Sea lettuce not confined to polluted waters

Press, Volume CXI, Issue 32587, 22 April 1971, Page 9

Sea lettuce not confined to polluted waters

The problem of sea lettuce is not confined to those estuaries where there is sewage pollution of the water, according to the chief engineer of the Christchurch Drainage Board (Mr P. J. McWilliam). Quoting a recent statement by the Department of Health, Mr McWilliam said that sea lettuce had been found in huge quantities at Portobello, Dunedin, where there was no sewage pollution of the water. Mr McWilliatn was replying to a correspondent, “Not a Water Skier,” who has asked if sea lettuce is a major factor in estuaries which receive no pollution. “Sea lettuce, like any other plant, requires a food supply containing a source of carbon, nitrogen, phosphorus, and various other trace elements and compounds,” said Mr McWilliam. “This can be from several sources which include the breakdown of animal or vegetable matter, and it is possible some of the nitrogen is obtained from the atmosphere. In the case of the Estuary, the derivation of the food supply used by sea lettuce and the relative amounts from the various food sources are at the moment being studied,” he said. The correspondent also asks: “Would not the fillingin of the McCormacks Bay basin before the full Wallingford report is known negate all its findings?" Mr McWilliam said that the hydraulics research station had been made aware of the possibility of the fill-

ing-jn of McCormacks Bay and had taken that into ac- ; count in the investigations. Asked by the correspond|ent why no further action has been taken against a firm “which released hundreds of gallons of oil into the Heath- ‘ cote River last August, and who paid for its cleaning up,” 1 Mr McWilliam said that three c companies had been involved > in the oil-spill, and that the ■ distribution of liability was r still being resolved. “At this stage, the board J has not yet received any re-J compense for its costs, but® Jit has made it plain to the J J parties concerned that it will' ’ take legal action if necessary/ Jin order to obtain a refund s of them. An oil company I * . that helped cleaning up had ■ , considerable direct costs of 1 . its own. At the moment, the c ’ board is more concerned in ' ’ recovering its costs,” said Mr r [ McWilliam. The correspondent further;! I asks if it is true that the ‘ board had agreed to attend ‘ ; an “Estuary protest meeting” ? ’ only after assurances were ? received that the questions ’ ’ would be notified in advance. ■ 1 ’ “I found myself, in spite 1 ; of these questions, on the • ‘ side of the Drainage Board, 1 ’ which is on the correct path, j J and was disgusted at the dis- 1 ’.play of selfish interests ! ’ shown by many of the groups present at the meeting,” says “Not a Water Skier.” ’■ Mr McWilliam said: “The ' board agreed to attend the ' meeting without setting any E conditions, but it did ask for; prior notification of questions so that information could be ‘ obtained, and answers pree pared and given to the meet-, ’ing. “The organisers did forward a list of questions to the board and the prior notification did ensure that the questioners were getting the information being sought. However, there were still several questions not covered in the supplied list py.t to the board’s representatives,” he said.