Mapping the seas of the British Isles: The English Channel

20th November 2016

With a coastline approaching 14,000 miles long (including Ireland and our many islands), the British Isles has a unique structure having many bays, inlets, estuaries, islands and peninsulas. It has a fractal (“wiggliness”) of 1.25 which means that, compared to countries of larger sizes, the British Isles has significantly more coastline. Australia, for example has a fractal ratio of 1.13 and South Africa of 1.03. Ranking 12th in the world for its coastal length, the British Isles has the 4th highest coast to land ratio and with no inhabitant of the country living more than 70 miles from the coast it is little wonder that we have such an affinity with the sea.

The British Isles has more than 1000 islands, some of which are little more than windswept outcrops of rocks whilst others are permanently inhabited; approximately 130 islands fall into this last category.

Surrounded by seas with their own distinct characteristics, traversing the waters around this lengthy coastline can be tricky without prior knowledge, up-to-date shipping forecasts and reliable navigational equipment. All seas are dangerous and each region carries its own hazards, unique features and conditions so we’ve put together a personality guide on the main shipping areas around the UK.

In this piece, we’ll be focusing on the English Channel


There are plenty of small harbours along the UK stretch of the English Channel with several important commercial ports thrown in, including:

  • Southampton
  • Portsmouth
  • Langstone
  • Portland
  • Millbay
  • Fowey
  • Ryde
  • Poole
  • Weymouth
  • Plymouth
  • Teignmouth
  • Folkestone
  • Falmouth
  • Par
  • Dartmouth

The operations at these ports varies from passenger ferries to industrial shipping, recreational use and, of course, fishing. In our series on fishing ports we have covered the activities of some of these locations in more detail.

Fishing in the English Channel

According to the Marine Management Organisation, approximately 64,000 tonnes of fish were landed from the English Channel in 2013 having a total value of £91.7 million.

Fed by the plankton rich currents from the Atlantic and the North Sea, cod, hake, whiting and pilchard are commonly associated with these waters and coastal fishing remains an important industry for the small English ports as well as Brittany.

Research conducted by the International Council for the Exploration of the Seas in 2014 produced a report which suggested that decades of plentiful fishing in the Channel has depleted stocks of upper trophic species of fish. The removal of this top level of larger species including predators such as sharks, cod, haddock and rays has meant that lower trophic species such as shellfish are more plentiful. The report goes on to suggest that species such as the, once abundant and iconic, Dover sole are becoming more of a rarity.

The fact that the waters are fished by both French and English fisherman has resulted in controversies over the years including the Scallop Fishing Dispute of 2012.

However, neither disputes nor controversies over overfishing are new to the English Channel with records dating back to the 17th century pointing accusatory fingers on both points.

English Channel

The English Channel, also known as La Manche (or just ‘The Channel’), separates Northern France and Southern England. It is a conduit from the southern stretch of the North Sea to the rest of the Atlantic Ocean and covers an area of approximately 75,000 km2.

With the Celtic Sea to the West and the Strait of Dover to the East, the English Channel is the world’s busiest stretch of sea, typically accommodating around 500 ships each day. The hazards of such a densely traversed stretch of water were (and can still be) very treacherous. Following a series of tragic incidents in 1971, the International Maritime Organization was forced to invest in the world’s first radar controlled traffic system. The system, still in operation today, operates much like an air-traffic control system with port authorities and skippers able to reduce the number of collisions. Accidents are now a rarity rather than a frequent occurrence with one or two incidents recorded each year.

The Channel is home to the, so-named, Channel Islands of Jersey, Guernsey, Alderney and Sark as well as the Isle of Wight. There are also a handful of other islands including the uninhabited Eddystone Rocks.

Although the seabed shelves at regular intervals the Channel is actually quite flat and is one of the smallest shallow seas around Europe. With average depths ranging from 400-150’ the surface of the sea floor is quite uniform and relatively featureless. The western side of the channel has a handful of submerged cliffs dating to the Pleistocene Epoch when the channel was carved by receding glacial waters whereas the central Channel has several areas which cause shipping restrictions. The depths here can vary from 6-160’ with banks such as the Ridge and the Varne constricting passage in this area.

The deepest point of this stretch of water can be found a few miles north of Guernsey with a depth of 590’ and is rumoured to be the dumping ground of many German weapons from World War I and World War II, including poison gas shells.

The tides in the English Channel are quite strong with ports such as Southampton experiencing a prolonged high tide and the Gulf of Saint Malo (between Jersey and St Malo) experiencing a tidal range of 28’.

The sea bed is home to hundreds of shipwrecks from the historical remains of timber warships such as the HMS Dragon (1647) to the West of Alderney, HMS Royal Anne Galley (1709) off Lizard Point and, of course, HMS Victory. The collection of lost vessels also includes the wrecks of boats from both World Wars and more modern casualties of incidents including the MV Nyon, a cargo ship that collided with another vessel a few miles off Beachy Head and now rests on the sea floor.

The wrecks are a problem for trawl nets and their locations can be identified using online facilities such as ShipWrecks UK.

Navigating the Channel can be a problem, particularly in the Dover strait due to the sheer volume of traffic, excessive speeds employed by some and the shallow waters contributing to groundings. Passage planning guides are available which make traversing these waters infinitely safer.

The weather in the Channel can be very varied and is largely depending upon the season; however, strong winds and gales come predominantly from the south-west or west. Rainfall is on average around 28-30” per annum with winter air temperatures falling between minus 5 to 12 deg C and summer between 20-30 deg C. The sea surface temperature also varies from 7-16 deg C with the depths of the channel being an almost constant 5-7 deg C.

The flow towards the North Sea which starts with salinity levels of around 35.5 parts per thousand decreases with the influx of fresh water and takes around 500 days to completely replace.

However and wherever you traverse the waters of the English Channel you can find the perfect boat to enable you to do so with Find A Fishing Boat so be sure to look at our adverts and, if you’ve enjoyed this article, don’t forget to spread the word on social media using our links above. We’d be very grateful.

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