Status of Introductions of Non-Indigenous marine species to North Atlantic waters, 1981-1991

Recording the flora and fauna of habitats has long been practised. In more recent times much attention has been and is being paid to both the deliberate introduction by man of species exotic to marine areas and to the inadvertent appearance of such alien species by factors involving man and other agents. In the marine environment of the ICES area it is inevitable that almost all observations are confined to coastal zones in the ‘open’ marine habitat of the North Atlantic. For ‘semi-enclosed’ areas such as the Mediterranean, Baltic and North Seas and ‘enclosed’ areas such as the Great Lakes a greater degree of observation over the whole is possible. Part of this recording of new introductions and transfers of exotic species which are part of an established trade are observations of the impact of the exotic either because it is successful in establishing reproducing populations or because of its presence. The First (1980) Status Report on Introductions of Non-Indigenous Marine Species to North Atlantic Waters was prepared by the ICES Working Group on Introductions and Transfers on Marine Organisms (WGITMO) (Anon 1982). This second report, also prepared by WGITMO, covers the decade 1981–1991. It includes summaries of the national reports to the working group from member countries of ICES of introductions and transfers of fish and invertebrates. Because there has been a limited response on plant introductions both in the previous and current decade a comprehensive review of plant introductions with an additional section on the threat from the green algae Caulerpa taxifolia has been included.

In addition to deliberate and inadvertent introductions there is much more awareness of the impact of mans increasing activities in coastal zones and adjacent seas e.g., by chemical pollution, fishing, extraction of sediments and hydrocarbons, mariculture, ballast discharge and land reclamation. These activities lead to change and often degradation of the environment a situation leading to new pressures on existing population structures and providing possible added opportunity for establishment of exotic species which did not exist before. It is therefore increasingly important that recording of the fate of introduced species continues. Part of the duties of the Working Group is to advise and recommend acceptance or otherwise to the Council of ICES on proposals to introduce exotic species formulated in accord with the ICES Code of Practice on Introductions and Transfers (reproduced in this report as Annex 1). This is achieved by use of the scientific literature, the experience of the members of the Working Group, reports of the nature and changes of local environments, and guided by the Code.

In this volume Section 1 on ‘Introductions and Transfers of Plants’ and Section 2 on Status of the Invasion of the Green Alga Caulerpa taxifolia in the Mediterranean Sea and Prospects for the Invasion of Western Europe’ were written by Inger Wallentius.