It is tempting to avoid the numerous risks inherent in introductions and transfers of living aquatic organisms by prohibition of all further movements of biotic material of this type. This solution is overly simplistic, firstly because further introductions will continue to be needed for sound development and management of inland fisheries and aquaculture and secondly because established commercial practices make such prohibition virtually impossible to enforce. It is important, therefore, for individual countries to adopt regulations and procedures which will minimize the risks arising from introductions. As introductions into one country frequently find their way into the waters of adjacent nations it is also important that the various national legislations be harmonized for any continental area.
At present compilations from Europe and from Latin America show that existing legislation is haphazard and in some cases non existent. There are frequently loopholes which exclude complete categories of organisms such as those imported for food, for scientific purposes or for ornament. Often too regulations governing importation of fish are included in more general provisions for import of all living organisms administered by agencies having scant comprehension of the problems of the aquatic sector.
Several authors have addressed the problem of the types of action needed to rectify this situation both at national and international levels (see for example Kohler and Stanley, 1984; Rybbink, 1987). Such proposals usually include recommendations that detailed studies be carried out on candidate species for introduction, and that once the decision to introduce is taken biotic material for introduction be imported as eggs and that some type of quarantine procedures be adopted for introduced material prior to its release into natural waters. Such codes of practice may also be supported by more detailed protocols which describe the precise steps to be taken for study, quarantine and release of imported material (e.g. Kinkelin et al., 1985). There are those who are of the opinion that it is impossible to be completely certain as to results of any introduction. While this view is in part correct because of the unpredictability of the reactions of living organisms under novel situations, it is hoped that, by application of suitable codes of practice and protocols, the chances of such surprises would be very much reduced.
The major code that is being applied at present is that of the International Council for the Exploration of the Sea (ICES), which has also been adopted in slightly modified form by the FAO European Inland Fisheries Advisory Commission (EIFAC) (Turner, 1987). At the time of writing the same code is being studied for adoption by Regional Bodies in Africa, Asia and Latin America.