INVADERS

There are some occasions when an animal or vegetal organism of a specific geographic area travels either by natural or accidental causes to a different environment. This being, which is exotic to the new setting, can actually find the adequate conditions to grow and develop in it, especially for the fact that most of the times there will be no predator to keep its numbers controlled, hence attaining an unmeasured and aggressive development, hostile to the local flora and fauna.

These organisms are called "invaders". Most of the Nations use to have strict laws in order of avoiding or regulating the entrance and afterward reproduction of these mentioned organisms. The Patagonia is now facing a new intruder, only this time it is located in the coastal underwater.

The aggressor is an algae known as Undaria Pinnatifida, whose original environment are the Japanese coasts where it is known with the name of wakame. Only five years ago a diver from the City of Puerto Madryn gave the alert to the local authorities about the appearance of some sproutings of an exotic algae in the vicinity of the dock of the City. It is already known that this algae, which has already invaded zones of Baja California, Europe, New Zeeland and Australia (where is being intensively combated), can move through the oceans encrusted on the hull of the ships or inside their bilges, where their spores are able to outlive in the water used as counterweight by the ships. A research made in Europe in the year 2000 found specimens of these algae adhered to 20% of the fishing boats, 50% of the yachts and 35% of other boats.

In only few years the wakame managed to travel and to get randomly installed all around the extension of the Nuevo Gulf, where is causing an ecological damage as well as important changes within the ecosystem, displacing the populations of kelp, a highly nutrient natural plant, expanding its new territories towards the South, the zone of Camarones and Caleta Malaspina Inlet, threatening the major marine ecosystem of the southern area, where it displaced the gracilaria, an algae of great economical relevance and nutritional value, which is utilised in the making of a dessert of sweet potato, jellies and marmalades.

The undaria keeps a steady pace of growth, densely populating the marine bottom with undesirable shadows that ravages the natural living of bivalves, crabs and other residents. In the places where the undaria settles there are practically no fish, which make up the basic food of dolphins and sea lions. The three main populations of sea sealions in the Nuevo Gulf (Baliza, Punta Conscriptos and Punta Alta) have already been totally invaded.

It is asserted that the first spores of these algae firstly arrived in 1992 in the waters contained by the bilges of the Korean fishing vessels who came here searching for calamari and shrimp. The water in those bilges was supposedly discharged in port, a manoeuvre that is strictly forbidden by international laws.

It is also prejudicial to salmons, as well as to divers and the development of native populations of algae.

According to the scientists of the Centro Nacional Patagónico, the uncontrolled growth of the undaria could derive in the exodus of species as the salmon, which is an important source of income to the small scale fishermen. The main reason for this is that the undaria restrains the access of the fish to the underwater caves where they live and feed.

The first account of appearance of an undaria was reported in 1992, in the Almirante Storni haven in Puerto Madryn. It disappeared soon afterwards, but on Autumn of 1993 several colonies of these algae were again detected and had kept growing since in an uncontrolled way.

The native algae of the sea of Argentina are small sized and assemble in prairies at the bottom of the sea, but the undaria shows a different behaviour. There have been reported some specimens of 1,70 metres long. Every year it gains more territory, actually forming forests that prevent the pass of solar light, the local algae is unable to challenge this growth and so the invader numbers keep engrossing.

As difficult as it is to eliminate a weed from solid ground without endangering the native flora, the same thing happens undersea. The point is that the undaria, which is actually sowed in China, Japan and Korea for alimentary purposes, is already changing the rules of the sea bottom in Patagonia.

It is still uncertain if there is any fish who feds on these algae colonies, but in the supposed case that it does exist, its introduction as a solution to this problem would surely bring another unwanted problem, for it could result in a bigger predicament due to the presence of presently controlled species, with the resultant unbalancing of the thropic chain.

Acting as the villain of a movie, the undaria is also a foul for one of the most important tourist resources of the Chubut: diving, for it makes hard for the divers to reach the bottom of the sea to observe the populations of sea stars or other exotic species the tourist seeks to find.

It grows easily at the bottom of the sea -some populations have been reported to be found at 22 metres of depth- but it is also able to flourish over the riffs at the coasts. It is a nuisance for the bathers at the beach, and when it becomes rotten, its smell is not a very pleasant one.

Some eight thousand tons of marine seaweed becomes yearly lain over the beaches of Puerto Madryn, which actually hampers with the recreational and tourist activities, in order of which they are constantly being collected and removed by cleansing brigades.

Several experiments of aerobically bioconversion had been attempted seeking to the exploitation of this natural resource in order of obtaining a fertilising substance which could permit the improvement of the physic proprieties of those soils that are subjected to intensive cropping. The resultant compost has been tried as a growth improver on hothouse legumes with satisfactory results.

Researches seeking to optimise this processes are presently been performed, and some aspects related with the botanical composition of the marine algae, the levels of salinity in conditioning the use of the compost and some peculiar properties as the augment in the percentages of seed germination and their water retaining capacity are presently being subjected to more scientific research.

Besides the temperature rates of the water and an adequate bottom soil in which to get adhered, the undaria has found in the coasts of Argentina another factor that permits its unrestrained development: the passivity of the authorities which instead of fighting the intruder since its first appearance, are still debating upon which would be the best measures to take.

In the present, the possibility of utterly defeating the wakame is impossible. When the plant is sewn, its spores are freed and dispersed throughout the bottom, giving birth to new plants that will be once more driven by the ships and the currents in a progressive invasion which would become unbeatable by the day.

"You cannot possibly defend what you do not love and you cannot love what you do not know"

The information used to make this report was obtained from:

Technical report by the Lic. Piria and Lic. Casas from the Centro Nacional Patagonico - CENPAT.

Investigative article from the Clarín Newspaper.