Major threats to the ocean

Globally the ocean is in trouble. We are taking out too many fish and throwing in millions of tons of rubbish and pollution. Areas once rich in marine life are being heavily exploited and destroyed. Commercial fishing is reducing fish populations at an alarming rate, shark finning is big business and nowhere, not even Chagos, is safe from the impacts of climate change!

Coastal Development

60% of the world’s population live within 60km of the sea. Many of the world’s natural coastlines have been developed into major ports for ships, or have been lined with hotels, all competing for an ocean view.


  • Micro-plastics: If you use an exfoliating face wash or certain toothpastes, you may be sending thousands of tiny pieces of plastic into the ocean each day without realising! A single bottle can contain over 300,000 microbeads! Far too small to be stopped by the filters at sewage treatment plants, these plastics are eaten by fish and other marine life and make their way up the food chain, eventually killing the animals which have eaten them. However, there are alternatives, some facial scrubs use natural exfoliates like crushed apricot seeds.
  • Chemical: Chemical pollution often goes unnoticed and is rarely reported. 44% comes into the ocean from rivers and 33% is absorbed by the ocean from the air. It is a big problem around large coastal cities. Such chemicals can cause health issues to marine animals including tumours on turtles.
  • Plastics: We throw 6.4 million tons of plastic rubbish into the ocean every single year. Plastic can now be found in the deep sea, in Arctic Sea ice and even in the tiny polyps of corals.


Fishing is arguably THE most destructive activity we are doing to our oceans, with climate change in second place. 70% of all commercial fish species are thought to be exploited or severely depleted - in other words, we have taken too many fish from the sea so quickly that they cannot naturally replace themselves. As well as taking too much, we are also fishing in ways which damage many other forms of marine life that weren't targeted by the fishermen and are known as bycatch.


  • Trawling: Trawling involves a net being dragged behind a fishing boat. It can be dragged along the sea bed (like a farmer ploughing a field) or through the water column. Trawlers can be big, very big! Super trawlers can be 144m long and catch 250 tons of fish each day! The nets dragged behind super trawlers can hold 13 Jumbo Jets!
  • Longlining: A very long fishing line (up to a mile long!) with thousands of baited hooks is set from the back of a boat. Fishermen target large pelagic (ocean dwelling) fish such as tuna & marlin. The lines can be left for weeks and unfortunately any animal which bites down on the hook is stuck there. Leatherback turtles are accidentally caught and sharks can even be targeted by fishermen for their fins.
  • Illegal Fishing: It is incredibly difficult to track where the fish on your plate has come from. If a fish has been taken from the ocean by an illegal fishing boat it is common for it to be passed to a legal boat before it is landed and sold on. The truth about IUU fishing is we just don’t know how much of an issue it is as facts and figures are rare and unreliable. Old, illegal fishing boats are often home to many workers kept in slave-like conditions for months at a time.
  • Bycatch: Bycatch is everything caught in a fishing net which the fishermen wasn’t after. From dolphins, whales, turtles and seabirds, to small fish, crabs and starfish. The tuna fishery often finds dolphins caught in their nets. One way to avoid this is to change their fishing method - using poles and lines rather than large nets stops dolphins being caught.