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World Basking Shark Day

Basking shark

When eco-tour company Basking Shark Scotland realised there was no day dedicated to raising awareness about basking sharks, they decided to start one. This is taking place for the first time this year on November 3rd. Basking sharks are classed as an endangered species in the Northeast Atlantic and face a number of threats despite being protected in UK and Irish waters. Hopefully, World Basking Shark Day will become an annual event and help to highlight this fascinating but mysterious creature. There is also the hope that events like this will put an end to the sort of misguided tabloid stories that appeared earlier this year.

Mysterious Giants

Basking sharks are the second biggest fish in the world, growing up to 10 metres long. Only the whale shark is bigger, but while the whale shark lives in tropical waters, the basking shark prefers more temperate seas. Despite their size, both species are harmless filter feeders. This means that they pass gallons of sea water over their gills as they swim, sieving out tiny planktonic organisms. To take advantage of plankton swarms, basking sharks are migratory. A 2003 tagging project revealed that they can travel thousands of kilometres in their search for plankton hotspots. In UK and Irish waters, they seem to follow seasonal patterns and return each summer to favoured locations along the west coast. The Inner Hebrides, Isle of Man and Shetland are particularly good places to see them.

Basking Shark
Basking sharks usually feed close to the surface

Surprisingly little is known about basking sharks. When most leave our coasts for the winter, they head to various points in the Atlantic from the Azores to Newfoundland. No one knows if they feed during this period. Various behaviours that biologists assume are related to courtship are seen regularly in our waters in the summer months. These include groups of animals following each other nose to tail and two animals swimming side by side. The sharks are usually solitary but can form large groups at this time of year. Incredibly, research has recently been published that suggests they carry out their own version of speed-dating, as reported in our September news round-up. Researchers have never recorded mating itself, however.

Basking sharks swim slowly to filter huge quantities of water through their gills

From Hunting to Protection

Caught for centuries in smaller numbers, the basking shark hunt reached its peak in British and Irish waters in the 1930s, 40s and 50s. Fisheries were based in Achill (Ireland), the Inner Hebrides and the Clyde. Norwegian ships also came to UK waters to take advantage of the sharks’ presence. Gavin Maxwell, more famous for his book Ring of Bright Water about otters, also tried, but failed, to set up his own shark hunting venture. Most were after the large amount of oil stored in sharks’ livers. This oil, called squalene, was used in a number of industries including lighting. The cosmetic industry still uses it today. Between 1946 and 1986, nearly 80,000 sharks were taken by Irish, Scottish and Norwegian fisheries.

Happily, basking sharks have now received some measure of protection in UK and Irish seas. The Isle of Man was first to step in and introduced laws protecting them in Manx waters in 1990. Protection in English, Welsh and Scottish waters followed via a 1998 amendment to the Wildlife and Countryside Act. These only helped sharks in coastal waters, however. Due to their migratory habits, in 2005 they were added to the Bonn Convention on Migratory Species. This effectively closed all remaining fisheries in the North Atlantic. Ireland has also recently given them special protected status under the Wildlife Act.

Continuing Threats

Basking sharks may have greater protections than ever before, but they still face numerous threats both here and further afield. The Northeast Atlantic population is classed as endangered while globally they are classified as vulnerable. They are still hunted in large numbers outside the Atlantic due to the extremely lucrative shark fin market. Used both in soup and in traditional Chinese medicines, the fins are worth so much that hunters often cut them off the sharks when they are still alive. They then throw the less valuable bodies back into the sea, condemning the animal to a slow, agonising death. Up to 100 million sharks are killed each year from a range of species, threatening many with extinction. Sharks tend to have low reproduction rates which means populations are slow to recover from overfishing.

They are also at risk of entanglement due to both discarded fishing gear and land-based rubbish entering the oceans. Another big cause of death is through becoming bycatch when ships fishing for a particular food species accidentally catches non-target species. Boat strikes are also an increasing issue and sharks have been recorded with damaged dorsal fins. Not all survive these collisions. In addition, climate change has the potential to impact basking sharks negatively. As seas warm, plankton is moving north with sharks having to move with them. This year there were five times more sightings around Shetland than the previous high of 2020. This could be part of this shift but how these distribution patterns will affect them in the long-term isn’t yet known. We are also unsure of the affects of increased amounts of micro-plastics in our oceans. There are fears that these tiny specks of plastic will harm filter feeders as they inevitably ingest more.

Celebrating Sharks

Basking sharks are incredible creatures who live most of their lives far removed from the human gaze. There is still a huge amount to learn about these gentle giants, but what we do know is truly awe-inspiring. To find one for yourself, head to one of the UK’s hotspots between May and October and you might be lucky enough to see one of these enormous animals slowly moving through the water as it feeds.

World Basking shark day
This was one of over 100 sightings around Shetland during the summer of 2022

To get involved in World Basking Shark Day, head over to Basking Shark Scotland’s website. For more information on how you can help sharks around the world, the Shark Trust is a great place to start.