LONDEN, 2 april 2005 – De Noordzee herbergt in toenemende mate walvis- en dolfijnensoorten die doorgaans alleen in warmere wateren voorkomen. Ook “zuidelijker” vissoorten en andere zeedieren zoals bepaalde soorten inktvis en krabben komen steeds vaker in de Noordzee voor. Dat blijkt uit onderzoek van de Britse universiteit van Newcastle.
Volgens de Britse krant The Guardian , die zaterdag over het onderzoek berichtte, zijn onder meer Risso’s-dolfijnen steeds vaker te zien in de Noordzee. Ook het aantal orka’s en witsnuitdolfijnen neemt toe, vooral omdat ze in Noordzee nu meer te eten vinden zoals inktvissen.
De opwarming van het water in de Noordzee wordt toegeschreven aan klimaatveranderingen als gevolg van het versterkte broeikaseffect.
Whales and dolphins in the North Sea ‘on the increase’
Date released 2 April 2005
A project to map the presence of whales and dolphins off the North East coast has recorded sightings of no fewer than 614 individual creatures in the space of 12 months.
The Newcastle University project was led by Joanna Stockill, of the University’s Dove Marine Laboratory, at Cullercoats, which is located on the coast near Tynemouth.
Joanna enlisted the help of local fishermen and members of Royal Northumberland Yacht Club to carry out the study, as part of a project entitled: ‘The North Sea: A Sustainable Future’ which is supported by the Heritage Lottery Fund. They were given guidelines about species identification, and asked to complete questionnaires each time they made sightings of whales or dolphins while at sea.
The purpose of the study was to encourage people who use the North Sea regularly, for work or recreation, to put forward suggestions for the management of the coastal waters in order the protect their future.
‘Whales and dolphins are protected under international and European regulations, but we want to find out if anything can be done on a local scale. That is why we are asking people who use the sea on a regular basis to come up with ideas for raising awareness of the presence of whales and dolphins in the local environment’, says Joanna.
Some of the suggestions put forward include installing information boards on Blyth promenade showing the species that can be seen off the coast, producing leaflets for distribution in libraries and other public places, such as supermarkets, and preparing education packs for use in schools.
The study recorded sightings of six different species in an area stretching from North Northumberland to Whitby North Yorkshire. The species recorded were harbour porpoise, Common dolphin, Bottlenose dolphin, Risso’s dolphin, Long-finned pilot whales and White-beaked dolphin.
Linda Lane Thornton, honorary secretary of the Royal Northumberland Yacht Club, and her husband, Andy, go out most weekends during the sailing season in their yacht, Layback. Mrs Lane Thornton said: ‘We have been sailing from Blyth for three years, and we have definitely seen an increase in the numbers of whales and dolphins. The general feeling among yacht club members is that there are more about now’. Mrs Lane Thornton also spotted for the first time – and managed to photograph – a White-beaked dolphin with its calf off the coast of Embleton.
Rising water temperature and the abundance of food, such as herring and mackerel, now available are thought to be among the factors responsible for the increased numbers of whales and dolphins being reported from some parts of the North Sea.
White beaked dolphins were the most frequently-sighted species, including one particular sighting of a school – or group – of around 250 dolphins, 25 miles off Cullercoats, reported by fisherman Kevin Dickenson.
Other local fishermen have also confirmed that they see large schools of dolphins migrating to and from the central North Sea at the start and end of summer.
Peter Evans, Science Director of the Sea Watch Foundation, which monitors whale and dolphin distribution around the British Isles assisted with the identification process. Dr Evans said: ‘Numbers of white-beaked dolphins tend to build up in late summer, often associated with aggregations of mackerel or herring. They are the commonest dolphin in the North Sea, ranging over wide areas particularly in the northern and central parts’.
Perhaps the most surprising statistic revealed by the study was the number of sightings of Risso’s dolphin – a flat-nosed dolphin which can grow to up to 3.8 metres in length – which accounted for 12 per cent of the total sightings. ‘Risso’s dolphins are primarily a warm water species, with few records from the North Sea, so that could indicate that the North Sea is getting warmer’, said Joanna. ‘The sightings of common dolphin also support this theory, because they are more usually found off the South West of England, where the waters are warmer, extending in midsummer to the west coast of Scotland, but rarely into the North Sea, but in recent years, sightings have become more regular off North East Britain’.
Blyth fisherman, Stephen Moss, whose trawler Green Pastures is the only large trawler still fishing out of Blyth Harbour, says the presence of Risso’s dolphins in the North Sea could also be because of an increase in the numbers of squid, which are an important food source for Risso’s, as well as for White-beaked and common dolphins and the Long-finned pilot whale.
‘The sea is changing’, said Mr Moss, ‘As well as squid, we are now seeing commercial quantities of red mullet, and occasionally pilchard. This year, we were catching mackerel until Christmas, so we are definitely seeing change in the water temperature’.
The study also asked participants to record details of the behaviour of the creatures they spotted. Joanna comments: ‘The survey reported fairly standard behaviour in most cases, which helps us to be confident of our identification process. For example, Harbour Porpoise are a shallow water species, most commonly found swimming slowly close to the coast, and most of our sightings of them fitted this pattern of behaviour.
‘We did also record more varied activity among white-beaked dolphins, Risso’s dolphins and common dolphins. These species had more interaction with vessels, such as following the boat, rubbing on the hull, or even trying to score the occasional fish that escaped from the nets as they were being hauled in’, she added.
Notes for Editors
1. It is possible that the same whales or dolphins were seen by more than one respondent, and therefore they were recorded on more than one occasion.
2. Newcastle University is committed to bringing about change for the better at international, national and regional level. Its Transforming Horizons document states that the University is committed to transforming the environment by bringing together its wide-ranging expertise to focus on the major environmental issues of the day.
3. The Heritage Lottery Fund (HLF) enables communities to celebrate, look after and learn more about our diverse heritage. From our great museums and historic buildings to local parks and beauty spots or recording and celebrating traditions, customs and history, HLF grants open up our nation’s heritage for everyone to enjoy. We have supported more than 15,000 projects, allocating over £3 billion across the UK.
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