Marine Pollution Bulletin
imposed when affected samples from Marlborough Sound on South Island and from the Chatham Islands, 700 km southeast of Wellington, were found. The effect of the ban closed hundreds of mussel farms affecting over 1,000 jobs. New Zealand government scientists have undertaken a sampling programme covering some 250 sites over the 11,000 km of coastline affected.
War on Drift Netters Not Yet Over In spite of the 1989 world-wide ban on drift-nets, some boats are still in operation having failed to return to their home ports for decommissioning by the deadline, 15 December 1992. The United Nations sponsored moratorium allowed a 3-year period for fishermen to move to new fishing methods and this expired at the end of 1992. Driftnetting had been banned in response to the damage to fish stocks and sea mammals; between 300,000 and a million dolphins are thought to have been drowned by these nets between 1989 and 1990 alone. A large part of the international drift-net fishing fleet is composed of boats from Japan, Korea and Taiwan and the majority of vessels have now been decommissioned. Home ports are now littered with old nets and winding gear which has been replaced in favour of other fishing methods. The Taiwanese government's Council of Agriculture (COA) has introduced a buyback scheme for old boats since 1990 and a refitting scheme for newer vessels. Up to NTS5 million (US S192,000) can be made available to skippers on low loans. 76 old boats have been scuttled, 18 refitted and a further 54 involved in the scheme. The COA estimated that only 95 drift-netters were still operating in 1992 with catches dropping from 160,000 tonnes in 1990 to below 100,000 in 1992. Inspectors are being deployed to ensure that only legal fishing gear is being carried. It is therefore of some concern to the government that reports are emerging that a group of rogue Taiwanese boats may still be at sea. The reports have varied but some estimates seem to point to between 10 and 50, others 50 to 100, still operating drift-nets. Some photographs of vessels drift-netting after the deadline have been passed on to the government's fisheries department by US officials. The suspicion is growing that these boats may well have originated in Taiwan but they have been away for a long time and are no longer following the Taiwanese government's regulations. The numbers however, are not thought to be significant to fish stocks, as the fleet has dropped from between 800 and 1,000 vessels to these few rogue boats. They will also find it much more difficult to sell their fish as many quayside and cannery operations carry out their own inspections. Prices drop in response and it should become increasingly difficult for drift-netting to remain economically viable. 234
Oceanic Changes Affect Hawaiian Lobsters Changes in the ocean environment rather than overfishing may be affecting lobster population in the Hawaiian Islands according to a recent report in Fishing News International. Hawaii's once $6 million a year lobster fishery has dropped by two thirds to $2 million since the early 1980s. Hawaiian marine biologists, Drs Jeffrey Polovina and Gary Michum believe that the environment around Hawaii began changing in the mid-1970s. The most extreme change was reached in the early 1980s when conditions supported higher than normal levels of productivity. This was reflected in increased populations of sea birds, monk seals, coral reef fishes and lobsters. Scientists noticed these trends several years ago whilst investigating declines in the lobster fishery not related to over-fishing. They believe that the area could now be in the period of lower productivity in which lobster landings will stabilize at the current $2 million level.
Chemical Tanker Accidents Cause Concern There is increasing concern at the increase in chemical tanker accidents and 'the possible threat to the environment. In March the 17,000 tonne chemical tanker Shiokaze exploded and caught fire off the coast of the Netherlands. The vessel was en route from Rotterdam to Sweden with a cargo of 2500 tonnes of ethyihexanol and dioctyl hexanol. The explosion is believed to have centred on a tank holding the dioctyl hexanol. Earlier, in February, at least a thousand tonnes of poisonous lead sulphate concentrate escaped into the North Sea after the Norwegian vessel Nordfrakt sank taking the rest of her cargo down with her. According to a recent report in Lloyd's List, the safety record of the world's chemical tanker fleet is generally thought to be good, but there are worrying signs this could be jeopardized by ageing ships and low freight rates. Apparently 21% of the intercontinental tanker fleet (over 10,000 tonnes dead weight) is over 10-16 years old and the deliveries of new ships over the next few years amounts to less than 10% of the existing fleet. There is concern that the low freight rates do not encourage the building of new ships. The European Port State Control secretariat state that there has been a gradual increase in detention of chemical tankers; most of the ships were over fifteen years old and flying flags of convenience. Chemical tanker owners are subjected to some of the most strict regulations and inspections in shipping, but it has already been recognized that the fleet is rapidly ageing and many owners are only patch mending their ships, a policy that is storing up future problems for the industry.