Volume 36/Number 12/December 1998

Japanese Seaweed Invades Northern Ireland The general public is being asked to help in the attempt being made to prevent the spread of Japanese seaweed (known as Japwecd) along Northern Irish coasts. The seaweed is one of a number of species of Sargassum from the western Pacific which have recently been introduced and have spread across the coasts of North America and Europe. The accidental introduction has affected thousands of miles of coast- line as the biology of the alga makes it very well adapted to colonizing new areas. It grows up to five metres in a single season and as it is an aggressive colonizer it puts native communities at risk It also forms huge rafts which can then become hazards to small water craft and badly affects recreational water sports and other commercial interests.

A Wildlife Order in operation since 1984 put a complete ban on the introduction of the species into Irish waters. Despite this however, it was found in the Ringneill area in 1994. The Environment and Heritage Service (EHS) surveyed the extent of the invasion in 1995 and then hand pulled two tonnes of the weed and dumped it into landfill sites. The drastic action initially appeared to work as the extent of the weed was reduced in 1996 and no further sites were recorded. However by 1997 in spite of the removal of eight tonnes of weed from the Strangford Lough it was a losing battle and the weed outgrew its removal. Now, after the 1998, survey it has been agreed that the fight to stop the spread of weed in Strangford Lough has been lost and efforts are now turning to ways of preventing its further spread. Regular meetings are held to establish a long term strategy of monitoring, research and management. Members of the public are being asked to keep an eye out for the Japweed (Sargassum muticum) and report any siting of it. It is hoped that this will help to track the spread of the weed and assist in its management.

More Climate Clues From Greenland Ice Precise data on climate change over the years has become available during further work on Greenland's deep ice systems. A recent report produced by US Geological Survey (USGS) scientists in collaboration with the University of Copenhagen, Denmark records exact measurements of changes in climate temperature

over the last 22,000 years. At this time temperatures were as low as -23°C below current values. On the other hand during the time of the Vikings, 5000 years ago, the climate was warmer than current values by +2.5°C; during the Medieval Warm Period, 1000 years ago it was only I°C warmer and during the Little Ice Age, 1420 to 1890 AD, the area was colder than today.

To obtain these precise measurements high precision equipment, able to measure tiny temperature variations of only 0.0002°C was used. The probes were inserted into a 3,000 metre deep access hole which had been drilled through the ice by the European Science Foundation. Previous studies had used plant pollen stored in lake sediments, chemical isotope ratios stored in glaciers and other climate indicators to make predictions.

The Greenland area seems to be particularly sensi- tive to climatic change, probably as it is surrounded by the North Atlantic Ocean. This means that the area responds quickly with climatic change if the currents in the oceans alter in any way. For example warm surface waters may be swept into the area from the tropics, increasing the climate temperature.

It is vital to perform such studies to try and make sense of the current global warming debate. The research should reveal to what extent natural fluctua- tions in earth climate occur and hence predict whether the current temperature rise is just part of a natural fluctuation or caused by man-made changes in gases in the atmosphere; greenhouse gases.

Fish Poisoning Threatens Lake Victoria Using poisons to catch fish around Lake Victoria is rampant and fears are growing for the ecological integrity of the lake. The three countries bordering Lake Victoria, Kenya, Tanzania and Uganda were represented at a recent seminar at Kisumu, a lakeside Kenyan town. The meeting had been set up to discuss the increasing problems represented by fish poisoning. Many local fishermen are using a substance known locally as 'Ambush' to spray onto the surface of the lake waters which intoxicates the fish They are then easily collected and sold. Many fishermen are turning to this as a cheap alternative to the use of expensive fishing tackle. The poisoning as yet seems to mainly affect the Tilapia species in the shallow inshore waters of the lake with only a small proportion of Nile Perch being affected. Obviously the increased use of fish poisons is causing concern for both the environment and the consumers. Environmentalists and medical practitioners from Japan and East Africa were brought together for the seminar. The issue has been brought to a head by the EU ban on fish from Uganda,

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