Predators and methods of control in molluscan shelfish cultivation in North European waters
Spencer, B.E. (1992). Predators and methods of control in molluscan shelfish cultivation in North European waters, in: De Pauw, N. et al. Aquaculture and the Environment: reviews of the International Conference Aquaculture Europe '91, Dublin, Ireland, June 10-12, 1991. EAS Special Publication, 16: pp. 309-337 In: De Pauw, N.; Joyce, J. (Ed.) (1992). Aquaculture and the Environment: Reviews of the International Conference Aquaculture Europe '91, Dublin, Ireland, June 10-12, 1991. Special Publication European Aquaculture Society, 16. European Aquaculture Society: Gent. ISBN 90-71625-10-9. 536 pp., more In: Special Publication European Aquaculture Society. European Aquaculture Society: Bredene. ISSN 0774-0689, more |
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| Abstract | Most predators of molluscan shellfish in European waters are birds, fish, crustaceans, echinoderms and molluscs. Although the number of predatory species is quite small, the abundance of individuals may often be sufficiently high to cause substantial mortalities to crops at a local or wider level. Past cultivation practices, in an unenlightened era, have sometimes compounded problems with the unintentional introduction from overseas predators along with the intended commercial crop of a"non-native" species. Perhaps the best known example of an unwanted predator is the American whelk ringle (Urosalpinx cinerea) introduced into England along with American oysters (Crassostrea virginica) many years ago. This gastropod became established in some areas of Essex and Kent and caused high mortalities of the juvenile stages of the European flat oyster (Ostrea edulis) in east coast fisheries. Over the past 30 years, the development of commercial hatcheries producing large quantities of juvenile bivalves has required cost-effective methods to ensure the best possible survival of their valuable crops. On-growers of hatchery seed tend to use methods which exclude rather than control predators. Crops are kept in trays or bags, or behind fenced barriers, or beneath plastic netring, usually until they are of a size at which they are relatively safe from predators. Cultivators, however, who utilize natural stocks of molluscs, such as mussels and oysters, transplanted to ground plots, have of necessity to control predators such as crabs, starfish and tingles by trapping or catching them. |
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