Jun. and Lucian M. Sprague (eds) Academic Press, San Diego, 1991 ISBN 0-12-634345-4, $39.95 US Hard cover, pp. xviii + 285, acid-free paper, 14 tables, 63 figures
The global yield of fisheries is steadily approaching a level regarded as the maximum for conventional species, and warning lights are flashing in the form of collapsed stocks, widespread overfishing, and the need for increased effort in spite of more efficient finding and catching techniques. In these circumstances it is to be expected that new approaches are being sought. The possibilities of non-conventional species, including krill and certain deep-sea fishes, at present under investigation do not seem promising, while the other obvious avenue, aquaculture, although increasingly exploited in recent years, is already demonstrating its own problems, not least in habitat destruction and in marketing. Another approach, which is now beginning to receive more attention and which is the subject of this book, is the creation of artificial habitats for fish.
Although the application of artificial habitats and the techniques employed have greatly expanded in recent years, the concept is not new, and indeed it has been practised for centuries, since the earliest observation that debris in the water tended to attract fish. Freshwater locations, particularly in lakes, are documented, but the major activity is in the sea, and there is great diversity in the placing of structures in the water column or on the bottom, as well as in the range of materials used and the sophistication of deployment. Floating structures, often called fish aggregating devices (FADs), are set at the surface or at various levels below it, and may be constructed of automobile tyres, steel drums, or synthetic mesh, as well as such natural materials as connected cork blocks, long used in the Mediterranean, bundles of branches or brush (acadia) deployed in many parts of West Africa for over a century, and the bamboo rafts with coconut fronds popular in the Far East.
But the use of benthic structures is more widespread, and the maximum development is found in Japan and in the USA. In Japan, there are records from the late 17th Century of fish aggregated by fallen trees and sunken ships, as well as by intentionally placed rocks. Artificial habitat schemes were first incorporated there into fisheries management in the 1930s, became a major national programme in the early 1950s, and by 1970, 3866 concrete-block artificial reefs had been deployed at Japanese coastal locations. The number is much greater today, with the concept of creating entirely new fishing grounds, rather than simply enhancing those already known.
In the United States, development, although significant, has been less rapid, and it is only in recent years that fisheries managers have recognized that artificial reefs offer the serious prospect of enhanced yields. However, in the USA their use has been much more diverse than in Japan, and they are deployed for recreational fishing and sport diving as well as for commercial fishing, and have even been used in such contexts as waste disposal, pollution control and environmental mitigation. Also in the United States, operational petroleum platforms up to 20 miles offshore are highly popular with recreational