Toxic algal blooms (harmful algal blooms (HAB))
The potential of ballast water as a vector to introduce phytoplankton species outside their native range was firstly suggested by Ostenfeld (1908) after a phytoplankton bloom of
Odontella sinensis in the North Sea in 1903. More recent concerns arose after increasing
phytoplankton blooms around the world in the 1980s (Smayda 1990, Hallegraeff & Bolch 1992, Rigby et al. 1993). Increasing toxic algal blooms of non-indigenous species in Australian and New Zealandian waters have been associated with ballast water releases. Australian scientists have since intensified their ballast water studies (Hallegraeff & Bolch 1991, 1992, Baldwin 1992).
In 1992 an IOC-FAO Intergovernmental Panel on Harmful Algal Blooms (IPHAB) had its first session focusing meeting on the negative impacts of these blooms on public health and economy. The expansion of these blooms are related (at least at part) to the increasing exploitation of coastal waters (waste disposal, aquaculture, maritime commerce and other anthropogenic influences) as well as to the dispersal and proliferation of such species. It was noted that in order to foster the effective management of, and scientific research on harmful algal blooms to understand their causes, predict their occurrences and mitigate their effects a lack of information exists.
Several international institutions were interested in harmful algal blooms as e.g. UNEP, EEC, ICES and SCOR and formed the IOC-FAO Intergovernmental Panel on Harmful Algal Blooms. The IPHAB organized discussion / expert groups, training programmes on the taxonomy of harmful phytoplankton, design and implementation of monitoring programmes, funding research and forming an information network starting with the first issue of a newsletter Harmful Algal News published in 1992. The panel recognized in its1993 report that the problem of the transport of harmful algal blooms via ballast water was of major concern (IOC-FAO IPHAB 1992, 1993).
Particularly in regard to toxic marine phytoplankton species such as Alexandrium minutum,
Gymnodinium tamarense, G. catenatum and Gyrodinium aureolum which are known to have
occurred in blooms all over the worlds oceans.
Alexandrium species have caused outbreakes of Paralytic Shellfish Poisoning (PSP) in
Norwegian waters and coastal areas of the United Kingdom. A. minutum was observed for the first time at the Swedish west coast (Skagerrak) being abundant during end of June (Lindahl & Edler 1997) it was also present in samples of the North Sea and the Atlantic, the Mediterranean Sea, east coast of the USA, Japan, Australia and New Zealand (ICES 1997).
Gyrodinium aureolum has caused fish kills in the British Channel, western areas of United
Kingdom, Danish, Norwegian and Swedish waters (Swedish Environmental Protection Agency 1997).
In January 1993 the whole New Zealand shellfish industry (export and domestic use) was closed as a result of toxic algal blooms. Knowing that the transport the exotic phytoplankton species in ballast water may result in new phytoplankton blooms after discharge of the ballast water, vessels were requested not to discharge ballast water in any Australian or New Zealandian port or to exchange their ballast water before releasing it in an Australian or New Zealandian port.
Caulerpa taxifolia
The accidental introduction of the alga Caulerpa taxifolia into the Mediterranean Sea and its spread through regional shipping and boating had been subject of research by the European Union. The seaweed Caulerpa taxifolia was probably introduced into the Mediterranean Sea in the mid 1980s: First records were made in the Monaco area (Meinesz & Hesse 1991).
427 ha, in 1993 1,300 ha, in 1994 1,500 ha and in 1996 more than 3,000 ha. Today it covers the surface of thousands of hectares along the coasts of France, additional records were documented from Spain (the Balearean islands (21 ha covered)), Italy and Croatia (Adriatic Sea).
Caulerpa replaces the native seagrasses (e.g. Posidonia oceanica) limiting the habitat for
larval fish and invertebrates. It therefore endangers the continuity of their populations (Meinesz et al. 1997, Ribera pers. comm.).
In 1992 an international programme was launched to combat the further spread of the algae (Nolan 1994, UNEP(OCA)/MED WG.89/Inf.9 1995, Ribera et al. (eds.) 1996).
Undaria pinnatifida
The Japanese Brown Kelp Undaria pinnatifida is believed to have been introduced in Australia in a similar way as the North Pacific Seastar Asterias amurensis (see below) and has negatively effected fishing stocks in Tasmania. In 1988 it was first recorded, but it is known to have become established at sites of France as well as in New Zealand before 1988 (Byrne et al. 1997). By 1991 the temperate algae had spread over an area of 16 kilometres. It is likely to continue its spread as its spores are easily dispersed by currents and at this stage an eradication seems impossible. Based on temperature tolerances it may potentially survive from Cape Leeuwin (Western Australia) to Wollongong (New South Wales). The kelp has had already a detrimental impact on the abalone industry, as it attaches to rocks that are abalone feeding sites. It also makes the abalone extremely difficult to harvest. The kelp will have an even greater impact when it reaches oyster and other mussel farms and settles on racks, lines and other culturing material (MEPC33/INF.26). Physical removal of U. pinnatifida from a marine reserve area was undertaken. The success of this action is not yet known (ICES 1997).
In 1991 a proposal reached the European Commission requesting financial support for the introduction of the kelp (Undaria spp.) to the French coast of the Channel area for commercial exploitation. The proposal has been supported and “justified” by the planned provision of employment and the use of this additional food sources (Nolan 1994).
Sargassum muticum
Unintentionally introduced in France as packaging materials or as fouling species on imported oysters from Japan in the 1970s. This large brown algae is now being found along the coasts of Portugal, Spain (Atlantic coast), France (Atlantic coast), United Kingdom, The
Netherlands, Germany (North Sea) Denmark (North Sea), Norway and Sweden (west coast). Negative effects to native species are the competition with native species and a negative impact concerning light-penetration and water exchange, as well as the hindering of local fisheries (Swedish Environmental Protection Agency 1997).