Marine Pollution Bulletin
would take a year to filter the water. Such a shift has many effects on the bay as light levels, nutrient factors will be dynamics and other environmental altered by this, and this will alter the dynamics of the food web. The report goes on to state how few studies have explored the wider scale factors that control diversity; the seas of the world are all interconnected. Extinctions are largely undocumented and it is still possible for whole new groups of organisms to be discovered. The recent discovery of the phylum protochlorophytes has revealed the fact that up to 40% of primary production in certain parts of the oceans is due to these previously unknown microscopic algae. The WWF is drawing attention to their concern for the state of the oceans by holding a World Ocean Day on June 8th 1995. Their concern over pollution and overfishing is leading to the call for increased awareness of the need to manage and protect the seas. Environment ministers from the eight countries surrounding the North Sea are meeting in June to put forward an action plan for shipping, fishing and pollution controls. The recent North Sea Quality Status Report has shown higher levels of oil and chemical pollution and further declines in fish stocks. According to a WWF report, in spite of legal measures little is done to enforce the control of dumping of wastes at sea, or to match realistically the fish catches to the stock size. Sian Pullen, WWF-UK’s Marine Conservation Officer, also points out that if an ecological balance is to be maintained the importance of fish in maintaining the balance of food webs in the North Sea must also be addressed. She is also asking for more account to be taken of the sub-littoral impacts of chemicals which can alter the reproductive and nervous systems of animals. An example of this is Tributylin (TBT), an anti-fouling agent which can be used on ships over 25 m in length and which is known to be concentrated in food chains. Female dog whelks grow penises as TBT accumulates and this blocks the release of eggs and causes the animals to swell up and burst. Alkylphenolic chemicals, which are produced when detergent and paint surfactants are broken down, can act like female oestrogen hormones. Their feminising effects have been shown in male fish downstream of sewage outlets. These effects are not isolated to fish and recent research is showing a possible link between drops in sperm counts in young men and oestrogen mimics in the environment. PHILIPPA AMBROSE
Chemical Pollution May Damage Salmon Homing Sensor Salmon may lose their sense of smell if exposed to pesticide and fertilizer pollution, according to recent research at the Ministry of Agriculture in Lowestoft, England. This sense has already been shown to be adversely affected by acid rain or any factor which raises the acidity level of the river. This could have 292
widespread implications, as salmon rely on their sense of smell to find their way home from migration and to locate their own spawning river and hence breed. Salmon have recently been shown to release pheromones in their urine which can be used to locate members of their own family, and to recognize their own rivers, according to Michael Jack, Fisheries Minister. It is thought that the salmon may be following the pheromones secreted by their own offspring in the home river, as the young remain in the river for two years before moving down to the sea. If a salmon had a dulled sense of smell, it may not be able to respond to the pheromone stimuli and this could have important implications on the conservation of wild salmon stocks.
Fears Over Cholera Remain in Italy Rawsquid, believed to be contaminated by the cholera bacterium, has caused a 60% decrease in fish sales in Italy this year. Ten cases of the disease near the Adriatic city of Bari were thought to have been caused by people eating raw squid which had been infected by seawater contaminated by untreated sewage last October. Measures were immediately taken by the Italian authorities to reduce further risks (such as strict checks and bans on exports). Even though the contamination was sea-borne, freshwater farmed fish also came under suspicion. Italian fish farmers are claiming that the public are still very wary of eating fish and are calling for aid from the government to dispel the fears which they believe to be caused by inadequate knowledge of the true situation.
No Reprieve for Mudflats Mudflats of international importance for wader populations have been reclaimed as part of a port expansion, despite an appeal by conservationists to the House of Lords and an impending judgement on the case by the European Court of Justice (ECJ). Lappel Bank was to be designated as part of the Medway Estuary and Marshes Special Protection Area (SPA), on the Kent coast near the Thames Estuary, under the European Council Directive on the Conservation of Wild Birds (79/409/EEC). The Medway Estuary and Marshes is also a listed area under the Ramsar Convention for the Protection of Wetlands of International Importance (1975). Lappel Bank has been subject to reclamation over the years, and approximately 26 hectares remains. As such, it represents less than 0.5% of the total area of the Medway Estuary and Marshes, though it is recognised as an important component of the overall estuarine ecosystem, the loss of which would probably result in a significant reduction in the wader and wildfowl populations of the total area. The area was to be designated as part of the Medway SPA, the boundaries of which were being finalised in late 1993. However, the Medway