Scientists turn to fishermen for in-depth knowledge of the North Sea
The knowledge of local fishermen is just as important as that of scientists when it comes to assessing the health of the marine environment, according to a team of researchers from Newcastle Universitys Dove Marine Laboratory, who have been studying the future of the North Sea.
The team has spent the past three months carrying out a survey among fishermen, yachtsmen and boat operators based at the Northumberland (UK) ports of Blyth and North Shields, as part of a project entitled: The North Sea: A Sustainable Future which is supported by the Heritage Lottery Fund.
They found that local people who regularly go to sea can provide important information about the occurrence of whales and dolphins, which are good indicators of the health of the seas, and about the presence of what are usually considered to be warm water species in the cold waters of the northern North Sea.
Team member, Joanna Stockill, said: There is increasing recognition that we should listen more carefully to the opinions of people such as fishermen, who may have decades of experience working at sea or may come from families whose livelihoods have depended on the sea for generations.
Their knowledge is especially important in developing our views on matters such as the health of the marine environment and in deciding management policies, concerned with, for example, how best to conserve dwindling stocks of commercially-important fish, she added.
The results of the survey found that the general opinion among fishermen and others is that the health of the North Sea has improved, especially over the last 10 to 20 years.
In particular, the large majority of people that Joanna interviewed believe that chemical pollution, sewage inputs, oil spills and slicks caused through boats cleaning their tanks have decreased significantly during this time.
This theory is backed up by an increased number of sightings of porpoise, dolphins and even whales off the North East coast.
Sightings of minke whales are no longer unusual. Blyth fisherman, Peter Dent recently discovered the skull of a minke whale in a trawl off the North East coast. While minkes are among the smallest whales, the skull is nevertheless massive, measuring about 1.5 metres.
More common species such as harbour porpoise and white-beaked dolphin were seen by those interviewed on around half of all trips to sea, and offshore sightings were recorded all year round, showing that dolphins are always present close to the coastline.
Surprisingly, there have even been sightings of killer whales and long-finned pilot whales: around 30 per cent of interviewees report having seen these species off the coast. More exciting still were one or two replies which claim to have seen Blue Whale and Sperm Whale around the Farne Islands, both of which were hunted to near extinction before the ban on whaling.
Joanna concedes that the rarity of such sightings may raise questions about the reliability of the data from the survey.
She says: According to a recently published scientific atlas of whales and dolphins, Sperm and Blue Whales do not occur in the central parts of the North Sea. However, credibility can be given to the fishermens reports at least in the case of the Sperm Whale, because three of the creatures were stranded on the East coast of England in 1997. So, although scientists have not yet recorded sperm whales in the central North Sea, they certainly have occurred there, and there can be little doubt that the fishermen’s reports are accurate.
Interviewees were also asked to note any sightings of unexpected species encountered off the North East coast to investigate how issues like global warming are affecting the local marine environment. In August 2003, the crew of the Dove Marine Laboratory’s research vessel, Bernicia, recorded the highest sea surface water temperature for five years
Their responses implied that a range of warm water species are now found in the region, suggesting that species are moving north as the average sea temperature rises.
One of the most intriguing sightings was reported by a Blyth fisherman who had seen a striped dolphin, a warm water species typically found south of the English Channel. Again, records of strandings provide further evidence that this warm water species is now found off the North East coast. In 1999, a live striped dolphin was found stranded at Seaburn in Tyne and Wear.
Reports of other warm water species, such as the sunfish were noted, along with sightings of species more often seen on the warmer south and western coasts, including basking shark and leatherback turtle – a critically endangered species. Other reported changes included increasing numbers of Red Mullet, John Dory, velvet swimming crab, and octopus.
Overall, Joanna has been highly impressed by the intimate knowledge that sea-going people have of the seas and their understanding of the complexities of the marine environment.
Cullercoats fisherman, Dennis Clark, said: In my experience stocks of all marine species are constantly changing in their abundance and areas of distribution. Temperature and prevailing conditions seem to be the main factor affecting this. We can go for years and not see some species and then we get years when they just reappear and we cannot understand how and why they return. I come from generations of fishermen and my family can speak of many times in the past when species like cod have disappeared only to reappear again when conditions are right. The North Sea is very alive and dynamic and does forgive a lot of mistakes.
Professor Stewart Evans, who is leading the project, says: Of course, scientific knowledge is important in determining the policies that we adopt in managing the environment. However, so too is the knowledge of people who are in day-to-day contact with the environment and experience problems associated with it first hand. We believe that both kinds of knowledge, scientific and local, are valuable and are much more powerful if they are considered together.
Melanie Reed | University of Newcastle