Poisoning fears threaten new fishing venture

Press, 16 August 1980, Page 7

Poisoning fears threaten new fishing venture

New Zealand’s newly exploited deepwater fish species contain a possible health hazard which could threaten exports, according to fish researchers. The problem lies with wax discovered in the body oils of the orange roughy, oreo dory, spiky dory, and smooth dory. Most of the Auckland, Palmerston North, and Nelson' scientists who have done research work on the fish agree that the wax can cause diarrhoea, gastric disorders, and possibly even more serious effects.

Rats fed a variety of diets of up to 50per cent of fish containing the wax in Japanese experiments suffered emaciation and loss of hair and died after three to nine days. The Japanese have since banned imports of these New Zealand species. The Australians, who take much of the thousands of tonnes now caught annually by Japanese, Russian, and Korean joint-venture and licensed fleets in New Zealand waters, are also studying the possible dangers of the fish. A Nelson researcher who had planned a regular daily diet of the fish for two weeks to gauge the effects became so concerned as he learned more about the wax that he abandoned the idea.

The general manager of the Fishing Industry Board, Mr N. E. Jarman, denies that the fish are a health hazard but says that an investigation into the wax, known as wax esters, will be carried out by the Department of Scientific and Industrial Research. “This is a first-class eating fish which has been dammed by its association

with wax esters, most of which are removed by filleting,” he said. Opponents of foreign fleets fishing in New Zealand waters were promoting the wax fear' in a bid to harm ■ joint ventures, not because of their concern for the health of consumers, he said. The Japanese tests on rats were not of great value because rats were not people. “Often you would have to eat pounds and pounds of the stuff to equal the situation created in rat tests,” said Mr Jarman. Any world rejection of fish containing wax esters would hurt New Zealand most because as far as he knew this type of fish was being caught in quantity only in New Zealand waters.

Dr D. Body, a scientist in the D.S.I.R.’s appliedbiochemistry division in Palmerston North believes the wax esters could be a health problem. Dr Body, who has studied samples of New Zealand’s deepwater fish to determine the occurence and position of wax esters in the body of the fish, says that the esters account for more than 90 per cent of the oil in a fillet.

Experiments by two Japanese scientists in 1977 in which rats had been fed fish containing wax esters had produced, alarming results, he said. According to a summary of a paper written by the Japanese pair the rats had died in circumstances similar to the condition seborrhea after suffering “abnormal scour” and becoming covered in fatty excrement and emaciated.

Deep filleting the fish would help remove some of the wax content and would make the fish more acceptable for human consumption. If the fish was rejected as human food it had a valuable oil yield, similar to that taken from sperm whales, and could provide protein for animal feed.

Two Massey University scientists based at Port Nelson, Messrs N. Wilson and N. Boyd, who have been studying the deep-

water fish, orange roughy, during the last two years, agree, that the wax content poses a health hazard. Mr Wilson said the Japanese had banned New Zealand deepwater fish when the crew of a Japanese trawler had suffered gastro-intestinal upsets after eating fish they had caught.

Wax esters also occurred in other foods, such as in apple skins, but the human body had difficulty absorbing quantities of them.

“The wax content can be reduced by deep filleting from about 12 per cent of fillet to 7 per cent but the level is still quite

The' head of the D.S.I.R.’s fish-research unit at Mount Albert, Auckland, Dr D. Buisson, feels that the problem can be reduced by filleting techniques, cooking methods, and catching the

fish at the right time of the year. The assistant director of the Ministry of Agrciulture and Fisheries’ meat division, Mr A. Royal, said the Ministry was worried about the deepwater fish. “There is a lot of concern about the wax content,” he said. “I hear the Australians are looking at their imports from New Zealand carefully.” The Federation of Commercial Fishermen seeks action from the Government and the. Fishing Industry Board over the export of the fish. The federations liaison officer. Mr I. McWhannell, said much of the fish .was sold to Australia, a market on which New Zealand fishermen depended heavily for their livelihood. Exports of the fish could lead to swing against New Zealand fish.