Geese dying on lake shore

Press, 24 January 1985, Page 7

Geese dying on lake shore

The low level of Lake Ellesmere may be contributing to the plight of Canada geese dying on its shores.

A North Canterbury Acclimatisation Society ranger had found 69 dead birds on Greenpark sands on Tuesday, said the society’s secretary, Mr Brian Webb, yesterday. The problem was first brought to the society’s attention in December, but had been getting worse since then, Mr Webb said.

Three dying geese have been tested at the Lincoln College animal research laboratory and although lead shot was found in the gizzard of one, tests on the other two were inconclusive.

Mr Webb said they showed signs of lead poisoning, but this could be symp-

tomatic of a range of causes, including the effects of parasites. At this time of the year, the moulting season, the birds are in a weakened condition, unable to fly, and must feed from the edge of the lake.

The extremely low level of the lake, however, combined with the drought, had dried out the edges and there was little vegetation, Mr Webb said. Lead shot used at the lake over the years was left lying in the mud and the birds picked this up as they tried to feed. Sometimes they mistook the lead for grit for their gizzard, he said.

“There is nothing we can do to stop the geese dying.” ' The lake was the lowest it had been for several years and i| had accentuated the

problem. Black swans which also live at the lake do not seem to be as badly affected. Although some farmers have reported seeing “dopey” swans, none had been found dead, Mr Webb said.

The North Canterbury Catchment Board opened the lake in November. Sea conditions and northwesterly weather have meant it has stayed open.

A Catchment Board water rights officer, Mr Murray Love, said the lake would normally''have closed itself by now and the board would be considering reopening it to avoid drainage problems.

The board’s staff will measure temperatures at the lake and look at the opening, which he suspected had become tidal. In the meantime, farmers using water from the

Selwyn River and the lake’s smaller tributaries have been asked to roster their takes in the low-flow conditions.

Halswell River users would also be asked to limit their takes, he said.

In . spite of these measures, Mr Love did not expect the lake level to rise. The river levels were not expected to recover quickly and evaporation from the lake's surface was high. He thought the situation could become worse.

Even if the opening was closed the high evaporation would probably counter flows into the lake, he said.

Mr Webb said the plight of wildlife at Lake Ellesmere had been bad for years, particularly since the Wahine storm in 1968 which wiped out the beds of ruppia weed. Geese and swans used to nest in the weed, which

also helped keep the water clean, and stopped wave action and erosion. Since the weed disappeared plankton and algae had flourished, stopping light penetrating the water and preventing the regeneration of weed. “As long as this continues there will be a food problem,” he said.

The trout population had decreased, and the numbers of perch and carp had increased. Mr Webb said that the lake’s future would have to be discussed at a series of meetings between his society, the Catchment Board, the Wildlife Service, the Lands and Survey Department, and other interested groups.

The Catchment Board’s draft management plan for the lake is due for complev tion in 1987.